The fast automatic analysis method and device of tritium in water
Technical field
The present invention relates to nuclear energy and nuclear technology field of engineering technology, in particular to the fast automatic analysis side of tritium in a kind of water
Method and device.
Background technique
Currently, meeting the common people to daily life to ensure that government department grasps National Water Environmental radiological safety situation comprehensively
The informed requirement of water radiation safety is applied flexibly, the measurement work for carrying out waterborne radioactivity nucleic is particularly important.And Tritium measurement is to put
The important component of penetrating property Nuclide measurement work, is also more and more taken seriously and pays close attention in recent years.
The relevant technologies, researcher are generally dedicated to realizing by improving electrolytic enrichment process to the effective of low-level tritium
Analysis, no matter however how electrolytic enrichment device upgrades improvement, the time needed for electrolytic enrichment process also still needs to one day or more, sample
The problem of product pre-treatment overlong time, is not solved effectively.In addition, although some improved electrolysis units are certain
The automation of electrolytic enrichment process is realized in degree, but for tritium analytic process in entire water, still need to human attendance and hand
Dynamic to operate, the working efficiency of tritium analysis is unable to get breakthrough always in water.Meanwhile in existing water there is analysis in tritium analysis method
Overlong time or the excessively high problem of detection limit, it is difficult to meet the requirement analyzed tritium in ambient water.
Summary of the invention
The present invention is directed to solve at least some of the technical problems in related technologies.
For this purpose, an object of the present invention is to provide a kind of fast automatic analysis method of tritium in water, this method can be with
It effectively shortens time of analysis, improves the efficiency of analysis, and detection limit can be effectively reduced, effectively improve being applicable in for analysis
Property, realize the automated analysis of tritium, it is simple easily to realize.
It is another object of the present invention to the fast automatic analytical equipments for proposing tritium in a kind of water.
In order to achieve the above objectives, one aspect of the present invention embodiment proposes a kind of fast automatic analysis method of tritium in water,
The following steps are included: obtaining water sample to be measured, back segment filter liquor is obtained by reverse osmosis membrane purification;It is infused respectively into counting vial
Enter the back segment filter liquor of the first preset volume and the scintillation solution of the second preset volume, and counting vial fullys shake, back segment is filtered out
Liquid and scintillation solution are uniformly mixed, to obtain sample to be tested;Spectrometer is dodged by liquid, and count measurement is carried out to the sample to be tested, with
The analysis result of tritium into the water sample to be measured.
The fast automatic analysis method of tritium in the water of the embodiment of the present invention, using reverse osmosis membrane separation technology to water sample to be measured
Quick separating-purifying is carried out to reach the condition requirement for meeting liquid and dodging measurement, effectively shortens the pre-treatment time, is improved point
Efficiency is analysed, selects suitable liquid to dodge measurement method and count measurement is carried out to sample, so as to which detection limit is effectively reduced, with suitable
For the analysis of tritium in a variety of ambient waters, the applicability of analysis is effectively improved, realizes the automated analysis of tritium, it is simple easily to realize.
In addition, the fast automatic analysis method of tritium can also have following add in water according to the above embodiment of the present invention
Technical characteristic:
Further, in one embodiment of the invention, after injecting the first preset volume into counting vial respectively
After the scintillation solution of section filter liquor and the second preset volume, the bottle cap of the counting vial is screwed automatically, and count fulling shake
Bottle make back segment filter liquor and scintillation solution it is uniformly mixed after, wiping processing is carried out to the counting vial automatically.
Further, in one embodiment of the invention, the volume of the counting vial is 100ml, and described first is default
Volume and second preset volume are 50ml.
Further, in one embodiment of the invention, described to obtain water sample to be measured, pass through reverse osmosis membrane purification
Back segment filter liquor is obtained, further comprises: being rinsed using water sample to be measured;By reverse osmosis membrane separation filtering it is described to
Water sample is surveyed, to obtain spare water sample, and excludes waste water;The spare water sample is filtered again by the reverse osmosis membrane, with net
Change purification and obtains the back segment filter liquor;Empty remaining water sample to be measured.
Further, in one embodiment of the invention, further includes: detect the conductivity value of the back segment filter liquor;
Judge whether the conductivity value is less than default conductivity value;If the conductivity value is less than the default conductivity value,
The back segment filter liquor of the first preset volume is injected into the counting vial;If the conductivity value is more than or equal to described pre-
If conductivity value, then by reverse osmosis membrane purification back segment filter liquor again, until the conductivity value be less than it is described
Default conductivity value.
In order to achieve the above objectives, another aspect of the present invention embodiment proposes a kind of fast automatic analysis dress of tritium in water
It sets, comprising: back purge system obtains back segment filter liquor by reverse osmosis membrane purification for obtaining water sample to be measured;Automatically match
Liquid and conveying measuring system, for injecting the back segment filter liquor and the second preset volume of the first preset volume into counting vial respectively
Scintillation solution, and counting vial fullys shake, back segment filter liquor and scintillation solution is uniformly mixed, to obtain sample to be tested, and pass through
Liquid dodges spectrometer and carries out count measurement to the sample to be tested, to obtain the analysis result of tritium in the water sample to be measured.
The fast automatic analytical equipment of tritium in the water of the embodiment of the present invention, using reverse osmosis membrane separation technology to water sample to be measured
Quick separating-purifying is carried out to reach the condition requirement for meeting liquid and dodging measurement, effectively shortens the pre-treatment time, is improved point
Efficiency is analysed, and the liquid that reselection is suitable for dodges measurement method to sample progress count measurement, so as to be effectively reduced under detection
Limit, with the analysis of the tritium suitable for a variety of ambient waters, effectively improves the applicability of analysis, realizes the automated analysis of tritium, simply
Easily realize.
In addition, the fast automatic analytical equipment of tritium can also have following add in water according to the above embodiment of the present invention
Technical characteristic:
Further, in one embodiment of the invention, further includes: sample bottle automatic control system, for respectively
It injects after the back segment filter liquor of the first preset volume and the scintillation solution of the second preset volume, screws automatically described into counting vial
The bottle cap of counting vial, and fully shake counting vial make back segment filter liquor and scintillation solution it is uniformly mixed after, automatically to institute
It states counting vial and carries out wiping processing.
Further, in one embodiment of the invention, the volume of the counting vial is 100ml, and described first is default
Volume and second preset volume are 50ml.
Further, in one embodiment of the invention, the back purge system includes: water sample wash module, is used for
It is rinsed using water sample to be measured;Filtering module, for filtering the water sample to be measured by the reverse osmosis membrane separation, with
Spare water sample is obtained, and excludes waste water;Sample preparation module, for being filtered again by the reverse osmosis membrane to the spare water sample,
It proposes to obtain back segment filter liquor with purification;Drain module, for emptying remaining water sample to be measured.
Further, in one embodiment of the invention, further includes: detection module is filtered out for detecting the back segment
The conductivity value of liquid;Judgment module, for judging whether the conductivity value is less than default conductivity value;Processing module is used for
When the conductivity value is less than the default conductivity value, the back segment filter liquor of the first preset volume is injected into counting vial,
And when the conductivity value is more than or equal to the default conductivity value, by reverse osmosis membrane, purification back segment is filtered again
Liquid out, until the conductivity value is less than the default conductivity value.
The additional aspect of the present invention and advantage will be set forth in part in the description, and will partially become from the following description
Obviously, or practice through the invention is recognized.
Detailed description of the invention
Above-mentioned and/or additional aspect and advantage of the invention will become from the following description of the accompanying drawings of embodiments
Obviously and it is readily appreciated that, in which:
Fig. 1 is the decay scheme of the relevant technologies tritium;
Fig. 2 is that the relevant technologies tritium mutually converts situation map in natural environment;
Fig. 3 is the mass spectrometric pictorial diagram of the relevant technologies;
Fig. 4 is the pictorial diagram of a air-distillation equipment of the relevant technologies;
Fig. 5 is the relevant technologies film filtration schematic illustration;
Fig. 6 is the pictorial diagram of a traditional alkali formula electrolytic enrichment device of the relevant technologies;
Fig. 7 is three standards of the relevant technologies about tritium analysis sample-pretreating method contrast schematic diagram in water;
Fig. 8 is the schematic diagram of the improved alkali formula electrolytic enrichment unit of the relevant technologies;
Fig. 9 is the schematic diagram of the improved alkali formula electrolytic enrichment device of the relevant technologies;
Figure 10 is the relevant technologies solid polymerization film electrolysis principle schematic diagram;
Figure 11 is tritium automatic electrolysis unit structure chart of the relevant technologies based on SPE;
The contrast schematic diagram of method after Figure 12 is the relevant technologies conventional method and improves;
Figure 13 is the structural schematic diagram of surabaya electrolysis installation of the relevant technologies based on proton exchange membrane;
Figure 14 is the flow chart according to the fast automatic analysis method of tritium in the water of one embodiment of the invention;
Figure 15 is according to tritium automatic analysis method workflow in the water based on RO film sample preparation of one embodiment of the invention;
Figure 16 is the working principle according to the reverse osmosis membrane of one embodiment of the invention;
Figure 17 is the scope of application that membrane component is often used according to several moneys of certain brand RO film of one embodiment of the invention;
Figure 18 is the common household water filter structural framing schematic diagram of the relevant technologies;
Figure 19 is the RO UF membrane sample preparation device structural block diagram according to one embodiment of the invention;
Figure 20 is the pictorial diagram according to the RO UF membrane sample preparation device model machine of one embodiment of the invention;
Figure 21 is each link work flow diagram of RO UF membrane sample preparation device according to one embodiment of the invention;
Figure 22 is the RO UF membrane sample preparation device operation interface schematic diagram according to one embodiment of the invention;
Figure 23 is the pictorial diagram that spectrometer is dodged according to the LB7 type Low background liquid of one embodiment of the invention;
Figure 24 is the quenching correction principle figure according to the ESCR method of one embodiment of the invention;
Figure 25 is that three kinds of applicable capacity counting vials of spectrometer are dodged according to the LB7 type Low background liquid of one embodiment of the invention;
Figure 26 is the liquid flashing counting measurement flow chart according to one embodiment of the invention;
Figure 27 is to be filtered according to the early period of the visual obvious turbid water sample of one embodiment of the invention;
Figure 28 is to consume sample amount, wastewater flow rate and production sample amount experimental conditions reality according to each link that records of one embodiment of the invention
Object figure;
Figure 29 is according to the average time-consuming feelings of RO each link of UF membrane sample preparation device sample making course of one embodiment of the invention
Condition counts schematic diagram;
Figure 30 is the RO film preparation conductivity variation tendency schematic diagram according to one embodiment of the invention;
Figure 31 is the air-distillation experimentation schematic diagram according to one embodiment of the invention;
Figure 32 is the background spectrum according to one embodiment of the invention;
Figure 33 is the standard specimen spectrogram according to one embodiment of the invention;
Figure 34 is to test schematic diagram according to the water sample and scintillation solution ratio optimization of one embodiment of the invention;
Figure 35 is the change changed according to the sensitivity figure of merit SFOM of one embodiment of the invention with water sample and scintillation solution proportion
Change trend schematic diagram;
Figure 36 is according to this original pattern counting rate of one embodiment of the invention and the relation schematic diagram of time of measuring;
Figure 37 is according to the environmental water sample counting rate of one embodiment of the invention and the relation schematic diagram of time of measuring;
Figure 38 is according to the mark-on sample counting rate of one embodiment of the invention and the relation schematic diagram of time of measuring;
Figure 39 is the LB7 type scintillation counter quality control chart according to one embodiment of the invention;
Figure 40 is according to tritium concentration analysis of uncertainty in measurement schematic diagram in the water of one embodiment of the invention;
Figure 41 is the block diagram according to the fast automatic analytical equipment of tritium in the water of one embodiment of the invention.
Specific embodiment
The embodiment of the present invention is described below in detail, the example of embodiment is shown in the accompanying drawings, wherein identical from beginning to end
Or similar label indicates same or similar element or element with the same or similar functions.It is retouched below with reference to attached drawing
The embodiment stated is exemplary, it is intended to is used to explain the present invention, and is not considered as limiting the invention.
In the water for introducing the embodiment of the present invention before the fast automatic analysis method of tritium and device, first simply introduce
The status of tritium and the relevant technologies status for analyzing tritium.
The purpose of 1.1 embodiment of the present invention be to the feasibility of tritium automatic analysis method in the water based on RO film sample preparation into
Row research.Experimental study is carried out to the comprehensive performance of RO film sample preparation device first under existence conditions, grasps its basic performance simultaneously
It suggests improvements to the problem of discovery;Secondly measurement process measurement of correlation mode is dodged to liquid and measuring condition carries out theory and grinds
Study carefully, on this basis by experimental verification, determines that suitable liquid dodges measurement method and condition;Finally in front research achievement it
On, the experimental comparison that tritium is analyzed in water is carried out by the way of method comparison, to verify tritium acquired results in this method analysis water
Accuracy, thus for this research method later practice and popularization reference and foundation are provided.
1.2, the basic situation of tritium
Tritium belongs to the isotope of hydrogen, have radioactivity, half-life period about 12.32.One is generated respectively after one triton decay
It is a3He, anti-neutrino and ceiling capacity are no more than 18.6keV, the negative β particle of average energy about 5.7keV.The decay feelings of tritium
Condition is as shown in Figure 1.
There are many existence forms of Environmental Tritium, is broadly divided into the HTO, gaseous HT and CH of liquid3T and combination
The OBT of state, wherein HTO occupies absolute leading position in the environment.The Transport And Transformation of tritium in the environment is mainly also with the shape of HTO
State realizes that this has also embodied the importance that tritium analysis in water measures the research to Environmental Tritium.
As shown in Fig. 2, the tritium for describing the above various existence forms is rough in natural environment to mutually convert situation,
Specifically, and four boxes in Fig. 2 describe roughly the tritiums of various forms in air, in plant, in soil and people
With deposition, migration and the conversion process in animal.
