CN207586174U - Trace heavy metal detecting system based on time-measuring electric potential leaching - Google Patents
Trace heavy metal detecting system based on time-measuring electric potential leaching Download PDFInfo
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Abstract
The utility model discloses a kind of trace heavy metal detecting system based on time-measuring electric potential leaching, including time-measuring electric potential digestion instrument and screen printing electrode；The time-measuring electric potential digestion instrument includes housing, the work mainboard in the housing and electrode slot, built-in power, input unit and the output unit being loaded into respectively using the housing as platform on the housing；The screen printing electrode includes substrate, working electrode is printed on the substrate, to electrode and reference electrode, electrolysis cell cavity is formed together with trepanning on the insulating layer with opening up covered with a layer insulating, one end of three electrodes on three electrodes, the sample of detection is added dropwise in the electrolytic cell intracavitary；The screen printing electrode is inserted into the electrode slot of the housing, and reference electrode connector is connect with the constant potential module of the work mainboard.Detecting system composition is simple in the utility model, is easy to minimize, and with the use of screen printing electrode, avoids electrode pretreatment, easy to use.
Description
Technical field
The utility model is related to heavy metal analysis fields, and in particular to trace heavy metal field quick detection field.
Background technology
Heavy metal is widely present in nature, refers to that density is more than 5g/cm3Metal, there are about 45 kinds, as copper, lead,
Zinc, cadmium, manganese, iron, cobalt, mercury, gold, silver etc..Most of heavy metal such as lead, cadmium, mercury etc. are not that vital movement institute is required, threaten biology
Existence and human health.With process of industrialization, the mankind are to the exploitation of heavy metal, smelting, processing and business manufacturing activities day
The problem of benefit increases, Heavy-metal Polluted Environment becomes increasingly conspicuous, and many heavy metals is caused to enter in big gas and water, soil, by heavy metal
The water body and soil of pollution can be in plant and aquatic products body further accumulation.By heavy metal pollution food and drink
Water can endanger people's health.Since heavy metal is to be entered in food in the form of chemistry to the pollution of crops,
Can not be removed by simply impregnating and washing, heavy metal can not carry out biodegradation, by after the effect of food chain in people
It is accumulated in body.Strong interaction occurs for heavy metal energy and protein and various enzymes in human body, them is made to lose activity,
It can be enriched in certain organs of human body, if it exceeds the limit that human body is resistant to, can cause human body acute poisoning, Asia anxious
Property poisoning, slow poisoning etc., can cause human body very big harm.
It is influenced by increasing for heavy metal pollution event, higher requirement is proposed to heavy metal monitoring, also to heavy metal
Site Detection propose more urgent need.Therefore the content of heavy metal element in water, food is that accurately and quickly detected, for
Water quality safety, food quality evaluation, ecological environment examination and human health protection have extremely important meaning.Content of beary metal
Monitoring and control become be related to environmental protection, the major issue that sustainable development and Living consumption improve.With
The rapid development of analysis and testing technology not only has point that more and more methods can be applied to content of beary metal in different samples
Analysis, and the sensitivity detected and accuracy also greatly improve, and simple, quick, low cost the heavy metal of research quickly detects
Method will have important practical significance for effectively assessing with early warning pollution and guarantee people's health and ecological safety.
Currently used Analysis of Heavy Metal method includes spectrophotometry, atomic absorption spectrography (AAS), inductive coupling plasma
Body method, atomic fluorescence spectrometry, biological enzyme inhibition, immunoassay, biochemical sensor method and electrochemical methods etc..
