CN103594327B - Ionic migration spectrometer and the method improving its detection sensitivity - Google Patents
Ionic migration spectrometer and the method improving its detection sensitivity Download PDFInfo
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Abstract
The method improving ionic migration spectrometer detection sensitivity, including: sample is inserted the sampling device of ionic migration spectrometer; Spectral line acquisition operations is triggered by optocoupler induction apparatus; During quantity of information needed for the spectral line number collected reaches to be available for the explosive that accurately detection vapour pressure is higher, it is open in ionization reaction zone instantaneous addition adulterant by what control electromagnetic valve; When the spectral line number collected reaches to be available for the quantity of information needed for the explosive that accurately detection vapour pressure is relatively low, stop acquisition operations, simultaneously close off electromagnetic valve and stop adding adulterant in ionization reaction zone; It is analyzed obtaining testing result to the whole spectral lines gathered. By the addition opportunity of controlled doping agent, adulterant is played effectiveness in the detection of the relatively low explosive of some vapour pressure, make again the explosive when being not added with adulterant with relatively high detection sensitivity can analyze when dopant content is very low, take into account the instrument Detection results to different explosives, thus providing optimum efficiency.
Description
The application is the applying date, and to be on July 31st, 2009, application number be 200910089161.1 and the divisional application of application for a patent for invention that denomination of invention is " ionic migration spectrometer and the method improving its detection sensitivity ".
Technical field
The present invention relates to the detection equipment of a kind of explosive and detection method, particularly relate to a kind of ionic migration spectrometer detecting explosive and by addition opportunity of controlled doping agent to improve this ionic migration spectrometer method to explosive detection sensitivity.
Background technology
The instrument ionic migration spectrometer carrying out detecting based on Ion mobility spectrometry is the Site Detection instrument of a kind of quick, sensitive, portable operation. This instrument can detect trace contraband, such as the existence of explosive, drugs, chemical warfare agent etc., is widely applied with the field such as military in safety check at present.
The core component of ionic migration spectrometer is transference tube, and its carrier gas generally adopted is ambient air and atmospheric air. Through different input modes, the measured matter molecule collected can be made in a gaseous form along with air enters transference tube, ionization district at transference tube, first air molecule is ionized and forms reactant ion group, test substance molecule interacts with reactant ion group and forms new molecular ion group, i.e. sample products molecular ion group. When ion gate is opened, these molecular ions group enters migration area under the effect of electric field and continues to migrate under the effect of electric field to advance. In migration area, migration velocity and its quality of molecular ion group, the factors such as electrically charged number, space structure relevant, therefore the time that different molecular ion groups arrives the detector being positioned at migration area end is different, the ion time of advent of produced weak current and correspondence thereof on detector is struck by detecting ion cluster, and it is mated with standard substance storehouse, it is possible to judge the kind of material.
The ionization of the testing sample gas molecule carried out in the ionization district of transference tube is secondary ionization process: the concentration ratio of carrier gas and sample vapor causes that carrier gas molecules is more easy to as the ionization of ion source institute compared with sample vapor molecule, therefore first air molecule is carried out by ionization process, reaction of formation thing ion.Owing to the free path of ionization carrier gas molecules is far smaller than the physical dimension of reative cell, the carrier gas molecules of ionization and sample vapor are intermolecular by frequent impact, so that the carrier gas molecules that ionic charge is from ionization is transferred to sample molecule. Transfer reaction between this electric charge is determined by the proton of molecule or electron affinity participating in reaction, electric charge can from the little molecular transfer of proton or electron affinity to the big molecule of affinity above. Ionic migration spectrometer actually used in, change molecular composition and the ionization mechanism of reactant usually by the mode adding adulterant, thus changing the chemical composition of the product ion of generation, to improve detection sensitivity and the selectivity of instrument. Doping reagent molecule must possess lower than sample molecule (such as explosive) but higher than in carrier gas the electron affinity of other component contained, therefore preferentially ionization stable ion can be generated, to avoid the chaff interference in carrier gas with relatively low-affinity to participate in ionization reaction, simultaneously because the electron affinity of sample molecule is more than reagent molecule, these ions generate, with sample vapor molecular reaction, the sample molecule ion being available for detection then again. The spectrogram peak position that the addition of adulterant also can make the product ion of generation corresponding is moved, make that original impalpable quasi-molecular ions is separated owing to peak position overlaps when not adding doping reagent, thus realizing under chaff interference existence the identification to component to be measured.
Existing multiple Patents at present, the kind being respectively described adulterant in ionic migration spectrometer or other similar analytical tool selects and feed postition. The patent such as EP0135747 of early stage, describes in the detection of drugs and explosive sample, adds in carrier gas using acetone and carbon tetrachloride as adulterant respectively before sample injects, the dimer ion of generation or hydration Cl-Ion, can stop the indefinite composition Cluster Phenomenon of water so that it is the relatively-stationary narrow peak of forming position on ion spectrogram, can be used as the reference point of ECU algorithm, makes instrument have detection more preferably and identification specificity.