1.3, tritium analysis measurement is summarized in water
1.3.1, the development course of Chinese tritium analysis measurement
In China, for tritium research early start the sixties in last century, the main purpose of original research tritium be in order to
Ensure the radiological safety of nuclear facilities operation maintenance personnel;1970s, the analysis measurement work for tritium in natural environment are opened
Begin to occur, thus be brought into schedule for the analysis measurement work of low-level environment tritium;To the eighties, China has carried out several times
The analysis of tritium, monitoring are all incorporated into investigation content, the analysis measurement of Chinese tritium in national environmental radio activity level investigation work
It is developed.In the 21st century, is as Chinese nuclear technology is using horizontal fast development, along with the public to environmental quality
Growing interest, environmentally friendly supervision department and nuclear facilities unit of operation have carried out successively for tritium in the air around nuclear power station base
Tritium in tritium (including river water, well water, pond water, seawater) and biology in (including precipitation, vapor), water body (tissue free water tritium,
Organically combine tritium) analysis measure work.National 32 provincial radiation monitoring stations (including Qingdao City's radiation monitoring station)
The measurement work of the analysis to tritium in local air (including precipitation, vapor) is carried out in succession.In addition, some colleges and universities, scientific research
The units such as institutes also increasingly pay attention to the analysis measuring study to tritium.The introduction of increasingly advanced analysis measuring device and a large amount of
Tritium analysis measurement practice so that Chinese tritium analysis measurement capability achieves quick development.
1.3.2 the method for tritium analysis measurement mainly has gas counting method, liquid scintillation counting and mass spectrography etc. in water, under
Simple introduction is done in face of these types of method.
A, gas counting method.As the term suggests gas counting method gas and then is carried out again firstly the need of converting detected water sample to
Measurement.CH is generally converted for detected water sample by chemically synthesized mode4、C2H6Or C3H8Equal working gas, then by these
Count measurement is carried out in working gas input proportional counter.The advantages of this method is detectivity height, some researches show that,
Working gas selects C3H8In the case where, proportional counter tube can be promoted at double to the detectivity of tritium.Its shortcomings that, is also very bright
Aobvious: detected water sample is converted to that gaseous process is cumbersome and the gas that generates is inflammable and explosive, and there are certain danger.
B, mass spectrography.Mass spectrography is also known as3Growth measurement method in He is to utilize mass spectrograph (wherein, mass spectrograph is as shown in Figure 3)
Pass through the decay constant of measurement of tritium3He, then pass through a kind of anti-indirect measurement method for pushing away to obtain tritium.The principle of this method is
It is initially dissolved in detected water sample first with vacuum outgas removal3He, then by detected water sample be stored in one it is closed
In container (a usually glass marble), made by the sealed storage of a period of time (it is generally necessary to some months)3He accumulation.Then
It is generated during storage using mass spectrograph measurement detected water sample3He content is inferred to the content of tritium in sample in turn.Due to3He
It seldom is dissolved in organic compound, and easily enters gas phase, therefore the technology is suitable for various samples, such as food is planted
By etc..The major advantage of this method is can to drop to detection limit very low, therefore is adapted to extremely low tritium concentration sample
Measurement, document show the water sample for taking 20ml, and integration time 3 months, then detection limit can drop to the level of 0.15Bq/L.The party
Method another advantage is that the simplicity of operation, it is only necessary to two operating process, i.e. degasification and measurement, do not need to be fired
The tedious steps such as burning, distillation, concentration, therefore this method can also preferably avoid laboratory pollution.The shortcomings that mass spectrography is every
Secondary measurement requires enforceable Storage period for a long time.
C. liquid scintillation counting.Liquid scintillation counting is that up to the present technology is the most mature, is most widely used
A kind of measurement of tritium method.The detection efficient of this method is high, and time of measuring is compared also more excellent for the two methods of front
Gesture, the analysis work of tritium is all this measurement method used in overwhelming majority water at present.Therefore, it is necessary to this method into
Row introduces.
Liquid scintillation counting has certain requirement to the degree of purity and tritium concentration of detected water sample.If the degree of purity of sample
Not enough, containing more impurity, then it will increase the quenching degree of sample to reduce the detection efficient during count measurement;If sample
The tritium concentration of product is lower, and the detection limit all in measurement method is all not detected hereinafter, then will appear big measurements
Situation, thus can not achieve the effective monitoring to tritium.Therefore, selection liquid scintillation counting usually needs to carry out sample in advance
Purification is handled with concentration.
(1) it purifies
The mode of purification can have distillation, film filtering and ion exchange column etc..Laboratory generallys use often both at home and abroad at present
Pressure distillation mode (as shown in Figure 4) sample is purified, this way of purification effect is good, but distillation process needed for when
Between it is relatively long, generally at least need 2 to 3 hours.In addition, due to isotope effect, the content of tritium in accumulation distillation process
There are gradients, therefore the distillate for collecting same area is extremely important, and collecting for distillate simultaneously will also be by conductivity
Limitation, this carrys out certain difficulty to the collection selection work belt of distillate.
Film filtering separating-purifying mode filter film technology develop on the basis of gradually paid attention to, its principle with it is daily
Water purifier working principle in family life is similar, i.e., by water by filter membrane so that impurities in water is stopped by filter membrane, absorption and from
It is separated in water, to realize the effect of water quality purifying.The operation principle schematic diagram of membrane filtration impurities in water such as Fig. 5
It is shown.
Filter membrane type multiplicity, its filter capacity of different types of filter membrane differs greatly, to membrane filtration technique applied to tritium point
The result of study that analysis process carried out research shows: reverse osmosis (RO) membrane technology is a kind of alternative method.This method
The advantages of be water sample separating-purifying process it is fast, automation that is easy to operate and being easily achieved purification process, but there is also use
The problem of service life, needs periodically to replace filter membrane.
Once application was obtained in Tritium measure work in the separating-purifying mode of ion exchange column, and this separating-purifying mode can
To obtain more pure surabaya, but because there is recycling rate of waterused difference, utilization rate is not high, is not described in detail here.
(2) concentration
The mode of concentration is mainly electrolysed.Its principle is to decompose to generate hydrogen and oxygen when being electrolysed by water, is utilized
In hydrogen the content of tritium can lower than the property of tritium level in electrolyte, by electrolysis so that in final residue electrolyte tritium concentration
It increases, to realize the concentration of detected water sample tritium.Traditional alkali formula electrolysis method substantially process is as follows: being steamed for the first time to water sample
It evaporates in addition to sodium peroxide is added in distillate on the basis of impurity and organic matter, is then poured into electrolytic cell and carried out
Electrolysis need to finally obtain distillate, also need to sample during this after long-time is electrolysed to sample second distillation to remove alkali
Multiple weighing operation is carried out so that the cycles of concentration to sample calculates.It is illustrated in figure 6 a alkali formula currently on the market
Electrolytic enrichment device.It is very high that the advantages of electrolysis method, is that concentration factor can achieve, and can effectively solve ultra low levels tritium and be difficult to measure
The problem of, but the shortcomings that electrolysis method it is also obvious that traditional alkali formula electrolysis method not only process is cumbersome, complicated for operation and electrolytic process
It is very very long.
1.3.3, tritium analysis measures status and developing direction in water both at home and abroad
Analysis measurement for tritium in water, the national standard that Chinese nineteen ninety implements use " air-distillation+electrolytic enrichment
The analysis method of+liquid sudden strain of a muscle measurement "." test method of tritium level in drinking water " of American Society Testing and Materials (ASTM) and state
" the air-distillation+liquid sudden strain of a muscle that " the measurement liquid scintillation counting of water quality tritium activity concentration " of border standardization body (ISO) then selects
The analysis method of measurement ".The measurement method of three standards is close, but pretreatment process is respectively different.Their pretreatment process
Comparison is as shown in Figure 7.
By comparison as it can be seen that three of the above pre-treating method all select under alkaline environment addition strong oxidizer to sample into
Row distilation, wherein basic treatment is to remove the radioactivity that radioiodine, carbon etc. are easy to be distilled off with tritium
Nucleic.In addition, can inevitably have the case where containing organic matter in environmental water sample, although these content of organics are few, easily
With tritium be distilled off influence measurement process sample quenching degree, be added strong oxidizer can aoxidize these organic matters from
And eliminate its interference to measurement result.
Because of Chinese national standard electrolytic enrichment process more than another two standard, in the water that can be measured after the concentration ratio of tritium
The two is much lower, thus is more suitable for the analysis to low-level tritium.IAEA also suggests selecting " electrolytic enrichment pre-treatment in the world
The method of+liquid flashing counting measurement " realizes that effective analysis to low-level tritium measures.However, it is contemplated that traditional alkali formula is electrolysed
Method for concentration program is cumbersome, sample processing time is long and there are the danger of hydrogen detonation.For this purpose, mentioned in national standard, if instrument
Sensitivity is sufficiently high, can not electrolytic enrichment, the upper spectrometer measurement directly after normal pressure distilation.In consideration of it, many laboratories
In water in the analytic process of tritium, this pre-treatment is generallyd use by the analysis method of the tritium simplified.Experience have shown that existing
Some liquid dodges on Spectrometer performance basis, and detection limit obtained by the analysis method using this tritium simplified generally exists
1Bq/L or so, this is still more inadequate for the Tritium measure of current Chinese environmental water sample.
In order to realize that the environmental water sample to low-level tritium more effectively analyzes measurement, researchers at home and abroad generally post expectation
In improving or being promoted sample pretreatment process or device, conducted in-depth research in particular for electrolytic enrichment link.Pass through
Effort, various new electrolytic enrichment methods are found, and some of new methods are promoted and have corresponding product to come out.
A. the improvement and application of traditional alkali formula electrolytic cell
Based on traditional alkali formula electrolysis principle, the structure at electrolysis yin-yang the two poles of the earth is improved, it is as follows to improve content:
By cathode design at hollow lining, the structure of double-layer epispores, circulation cooling water between double-layer epispores interlayer, electrolyte is from yin
The export of pole lower part;Anode interior equally uses hollow structure, and outer wall is disposed with stomata, and exhaust outlet is arranged in top and condenser pipe connects
It connects, in order to which electrolytic process generates the export of gas.Improved electrolysis unit is big in terms of the rate of recovery of tritium and concentration efficiency
There is improvement, but it fails to make progress in terms of safety, ease of handling and electrolysis time.Its electrolytic enrichment cellular construction
Shown in as shown in Figure 8, several electrolytic enrichment units form the electrolytic enrichment device of a tritium, as shown in Figure 9.
B. application and development based on SPE electrolysis tech
SPE Chinese name is solid polymer electrolyte, the related content of SPE electrolysis tech and by verification experimental verification this
The reliability and superiority of one technology.The principle of this method is to can be used as the characteristic of electrolyte, electrolytic process based on SPE film itself
In, positive and negative catalysis electrode abuts against SPE film two sides, produces after catalyticing anode is decomposed by the detected water sample of air-distillation early period
Raw hydrogen ion and oxonium ion, to realize the electrolysis to water sample.Near anode, oxonium ion issues negative electron to become oxygen
Gas;Hydrogen ion passes through SPE film and reaches cathode and generate hydrogen in conjunction with negative electron near cathode.The oxygen and hydrogen quilt of generation
The isolation of SPE film, is discharged from different pipelines, and solid polymerization film electrolysis principle is as shown in Figure 10.
Compared with traditional alkali formula electrolysis method, this SPE electrolysis tech has following three advantages: first is that it is safer,
The hydrogen and oxygen that electrolytic process generates are come by SPE UF membrane, are not susceptible to the danger such as explosion.Second is that the promotion of concentration rate,
SPE film, which is utilized, in this method well can be used as the characteristic of electrolyte, and electrolytic process does not need that alkaline reagent is added, therefore remains
Object is few, and the enrichment factor of water has significant increase.Third is that process is simple, electrolysis time is short, and alkali on the one hand is added due to no before being electrolysed
Property reagent, just without being evaporated in vacuo again after the completion of electrolysis, process is simplified;Another aspect SPE film resistance very little, film
The electric current passed through between electrode is not easy to be saturated, so that high current electrolysis becomes feasible, to largely shorten electricity
Solve the time.Because SPE electrolysis tech solves many unavoidable difficulties of traditional alkali formula electrolysis method, thus this technology once
It is proposed is just widely studied and is used after promoted improvement by extensive investment.
In the related technology, another set of SPE film is electrolysed enrichment facility automatically, which has done two o'clock improvement: first is that electrolysis
The surface of plasma membrane, which has been done, slightly to be handled, and the separating property that gas is generated to electrolytic process is improved;Second is that in order to detect electrolyte
Liquid level is mounted with liquid level sensor, is automatically stopped electrolysis so that the device can according to need and collects sample, the apparatus structure
See as shown in figure 11.
Further, further the air-distillation purification process before electrolysis is replaced on the basis of SPE film electrolysis tech
It is purified at RO UF membrane, to establish this tritium analysis method by " RO UF membrane+SPE electrolysis+liquid dodges measurement ".This method
Have the following excellent compared with the method for traditional " air-distillation+alkali formula electrolytic tank electrolysis+vacuum distillation+liquid dodges measurement "
Gesture eliminates the addition of oxidant and alkaline reagent, time first is that replacing the air-distillation before electrolysis with RO UF membrane in program
On foreshortened to 40 minutes or so by original 2~3 hours;Replace alkali formula electrolytic tank electrolysis second is that being electrolysed with SPE, by original on the time
That comes foreshortens to 1~2 day for 7~10 days;Third is that addition of the new method because of not no alkaline reagent, no longer needs to carry out vacuum steaming after electrolysis
It evaporates, eliminates original 2~3 hours vacuum distillation time.Two methods comparison is as shown in figure 12.
In the related technology, the automatic electrolysis unit of each self application is successively designed using SPE membrane technology.These devices are set
It counts design just bright et al. with vegetarian rattan in principle and overall structure to be not much different, only done in terms of certain details respective
It improves.
C. based on the electrolysis tech of proton exchange membrane
Proton exchange membrane gains great popularity in water electrolysis hydrogen producing industry, because it has can under the working environment of high current
The ability of the electrolytic efficiency of superelevation is kept for a long time, this feature has proton exchange membrane very in the application of water electrolysis industry
Good prospect.By the inspiration of water electrolysis hydrogen producing industry, proton exchange membrane is applied to the field of tritium in electrolytic enrichment water, and is set
Count out the surabaya electrolytic enrichment equipment based on proton exchange membrane.The basic framework of the equipment and previously described SPE film, which are electrolysed, to be filled
Set it is similar, it is maximum to be modified in that SPE film is substituted by proton exchange membrane, by the excellent performance of the latter, so that the equipment exists
While having nearly all advantage of previously described SPE electrolysis unit, additionally it is possible to effectively solve existing for SPE electrolysis tech
The big problem of concentration dead volume, electrolysis time also further foreshortens to 24 hours, thus has more superiority than the former.Specific example
As shown in Figure 13.