In the above method：Spectrophotometry instrument is cheap, but cumbersome, and sensitivity is low, is not suitable for the detection of trace heavy metal；Atom
Absorption spectrometry, atomic fluorescence spectrometry, although inductively coupled plasma atomic emission spectrometry high sensitivity, all exists
Large-scale instrument is needed, is not suitable for onsite application, determination step is more, and the measure period is long, of high cost；Biological enzyme inhibition is immunized and divides
Though analysis method and biochemical sensor method are advantageously implemented heavy metal field quick detection, sensitivity and specificity are relatively low,
The type for detecting heavy metal is limited.Electrochemical Stripping Analysis high sensitivity, instrument is simple, and with respect to the above method, instrument is easy to small-sized
Change, applicable Site Detection.
Electrochemical methods be according to substance in the solution with set up based on the electrochemical properties on electrode one
Kind analysis method.Electrochemical methods be applied to detection heavy metal mainly include stripping voltammetry, polarography, potentiometric stripping,
The means such as conductimetry.
Wherein, stripping voltammetry is based on polarography, and it is a variety of to derive oscillographic polarography, anodic stripping voltammetry etc.
Method.The detection limit of Electrochemical Stripping voltammetry detection heavy metal is relatively low, and measurement sensitivity is higher, can measure the gold of umol/L
Belong to ion, be a kind of good trace heavy metal analysis means compared with polarography, conductimetry.Potentiometric stripping, such as specially
A kind of potential polarographic analyzing instrument disclosed in sharp CN1182389C is exactly the heavy metal detector based on potentiometric stripping technology
Device.
Potentiometric stripping and stripping voltammetry all include enrichment and two stages of dissolution in detection process：Concentration stage,
Various metals ion is reduced into heavy metal simple substance in electrode surface under electrochemical reduction effect in solution；In dissolution stage weight
Metal simple-substance dissociates from the ion that is oxidized to of electrode surface into solution, has dissolution peak, root under specific current potential (spike potential)
Come according to spike potential qualitative, the size of peak height quantifies.It is substantially the same in two methods in concentration stage, difference is mainly in dissolution rank
Section, dissolution is by electrochemical oxidation in stripping voltammetry, and it is current signal to obtain；Dissolution is to pass through chemistry in potentiometric stripping
Oxidation, it is voltage signal to obtain.
Because the concentration stage of the two is identical, therefore constant potential system is that identical (such as Fig. 1, working electrode connect on circuit
Ground, control reference electrode constant voltage realize constant potential function).Again because of the difference in dissolution stage, lead to stripping voltammetry and current potential
Leaching above makes a big difference in the design of instrument and the utilization of detection method, affects the instrument development difficulty or ease of two methods
Degree and cost.
Stripping voltammetry is to scan electric potential signal by the input between working electrode and reference electrode to detect work electricity
Pole and to interelectrode current signal (inputting scanning voltage on reference electrode), such as 201210417212 electrochemistry of patent CN
Stripping voltammetry quickly detects heavy metal device and its detection method.Because metal simple-substance is that electrochemical oxidation is molten in electrode surface
Go out, property belong to actively dissolve out, influenced by SOLUTION PROPERTIES it is small, and scan potential range it is wide, in positive and negative potential range
It can measure.In addition, with present micro- electric word technology development, the equipment of stripping voltammetry can be made it is portable, such as
A kind of Portable heavy metal fast detectors of patent CN201420513939.3, are exactly that the instrument of Anodic Stripping technology is portable
Change, be suitble to onsite application.But at the same time, since current signal reflects the concentration of heavy metal, current signal size variation is very
Greatly, what is had may cross over several orders of magnitude, and it by current signal by the electric resistance changing of feature is electricity to read current signal to be
Signal (the micro-current sensing circuit figure of such as Fig. 2) is pressed, A/D chips is transferred to and reads voltage signal.Current signal is in several quantity
The variation of grade, needs switching circuit that can be rapidly switched to corresponding resistance, this results in software and hardware in dissolution stage workload
Greatly, working to stripping voltammetry instrument, it is unstable to bring, and is mainly reflected in：1st, the variation of current signal needs to judge to need in advance
Which resistance is switched to, this adds increased the calculating processes of master chip；2nd, switching circuit can switch rapidly, need response speed
Soon, usually nanosecond, and leakage current during the disconnection of switching circuit is required to want very little, will not just interfere low current signal；It leads
Conducting resistance very little when logical, does not just interfere with big current signal, the switching circuit chip price met this requirement is high；
3rd, due to circuit, there are thermal noises, can interfere the acquisition of low current signal, to reduce thermal noise as far as possible in circuit design
Amplitude needs using high performance component, to bring the rising of cost；4th, current signal, the judgement to size are acquired, control is opened
The switching of pass, is required for the arithmetic unit of high speed, and high performance master chip could be competent at this work, while the compiling work of software
Content is more.