Relevant patent documentation such as WO2006123107, EP0509171, US5283199, US5234838, US5032721, DE19609582, DE10212110, WO2007085898 etc. describe the different types of adulterant that can be used for ion migration analysis of spectrum, it is adaptable to various detection demands. As utilized the adulterant containing two pentanones to improve, the such as mammal of Cucumber in gaseous sample is breathed out the identification ability of nitrogen-containing compound in gas; By controllable temperature osmos tube, a small amount of sulfur dioxide adulterant is added testing sample, the interference effect of the more weak acid gas components of electron affinity such as fluohydric acid gas sulfur dioxide mefenamic acid can be eliminated, improve the selectivity of instrument; Same by a small amount of substituted phenol (such as methyl salicylate, 2-hydroxy acetophenone) and amine (such as methylamine) as adulterant, the interference effect of chlorine can be eliminated; Utilize and add the cluster ions that adulterant dimethyl methyl phosphonate (DMMP) substantially can change with component ammonia to be measured generation migration time generation, it is thus possible to identify from the spectrogram of mixing gas easily; Add aromatic compound (benzene in the sample, toluene, dimethylbenzene) as adulterant, there is the energy equal to or less than VUV ray light quantum and be higher than the ionization potential of sample molecule, within the scope of VUV radioactivity ionization, can be used for detecting trace materials in air, it could even be possible to the material only with weak proton affinity detected, and the detection sensitivity of electronegativity material can be improved; By introducing ammonia in analyzing gas, make reactant ion peak and formaldehyde peak be separated, then PARA FORMALDEHYDE PRILLS(91,95) carries out quantitative analysis; Utilize amide-type ionization adulterant detection peroxide explosive etc.
On the feed postition of adulterant, the patent related to such as PCT Patent WO2006129101 and WO2004102611, the former described instrument adopts at least two storage tank to provide multiple different adulterant, storage tank is connected with the ionization room of spectrometer, add entrance to be located at permselectivity membrane and face the side of injection port, making sample gas namely contact with adulterant before ionization, migration tube internal recycle gas circuit is isolated with doping gas circuit;The system that the latter describes includes the molecular sieve adding adulterant, the first adulterant can be continuously added to, system also includes the other storage tank equipped with different dopant, arranges, by switching, other the different adulterant selectively added in air except the first adulterant. Additionally, the device that US Patent No. 6495824 relates to includes multiple storage tank equipped with multiple doping reagent, the change according to detection signal, the reagent that difference adulterated is introduced selectively in carrier gas stream, and example reaction generates and has adding and product of different mobility. An information bank can be set up, comprise the known response information of determinand and different dopant, by being compared with the data in information bank by the observed result of relatively multiple for sample doping reagent particular combination, namely can determine that in sample whether really contain test substance. Patent WO2007082941 injects determinand by the normal pressure ionization interface of instrument entrance, is added in atomizing gas by additive simultaneously. Doping source of the gas and dry cleansing device are then combined by US2002088936. In US5491337 hermetic container before being placed in instrument sample air intake, the adulterant of low concentration is mixed mutually with carrier gas, and sample gas is introduced into ionization room. EP1672363 mixes mutually with impurity gas before sample gas enters instrument, or is added by impurity gas in migration gas, eliminates interference problem during noble gas test sample a large amount of with ionic migration spectrometer analysis.
In these prior aries, the adulterant for explosive detection mostly is halogenated hydrocarbon, such as chloralkane. Container for containing adulterant need to have the flow rate control device such as temperature and semipermeable membrane, to produce the sample introduction gas with constant flow rate containing specific dopant content. Device can comprise the container of two or more splendid attire variety classes adulterant, arranged by electromagnetic valve etc. and control selectively adding of inhomogeneity adulterant, the ability of determinand is correctly identified improving instrument when chaff interference exists, or the detection demand for different determinands.
The practical operations such as safety check find, detection sensitivity and the selectivity of some important explosives such as hexogen RDX, too peace PETN etc. are had good improvement result by adulterant, but the detection performance of all explosives is not had improvement result by adding of adulterant, to some explosive, such as DNT, black powder etc., under no dopant existent condition, higher detection sensitivity can be realized, the addition of adulterant such as chlorohydrocarbon molecule, sensitivity can be made on the contrary to be substantially reduced. Therefore, if according to the method providing the dopant dose with constant density by temperature control and osmos tube generally adopted, it is difficult to realize the optimum detection performance index to above-mentioned different explosives simultaneously, and the preparation of temperature control and permeability apparatus and replacing, add complexity and the cost of instrument.
Summary of the invention
Shortcoming for above-mentioned prior art, the present invention provides a kind of ionic migration spectrometer detecting explosive and by the addition opportunity of controlled doping agent, with the method realizing, at this ionic migration spectrometer of front and back that adulterant adds, different explosives is respectively provided with high detection sensitivity.