1.3.4, however, from the point of view of by the status of tritium analysis in the above water, researcher is generally dedicated to being electrolysed by improving
Concentration process realizes effective analysis to low-level tritium.No matter however how electrolytic enrichment device upgrades improvement, electrolytic enrichment
Time needed for process also still needs to one day or more, and the too long problem of time for sample pretreatment is not solved effectively.Though in addition,
Right some improved electrolysis units realize the automation of electrolytic enrichment process to a certain extent, but with regard to tritium in entire water
For analytic process, still needs to human attendance and be manually operated.The working efficiency that tritium is analyzed in water is unable to get breakthrough always.
1.4, the purpose of the embodiment of the present invention is the feasibility to tritium automatic analysis method in the water based on RO film sample preparation
It is studied.The main contents of research include the applicable water sample condition of RO film sample preparation device, the stabilization of module operational process, reliable
Property and operational process parameters performance indicator.The suitable liquid of research dodges measurement method, to solve the problems, such as that detection limit is high, and
Optimize every measuring condition parameter for the measurement method.Finally, by method compare, verifying this time research based on RO film system
Tritium automatic analysis method precision of analysis in the water of sample.
It is based on above-mentioned reason, in order to solve the problems, such as that technology exists, the embodiment of the present invention proposes tritium in a kind of water
Fast automatic analysis method and device.
The fast automatic analysis method and device of tritium in the water proposed according to embodiments of the present invention are described with reference to the accompanying drawings,
The fast automatic analysis method of tritium in the water proposed according to embodiments of the present invention is described with reference to the accompanying drawings first.
Figure 14 is the flow chart of the fast automatic analysis method of tritium in the water of one embodiment of the invention.
As shown in figure 14, in the water tritium fast automatic analysis method the following steps are included:
In step sl, water sample to be measured is obtained, back segment filter liquor is obtained by reverse osmosis membrane purification.
It is understood that water sample to be measured is referred to as detected water sample, the initial framework of the method for the embodiment of the present invention
System is " RO film (reverse osmosis membrane) separates sample preparation+liquid flashing counting measurement ", as shown in figure 15, firstly, detected water sample enters RO film
Sample preparation device is separated, enters RO film after can handling with premenstruum (premenstrua) coarse filtration and is cleaned purification, it is of course also possible to directly by reverse osmosis
Film purification obtains back segment filter liquor, and those skilled in the art can be configured according to practical situation, not do have herein
Body limits.
It should be pointed out that the workflow described above for this research process this method.During studying herein,
The model machine for only producing RO UF membrane sample preparation, realizes the automatic processing of water sample, and rest part requires to manually complete.But
This has no effect on the purpose studied herein the feasibility of tritium automatic analysis method in the water based on RO film sample preparation.Pass through this
Secondary research while verifying this method feasibility, grasps correlation performance parameters and proposes to be correspondingly improved suggestion.On this basis
Sample preparation module need to be only connected in a modular manner by technological design with measurement module, complete analysis process can be realized
Automation.
Specifically, RO film, the entitled reverse osmosis membrane of Chinese, are the cores of this research sample preparation device, working principle is shown in
Shown in Figure 16.In Figure 16, in figure, left side is weak solution, and right side is concentrated solution, intermediate semi-permeable membrane, that is, RO film.It is left at the beginning
The solvent of side is passed through under the action of infiltration on the right side of RO film flow direction.After reaching balance, left side liquid level will be less than right side, and generate one
A pressure difference (osmotic pressure).At this time after right side applies the pressure greater than osmotic pressure, the flow direction of solvent will be in reverse to
Direction before, this process are as reverse osmosis.This method relies on the selective penetrated property that has of RO film, make solvent by solution with
Solute separation, to achieve the purpose that purification.
The category of RO membrane technology relative maturity, film manufacturer and film is numerous, and manufacturer is for different application and makes
There is the membrane component product of respectively corresponding model with condition.This project researching and designing personnel are in early period to the RO membrane element of a certain brand
Part is investigated, it is thus understood that the condition and range of some each self applications of variety classes RO film of the brand is as shown in table 1.Figure 17 is from water
The angle of salt content intuitively give several moneys of the brand and often use the scope of application of film.According to investigation situation, the present invention is real
The RO film sample preparation device for applying example has selected a RO membrane component for being suitable for handling low salinity water of the brand.Wherein, table 1 is certain
The scope of application table of brand RO film different model membrane component.
Table 1
Further, in one embodiment of the invention, water sample to be measured is obtained, is obtained by reverse osmosis membrane purification
Back segment filter liquor further comprises: being rinsed using water sample to be measured;Water sample to be measured is filtered by reverse osmosis membrane separation, with
To spare water sample, and exclude waste water;Spare water sample is filtered again by reverse osmosis membrane, back segment is obtained with purification and is filtered out
Liquid;Empty remaining water sample to be measured.
It is understood that the embodiment of the present invention is using coarse filtration, treated that water sample to be measured is rinsed, so as to have
Effect excludes last measurement residual and interferes to this analysis, to effectively reduce error, improves the accuracy of analysis.And
And after water sample to be measured is prepared, timely emptying thus water sample to be measured, analyzed next time thus convenient.
In addition, RO UF membrane sample preparation device will be described in detail below.
2.1, sample preparation device is constituted
It is net to have used for reference current common household for the core of tritium RO UF membrane sample preparation device in the water of the embodiment of the present invention
The structural framing of hydrophone.The generally built-in Pyatyi filtering of common household water filter, first, the third level be that PP cotton is filtered, the second, the 5th
Grade is that active carbon filters, and the fourth stage is the filtering of RO film.Common household water filter structural framing is as shown in figure 18.
The RO film sample preparation device of the embodiment of the present invention utilizes the RO determining through investigation based on structural framing shown in Figure 18
Membrane component, then it is aided with the main components such as water valve, liquid level sensor, water pump, flowmeter, designing after engineered can be used in water
The RO UF membrane sample preparation device of tritium analysis.As shown in Figure 19, the model machine of device is as shown in Figure 20 for the structural block diagram of the sample preparation device.
2.2, sample preparation workflow
The water sample treatment process of the device can be divided into sample water and rinse, primary filtering, sample preparation, drain four processes altogether.
Wherein sample water flushing link rinses entire sample-preparing system using a large amount of water samples, caused by excluding the residual because of a upper sample as far as possible
Interference to this sample;Water sample is flowed through RO film and carries out separating and filtering, the pure water generated after film filters by primary filtering link
It is stored in spare in three holding barrels, waste water is expelled directly out;Sample preparation link will be stored in spare pure water in holding barrel import RO film into
Capable filtration treatment again, takes its back segment filter liquor as final detected water sample;Last draining link is by this sample treatment
Remaining water sample emptying, prepares in process apparatus to can handle next water sample at any time.In conjunction with RO UF membrane system in Figure 19
The structural block diagram of sampling device describes the specific workflow of each link as shown in figure 21.
The stopping of each link of Figure 21 relies primarily on the flowmeter of connection RO film pure water mouth to realize.Pre-set each link
The limit current value of flowmeter is flowed through, once the pure water amount for flowing through flowmeter in operational process reaches preset limit value, pump 1 just stops
Work is cut off into the water source of RO film, and the working link stops immediately after remaining process.
RO UF membrane sample preparation device design has " automatic " and " manual " two kinds of operating modes." automatic " mode can realize one
Key starting, the degree of automation is relatively high, only need to click "start" button after, device can according to program setting, strictly in order according to
The secondary sample water that enters rinses, primary filtering, sample preparation, empties work.Difference of " manual " mode compared to " automatic " mode is often
The starting of one link requires manually implemented, and the degree of automation is relatively low, but this mode can select current institute as needed
The working link needed, flexibility are relatively stronger.As shown in Figure 22, left side is RO UF membrane sample preparation device operation interface in figure
" automatic " mode interface, right side are " manual " mode interface, may be implemented mutually to switch at any time between two operation interfaces.
In step s 2, the back segment filter liquor and the second preset volume of the first preset volume are injected into counting vial respectively
Scintillation solution, and counting vial fullys shake and makes being uniformly mixed for back segment filter liquor and scintillation solution, to obtain sample to be tested.
It is understood that as shown in figure 15, the back segment filter liquor of certain volume by injection counting vial, the backward counting
The scintillation solution of certain volume is injected in bottle and screws bottle cap, is uniformly mixed the filter liquor in bottle with scintillation solution through fulling shake.
Wherein, in one embodiment of the invention, in the back segment filter for injecting the first preset volume into counting vial respectively
Out after liquid and the scintillation solution of the second preset volume, the bottle cap of counting vial is screwed automatically, and after counting vial fullys shake and makes
Section filter liquor and scintillation solution it is uniformly mixed after, wiping processing is carried out to counting vial automatically.
Certainly, the embodiment of the present invention can also screw the bottle cap of counting vial by artificial mode, and through fulling shake
It is uniformly mixed the filter liquor in bottle with scintillation solution.After carrying out wiping processing to counting vial outer wall with alcohol swab, so as to have
Effect reduces electrostatic interference.
Wherein, in one embodiment of the invention, the volume of counting vial is 100ml, and the first preset volume and second is in advance
If volume is 50ml.
It is understood that, to reduce detection limit, liquid dodges measurement because water sample pretreatment process does not carry out electrolytic enrichment
100ml capacity counting vial measurement pattern is selected, this can make detection limit be reduced to 0.4Bq/L or so, efficiently solve detection
The excessively high problem of lower limit;When selecting 100ml capacity counting vial measurement pattern, water sample and scintillation solution use the embodiment of the present invention
The volume proportion of 50:50 is than convenient;By the research to sample time of repose, by standard sample, to be measured when determining measurement
Sample and this original pattern are successively placed in liquid and dodge spectrometer, only need to set suitable time of measuring, can measure, keep away immediately without specially standing
Light.
In step s3, spectrometer is dodged by liquid and count measurement is carried out to sample to be tested, to obtain point of tritium in water sample to be measured
Analyse result.
It is understood that as shown in figure 15, being suitable for by the incoming liquid sudden strain of a muscle spectrometer of manufactured sample to be tested and as required setting
Measuring condition after carry out count measurement.
Spectrometer measuring device will be dodged to liquid below to describe in detail.
2.3 liquid dodge spectrometer measuring device
2.3.1 the working principle that liquid dodges measurement is fitted into same counting vial sufficiently approximately as: sample and scintillation solution
Mixing, the β ray energy that sample generates is direct or indirect to be absorbed by the organic scintillator in scintillation solution, causes the molecule of the latter
Be excited, the organic scintillator molecule being excited by launch outward it is photoelectronic in a manner of de excitation to returning to ground state, and launch
Photoelectron received by photomultiplier tube after through nuclear power sub-control system be converted into count signal, be excited scintillator molecular emission
Photoelectron number it is related with the β ray energy that sample generates, it is final to realize between count signal and β ray energy by conversion
Corresponding relationship, to realize measurement to low energy β radiation sample.It, can be with because sample is sufficiently mixed with scintillation solution
It is regarded as sample to be surrounded by scintillation solution, the β ray energy that the former emits can not be influenced by sample self-absorption and directly be shifted
To scintillator, therefore, the measurement of 4 ∏ solid angles may be implemented on this theoretical method.During actual measurement, liquid flashing counting is surveyed
Amount is often influenced by system quenching effect, it is therefore desirable to the suitable quenching school of actual conditions selection according to sample
Correction method is to obtain accurate system detection efficient.
2.3.2 measuring system is constituted
A. liquid dodges spectrometer
As liquid dodges the increasingly mature of measuring technique, liquid dodges measuring device and has also obtained quick development, and device performance has
It is obviously improved.Currently, the liquid generally used both at home and abroad, which dodges spectrometer, mainly the PE from the U.S., Japanese Aloka and sweet smell
The series such as blue Hidex.The Low background liquid that Figure 23 show a LB7 dodges spectrometer.
Although the manufacturer of liquid sudden strain of a muscle spectrometer and model are different, it to be used for basic principle, structural framing and the survey of Tritium measure
Amount performance is not much different.Therefore, this research experiment measurement process selects LB7 type Low background liquid to dodge spectrometer and carries out counting survey
Amount.The structure of the device is constituted and performance parameter is substantially as follows: by photomultiplier tube, (3, be mutually the panel detector structure 1. used
Hexagonal angle is laid), the Anticoincidence shield detector and thick and heavy lead screen module composition in delayed coincidence counting circuit.Photoelectricity times
Increase that pipe thermal noise is low, equipment high-voltage-stable, instrument shield effectiveness are good, this makes the device have the Tritium measure performance of high level;
2. use 4000 multichannel analyzer and automatically switch gain make the counter have high level resolution ratio;3. can be used
The Quench Correction Methods of ESCR (External Standard Channel Ratio).One piece of activity is housed inside the counter
About 740kBq's133The source Ba is used before each count measurement133The source Ba carries out gamma-radiation to sample to obtain the Compton of sample
Spectrum, is analyzed by multichannel analyzer, as shown in figure 24, will account for the spectrum road of tale 75% as quenching indication parameter (i.e. ESCR
Value).The correction range of this Quench Correction Methods is wide, is suitable for low-activity activity sample;4. it is as shown in figure 25, it is surveyed except having
Outside the counting vial function of measuring most common 20ml capacity, the counting vial of 100ml, 145ml capacity can also be measured, be led to
Crossing increase sample size can make the detection limit of measurement result lower.
B. scintillation solution
By previously described liquid flashing counting measuring principle it is found that scintillation solution acts as in entire liquid flashing counting measurement process
The effect of one detector: it detects the β ray energy of sample sending and is absorbed, is converted into photoelectron.It is different types of
Scintillation solution absorbs, the ability difference of conversion β ray energy, thus is suitable for the measurement of different samples.Therefore, according to tested
The difference of sample selects the scintillation solution adaptable with it just to seem necessary.The embodiment of the present invention is to current utilization rate highest
Two serial scintillation solutions of Optiphase HiSafe and Ultima Gold investigated, it is thus understood that Optiphase
The scintillation solution of HiSafe series has mainly used diisopropyl naphthalene (DIN) as scintillator, it be mainly characterized by do not reducing
Safety obtains certain promotion in the case where scintillation solution performance.And Ultima Gold series belongs to slow scintillation solution, it is main special
Point is that have high flash-point, detection efficient high and low malicious and not volatile.Table 2 lists the common sudden strain of a muscle of the two serial several moneys
Bright liquid and its correlated performance feature.Wherein, table 2 is that several moneys often use scintillation solution correlated performance feature contrast table.
Table 2
LLT the and u LLT type scintillation solution of Ultima Gold series is all suitable for the sample measurement of environment low-level tritium, with
Purpose phase one of the tritium automatic analysis method mainly for the analysis of tritium in ambient water in the water based on RO film sample preparation studied herein
It causes.Wherein u LLT type ratio LLT type scintillation solution has lower background count, therefore selects in the experimentation of this research
Ultima Gold u LLT type scintillation solution with ultralow background, control environment monitoring application.