Ionic migration spectrometer of the present invention, specifically includes that sampling device, migration tube, air-channel system and circuit control system. Described migration tube is divided into ionization reaction zone and gas migration area by ion gate, and described air-channel system includes: dry gas circuit, migration gas circuit, doping gas circuit and unloaded gas circuit, wherein,
Described dry gas circuit is for respectively to the air migrating gas circuit, gas circuit of adulterating, unloaded gas circuit provide dry decontamination to cross;
The air that described migration gas circuit is crossed for importing above-mentioned dry decontamination from instrument rear end to gas transfer district is as migrating air-flow;
Described doping gas circuit is used for providing appropriate adulterant steam, and dries, according to external control instruction connection, the air that the dry decontamination of gas circuit is crossed, and adulterant steam is imported ionization reaction zone;
Described unloaded gas circuit for importing the air that above-mentioned dry decontamination is crossed to ionization reaction zone.
In ionic migration spectrometer of the present invention, described dry gas circuit includes the air pump from external world's extraction air and the device for drying and filtering for this outside air of dry decontamination.
In ionic migration spectrometer of the present invention, described doping gas circuit includes the inlet solenoid valve being connected with dry gas circuit and the outlet solenoid valve being connected with ionization reaction zone, the container containing adulterant it is provided with between described inlet solenoid valve and outlet solenoid valve, described inlet solenoid valve is a two-position three-way valve, selects make dry gas circuit be connected with doping gas circuit or make dry gas circuit be connected with unloaded gas circuit according to external control instruction;
When the content of external control instruction is for opening, described outlet solenoid valve is opened, and inlet solenoid valve connection dries gas circuit and doping gas circuit;
When the content of external control instruction is for closing, described outlet solenoid valve is closed, and inlet solenoid valve connection dries gas circuit and unloaded gas circuit.
The present invention also provides for a kind of method improving ionic migration spectrometer detection sensitivity, comprises the steps:
Step one, inserts the sampling device of ionic migration spectrometer by testing sample;
Step 2, the spectral line acquisition operations of ionic migration spectrometer is triggered, the real time information of the weak current of the sign ionic strength that spectral line that this collects display ionic bombardment produces to detector and ion time of advent by being arranged on the optocoupler induction apparatus at sampling device place;
Step 3, when the spectral line number collected reaches to provide the quantity of information needed for the explosive that accurately detection vapour pressure is higher, by controlling opening state instantaneous addition adulterant in ionization reaction zone of electromagnetic valve;
Step 4, when the spectral line number collected reaches to provide the quantity of information needed for the explosive that accurately detection vapour pressure is relatively low, stops acquisition operations, stops adding adulterant in ionization reaction zone by the opening state of control electromagnetic valve simultaneously;
The above-mentioned whole spectral lines collected are carried out Algorithm Analysis, obtain testing result by step 5.
In the step 2 of the method for raising ionic migration spectrometer detection sensitivity of the present invention, the insertion time of described optocoupler induction apparatus perception sample, and immediately trigger the spectral line acquisition operations of ionic migration spectrometer.
In the step 2 of the method for raising ionic migration spectrometer detection sensitivity of the present invention, described spectral line information is the scanning meansigma methods of the real time data representing the weak current that detects of detector and ion time of advent.
In the step 2 of the method for raising ionic migration spectrometer detection sensitivity of the present invention, described low current signal is to be detected by the detector being positioned at migration tube end, the current inductor that the molecular ion group that this low current signal is formed by measured matter molecule clashes on detector under electric field action after migration tube separates produces, and the intensity that molecular ion is rolled into a ball can be characterized, described electric field is formed by ring electrode sheet.
In the step 3 of the method for raising ionic migration spectrometer detection sensitivity of the present invention, described adulterant is the solid dopants that volatile quantity is little.In the present invention, the preferred version of described adulterant is hexachlorethane.
In the step 3 of the method for raising ionic migration spectrometer detection sensitivity of the present invention, the gas circuit adding adulterant includes the polytetrafluoro container of accommodating adulterant, and these container two ends are provided with electromagnetic valve.
In the method for raising ionic migration spectrometer detection sensitivity of the present invention, also include migrating gas circuit, the gas circuit of this migration gas circuit and described addition adulterant is arranged in parallel, when the content of the external control instruction received is for closing, the dry gas circuit of electromagnetic valve connection and the unloaded gas circuit that the polytetrafluoro container two ends of accommodating adulterant are arranged, making the air part after drying gas circuit dry decontamination be used as the migration gas added from migration tube tail end, part is directly entered the ionization reaction zone of migration tube; When the content of the external control instruction received is for opening, the dry gas circuit of electromagnetic valve connection and the doping gas circuit that the polytetrafluoro container two ends of accommodating adulterant are arranged, make the air after part drying gas circuit dry decontamination by gas circuit of adulterating, carry adulterant and enter the ionization reaction zone of migration tube.
In the method for raising ionic migration spectrometer detection sensitivity of the present invention, analyze the spectral line number gathered needed for opening before the electromagnetic valve that controlled doping agent adds for pre-setting every time.
In the step 5 of the method for raising ionic migration spectrometer detection sensitivity of the present invention, the ion intensity of flow peak value shown by spectral line and corresponding ion thereof are mated with standard substance storehouse the time of advent, to determine measured matter kind.
The present invention only uses a kind of adulterant, by the addition opportunity of controlled doping agent, the difference of the gasification rate according to different explosives and the adulterant impact on its actually detected performance, ensure that the explosive that those detection sensitivities when being not added with adulterant are higher can be analyzed when dopant content is relatively low, simultaneously, those explosives that detection sensitivity is higher when adding adulterant are enable to obtain detection signal when dopant dose is heightened, thus take into account actually detected in sensitivity requirement to different explosives, and the selectivity of instrument can be improved, reduce rate of false alarm.