C. counting vial
The β ray of electromagnetic radiation absorbs and is converted into photon by scintillator, and photon needs guiding through counting vial and gets to photoelectricity
Multiplier tube.And the material of counting vial and its thickness etc. will cause directly to influence on the penetration capacity of photon, to influence survey
The detection efficient of amount system.Common counting vial material has polyethylene, polytetrafluoroethylene (PTFE) or the meter containing polytetrafluorethylecoatings coatings
Several bottles, low potash glass etc..Table 3 gives the respective advantage and disadvantage of counting vial and its applicable range of above a few money unlike materials.
Wherein, table 3 is the comparison table of unlike material counting vial.
Table 3
Counting vial material |
Advantage |
Disadvantage |
The scope of application |
Polyethylene |
Detection limit is low, price is low |
Poor transparency |
High-volume Analysis of environmental samples |
Polytetrafluoroethylene (PTFE) |
Detection limit is low, transparency is high |
Price is high |
A small amount of sample, high-acruracy survey |
Low potash glass |
Transparency is high |
Background count is high |
Generally it is chiefly used in14The measurement of C |
Tritium automatic analysis method is on the one hand mainly in ambient water in the water based on RO film sample preparation of the embodiment of the present invention
The analysis application of tritium;The automation of tritium analysis overall process in water finally can be achieved in another aspect this method, can be used for high-volume sample
The analysis of product.In conjunction with table 3, the embodiment of the present invention selects the counting vial of polyethylene material, and certainly, those skilled in the art can root
According to the counting vial of actual demand selection other materials, herein only as an example, being not specifically limited.
2.3.3 count measurement process
As shown in figure 26, water sample after the processing of RO UF membrane sample preparation device purification, is obtaining meeting liquid sudden strain of a muscle measurement
The filter liquor of condition.Filter liquor and scintillation solution are injected into counting vial by a certain percentage, screwing bottle cap and fulling shake mixes the two
Uniformly and with alcohol swab wiping counting vial outer wall to reduce electrostatic interference.Then sample to be tested is passed to liquid to dodge in spectrometer, by wanting
It asks and starts to measure after setting measuring condition.
To sum up, tritium automatic analysis method is in the water based on RO film sample preparation with " RO UF membrane sample preparation+liquid dodges spectrometer and counts survey
Amount " is frame.RO membrane separation technique, which is mainly utilized, can carry out quick separating-purifying to water sample processed to reach symbol
Close the requirement that liquid dodges measuring condition.Then it selects a kind of suitable liquid to dodge measurement method and count measurement is carried out to sample, with effective
Reduce detection limit, to solve existing method presently, there are time for sample pretreatment is too long and measurement detection limit is high asks
Topic, the final effective analysis realized to tritium in ambient water.
Above-described embodiment describes the fast automatic analysis method of tritium in water in detail, will pass through another embodiment pair below
The fast automatic analysis method of tritium is introduced in water, and in the present embodiment, automatic measurement conductivity uses results of conductivity measurement
Control sample crosses film number.
Further, in one embodiment of the invention, further includes: the conductivity value of detection back segment filter liquor;Judgement
Whether conductivity value is less than default conductivity value;If conductivity value is less than default conductivity value, the is injected into counting vial
The back segment filter liquor of one preset volume;If conductivity value is more than or equal to default conductivity value, again by reverse osmosis membrane
Secondary purification back segment filter liquor, until conductivity value is less than default conductivity value.
It is understood that it be easy to cause reverse osmosis membrane to block when default conductivity value is arranged higher, and default conductivity
When value setting valence is low, the back segment filter for meeting liquid sudden strain of a muscle measurement request can be prepared by needing multipass reverse osmosis membrane purification
Liquid out, therefore, those skilled in the art need to need to be arranged the occurrence for presetting conductivity value according to actual use, so as to
In the case where guaranteeing to be prepared the back segment filter liquor for meeting liquid sudden strain of a muscle measurement, also effectively control sample crosses reverse osmosis membrane number,
To effectively improve the access times of reverse osmosis membrane, cost is reduced.The embodiment of the present invention does not do specific limit by taking 5 μ s/cm as an example
It is fixed.
Specifically, below will be to will combine conductivity that RO film sample preparation device comprehensive performance is described in detail.
3.1, the RO film sample preparation device model machine design, produced, what is faced first is following problem: first is that the system
The applicable water sample ambit of sampling device, tentatively grasping which kind of water sample is just suitable for carrying out sample preparation using the device;Second is that making
Time needed for carrying out one sample of sample size situation and preparation that sample preparation needs to prepare with the device;Third is that the device
The problem of with the presence or absence of tritium residual, or when need to consider that tritium residual will cause influence to sample analysis result;
Fourth is that the case where RO film sample preparation device service life, substantially grasp the device and need to carry out RO film after preparing how many times sample
Replacement.This chapter will be operated from above four problems by a large amount of actual motion, be verified and tentatively be grasped the RO UF membrane
The comprehensive performance of sample preparation device provides safeguard for effective operation of entire analysis method.It below will be from the following aspects to system
Sampling device is further elaborated.
3.2, the applicable water sample range research of sample preparation device
The task of the sample preparation device is to be filtered purification to detected water sample using RO film, and purified water sample meets liquid
The count measurement that machine on scintillation solution directly carries out tritium can be added by dodging measuring condition.But it is limited by RO film process water sample ability,
Not all water sample is all suitable for being handled with the sample preparation device.Therefore, it is outstanding to grasp the applicable water sample range of the sample preparation device
It is important.
For convenient for carrying out effective evaluation to water sample range from the angle of quantization, introducing conductivity and turbidity herein, the two are general
It reads.Wherein conductivity is to evaluate the salt content in water sample, important indicator and liquid flashing counting method containing ion and impurity component etc.
Can tritium examination final sample be surveyed enter the index that liquid sudden strain of a muscle spectrometer measures.And turbidity be evaluation water in it is various it is inorganic with have
The suspended matter of machine is to the obstruction degree of light, and the big water sample of turbidity easily results in blockage and damages to RO film, to seriously affect RO
The use of film sample preparation device.
The water sample range test research process being applicable in RO film sample preparation device is as follows:
1) surface water, underground water, the water sources such as enough various environmental water samples, including rivers, reservoir is acquired as required to drink
Ground water and rainwater, tap water etc.;
2) measurement of conductivity and turbidity is carried out to the environmental water sample of each acquisition, and records measurement data in detail;
3) it is protection RO film sample preparation device, manual filtering early period is carried out to visually obvious muddy water sample.Method is as follows: adopting
With suction type filtering device, the interior bilayer diameter that is laid with carries out the water sample of obvious muddiness for the 102 middling speed type qualitative filter papers of 18cm
Early period filters to obtain relatively limpid filtrate, and early period, manual filtration process was as shown in figure 27.
4) conductivity and turbidimetry are carried out to the opposite clear filtrate after premenstruum (premenstrua) manual filtration again, and recorded in detail
Measurement data;
5) enough environmental water samples are accessed into RO film sample preparation device water inlet, according to " automatic sample " of 2.2.3 section description
Mode carries out separating-purifying processing to water sample.
6) whether low the measurement for carrying out conductivity after " automatic sample " to obtained filter liquor, observe its conductivity value
In 5 μ s/cm.If so, stopping sample preparation and recording the conductivity value of current filtrate;If it is not, " manual mode " is then selected, to this
Environmental water sample carries out multiple " filtering+sample preparation " operation.After obtaining enough filter liquors, " filtering+system is carried out again to filter liquor
Sample " operation, obtains secondary treatment filtrate, measures and records its conductivity value.
It will be respectively necessary for being listed in respectively through the water sample and its experimental result of RO film sample preparation device single treatment and reprocessing
Table 4 and table 5.
Table 4
Table 5
By table 4 with table 5 as it can be seen that the initial conductivity of the environmental water sample for the embodiment of the present invention is supreme from several μ s/cm
Thousand μ s/cm, conductivity value distribution is relatively extensive, has good representativeness;The turbidity of most environmental water samples all exists
1.00NTU is hereinafter, only few several visual obvious muddy its turbidity of water sample are greater than 1.00NTU, but are passing through simply
Its turbidity value is also all reduced to 1.00NTU or less after early period coarse filtration.This experimental result is shown: initial conductivity is in 6.98
Between~919 μ s/cm, and conductivity is lower than the environmental water sample of 1.00NTU, after RO film sample preparation device single treatment
Realize that filter liquor conductivity is lower than the purpose of 5 μ s/cm;And initial conductivity is between 1124~1744 μ s/cm, wherein
It, need to be through two using RO film sample preparation device after the processing of part turbid water sample premenstruum (premenstrua) coarse filtration makes haze reduction to 1.00NTU or less
Secondary processing can make filter liquor conductivity be reduced to 5 μ s/cm or less.
In general, primarily determine the RO UF membrane sample preparation device to turbidity lower than 1.00NTU, conductance by this experiment
Rate has good treatment effect in 900 μ s/cm environmental water samples below.And by experiment as it can be seen that most of environmental water samples are symbols
This requirement is closed, therefore the water sample range that the device is applicable in is satisfactory.Due to limited conditions, this experiment only selects
The environmental water sample of Tianjin, sample type and quantity are relatively fewer, also need to acquire more differences in China in next step
The environmental water sample of type carries out similar experiment, to further determine that the applicable water sample ambit of the RO film device.
3.3, sample making course consumption sample amount and time-consuming research
3.3.1, sample making course consumes sample amount situation
It is further every to the sample preparation device after tentatively having grasped RO UF membrane sample preparation device and being applicable in water sample ambit
The sample size that a sample substantially needs to consume is prepared to be counted and grasped.
Inevitably there is certain pure waste water ratio because of the working mechanism of film itself in RO UF membrane sample preparation device.This
Outside, the interference for being the complete sample of pre-treatment that eliminates as much as to sample below, sample preparation device design increase sample water washing ring
Section.The sample size of required consumption is bigger when therefore, using device progress water sample processing.Specifically to grasp RO UF membrane
The sample size situation of required consumption when sample preparation device handles water sample, herein in the following ways to each water sample of RO film device at
Each link water consumption of reason process, wastewater flow rate and production sample amount situation are recorded and are counted:
1) water sample to be processed is filled with the plastic barrel that volume is 25L, then bucket is placed on electronic scale, record the device
During processing water sample each link start with finish time electronic scale numerical value, the concrete water quality of each link consumption is obtained through converting;
2) selecting volume is the beaker access of the 10L device in processing each link of water sample process, through discharge outlet 1, draining
Mouth 2 and the wastewater flow rate of gap (as shown in Figure 19) discharge, and make a record;
3) selecting volume is the beaker access of the 3L device in processing each link of water sample process, is abandoned liquid mouth (see Figure 19
It is shown) sample size of discharge, and it makes a record.
Secondary processing environment water samples according to said method tens of to the device and the originally water consumption of each link of water sample, discharge waste water
Amount and production sample amount are all recorded, as shown in Figure 28.The data of record are collated, summarize and be listed in shown in table 6.
Table 6
By upper table data as it can be seen that the process for needing to consume water sample, which concentrates on sample water, rinses and once filter link, and two
The concrete water quality of link consumption is substantially suitable;Four processes can all have waste water generation, and the waste water that wherein sample water flushing link is discharged is about
For one times or so for once filtering link discharge waste water, the wastewater flow rate that two links of sample preparation and emptying generate is not much different;Sample
Generation process occurs in sample preparation link.All in all, this research sample preparation overall process of RO UF membrane sample preparation device consumes
Concrete water quality range is 11.0~15.3L, mean consumption 12.9L;The wastewater flow rate range of overall process discharge is 9.5~13.8L, average
Waste water 11.4L is discharged;The sample size of generation is fixed on 1.5L, generally takes the 100ml of latter end or so sample stand-by.Accordingly, it is proposed that
When prepared by the water sample for carrying out tritium analysis in water using the device, for the sake of insurance, the water sample for preparing 16L or so is to compare conjunction
Suitable.
It should be noted that being the case where only needing RO film device single treatment above.When encountering at special needs repeat
The sample of reason is needed on this basis if the higher water samples of initial conductivity some in table 3.2 using " manual " sample preparation mode, weight
Multiple 3~4 " primary filtering+sample preparation " links are to collect enough pure water through device single treatment.Then by device water inlet
In the above pure water collected of merging, then 1 " primary filtering+sample preparation+emptying " link is carried out, water sample can be made to meet measurement and wanted
It asks.So need the concrete water quality consumed and will increase to 32~39L or so.
3.3.2, sample making course time-consuming situation
Tritium analysis method all has that sample preparation procedure takes long time in existing water.It forgoing describes using biography
The alkali formula electrolytic enrichment method sample preparation of system need to consume a week even more than ten days time;Electrolytic enrichment device after improvement
It needs one day time-consuming or more;And time-consuming is needed at least because saving the air-distillation sample preparation method that electrolytic enrichment process is greatlied simplify
It 2~3 hours, is distilled if you need to repeat, then spent time will be increased to 12~16 hours or so.The embodiment of the present invention based on RO film
Isolated sample preparation device purifies water sample by film filtering, and advantage should be theoretically had more in time-consuming.
The time situation of required consumption when to grasp RO UF membrane sample preparation device processing sample, herein to entire research process
In the tens of secondary water sample treatment processes of the device recorded in the time-consuming situation of each link, the data of record are collated, summarize
It is listed in shown in table 7.
Table 7
A link time-consuming situation is handled further intuitively to understand the device water sample, is drawn out respectively according to 7 column datas of table
The average time-consuming pie chart of link, as shown in figure 29.
The above experimental result is shown, when carrying out water sample processing using the RO UF membrane sample preparation device, entire treatment process institute
Time-consuming range is 35~52 minutes, and average time-consuming needs 41 minutes.It is wherein time-consuming longest for sample water flushing link, the link
Spent time accounts for 60% or more of entire sample making course.Specific each link time-consuming situation approximately as: sample water flushing link is time-consuming
It is range 19~40 minutes, average 26 minutes time-consuming;Primary filtering link time-consuming range 3~12 minutes, it is average 5 minutes time-consuming;System
It is sample link time-consuming range 4~7 minutes, average 5 minutes time-consuming;Last emptying link time-consuming range 3~6 minutes, average time-consuming 5
Minute.