Accompanying drawing explanation
Fig. 1 is the structural representation of the ionic migration spectrometer of the described method application of the present invention;
Fig. 2 is the flow chart of the method for raising ionic migration spectrometer detection sensitivity of the present invention;
Fig. 3 is in embodiments of the invention, the Spectral Overlapping schematic diagram automatically gathered after 10ngDNT sample introduction when being added without adulterant;
Fig. 4 is in embodiments of the invention, the Spectral Overlapping schematic diagram automatically gathered after 50ngRDX sample introduction when being added without adulterant;
Fig. 5 A, 5B are in embodiments of the invention, add 50ngRDX testing result contrast before and after doping: wherein under similarity condition, and Fig. 5 A is for adding the front spectrogram of doping, and Fig. 5 B is for adding spectrogram after doping;
Fig. 6 A, 6B are in embodiments of the invention, add 10ngDNT testing result contrast before and after doping: wherein under similarity condition, and Fig. 6 A is for adding the front spectrogram of doping, and Fig. 6 A is for adding spectrogram after doping;
Fig. 7 A, 7B are in embodiments of the invention, explosive (50ngRDX) is detected the improvement result schematic diagram of performance opportunity by the addition of controlled doping agent: wherein, 10 Spectral Overlapping schematic diagrams after sample introduction when Fig. 7 A is be not added with adulterant, Fig. 7 B be by the instantaneous unlatching doping valve sample introduction of Article 3 spectral line after chart adding schematic diagram.
Fig. 8 A, 8B are in embodiments of the invention, explosive (10ngDNT and 50ngRDX) is detected the improvement result schematic diagram of performance opportunity by the addition of controlled doping agent: wherein, 10 Spectral Overlapping schematic diagrams after 10ngDNT sample introduction when Fig. 8 A is be not added with adulterating, Fig. 8 B be by Article 3 spectral line instantaneous unlatching doping valve 10ngDNT and 50ngRDX biased sample sample introduction after chart adding schematic diagram.
Detailed description of the invention
In conjunction with accompanying drawing, illustrate in detail below to improve the ionic migration spectrometer method to explosive detection sensitivity, and realize the specific configuration of the equipment of this method.
The present invention is based on the recognition that, by the addition opportunity of controlled doping agent, improve the ionic migration spectrometer detection sensitivity to variety classes explosive. When adulterant being joined ionization region, electric charge being at war with property will distribute between dopant molecule and air molecule, preferentially ionization can generate stable ion, the sample molecule ion being available for detection is generated again with sample vapor molecular reaction, to avoid the chaff interference in carrier gas with relatively low-affinity to participate in ionization reaction, thus improving detection sensitivity and the selectivity of instrument.
All explosive detection effects are not all had improvement result by the addition of adulterant, and actually some explosive can have detection sensitivity more preferably when no dopant exists. Therefore, by the setting to the trigger timing adding adulterant, it is possible to control the joining day of adulterant in test process, this can realize the Detection results taking into account instrument to different explosives, thus providing best performance indications.
As shown in Figure 1, according in the raising ionic migration spectrometer method to explosive detection sensitivity of the present invention, the ionic migration spectrometer 1 applied includes sampling device 2, migration tube 3 and the air-channel system being made up of dry gas circuit 14, migration gas circuit 15, doping gas circuit 16.
Described migration tube 3 is the core component of ionic migration spectrometer, and it is separated into ionization reaction zone 4 and gas migration area 6 by ion gate 5. In gas transfer district 6, impose voltage by the ring electrode sheet 7 arranged and equally distributed electric field is provided, the measured matter molecule gathered then in a gaseous form by sampling device 2 along with air enter migration tube 3, ionization reaction zone 4 at migration tube 3, air molecule is ionized and is formed ion cluster, and explosive molecule interacts with these ion clusters and forms new molecular ion group. When ion gate 5 is opened, migrates under the effect of the electric field that these molecular ions group is formed at ring electrode sheet 7 and advance, and arrive the detector 8 of gas transfer district 6 end. Owing to the time of different molecular ion group arrival detectors 8 is different, therefore the time of advent of weak current and the correspondence thereof produced on detector can be struck by detection molecules ion cluster, and it is mated with standard substance storehouse, thus can determine that the kind of measured matter.
Now described air-channel system is further described through, so that the operation principle of present device is explained in greater detail. According to Fig. 1, the dry gas circuit shown in labelling 14 includes air pump 9 and device for drying and filtering 10. The air extracted from external environment by air pump 9, after device for drying and filtering 10 purge drying, it is partly into the migration gas circuit shown in labelling 15, it is used as to migrate air-flow and enters gas transfer district 6 from the rear end of instrument (migration tube 3), a part of then by with migrate gas circuit 15 other gas circuit in parallel and enter the ionization reaction zone 4 that instrument is anterior, this another gas circuit is formed in parallel with the unloaded gas circuit (in figure, unused labelling illustrates) being not provided with adulterant adding apparatus by the doping gas circuit 16 arranging adulterant adding apparatus.The addition operation of controlled doping agent can be realized by gas circuit 16 of adulterating is placed the on off state of the electromagnetic valve 11 and 13 that polytetrafluoro container 12 two ends of adulterant are arranged. Wherein, the inlet solenoid valve 11 of described doping gas circuit is such as two-position three-way valve, it is connected with the entrance of the outlet of the dry gas circuit 14 comprising device for drying and filtering 10 and unloaded gas circuit respectively, it connects dry gas circuit 14 and doping gas circuit 15 when the first state, and it connects dry gas circuit 14 and unloaded gas circuit when the second state. The outlet solenoid valve 13 of described doping gas circuit is connected with the gas access of ionization reaction zone 4.
When the external control instruction that electromagnetic valve 11 and 13 receives is the first state, the two ends electromagnetic valve 11 of the shown polytetrafluoro container 12 that placed adulterant makes dry gas circuit 14 connect with unloaded gas circuit with 13 status, thus the air part after drying gas circuit dry decontamination is used as the migration gas added from migration tube 3 tail end, remaining part directly enters the ionization reaction zone 4 of migration tube through unloaded gas circuit simultaneously. When the content of the external control instruction that electromagnetic valve 11,13 receives is the second state, electromagnetic valve 11 makes dry gas circuit 14 connect with doping gas circuit 16 with 13 status, so that the air after part drying gas circuit dry decontamination is by gas circuit 16 of adulterating, carries adulterant simultaneously and enter the ionization reaction zone 4 of migration tube 3.
Described doping gas circuit 16 can provide appropriate adulterant steam. According to external control instruction, the dry gas circuit 14 of its connection, the air that drying is cleaned, adulterant steam is imported to ionization reaction zone 4. In the present invention, for instance using hexachlorethane (solid) as a kind of exemplary adulterant. In embodiments of the invention, take in the polytetrafluoro container 12 that a small amount of hexachlorethane loads cleaning, container two end cap arranges pore, again this container is placed in stainless steel storage tank, its two ends are connected with pipeline, and by electromagnetic valve 11,13, define shown doping gas circuit 16.
Described is single pipeline with the doping unloaded gas circuit that is arranged in parallel of gas circuit 16, any extra device is not set especially, its one end is connected with dry gas circuit 14 outlet comprising device for drying and filtering 10 by inlet solenoid valve 11, and the other end is connected with the gas access of ionization reaction zone 4.
As described above, the Income Air Status of the gas access of ionization reaction zone 4 includes two kinds of situations: one is, outlet solenoid valve 13 in doping gas circuit 16 is closed, when inlet solenoid valve 11 has connected dry gas circuit 14 and unloaded gas circuit, the gas of entrance be purified after dry air; Another kind is, the outlet solenoid valve 13 in gas circuit 16 of adulterating opens simultaneously inlet solenoid valve 11 when having connected when dry gas circuit 14 and doping gas circuit 16, and adulterant steam air after drying purifies carries lower entrance ionization reaction zone 4.
On the basis being described above, for technicians it can be readily appreciated that the ionic migration spectrometer according to the present invention also includes control circuit, it can be used for realizing the control to electromagnetic valve 11 and 13, although being not shown. It addition, also control circuit also controls the real-time information collection operation of detector. And also include analytical equipment, contrast for data analysis with according to the standard substance storehouse prestored. This control circuit and analytical equipment can separate, and can carry out signal communicating, can also integrate alternatively between now. And it is possible to realized by hardware, or can be realized under the operation of programming software by general processor, and can be realized by combination of hardware software.
Illustrate further referring to Fig. 2 and in conjunction with Fig. 1 to improve the ionic migration spectrometer method to explosive detection sensitivity.Specifically, the method comprises the following steps that
Step 101, the object that testing sample such as contains explosive is inserted into the sampling device 2 of ionic migration spectrometer 1.
In this step, measured matter imports migration tube with gaseous molecular form after the sampling device of ionic migration spectrometer passes through gasification (volatilization).
Step 102, by being arranged on the optocoupler induction apparatus at sampling device place, trigger the spectral line acquisition operations of ionic migration spectrometer, the spectral line collected can show real time information, and this information represents the time that the produced weak current characterizing ionic strength of ion striking on detector and this ion arrive.
In this step, air molecule is ionized formation reactant ion group in ionization reaction zone, and tested explosive molecule then interacts with these ion clusters and forms new product: molecular ion group.
When ion gate 5 is opened, these molecular ions group enters migration area under the effect of the electric field of ring electrode sheet 7 formation, and continues to migrate under the effect of electric field to advance, and eventually arrives at detector 8.
It should be noted that, due to the molecular ion group migration velocity in gas transfer district and its quality, the factors such as electrically charged number, space structure relevant, therefore, the time of different molecular ion group arrival detectors is different, that is, detector can detect the time dependent information that can survey peak shape that shows as, and represents the ion intensity of flow of the measured matter successively arrived at, and namely it obtain for the spectral line analyzed or spectrogram after data process.