It equally, is the case where only needing RO film sample preparation device single treatment above.The sample that special needs are reprocessed
Product, need on this basis utilize " manual " mode increase by 3~4 times " primary filtering+sample preparation " operation and 1 time " once filter+
Sample preparation+emptying " operation, required time increase accordingly by 85~95 minutes or so.
By conclusions as it can be seen that the sample preparation device based on RO UF membrane the studied herein sample preparation that tritium is analyzed in water
For process compares the method for making sample that tritium is analyzed in existing water, have a clear superiority in spent time.
3.4, the research of RO film sample preparation device tritium remaining influence
The problem of inevitably bringing contamination using RO UF membrane sample preparation device, i.e. sample are through the filtering point of RO film device
After purification, the impurity in the sample, which inevitably understands some, can be stopped in the device, after next sample enters the device,
A part of impurity stopped before in the device may can be mixed into the sample to pollute it.And the tritium in water is very
This process may be participated in, this will cause directly to influence on the analysis result of tritium in sample.
In this regard, the RO UF membrane sample preparation device that this research uses devises the sample water cleaning procedure of long period.It is expected that leading to
The interference of sample carryover impurity before in excessive bulk, prolonged sample water flushed zone walking apparatus.To verify having for this measure
Effect property, grasps the anti-tritium remaining influence ability of the RO UF membrane sample preparation device, has carried out tritium residue test below herein.
1) laboratory originally water sample tritium analysis measurement
" automatic sample " mode is selected using RO UF membrane sample preparation device, originally water sample is filtered at purification to laboratory
Reason.It takes latter end filter liquor of the 50ml conductivity lower than 5 μ s/cm to contain in 100ml counting vial, 50ml flashing is then injected into bottle
Liquid, counting vial, which fullys shake, to be uniformly mixed the two and wipes bottle outer wall with alcohol swab.Then sample to be tested merging liquid is dodged into spectrum
In instrument and suitable time of measuring is set, after standing in spectrometer after sample, being protected from light 12 hours, starts to measure and record measurement knot
Fruit.
Repeat above step, prepare three laboratories originally water sample and carry out tritium counting rate measurement, measurement result is made
For tritium counting rate horizontal reference value in this laboratory tap water.Measurement data is shown in Table 8.
Table 8
Sample number into spectrum |
Time of measuring (min) |
ESCR value |
Counting rate (cpm) |
Tap water 1 |
1000 |
11.22 |
4.243 |
Tap water 2 |
1000 |
11.21 |
4.402 |
Tap water 3 |
1000 |
11.24 |
4.397 |
Average value |
|
|
4.347 |
2) configuration of tritium mark-on sample
The laboratory tap water that electronic scale weighs 20kg is contained spare in 25L bucket.The liquid-transfering gun for the use of range being 1mL
The tritium standard solution that 0.2mL initial concentration is 1009Bq/g is pipetted, then weighs up this using the electronic balance that precision is 0.1mg
The tritium standard solution quality pipetted is 0.2002g.Both make in spare tap water before weighed tritium standard solution is poured into
It is sufficiently mixed the tritium mark-on sample for being configured to that tritium concentration is about 10Bq/L.
3) the tritium retention analysis measurement of mark-on sample
By method in step 1), using RO UF membrane sample preparation device, it is about to configured tritium concentration in 2) step first
The mark-on sample of 10Bq/L is handled and is prepared into mark-on sample to be measured, then continuously prepares multiple laboratories originally water sample, successively
Number is C1、C2、C3... all liquid that are placed in together to test sample prepared are finally dodged progress tritium counting rate survey in spectrometer by ..
It measures and records measurement result.
4) the tritium retention analysis measurement of various concentration tritium mark-on sample
By step 2), 3) in method, configuring in order tritium concentration is about 50Bq/L and the mark-on sample of 100Bq/L, is then carried out
Sample preparation and tritium residue test measure, and record to test result.This time tritium residue test the results are shown in Table shown in 9.
Table 9
Above-mentioned test result is shown: the RO UF membrane sample preparation device is handling the mark-on sample that tritium concentration is about 10Bq/L
Afterwards, originally the tritium counting rate of water sample is referred to laboratory tap water tritium counting rate in table 3.5 in continuous 4 laboratories immediately after
Value is suitable.And after having handled tritium concentration and being about 50Bq/L and the mark-on sample of 100Bq/L, preceding several laboratories immediately after are certainly
Carrying out the tritium counting rate of water sample, than before there is the phenomenon that increasing in laboratory tap water tritium counting rate reference value, until the 3rd or the 4th
Its tritium counting rate of sample is horizontal before being just gradually restored to.
Accordingly, it can tentatively be concluded that for water sample of the tritium concentration lower than 10Bq/L, use the RO film
It separates after sample preparation device carries out water sample processing, without considering the influence because of device tritium residue problem to sample handled by later;But
When the tritium concentration of water sample processed is higher than 10Bq/L, tritium residue problem should arouse attention.Specific influence degree optionally and
It is fixed, it is generally available the ambient water of tritium counting rate level known to locality or the multiple sample preparation of tap water is rinsed, until what is be processed works as
The tritium counting rate of ground ambient water or tap water is restored to initial level, which can continue investment normal use.
For normal environmental water sample, tritium concentration is substantially all in 10Bq/L hereinafter, therefore using the RO film point
When from sample preparation device processing environment water sample, the remaining influence of sample preparation device tritium can be ignored substantially.
3.5, RO film sample preparation device service life case study
The service life of device is an important technical indicator, for non-disposable use equipment, even if it makes
With process again facilitate, other performance it is superior again, if service life is too short, which is also difficult to be promoted the use of.Therefore, understand
Service life situation of the RO UF membrane sample preparation device for tritium analysis sample making course in water, makes the popularization of this method next step
With particularly significant.
For RO UF membrane sample preparation device, the part for being used for deciding factor from the service life is RO film.With
The increase of RO film process concrete water quality, the surface of film by gradually by the impurity in water block or because friction effect, film surface quilt
Impurities in water damage, eventually leading to the device reduces the detergent power of water.When use, the device carries out water sample processing, acquisition
Filter liquor is difficult to realize conductivity lower than 5 μ s/cm, thus when no longer meet that tritium analyzes measurement request in water, it is necessary to it is right
RO film in device is replaced.
Before this research experiment, device research staff is being designed the RO UF membrane sample preparation device and limber up period
Between, the originally water sample processing test (be wherein no lack of plus the originally water sample of salt is tested) up to more than 40 times had once been carried out to it.Debugging
After, in the case where no replacement RO film, using the device, to the environmental water sample of acquisition and originally, water sample has carried out this
Research experiment.In experimentation, complete water sample per treatment to RO film device has all carried out measurement and the record of conductivity, and according to
The trend that this conductivity for delineating sample prepared by the device prepares the variation of sample number with it is as shown in figure 30.It is horizontal in figure
Coordinate is this research experiment sample preparation number, and ordinate is the conductivity value for having prepared sample.
As seen from Figure 30, generally speaking with the increase of RO UF membrane sample preparation device processing sample number, after processing
The trend slowly risen is presented in water sample conductivity.There is obvious liter in the conductivity of wherein the 17th time, 27 times, 31 times processing water sample
High situation, being checked, this increases the first of the underground water, drinking water source 5 and the river 1 that are corresponding in turn in table 5 extremely three times
Secondary processing result, it is seen that this abnormal increase is excessively high caused by water sample initial conductivity processed.Since the 33rd time, it
What the conductivity of continuous 4 water samples was all stable afterwards is maintained at 6 μ s/cm or more, through looking into, this 4 water samples be use for laboratory originally
Water.Therefore, it can be confirmed that the RO film process concrete water quality has reached its own limit value, it need to be replaced.
So far, which designs more than 40 originally water sample processing and this experimental stage in debugging stage before it experienced
More than 30 environmental water samples and originally water sample processing after, reached it and used the phase in longevity.It should be pointed out that the use of RO film
Service life with the water sample water quality that it is handled be it is directly related, the water sample water quality of RO film process is better, and service life also will be longer.
RO film used is this time tested, it includes due to adding salt that front and back completes more than 70 water sample preparations altogether among these
The originally water sample and the higher environmental water sample of self-conductance rate for having high conductivity.It is ensured that ensuring to enter RO film
The water sample of sample preparation device is meeting under the applicable environmental water sample range of condition of the device, which analyzes sample preparation for tritium in water
Service life will be not less than 70 times.
To sum up, by the above experimental study, the RO UF membrane sample preparation device is tentatively grasped for tritium analysis sample preparation in water
The comprehensive performance parameter of journey is as follows: 1. the device is lower than 1.00NTU to turbidity, and initial conductivity is in 900 μ s/cm environment below
Water sample has good treatment effect, only needs single treatment that can complete sample preparation;2. handle such environmental water sample using the device
The sample size needed is relatively large, need to averagely consume sample about 13L, for the sake of assurance, it is proposed for preparing water sample before each sample preparation
16L or so;3. spent time is average when handling such environmental water sample using the device only needs 40 minutes or so, in existing water
Tritium analysis method is compared and is had a clear superiority;4. the device is when processing meets the environmental water sample of conditions above, the use of device
Service life is not less than 70 times;5. when processing environment water sample normal using the device, without considering between the sample of front and back because tritium is remaining
Problem has an impact analysis result, but after processing complete has the water sample of higher tritium concentration (10Bq/L or more), tritium residual is asked
Topic need to arouse attention.
Further, the optimization of determination and measuring condition to measurement method is described in detail below.
4.1, two conflicting problems that tritium analysis work mainly faces in current water have been previously noted: or before sample
The treatment process used time is too long or detection limit is excessively high.The 3rd chapter has been verified that the system based on RO UF membrane of this time research herein
Quadrat method can be such that the sample pretreatment process used time greatly shortens.How this chapter will make under detection from the angle research of count measurement
Limit the method being effectively reduced.
The detection limit calculation formula of tritium is as follows:
In formula: NbIndicate background sample counting rate, min-1;
E indicates detection efficient, %;
V indicates sample amount, ml;
tbIndicate the time of measuring of this original pattern, min;
By above formula as it can be seen that the principal element for influencing detection limit has following two in the case where detection system determines relatively
Point: first is that the influence of measurement method, such as sample size number, quenching correction method determination;Second is that the selection of background water
And its length of time of measuring.In addition, also needing to consider to carry out measuring condition excellent in the case where the above parameters all determine
Change, such as stands the optimization for being protected from light the time before the optimization of energy window, the optimization of water sample and scintillation solution proportion, sample measurement.
In the following, the discussion that will conduct a research respectively in terms of above-mentioned two, to determine that one kind is suitable for based on RO film
The liquid for separating sample preparation dodges measurement method and optimal count measurement condition.
4.2, the determination of measurement method
4.2.1 the selection of sample size
By formula 1 as it can be seen that the number of sample amount will cause to directly affect to detection limit.It is determined in counting vial capacity
In the case where constant, the change of sample size this means that scintillation solution volume change, and scintillation solution is excessive or very few, is all not suitable for
In the measurement of sample.Experience have shown that the volume ratio of sample and scintillation solution is between 8:12 and 10 for the counting vial of 20ml capacity:
It is than convenient between 10.But the sample volume variation in this range influences the change of detection limit little.
Therefore, it is necessary to break through the limitation of counting vial total capacity.Theoretically, sample size is bigger, the detection limit value of acquisition
It will be lower.In the case where ensuring sample and scintillation solution suitable proportion, with the increase of counting vial capacity, sample size also increases therewith
Add, but background counting rate NbAnd the detection efficient E of instrument tritium also will change therewith, and the range changed is unclear,
Want to show that detection limit is relatively difficult with the increased detailed situation of change of sample size by theoretical calculation.So only passing through reality
Suitable sample size is found in border measurement.
It forgoing describes LB7 type Low background liquid and dodges the counting vial that spectrometer has tri- kinds of different capabilities of 20ml, 100ml, 145ml
Measure function.Here, we first select 20lm and 100ml capacity counting vial to carry out the control experiment of detection limit, experimental procedure
It is as follows:
1) it selects two sets of identical laboratory atmospheric distillation plants to same a collection of background water, is carried out according to standard practice
Air-distillation.Distillation process is preferably slow, in order to which single flash can obtain the distillate that conductivity is lower than 5 μ s/cm.Distillation process
As shown in figure 31;
2) the qualified distillate that the distillation of two covering devices obtains is mixed, total 130ml.Then four are divided into liquid-transfering gun
Part, wherein two parts of 10ml are respectively charged into 20ml capacity counting vial, two parts of 50ml are respectively charged into 100ml capacity counting vial.It is surplus
Remaining distillate discards;
3) distillate for respectively selecting portion 10ml and 50ml is added suitable tritium standard solution configuration thereto respectively and survives
Similar tritium standard specimen is spent, another set distillate is as this original pattern;
4) it sequentially adds into four counting vials and is flashed with the isometric Ultima Gold u LLT type of contained distillate
Liquid carries out sample mark with signature pen after screwing bottle cap on bottle cap, and concussion is allowed to uniformly mixed;
5) after alcohol wipe outer wall, sample is put into LB7 Low background liquid and dodges spectrometer.All by the time of measuring of all samples
It is set as 100 minute/time of single measurement, duplicate measurements 11 times.After sample stands in spectrometer and is protected from light 12 hours, that is, carry out tritium meter
Number measurement, measurement result, which is computed, arranges rank rear in table 10.
Table 10
Table 10 shows that the corresponding detection limit of 20ml capacity counting vial is in 1Bq/L or more, the detection of 100ml capacity counting vial
Lower limit is lower than 0.4Bq/L.
According to " Chinese quality of radioactive environment report in 2016 " and " state key supervision cores in 2016 and radiating facility week
Enclose the report of radiation environment supervisory monitoring ", tritium concentration range is 0.28~2.7Bq/L in the Some City precipitation of China in 2016,
The tritium concentration of most precipitation is in 1Bq/L or so;It is 0.41 that tritium concentration range in point dewatering is compareed around most of nuclear power
~2.7Bq/L.There is data to show, the source of China's environment surface water, the water such as Ru Jiang, river and reservoir is derived mainly from precipitation.
Therefore, 100ml capacity counting vial measurement pattern of the detection limit lower than 0.4Bq/L is can satisfy substantially to China's ring
The requirement that tritium is effectively analyzed in the water of border;20ml capacity counting vial measurement pattern is because detection limit is too high, in 1Bq/L or more,
Therefore it should not select;If predictably selecting the counting vial of 145ml capacity, detection limit can be further decreased, but be counted
The increase of several bottles of capacity also brings along the problem of scintillation solution dosage increase, and scintillation solution is toxic and reluctant.Therefore, comprehensive
It closes and considers, selecting applicable 100ml capacity counting vial measurement pattern is that comparison is reasonable.