Specifically, the spectrogram collection of detector and analysis process can the signal of optocoupler induction apparatus by arranging at sampling device start. Optocoupler induction apparatus, when sample is inserted into sampling device, produces electronic signal by the change of light path, thus immediately trigger the spectral line acquisition operations of ionic migration spectrometer when sample is inserted into sampling device. The spectral line collected is then weak current and the real time information of ion time of advent of the sign ionic strength showing to come self-detector. Generally, the actual spectral line information chosen indicates that the scanning meansigma methods of the real time data of weak current that detector detects and ion time of advent. Described low current signal is detected by the detector being positioned at migration tube end, this low current signal is that the current inductor that the molecular ion group formed by measured matter molecule clashes on detector under electric field action after migration tube separates produces, and can characterize the intensity of molecular ion group. Described electric field is formed by ring electrode sheet.
Step 103, when the spectral line number collected reaches to provide the quantity of information needed for the explosive that accurately detection vapour pressure is higher, by controlling opening state instantaneous addition adulterant in ionization reaction zone of electromagnetic valve.
Test substance needs the regular hour in the gasification of sampling device, and the gasification rate of variety classes explosive is different, so that enough quantity of information could be obtained when collecting the spectral line of some (such as 10) the existence of various explosive composition to be detected.
Component to be measured saturated vapour pressure such as some explosive such as DNT, black powder etc. is higher, fast at air inlet gasification rate, goes out peak speed also fast; And the saturated vapour pressures such as some explosive such as RDX, PETN are relatively low, slow at air inlet gasification rate, corresponding to go out peak speed also slow. As shown in Figures 3 and 4, demonstrate respectively when being added without adulterant, the spectral line group figure of continuous acquisition during the test higher explosive DNT of saturated vapour pressure and saturated vapour pressure relatively low explosive RDX, this can reflect that the explosive that vapour pressure is different goes out the difference of peak speed.Fig. 3 is 8 spectral lines collected after 10ngDNT sample introduction, and wherein, material property peak occurs at Article 2 spectral line, namely reaches peak-peak at Article 3 spectral line. Therefore, after instrument starts spectral line acquisition operations, quickly can reflect from the spectral line of real-time change component to be measured corresponding go out peak information, some spectral lines (such as first three) that namely instrument gathers at first can comprise enough analyze quantity of information, it was demonstrated that the presence or absence of this type of explosive. Fig. 4 is 10 spectral lines collected after 50ngRDX sample introduction, and wherein, material property peak occurs in Article 4 spectral line, just reaches peak-peak at Article 7 spectral line. Therefore, after instrument starts spectral line acquisition operations, by observing the spectral line of real-time change, it is necessary to certain time just can reflect component to be measured corresponding go out peak information, some spectral lines (such as 7 subsequently) that namely instrument collects below just comprise the information of presence or absence of this type of explosive of proof.
The sample characteristic peak collected in equal amount explosive sample test process is reached spectrogram during peak or spectral line by instrument before and after contrast addition adulterant under similarity condition, and observable goes out the adulterant impact on different explosive detection performances. According to actually detected result, although detection sensitivity and the selectivity of some important explosives such as hexogen RDX, too peace PETN etc. are had good improvement result by adulterant, but it is higher that some explosive deposits detection sensitivity in case in no dopant, such as DNT, black powder etc., the addition of adulterant such as chlorohydrocarbon molecule, can make the detection sensitivity of sample be substantially reduced on the contrary. As shown in Fig. 5 A, 5B and Fig. 6 A, 6B, demonstrating when being added without adulterant (Fig. 5 A, 6A) and adding adulterant (Fig. 5 B, 6B) respectively, the sample characteristic peak gathered during test explosive RDX and DNT reaches spectrogram contrast during peak. In Fig. 5 A, 5B, the test result of 50ngRDX shows, the detection sensitivity of sample and selectivity and sample characteristic peak height and peak shape are all improved significantly by adding of adulterant; And the test result of 10ngDNT shows in Fig. 6 A, 6B, the addition of adulterant makes sample detection sensitivity and sample characteristic peak height significantly reduce. Therefore, if adopting prior art, test process adds the adulterant of equivalent all the time, this Detection results that actually cannot realize different explosives all obtain the best.
Consider different explosive and go out the difference of peak speed, present inventors have realized that: deposit the higher explosive such as DNT of detection sensitivity in case in no dopant, the component to be measured such as black powder only needs former spectral lines can obtain the quantity of information enough analyzed, in order to detect whether determinand exists, and the explosive such as RDX that detection sensitivity is higher when adding adulterant, PETN etc., due to slow at sampling device gasification rate, until collecting some spectral lines below could obtain the maximum fault information of sample, presence or absence with this type of explosive of valid certificates. therefore, the addition opportunity of controlled doping agent can be passed through, realize the different explosive different requirements to dopant dose.
In the present invention, when initially such as startup spectral line acquisition operations under the promoting of photosensor signal, the outlet solenoid valve of doping gas circuit is in the state of closedown, and make dry gas circuit and unloaded gas circuit communicate by inlet solenoid valve, this can ensure explosive that those detection sensitivities when being not added with adulterant are higher can without adulterant or content very low time carry out spectrum analysis; And when the spectral line number collected reaches to provide accurate analysis DNT, black powder etc. containing the quantity of information needed for the explosive composition that vapour pressure is higher, after three spectral lines, namely the electromagnetic valve state of doping gas circuit is changed, the outlet solenoid valve of doping gas circuit is opened, and make dry gas circuit and doping gas circuit communicate by inlet solenoid valve, thus adulterant steam is imported ionization reaction zone.The explosive gasification rate higher due to the detection sensitivity when adding adulterant is slow, therefore, can obtain these detection signals when dopant dosage is heightened, take into account the sensitivity technique requirement to different explosives in actually detected process.
Then, in this step, when the spectral line number collected reaches to provide the quantity of information needed for the explosive composition that accurate analysis such as DNT, black powder etc. are higher containing vapour pressure, when being three such as spectral line number, can by the unlatching of control electromagnetic valve with addition adulterant instantaneous in ionization reaction zone. Concrete, changing the required spectral line number gathered before electromagnetic valve state controlled doping agent adds can be configured by the software system that instrument is built-in every time in advance, it is also possible to modify according to condition. As shown in fig.7b, when detecting 50ngRDX, add adulterant immediately when collecting vapour pressure higher explosive DNT and spectral line (i.e. Article 3 spectral line) corresponding to maximum characteristic peaks occurring. Can be seen that, due to hysteresis effect, at Article 6 spectral line, obvious adulterant characteristic peak occurs, and, contrasted by the spectral line with Fig. 7 A, can find that peak height and the peak shape of the characteristic peak adding the explosive RDX that vapour pressure is relatively low of adulterant all improve significantly, namely significantly improve detection sensitivity and the selectivity of sample. And, as shown in Figure 8 B, when detecting simultaneous 10ngDNT and 50ngRDX sample, same at the instantaneous addition adulterant of Article 3 spectral line, show with Fig. 8 A comparing result: affiliated adulterant, while the peak shape of RDX characteristic peak and peak height are had being obviously improved, does not have influence on the peak shape of characteristic peak of DNT and the peak height that go out peak at former spectral lines, it is seen that, by the addition opportunity of controlled doping agent, the ionic migration spectrometer sensitivity to different explosive detection can be taken into account.
Described adulterant is generally the solid dopants that volatile quantity is little. In the present invention, the preferred version of described adulterant is hexachlorethane solid. The gas circuit of described addition adulterant then includes the polytetrafluoro container of accommodating adulterant, and is provided with the electromagnetic valve of controllable operation state at these container two ends.
The present invention may also include migration gas circuit, the gas circuit of this migration gas circuit and described addition adulterant is arranged in parallel, the switch connected state of electromagnetic valve is controlled by external command, the air part after drying gas circuit dry decontamination is made to be used as the migration gas added from migration tube tail end, remainder is directly entered the ionization reaction zone of migration tube by unloaded gas circuit, or by gas circuit of adulterating, carry adulterant and enter the ionization reaction zone of migration tube.
Step 104, when the spectral line number collected reaches to provide the quantity of information needed for the explosive that accurately detection vapour pressure is relatively low, stops acquisition operations, stops adding adulterant in ionization reaction zone by the opening state of control electromagnetic valve simultaneously.
In this step, when the spectral line number gathered reaches quantity of information that accurate analysis can be provided to include needed for the various explosives relatively low containing vapour pressure, such as, when spectral line number is 10, namely acquisition operations it is automatically stopped, simultaneously close off doping gas circuit outlet solenoid valve and by the dry gas circuit of inlet solenoid valve connection and unloaded gas circuit, stop adding adulterant in ionization reaction zone. Spectral line number corresponding to above-mentioned stopping acquisition operations can be pre-set by instrument embedded software system.
The whole spectral lines collected are carried out Algorithm Analysis, obtain testing result by step 105.
In the present invention, the spectral line collected includes the real time information of ion time of advent of weak pulse electric current that detector detects and correspondence thereof, it is mated with standard substance storehouse, namely can determine that the kind of measured matter.
After completing one-time detection, need to close adulterant gas circuit, namely the outlet solenoid valve of adulterant gas circuit is closed and by the dry gas circuit of inlet solenoid valve connection and unloaded gas circuit, so, terminating spectral line, ionic migration spectrometer can gather in latter 20 seconds that to substantially return to doping very low or close to undoped state, ready for detecting next time.
In the detection SBR of above-mentioned judgement ionic migration spectrometer, can judge by arranging the ratio of dopant ion correspondence peak height peak height corresponding to carrier gas molecules ion and reactant ion. If instrument adopts gas sampling pattern, then need to wait for this ratio and drop to below certain numerical value and just can test, although so can extend analysis time, but relative to the benefit brought in the raising of sensitivity, or of great practical value. And in actual anti-explosion safety inspection operation, the solid sampling patterns that adopt, sampling process is also required to the regular hour, can reduce the impact waiting that dopant dose level was recovered analysis time more.