4.2.2 the selection of Quench Correction Methods
Quenching is to influence one of the maximum interference factor of liquid flashing counting measurement result.Strictly, sample is different, quenches journey
Degree is different, and measurement efficiency is not also identical.The basic goal of quenching correction is the liquid flashing counting measurement efficiency of determining sample,
Thus detection limit value is affected indirectly whether quenching calibration accuracy.There are many available Quench Correction Methods, such as: internal standard method,
External standard method, sample channels ratio(SCR) method, sample Spectral index method, isotope quenching method etc..It is mainly internal standard method that utilization rate is highest at present, outer
Mark method and relative measurement method.
A. internal standard method
Internal standard method begins to be applied to Tritium measure process very early, and substantially steps are as follows: sample being placed in liquid first
It dodges in spectrometer and measures, the tritium standard liquid of known activity is added after measurement in sample, and measure again.By measuring again
As a result the known activity that tritium standard liquid is added is combined, measurement efficiency can be obtained by being computed, which is that can be considered the survey of sample
Amount efficiency.The variation of quenching degree can be ignored before and after this method requires sample that tritium standard liquid is added, therefore it is required that
The concentration of tritium standard liquid is higher, and the volume change that standard liquid front and back sample is added is little.
B. external standard method
External standard method is relatively complicated, it is to dodge gamma ray radiator built-in in spectrometer using liquid to shine sample
It penetrates, obtains a Compton scattering spectrum, the different sample of quenching degree, distribution of the Compton scattering spectrum in multiple tracks is different,
I.e. road ratio is different, this road ratio is the quenching degree for reflecting sample, can be referred to as quenching coefficient.Principle accordingly, can
The tritium standard specimen of the different known activity of one group of quenching degree of configured in advance, available one group of quenching system after liquid dodges spectrometer measurement
The data of the corresponding measurement efficiency of number, become required Quench correction curve after being fitted.When measuring sample later, it is known that its
Quenching coefficient can obtain its measurement efficiency according to the Quench correction curve of fitting.There is configured quenching series source in external standard method
The problem whether being applicable in sample to be tested, and the configuration process for quenching serial source is relatively cumbersome.
C. relative measurement method
Relative measurement method is similar with internal standard method from principle, the difference is that this method does not need to add sample
The measurement twice of front and back is marked, but is prepared using identical method for making sample to test sample, this original pattern and standard sample, then will
Three is placed in liquid together and dodges count measurement in spectrometer.Since sample preparation methods are identical, it is believed that the quenching degree one of three
It causes, therefore the detection efficient of the standard sample of known activity is the detection efficient to test sample.This method is at present in radiation environment
It is widely adopted in monitoring.
Comprehensively consider, relative measurement method is selected to carry out the quenching correction of sample herein.To ensure to test sample and this original pattern, mark
The quenching degree of quasi- sample is consistent, and is obtained in advance with the source the γ irradiation built in spectrometer to test sample, this original pattern and standard sample
The quenching coefficient of three.Theoretically, when the quenching coefficient similar of sample, they dodge the counting on spectrometer in same liquid
Efficiency should also be similar, there is pertinent literature[24,25]Verifying was carried out to this theory by up to a hundred actual measurements.
Using same method multiple tritium standard specimens are carried out with the experiment of quenching coefficient and the measurement of tritium counting rate herein, then
According to resulting tritium standard specimen counting rate is measured, it is computed and show that it measures activity, the practical activity in conjunction with known to tritium standard specimen
Obtain the counting efficiency of different tritium standard specimens.Experimental result is shown in Table shown in 11.
Table 11
By table 11 as it can be seen that the tritium standard specimen of different activity, as long as quenching coefficient similar, their counting efficiency difference would not
It is too big.The reliability of the quenching correction method of relative measurement is demonstrated again.
4..3, the determination of background water and sample-out count time
4.3.1 the selection of background water
Being related to nuclear activity by the mankind is influenced, and real tritium-free water is seldom even not present in global range at present.And this
Bottom water has direct influence to sample final measurement and detection limit, therefore particularly significant.In actual measurement, Wo Menchang
Select the alap environmental water sample of tritium counting rate convenient for obtaining as background water sample.
To select suitable background water sample, once to certain two provincial radiation stations background water sample and Tianjin two at
Sampling of ground water carries out the measurement of tritium counting rate, and measurement result is shown in Table 12.
Table 12
It is shown according to table 12, the minimum background water sample for radiation station 2 of tritium count rate measurement, is secondly Tianjin underground
Water 2, and the two measurement result is not much different.In view of the comfort level that water sample obtains, the work of Tianjin underground water 2 is had finally chosen
For the background water sample of this laboratory tritium analysis.
4.3.2, the selection of sample-out count time
Formula 1 is as it can be seen that the time of measuring of this original pattern constitutes direct influence to detection limit.When this original pattern counting rate is stablized
Afterwards, with the extension of time of measuring, background counting rate is relatively constant, and detection efficient is also relatively constant, and sample volume and background
Time of measuring is unrelated.So, it is believed that sample-out count time and detection limit are at evolution inverse relation.Theoretically obtain, this
Bottom time of measuring can change detection limit, but it is limited to change ability.
Tritium analysis requires at 1000 minutes or more the time of measuring of this original pattern in general current water.Comprehensively consider, herein
This original pattern time of measuring is set as 1000 minutes by selection.
4.4, the optimization of measuring condition
After measurement method determines, measurement result can need to be caused centainly on the basis of the measurement method to some
The measuring condition of influence optimizes.Such as the optimization of the optimization of energy meter number interval, water sample and scintillation solution proportion and to test sample
Product stand the optimization etc. for being protected from light the time.
4.4.1, the optimization of energy meter number interval
The variation of energy meter number interval to a certain extent can impact detection limit, for reasonable selection energy meter
For number interval to improve detection limit as far as possible, spy introduces the concept of quality factor (FOM).People are by Liquid Scintillation Count Efficiency
Square quality factor is defined as with the ratio of background counting rate[26].For specific sample, when quality factor takes most
When big value, the optimal selection of its energy meter number interval is corresponded to.Quality factor formula is as shown in Equation 2:
In formula: NbIndicate background counting rate, min-1;
E indicates that detection efficient, calculation formula are as shown in formula 3:
In formula: NsIndicate standard sample counting rate, min-1;
D indicate standard sample in per minute tritium decays, min-1。
For the maximum value for finding and determining quality factor, following experiment has been carried out:
1) take high purity water of the 50ml conductivity less than 5 μ s/cm and 50ml Ultima Gold u LLT type scintillation solution in
Sample to be tested is made after concussion mixes them thoroughly in 100ml polyethylene counting vial;
2) it is put into LB7 type liquid after wiping counting vial outer wall with alcohol swab to dodge in spectrometer, sets 100 for time of measuring
Minute/time, duplicate measurements 11 times, correction method selects " ESCR ".After sample standing is protected from light 12 hours, start to measure.By this
Measurement result is as background values;
3) after sample-out count, sample is taken out, the tritium standard solution that activity is 197Bq is wherein being added, is being shaken through concussion
It is even that tritium standard specimen is made;
4) the tritium standard specimen counting vial outer wall made of alcohol swab wiping previous step, is then put into LB7 type liquid and dodges spectrometer
In, 10 minutes/time are set by time of measuring, duplicate measurements 11 times, correction method selects " ESCR ".It is small that 12 are protected from light to sample standing
Shi Hou starts to measure.
Figure 32 and Figure 33 is respectively that background spectrum and standard specimen compose spectrogram.
LB7 type liquid dodges the entire window energy range of spectrometer Tritium measure by 0 to 200keV, is divided into 4000, per together
Corresponding energy 0.05keV.Correctly to find and determining optimal energy meter number interval, need to count peak it is high and low can both ends by
Secondary card road records the tritium counting rate of every secondary card road corresponding standard specimen and background, is then calculated every time using formula 2 and formula 3
The corresponding FOM value in card road.The maximum value of FOM is found, energy section corresponding to card road is optimal energy meter number interval.
The FOM Data-Statistics situation of each energy meter number interval is shown in Table 13.
Table 13
Upper table is shown, when energy meter number interval takes 1.00~4.70keV, it is 142.42 that maximum value, which occurs, in quality factor,
Corresponding detection limit is also minimum, is 0.4107Bq/L.Thereby determine that the energy window that the liquid is dodged spectrometer Tritium measure is set as
1.00~4.70keV.
Spectrometer parameter setting method is as follows: selecting " other (FREE) " first in the nucleic column of the primary condition page, so
The minimum (L.L.) of power spectrum window is set as 1.000 in the FREE power spectrum window setting of the measuring condition page afterwards, highest limit
(U.L.) 4.700 are set as, " ok " is clicked and saves setting.
4.4.2 the optimization of water sample and scintillation solution proportion
Suitable water sample and scintillation solution matches, and is more advantageous to the effective analysis for realizing tritium in water.To find optimal water sample
With scintillation solution volume proportion, the concept of sensitivity figure of merit SFOM, the sensitivity figure of merit are further introduced on the basis of quality factor
For the product of quality factor and sample volume square.
In formula: V indicates the volume of detected water sample, ml;Remaining parameter meaning is identical as formula 2,3.
Optimal sample volume is corresponded to when SFOM is maximized, i.e., optimal water sample and scintillation solution match ratio.For
Maximum SFOM value is found, is proceeded as follows:
1) it uses high purity water as detected water sample, it is matched according to difference respectively with Ultima Gold u LLT type scintillation solution
Than being fitted into 100ml polyethylene counting vial, after concussion shakes up, one group of difference sample is made with scintillation solution proportion to test sample
Product.As shown in figure 34;
In upper figure, it is followed successively by water sample and scintillation solution from left to right by 70:30,65:35,60:40,55:45,50:50,45:
55, the volume of 40:60,35:65,30:70 configure.As seen from Figure 34, from right to left, the transparency of sample gradually decreases,
Muddy opaque shape is substantially presented in three samples of the leftmost side, this is because water sample is excessive, tritium cannot be filled by scintillation solution in water
Caused by dividing dissolution.
2) all of above sample to be tested counting vial outer wall is wiped to eliminate electrostatic interference with alcohol swab, then successively put it
Enter LB7 type liquid to dodge in spectrometer.100 minutes/time are set by measuring condition, duplicate measurements 11 times, correction method selects " ESCR ", to
Sample stands in spectrometer and is protected from light after 12 hours, starts to measure, and measures the data obtained as background values;
3) it is taken out after sample measurement, the tritium that about 0.2g initial concentration is 1009Bq/g is successively added in each sample
Standard solution, concussion shake up rear to be measured;
4) with alcohol swab wipe outer wall after place a sample into again liquid dodge spectrometer in, except by time of measuring be changed to 10 minutes/
Secondly, being consistent in other measuring conditions and 2) step.This time measurement data is mark-on sample measured value;
5) it arranges and measures the data obtained twice, it is corresponding with scintillation solution proportion that different water samples are calculated via correlation formula
Detection efficient and SFOM value, are listed in table 14.
Table 14
According to table 14, the trend that sensitivity figure of merit SFOM changes with sample and scintillation solution proportion and changed is drawn out, is such as schemed
Shown in 35.
It is above-mentioned the results showed that 1. with the decline of water sample and scintillation solution proportion ratio, the ESCR value of matched sample with
Raising, i.e. the quenching degree of sample reducing.But the ESCR value variation before and after same sample mark-on is less, illustrates sample mark-on
The quenching degree of front and back is substantially suitable, ensure that the consistency of detection efficient before and after same sample mark-on;2. the detection of sample is imitated
Rate matches the decline of ratio with scintillation solution with water sample and gradually rises, this is because the increase of scintillation solution volume, leads to detected sample
The light conversion ratio of product increases, and the received optical signal of photomultiplier tube increases, so that detection efficient increases;3. the sensitivity figure of merit
SFOM is in downward trend after first rising with the decline of water sample and scintillation solution proportion ratio, this is because with the reduction of water sample,
Detection efficient dramatically increases, and background counting rate is relatively stable, thus SFOM value increases.Later, water sample is further reduced, detection
Efficiency increase slows down, and when the contribution that detection efficient increases is not enough to make up the contribution of volume of water sample reduction, SFOM value is
It is on a declining curve.Figure 35 intuitively shows this variation tendency, and clearly shows that in sample and scintillation solution proportion be 50:
SFOM value is maximum when 50.Accordingly, it is determined that the experiment measurement part of this research selects the water sample of 50:50 to match with scintillation solution
The mode of ratio.
4.4.3 it stands and is protected from light and the optimization of time of measuring
Rigid configured sample generally requires the standing of a period of time before measuring and is protected from light processing, this is because if surveying immediately
Amount, measured result are often bigger than normal.The reason of causing this phenomenon is the rigid configured sample mistake stable there are a quenching
Journey is generally protected from light to eliminate this influence by standing.But specific stand is protected from light the time currently without final conclusion, most of provincial
The selection of Radiation monitoring mechanism laboratory is protected from light 12 hours even 24 hours.Also there is document suggestion sample lower for tritium concentration quiet
It sets and is protected from light 6 hours or more the measurement that is just available on the machine, and sample higher for tritium concentration, then the time is protected from light without too long of standing.
To determine that the standing for being suitable for this research method is protected from light the time, promotes this method tritium and analyze working efficiency, carry out
Following experiment:
1) production and measurement of this original pattern: fresh background water sample is acquired, is distilled with atmospheric distillation, takes middle section
Distillate 50ml of the conductivity lower than 5 μ s/cm is added in 100ml counting vial, and 50ml scintillation solution is then added, and concussion, which shakes up, to be used in combination
After alcohol wipe counting vial outer wall, it is immediately placed in liquid sudden strain of a muscle spectrometer and starts to measure, time of measuring is 100 minutes/time, duplicate measurements
18 times.It is as shown in figure 36 that each measurement result with time of measuring situation of change is depicted as column diagram;
2) production and measurement of environmental water sample: selecting a certain environmental water sample, using with the identical method of step 1) into
Row sample preparation and measurement.Measurement result is as shown in figure 37 with time of measuring variation column diagram;
3) production and measurement of mark-on sample: this original pattern is made by step 1) first, is then injected thereto a certain amount of
Tritium titer, be configured to the mark-on sample that concentration is about 100Bq/L, be put into after wiping liquid dodge spectrometer in immediately begin to measure,
Time of measuring be 60 minutes/time, duplicate measurements 24 times.Measurement result is as shown in figure 38 with time of measuring variation column diagram.
Figure 36, Figure 37 show that sample meter early period digit rate is higher, but over time, counting rate gradually under
Drop, final entirety tend towards stability.The difference is that counting rate, which reaches, stablizes required time difference.The extremely low background of tritium concentration
Sample, after about 500 minutes, counting rate tends towards stability;The lower environment sample of tritium concentration, after about 300 minutes, counting rate is
It tends towards stability.And as seen from Figure 38, the higher mark-on sample (about 100Bq/L) of tritium concentration, counting rate tends towards stability at the beginning of measurement,
It is protected from light substantially without standing.Whether it is every to dodge spectrometer using LB7 type liquid in addition, recognizing that sample is stood by experiment usually or not
There is obvious higher phenomenon in the ESCR value of first data of secondary measurement, usually do first measurement data give up thus
Processing.
In consideration of it, in conjunction with this research select relative measurement Quench Correction Methods the characteristics of, use the research method
When carrying out sample measurement, after test sample configures and finishes, can successively it be set by standard sample (about 100Bq/L), to test sample, this original pattern
Enter liquid to dodge spectrometer and measure immediately.Wherein, the time of measuring suggestion of standard sample is set as 60 minutes/time, and duplicate measurements 11 times;To
The time of measuring suggestion of test sample and this original pattern is set as 100 minutes/time, and duplicate measurements 11 times.Data handling procedure, each sample
First measurement data be not included in statistics calculating process.Whole process is protected from light processing without deliberately standing.
To sum up, by the above experimental study, the liquid flashing counting measurement method for being suitable for this research method and measurement item are determined
Part is as follows: 1. for detection limit is effectively reduced, selecting the measurement pattern of 100ml capacity counting vial and the quenching school of relative measurement
Correction method is that comparison is reasonable;2. selection convenient for acquisition and relatively low my the unit laboratory of counting rate at present Tianjin
A certain underground water is set as 1000 minutes as background water sample, all original pattern time of measuring;3. in terms of the optimization of measuring condition,
Select the energy meter number interval of 1.00~4.70keV;Water sample and scintillation solution press the volume proportion of 50:50;When count measurement, it is not necessarily to
It specially stands and is protected from light, liquid can be sequentially placed in by standard sample (about 100Bq/L), to test sample, this original pattern and dodges spectrometer and measures immediately,
The time of measuring of Plays sample is set as 60 minutes/time, and duplicate measurements 11 times;Time of measuring to test sample and this original pattern is respectively provided with
For 100 minutes/time, duplicate measurements 11 times, first measurement data of each sample is not included in statistics calculating process.
The fast automatic analysis method of tritium in water will be further elaborated by way of specific embodiment below.
5.1 above-described embodiments are carried out to RO UF membrane sample preparation device comprehensive performance and liquid flashing counting measurement method and condition
Research determines and optimization, ultimately forms and the relatively complete of tritium automatic analysis method in the water based on RO film sample preparation has been determined
Frame system.
The purpose of any analysis method, be finally provided to obtain it is accurate, reliably analyze measurement result.In order to originally grinding
Study carefully method in water tritium analysis result on accuracy verified, this chapter by using method compare by the way of respectively to different
The mark-on sample of environmental water sample and various concentration carries out the matching measurement of tritium, and by analyzing comparison result, determination is originally ground
It is whether accurate in measurement result to study carefully method.
5.2 Experimental comparison
5.2.1 comparison method
Tritium automatic analysis method is for existing method in the water based on RO film sample preparation of the embodiment of the present invention,
One of main feature is RO film sample making course.And measurement process has then still continued to use liquid and has dodged measuring technique, although in order to reduce
Detection limit, although with the counting vial of 100ml capacity instead of currently used 20ml capacity counting vial, entire measurement procedure
Without too big change.In order to guarantee the comparativity of experimental result, this time comparing will set about from sample preparation link, and mesh is respectively adopted
Two kinds of method for making sample of RO UF membrane of preceding common air-distillation and this research are to various environmental water samples and various concentration mark-on sample
Sample preparation is carried out, then dodges what measurement method was prepared two kinds of different method for making sample from condition using the liquid that this is determined
Sample measures comparison.
A. air-distillation sample preparation
Air-distillation sample preparation operating process approximately as:
1) potassium permanganate for weighing 0.25g or so natrium carbonicum calcinatum and 0.125g or so in the balance, sequentially adds 500ml's
In distilling flask, the detected water sample of about 300ml is injected into bottle, and ground glass stopper is covered tightly after shaking up and is connect with serpentine condenser
It is good, it opens electrothermal furnace and controls temperature, distill the sample in distilling flask slowly in the case where not boiling acutely;
2) conductivity for collecting about 70ml is spare lower than the middle section distillate of 5 μ s/cm, needs if conductivity is higher than 5 μ s/cm
It repeatedly collects enough distillates and carries out second distillation, until conductivity lower than until 5 μ s/cm;
3) liquid-transfering gun for being 10ml with range pipettes the spare distillate injection 100ml polyethylene of 50ml in five times and counts
In bottle, 50ml Ultima Gold u LLT type scintillation solution is then added, concussion, which shakes up, is made sample to be tested;
4) fresh background water is acquired, 1) manufactures two samples to the process of 3) step in the method, wherein a sample
It being added in product and passes through diluted tritium titer, concussion is configured to the tritium standard sample that tritium activity is about 5Bq or so after shaking up, another
Not plus the sample of tritium standard liquid is as this original pattern.
B.RO UF membrane sample preparation
RO UF membrane sample preparation operating process approximately as:
1) water sample (about 16L) for acquiring enough volumes is connected in the water inlet merging sample water of RO UF membrane sample preparation device
Installation's power source clicks " starting " at " automatic mode " interface, and sample preparation device starts to be filtered water sample purification;
2) about 70ml filter liquor is taken out from sample tap after to be filtered and measures conductivity, if its conductivity is lower than 5 μ s/
Cm is then retained for use, if its conductivity is higher than 5 μ s/cm, enough filter liquors need to be collected from sample tap and carry out film again
Filtration treatment is lower than 5 μ s/cm until the conductivity of final filter liquor;
3) liquid-transfering gun for being 10ml with range pipettes the spare filter liquor injection 100ml polyethylene of 50ml in five times and counts
In bottle, 50ml Ultima Gold u LLT type scintillation solution is then added, concussion, which shakes up, is made sample to be tested;
4) 1) the fresh background water sample for acquiring enough volumes, manufactures two samples to the process of 3) step in the method,
It is added in one of sample and passes through diluted tritium titer, concussion is configured to the tritium mark that tritium activity is about 5Bq or so after shaking up
Quasi- sample, another does not add the sample of tritium standard liquid as this original pattern.
It should be noted is that regardless of with which kind of method sample preparation, this original pattern and standard sample all be can be reused.
In measurement process, as long as keeping normal relatively stable at the beginning of the quenching coefficient and counting rate of the two and sample preparation, they are can
?.Until measurement finds that quenching coefficient or counting rate occurs significant change, just needs to prepare again.
C. liquid dodges measurement and compares
After the completion of sample preparation, carry out matching measurement according to the following steps:
1) with the counting vial outer wall of the above prepared two groups of samples of alcohol swab wiping to eliminate electrostatic interference, then by two
A standard sample, two to test sample, two this original patterns sequentially simultaneously be placed in LB7 type Low background liquid dodge spectrometer in;
2) the Tritium measure window of spectrometer is set as to the energy meter number interval of 1.00~4.70keV;When the measurement of standard sample
Between be set as 60 minutes/time, the time of measuring to test sample and this original pattern is set as 100 minutes/time, each sample duplicate measurements 11
Secondary, correction method selects then " ESCR ", then starts to measure.First measurement data of each sample is not included in calculating process.
5.2.2, environmental water sample ratio
Comprehensively to verify this research method as far as possible to the reliability of various environmental water samples, Tianjin linchpin has been selected herein
A variety of environmental water samples such as river, reservoir water, potable water source district water and rainwater in area carry out this control experiment.Due to RO
Concrete water quality needed for UF membrane sample preparation device is relatively more, this sub-sampling acquires water sample 50L in each point.Because concrete water quality is big,
It is difficult to find suitable glass container and preservation is sealed to the water sample of acquisition, tritium is sent out in tritium and ambient enviroment in water sample to reduce
Raw exchange, entire sample collection process are conducted batch-wise, it is ensured that each water sample acquired back can be handled as early as possible.Specifically
Preparation and measurement procedure are carried out in strict accordance with the description in 5.2.1 trifle.The raw measurement data of comparison is shown in Table 15, table 16 respectively
And shown in table 17.Wherein, table 15 is rivers, tritium concentration matching measurement tables of data in reservoir water, and table 16 is in potable water source district water
Tritium concentration matching measurement tables of data;Table 17 is tritium concentration matching measurement tables of data in rainwater.
Table 15
Note: " * " mark indicates that sample passes through pre-treatment twice in table.
Table 16
Note: " * " mark indicates that sample passes through pre-treatment twice in table.
Table 17
5.2.3 mark-on sample compares
Further to verify this research method to the reliability of the water sample measurement result polluted there may be tritium, spy is configured with
Tritium concentration is respectively three groups of mark-on samples of 9.68Bq/L, 50.5Bq/L, 104Bq/L, then according to 5.2.1 trifle process, successively
This three groups of mark-on samples are carried out with the control experiment of tritium analysis.It is every compared one group of mark-on sample after, all with laboratory tap water to RO
Film sample preparation device is cleaned, until through the device treated originally water sample tritium counting rate be restored to initial level.Mark-on sample
Matching measurement initial data is shown in Table 18.
Table 18
5.2.4 quality assurance
Data to guarantee this experiment acquisition are accurate and reliable, and whole experiment process is all in the quality certification system frame of our unit
It is executed under frame.Key instrument equipment and reagent consumptive material used in experimentation are shown in Table 19.
Table 19
Title |
Model or specification |
Production firm |
Low background liquid dodges spectrometer |
LB7 |
ALOKA |
Scintillation solution |
Ultima Gold u LLT |
Perkin Elmer |
Tritium standard solution |
1009Bq/g, error 3.0% |
Eckert&Ziegler |
Electronic balance |
BSA224S |
Sai Duolisi scientific instrument (Beijing) Co., Ltd |
Conductivity meter |
MP513 |
Believe instrucment and meter plant in Shanghai three |
Title |
Model or specification |
Production firm |
Counting vial |
Polyethylene, 100ml |
Perkin Elmer |
Potassium permanganate |
It analyzes pure |
|
Natrium carbonicum calcinatum |
It analyzes pure |
|
Dehydrated alcohol |
It analyzes pure |
|
Wherein, tritium standard solution can trace to the source to German certification and accreditation committee Dakks, and liquid dodges the instrument such as spectrometer, electronic balance
Device equipment is through metrological service's assay approval, and within validity period.The configuration of instrument producer is utilized during entire experiment
Non- this original pattern of quenching carries out irregular confirmatory measurement, sees Figure 39 by the quality control chart that measurement result draws out liquid sudden strain of a muscle spectrometer
It is shown.
As seen from Figure 39, during entire experiment, the non-quenching background counting rate of LB7 type scintillation counter is at mean value
In 3 times of Standard deviation-Ranges, Spectrometer performance is relatively stable, meets quality control related request.
5.3, data processing
5.3.1 the calculating of tritium concentration and detection limit
Tritium activity concentration calculation is shown in formula 5 in water, and formula 1 is shown in detection limit calculating.
In formula: C indicates the activity concentration of tritium in detected water sample, Bq/L;
NcIndicate detected water sample counting rate, min-1;
NbIndicate background sample counting rate, min-1;
E indicates detection efficient, %;
V indicates sample amount, ml;
6×10-2For unit conversion coefficient.
5.3.2 the evaluation of uncertainty
It is all inevitably to there is error between obtained result and true value by measuring, because of measuring condition unreasonably
Wanting and practical true value can not determine, so the size of error is often also difficult to determine.For this purpose, International Metrology Commission (CIPM)
It is recommended that the result with uncertainty substitution error to indicate experiment.Uncertainty has comprehensively considered all factors for causing error
The degree that final experimental result is had an impact.
A. standard substance, measurer and the instrument being related to
(1) tritium standard substance: U=3.0%, k take 2;
(2) the ultralow background liquid of LB7 type dodges spectrometer;
(3) 10ml liquid-transfering gun: the limits of error (MPEP) it is ± 0.06ml, according to being uniformly distributed, k value
(4) BSA224S type electronic balance: the limits of error (MPEB) it is ± 0.5mg, according to being uniformly distributed, k value
B. the foundation of mathematical model
The mathematical model of this research method uncertainty of measurement is established according to formula 5-1.
C. the source analysis of uncertainty
The measurement of tritium concentration is by the decay of detected sample, the fluctuation of background, the uncertainty of standard substance and instrument in water
Device measures the combined influence of the factors such as uncertainty.According to relevant criterion combination formula 5-1, tritium concentration uncertainty of measurement in water
Analysis is as shown in Figure 40.
As seen from Figure 40, the uncertainty source of the two methods analysis result this time compared is consistent, it is anticipated that
The range of uncertainty difference that two methods analyze result is not too large.
D. the evaluation of partial uncertainty
(1) the uncertainty u of sample measurement1:
In formula: Nc indicates sample meter digit rate, min-1;
NbIndicate background counting rate, min-1;
tcIndicate sample time of measuring, min;
tbIndicate sample-out count time, min.
(2) the uncertainty u that instrument efficiency calibration generates2, as shown in Figure 40, the uncertainty that efficiency calibration generates is main
From following three aspects.
First is that the uncertainty u of tritium standard specimen measurement21:
In formula: NsIndicate tritium standard sample meter digit rate, min-1;
NbIndicate background counting rate, min-1;
tsIndicate tritium standard sample time of measuring, min;
tbIndicate sample-out count time, min.
Second is that tritium standard specimen concentration uncertainty u22, tritium standard specimen is diluted by the tritium standard substance bought to be got.Mainly by tritium mark
Quasi- material concentration uncertainty u221, tritium standard substance weigh uncertainty u222、
Tritium standard substance dilutes uncertainty u223It constitutes.
u221、u222、u223Calculation formula enumerate respectively it is as follows:
In formula: U221For the expanded uncertainty provided in tritium standard substance certificate, k takes 2.
In formula: MPEBIndicate the electronic balance limits of error, mg;
M expression weighs tritium standard substance quality, mg;
K takesAccording to being uniformly distributed.
In formula: MPEBIndicate the electronic balance limits of error, mg;
M expression is weighed for diluted tritium-free water quality, mg;
K takesAccording to being uniformly distributed.