In the raising ionic migration spectrometer of the present invention method to explosive detection sensitivity, only use a kind of adulterant, joining day by controlled doping agent, the difference of the gasification rate according to different explosives and the adulterant impact on its actually detected performance, ensure that the explosive that those detection sensitivities when being not added with adulterant are higher can be analyzed when dopant content is relatively low, simultaneously, those explosives that detection sensitivity is higher when adding adulterant are enable to obtain detection signal when dopant dose is heightened, thus take into account actually detected in sensitivity requirement to different explosives, and the selectivity of instrument can be improved, reduce rate of false alarm.
It is emphasized that " include/comprise " as used in this specification is only for listing the existence of described parts, step or element in detail, but be not precluded from there is also or be attached with other one or more parts, entirety, step, element or their combination.
For one of ordinary skill in the art, various aspects of the invention described above, it is clear that can use the multi-form software in embodiment shown in the drawings, firmware and hardware and be carried out. The present invention is not caused restriction by actual software code and the concrete hardware that controls that the various piece for implementing to meet the principle of the invention adopts. Therefore, to the operation of the present invention part and the description of performance not with reference to concrete software code. It can be appreciated that any one of ordinary skill in the art, can describe, according to the present invention, the software designed for implementing various piece of the present invention and control hardware.
Claims (13)
1. improving a detection method for ionic migration spectrometer detection trace explosive performance, described method includes:
Step one, inserts the sampling device of ionic migration spectrometer by testing sample;
Step 2, triggers the spectral line acquisition operations of ionic migration spectrometer by being arranged on the induction apparatus at sampling device place, the real time information of the weak current of the sign ionic strength that spectral line that this collects display ionic bombardment produces to detector and ion time of advent;
Step 3, when the spectral line number collected reaches to provide the quantity of information needed for the explosive that accurately detection vapour pressure is higher, by controlling opening state instantaneous addition adulterant in ionization reaction zone of electromagnetic valve;
Step 4, when the spectral line number collected reaches to provide the quantity of information needed for the explosive that accurately detection vapour pressure is relatively low, stop acquisition operations, simultaneously by the switch of the described electromagnetic valve of control to stop adding adulterant in ionization reaction zone, and connecting dry gas circuit and unloaded gas circuit, described unloaded gas circuit for importing the air crossed by described dry gas circuit dry decontamination to ionization reaction zone;
The above-mentioned whole spectral lines collected are carried out Algorithm Analysis, thus obtaining testing result by step 5.
2. the method for claim 1, it is characterised in that in described step 2, the insertion time of described induction apparatus perception sample, and immediately trigger the spectral line acquisition operations of ionic migration spectrometer.
3. the method for claim 1, it is characterised in that in described step 2, described spectral line information is the scanning meansigma methods of the real time data characterizing the weak current that detects of detector and ion time of advent.
4. the method for claim 1, it is characterized in that, in described step 2, described weak current is to be detected by the detector being positioned at migration tube end, the current inductor that the molecular ion group that this weak current is formed by measured matter molecule clashes on detector under electric field action after migration tube separates produces, and the intensity that molecular ion is rolled into a ball can be characterized, described electric field is formed by the ring electrode sheet being positioned at migration tube.
5. the method for claim 1, it is characterised in that in described step 3, described adulterant is the solid dopants that volatile quantity is little.
6. method as claimed in claim 5, it is characterised in that described adulterant is hexachlorethane.
7. the method for claim 1, it is characterised in that in described step 3, the doping gas circuit adding adulterant includes placing the polytetrafluoro container of adulterant, and its two ends are provided with controlled electromagnetic valve.
8. method as claimed in claim 7, it is characterised in that the ionic migration spectrometer used includes migration gas circuit, and this migration gas circuit is in parallel with the doping gas circuit of described addition adulterant;
When described electromagnetic valve is the first state according to control signal, the dry gas circuit of connection and doping gas circuit, wherein the air part after drying gas circuit dry decontamination is used as the migration gas from the addition of migration tube tail end, simultaneously other part is by gas circuit of adulterating, and carries the ionization reaction zone of adulterant steam entrance migration tube; When described electromagnetic valve is the second state according to control signal, the dry gas circuit of connection and unloaded gas circuit, an air part after drying gas circuit dry decontamination is used as the migration gas added from migration tube tail end, and additionally part is directly entered the ionization reaction zone of migration tube simultaneously.
9. method as claimed in claim 8, it is characterised in that make electromagnetic valve be in the control signal of the first state and provided based on predetermined algorithm according to the signal of telecommunication of detector collection by controlling device.
10. the method for claim 1, it is characterised in that in described step 5, carries out mating to determine the kind of tested substance by the ion intensity of flow peak value shown by spectral line and corresponding ion time of advent thereof with standard substance storehouse.
11. the method for claim 1, it is characterized in that, in described step 3 and step 4, described the explosive that accurately detection vapour pressure is higher is provided needed for quantity of information and quantity of information needed for the explosive that accurately detection vapour pressure is relatively low can be provided collected enough spectral lines by detector and represent.
12. method as claimed in claim 11, it is characterised in that the described enough spectral lines in step 3 are 3 spectral lines; Described enough spectral lines in step 4 are 10.
13. the method for claim 1, it is characterised in that judge the detection SBR of ionic migration spectrometer by arranging the ratio of dopant ion correspondence peak height peak height corresponding to reactant ion.
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