Third is that tritium standard liquid weighs the uncertainty u of generation23:
In formula: MPEBIndicate the electronic balance limits of error, mg;
M indicates to weigh the quality of tritium standard liquid, mg;
K takesAccording to being uniformly distributed.
(3) liquid-transfering gun pipettes the uncertainty u of analysis sample3:
In formula: MPEPIndicate the limits of error of 10ml liquid-transfering gun, ml;
V indicates to pipette the volume of sample, ml;
K takesAccording to being uniformly distributed;
It represents 10ml liquid-transfering gun point 5 times and pipettes the synthesis that total 50ml sample causes uncertainty.
E. the evaluation of Composite Seismogram
F. the calculating of expanded uncertainty
U=kuc (16)
K generally takes 2 in formula.
5.3.3 Appreciation gist
According to relevant criterion requirement, this paper selection ratio value En is evaluated experimental result is compared.En value indicates normalizing
The error of change, calculation formula are as follows:
In formula: the tritium concentration that tritium analysis method measurement obtains in water of the LAB expression based on RO film sample preparation is as a result, Bq/L;
REF indicates the tritium concentration of air-distillation method measurement as a result, Bq/L;
ULABIndicate that (confidence level is for the uncertainty of tritium analysis method measurement result in the water based on RO film sample preparation
95%), Bq/L;
UREFIndicate the uncertainty (confidence level 95%) of air-distillation method measurement result, Bq/L.
When the absolute value of En value is not more than 1, i.e., | En | it is satisfied that≤1 Shi Ze represents comparison result, and experiment measured result is can
Within the scope of receiving.And | En | value is smaller, indicates that comparison result is closer, effect is better.
5.4, experimental result and analysis
5.4.1 environmental water sample comparison result and analysis
By the environmental water sample control experiment raw measurement data of table 15, table 16 and table 17, the data described according to 5.3 trifles
Processing method after collated, calculating, show that the comparison result of environmental water sample is listed in table 20, table 21 and table 22.
Table 20
Table 21
Table 22
Above-mentioned comparison result is shown: 1. from the point of view of measurement result, in addition to except Ninghe north, water head site is not detected, and remaining all the points
The environmental water sample of position, the tritium concentration range obtained through the analysis of air-distillation sample preparation method is 0.55~2.27Bq/L, through RO UF membrane
The tritium concentration range that sample preparation method analysis obtains is 0.69~2.11Bq/L, is in tritium concentration in current China's natural environmental water
Within normal range (NR), analysis result is reliable;2. for comparison result, the range of uncertainty of atmospheric distillation measurement is
The range of uncertainty of 10.93%~39.53%, RO UF membrane sample preparation method measurement is 11.59%~31.65%, the two difference
Less.Two methods are 2.61%~25.45% to the relative deviation absolute value range of tritium comparison result in ambient water, are all existed
Within 30%, the absolute value range of rate value En is 0.06~0.79, | En | < 1, comparison measurement results can receive.
In addition, two kinds of analysis methods show that tritium concentration is lower than detection limit in the water head site water of Ninghe north in table 21, through looking into
It learns that Ninghe north water source belongs to and buries type groundwater source, tritium concentration is low in water, therefore fails to detect.In table 22, rainwater 1 and rain
Two rainwater samples that water 2 is acquired from the different times of same point, but two kinds of analysis methods are all shown in rainwater 1 and rainwater 2
Tritium concentration difference is larger.Through analyzing, this may be as caused by the collection process difference of two rainwater samples.Wherein, rainwater 1
From in the rainfall of multiple small rainfall, the sample collection time is long, the degree that the rainwater sample of collection is exchanged with ambient enviroment generation tritium compared with
Greatly.And rainwater 2 increases rainwater-collecting equipment from heavy rain, and in advance, therefore the sample collection time is short, the rain of collection
The degree that water is exchanged with ambient enviroment generation tritium is small.
5.4.2, tritium mark-on sample comparison result and analysis
By the mark-on sample control experiment raw measurement data of table 19, after collated, calculating, various concentration mark-on sample is obtained
Comparison result is listed in table 23.It should be pointed out that it is bigger with addition of standard specimen volume because of institute, tap water is weighed in configuration process
Sample uses simple electronic scale, and the scale precision is inadequate and uncertified.Therefore with addition of standard specimen concentration it is for reference only
Value rather than standard value.
Table 23
By table 23 as it can be seen that same mark-on sample, the tritium concentration result that is obtained respectively with atmospheric distillation and RO membrane separation process
It is not much different, the absolute value of rate value En is respectively less than 1, and comparison result is satisfied.It is relatively inclined between measurement result and reference value
From the point of view of difference, the latter's relative deviation is smaller, closer to reference value.
To sum up, visible by the above control experiment: 1. for environmental water sample, two methods analysis result be in it is current I
In state's natural environmental water within the normal range (NR) of tritium concentration, the two result relative deviation absolute value range be 2.61%~
25.45%, all within 30%, the absolute value range of rate value En is 0.06~0.79, and less than 1, comparison measurement results can be with
Receive;2. the absolute value of rate value En is respectively less than 1, and comparison result is satisfied, wherein the analysis method of RO film sample preparation for mark-on sample
Acquired results are closer with reference value.
Accordingly, it demonstrates tritium automatic analysis method in the water based on RO film sample preparation of this research and analyzes tritium acquired results in water
It is accurate, reliable.
Further, in summary, 1) system of tritium automatic analysis method in the water based on RO film sample preparation is constituted and is carried out
It introduces.Wherein introduce the working principle of RO UF membrane sample preparation device, device is constituted and the device is for tritium in water
The sample preparation workflow of analysis.In addition, having carried out brief Jie to relevant issues such as principle, the workflows of liquid flashing counting measurement
It continues.
2) comprehensive performance of RO UF membrane sample preparation device is had studied.Using the RO film sample preparation device to varying environment water sample
Treatment effect has carried out research, and the preliminary identification device is lower than 1.00NTU to turbidity, and conductivity is in 900 μ s/cm environment below
Water sample has good treatment effect;The research for having carried out device processing water sample process consumption sample and time-consuming situation, as the result is shown should
Device normally prepares sample average consumption water sample 13L or so, average about 40 minutes time-consuming, consumes compared with atmospheric distillation
Sample size greatly increases, but the required time has and significantly shortens;Carry out the research of service using life situation, research shows that
The number that the device normally can effectively deal with water sample should be at 70 times or more, and specifically used life situations and device handle water sample
Water quality is related, and water quality is better, and the service life of device is longer;The tritium residue problem of RO film in device is studied, as a result
When showing the normal processing environment water sample of the device, analysis result is impacted without considering that the tritium of RO film remains, but when processing
After complete has the water sample of higher tritium concentration (10Bq/L or more), the tritium residue problem of RO film need to arouse attention.
3) optimization of liquid flashing counting measurement method and condition is studied.100ml capacity counting vial is selected, it is corresponding to visit
Lower limit is surveyed to be greatly reduced to 0.4Bq/L or so, can effectively solve at present because detection limit be too high to tritium in ambient water into
The problem of row is effectively analyzed.Under 100ml capacity counting vial measurement pattern, water sample uses the volume proportion of 50:50 with scintillation solution
It is than convenient.Experimentation discovery, whether no matter standing, there are larger waves for first measurement data of each sample
It is dynamic, statistics should not be included in and calculated, in addition, result of study is not necessarily to too long of standing for showing standard sample higher for tritium concentration
It is protected from light the time.For this purpose, can sequentially be placed in liquid by standard sample, to test sample and this original pattern dodges spectrometer, standard sample measures 60 minutes/time,
Remaining sample measures 100 minutes/time, and each sample duplicate measurements 11 times is protected from light without specially standing, can measure immediately.
4) the method for developing compares, to verify this research method tritium precision of analysis.Air-distillation and RO are used respectively
Two kinds of method for making sample of UF membrane carry out sample preparation to the tritium mark-on sample of various environmental water samples and various concentration, are then studied with this
Determining liquid dodges measurement method method and measures comparison to the above sample.The results show that for environmental water sample, two methods ratio
Relative deviation absolute value range to result is 2.61%~25.45%, and the absolute value range of rate value En is 0.06~0.79,
|En|<1;For tritium mark-on sample, two methods analyze the rate value of result | En | < 1, and the analysis method gained of wherein RO film sample preparation
As a result closer with reference value.It demonstrates tritium automatic analysis method in the water based on RO film sample preparation of this research and analyzes tritium institute in water
It obtains the result is that accurate, reliable.
The fast automatic analysis method of tritium, utilizes reverse osmosis membrane separation technology pair in the water proposed according to embodiments of the present invention
Water sample to be measured carry out quick separating-purifying with reach meet liquid dodge measurement condition requirement, effectively shorten pre-treatment when
Between, analysis efficiency is improved, and the liquid that reselection is suitable for dodges measurement method to sample progress count measurement, so as to effectively drop
Low detection limit effectively improves the applicability of analysis with the analysis of the tritium suitable for a variety of ambient waters, realizes the automation point of tritium
Analysis, it is simple easily to realize.
The fast automatic analytical equipment of tritium in the water proposed according to embodiments of the present invention referring next to attached drawing description.
Figure 41 is the structural schematic diagram of the fast automatic analytical equipment of tritium in the water of one embodiment of the invention.
As shown in figure 41, in the water the fast automatic analytical equipment 10 of tritium include: back purge system 100 and automatic liquid matching with
Convey measuring system 200.
Wherein, back purge system 100 obtains back segment by reverse osmosis membrane purification and filters out for obtaining water sample to be measured
Liquid;Automatic liquid matching and conveying measuring system 200 be used for injected respectively into counting vial the first preset volume back segment filter liquor and
The scintillation solution of second preset volume, and counting vial fullys shake and makes being uniformly mixed for back segment filter liquor and scintillation solution, to obtain
Sample to be tested, and spectrometer is dodged by liquid, count measurement is carried out to sample to be tested, to obtain the analysis result of tritium in water sample to be measured.This
The device 10 of inventive embodiments can effectively shorten the time of analysis, improve the efficiency of analysis, and detection can be effectively reduced
Lower limit effectively improves the applicability of analysis, realizes the automated analysis of tritium, simple easily to realize.
It should be noted that back purge system 100 can be RO UF membrane sample preparation device, RO UF membrane sample preparation device is in side
Method part has been discussed in detail, and to avoid redundancy, this will not be repeated here.
Further, in one embodiment of the invention, the device 10 of the embodiment of the present invention further include: sample bottle is automatic
Control system.Wherein, sample bottle automatic control system is used in the back segment filter for injecting the first preset volume into counting vial respectively
Out after liquid and the scintillation solution of the second preset volume, the bottle cap of counting vial is screwed automatically, and after counting vial fullys shake and makes
Section filter liquor and scintillation solution it is uniformly mixed after, wiping processing is carried out to counting vial automatically.
Further, in one embodiment of the invention, the volume of counting vial is 100ml, the first preset volume and the
Two preset volumes are 50ml.
Further, in one embodiment of the invention, back purge system 100 includes: water sample wash module, primary mistake
Filter module, sample preparation module and drain module.
Wherein, water sample wash module, for being rinsed using water sample to be measured;Filtering module, for passing through reverse osmosis
Permeable membrane separating and filtering water sample to be measured, to obtain spare water sample, and excludes waste water;Sample preparation module, for passing through the reverse osmosis membrane
The spare water sample is filtered again, proposes to obtain back segment filter liquor with purification;Drain module, for emptying remaining water to be measured
Sample.
Further, in one embodiment of the invention, the device 10 of the embodiment of the present invention further include: detection module,
Judgment module and processing module.
Wherein, detection module, for detecting the conductivity value of back segment filter liquor;Judgment module, for judging conductivity value
Whether default conductivity value is less than;Processing module, for being injected into counting vial when conductivity value is less than default conductivity value
The back segment filter liquor of first preset volume, and when conductivity value is more than or equal to default conductivity value, pass through reverse osmosis membrane
Purification back segment filter liquor again, until conductivity value is less than default conductivity value.
It should be noted that the aforementioned explanation to the fast automatic analysis method embodiment of tritium in water is also applied for this
The fast automatic analytical equipment of tritium in the water of embodiment, details are not described herein again.
The fast automatic analytical equipment of tritium, utilizes reverse osmosis membrane separation technology pair in the water proposed according to embodiments of the present invention
Water sample to be measured carries out quick separating-purifying to reach the condition requirement for meeting liquid and dodging measurement, effectively shortens separating-purifying
Time improves the efficiency of analysis so as to effectively shorten time of analysis, and the suitable liquid of reselection dodges measurement method pair
Sample carries out count measurement and, with the analysis of the tritium suitable for a variety of ambient waters, effectively mentions so as to which detection limit is effectively reduced
The applicability of high analyte realizes the automated analysis of tritium, simple easily to realize.
In addition, term " first ", " second " are used for descriptive purposes only and cannot be understood as indicating or suggesting relative importance
Or implicitly indicate the quantity of indicated technical characteristic.Define " first " as a result, the feature of " second " can be expressed or
Implicitly include at least one this feature.In the description of the present invention, the meaning of " plurality " is at least two, such as two, three
It is a etc., unless otherwise specifically defined.
In the present invention unless specifically defined or limited otherwise, fisrt feature in the second feature " on " or " down " can be with
It is that the first and second features directly contact or the first and second features pass through intermediary mediate contact.Moreover, fisrt feature exists
Second feature " on ", " top " and " above " but fisrt feature be directly above or diagonally above the second feature, or be merely representative of
First feature horizontal height is higher than second feature.Fisrt feature can be under the second feature " below ", " below " and " below "
One feature is directly under or diagonally below the second feature, or is merely representative of first feature horizontal height less than second feature.
In the description of this specification, reference term " one embodiment ", " some embodiments ", " example ", " specifically show
The description of example " or " some examples " etc. means specific features, structure, material or spy described in conjunction with this embodiment or example
Point is included at least one embodiment or example of the invention.In the present specification, schematic expression of the above terms are not
It must be directed to identical embodiment or example.Moreover, particular features, structures, materials, or characteristics described can be in office
It can be combined in any suitable manner in one or more embodiment or examples.In addition, without conflicting with each other, the skill of this field
Art personnel can tie the feature of different embodiments or examples described in this specification and different embodiments or examples
It closes and combines.
Although the embodiments of the present invention has been shown and described above, it is to be understood that above-described embodiment is example
Property, it is not considered as limiting the invention, those skilled in the art within the scope of the invention can be to above-mentioned
Embodiment is changed, modifies, replacement and variant.