Potentiometric stripping is by chemical oxidation in the dissolution stage, and it is voltage signal to obtain.Because without stripping voltammetry
The complexity and difficulty of sensed current signal enormously simplify Signals collecting function circuit part (such as the right in Fig. 1 on hardware
Partial circuit), at the same it is also relatively easy in software processing.The instrument of potentiometric stripping can be done smaller, and power consumption is more
Low, the noise of instrument itself is small, high sensitivity, is more suitable for making portable detector.But since metal simple-substance in electrode surface is
It is dissolved out by chemical oxidation, is passively to dissolve out, oxidation-reduction quality is influenced greatly in by solution, and the potential range scanned is relatively
It is narrow, it is usually measured under negative potential, the element that can be measured is relatively less.
Above-mentioned two methods be can be seen that when for heavy metal analysis, while with some superiority, there is also
The defects of being difficult to overcome.There is a kind of time-measuring electric potential leaching in Electrochemical Stripping method, it is less to be concerned, also do not see
Apply the report in heavy metal analysis.Time-measuring electric potential leaching is identical with above-mentioned two method, there is identical concentration stage, is dissolving out
Stage gives the input of working electrode constant current, detects reference electrode voltage signal.What it is due to acquisition is voltage signal, circuit part
It is all fairly simple with software section, constant current modules only more multiple than potentiometric stripping, therefore using the instrument of time-measuring electric potential leaching
Device can have the advantages that identical with the instrument of potentiometric stripping, and power consumption is low, high sensitivity；Meanwhile in work electricity during dissolution
There is input current in pole, and metal simple-substance is electrochemical oxidation dissolution in electrode surface, thus equally has the advantage of stripping voltammetry,
The influence of SOLUTION PROPERTIES is small, and the potential range of scanning is wide, the same stripping voltammetry of element that can be measured.
Therefore, it if can time-measuring electric potential leaching be applied to heavy metal analysis field, can necessarily be monitored to heavy metal
Far-reaching influence is brought with the Site Detection of heavy metal.But, as said before, time-measuring electric potential leaching is less is concerned, more
It applies precedent in heavy metal analysis field to no-trump, therefore how time-measuring electric potential leaching is applied to heavy metal analysis, special
It is not the heavy metal analysis of trace, it is still desirable to further research.
In addition to this, traditional Electrochemical Stripping Analysis heavy metal analysis uses three electrode of solid, including glass-carbon electrode, reference
Electrode and to electrode, it is inconvenient to carry, and glass-carbon electrode needs grinding process before every use, and reference electrode wants daily dimension
Shield, sample required for detection is more, makes troubles to Site Detection, substantially increases the workload of operating personnel.And silk screen
Application of the electrochemical method in real work has been expanded in the use printed electrode significantly, much research shows that screen printing electrode can
Detect heavy metal to replace conventional solid electrode, wherein application it is more be using conventional anodic stripping voltammetry
(stripping voltammetry) detection technique, working electrode is mostly carbon material, such as 201310070755 Portable heavy metal instrument of patent CN
The production method to print electrode prints three electrodes the distinctive method that uses, and patent CN 201210595249 is dissolved out based on square wave
The method that voltammetry and three electrode sensors quickly measure copper, a kind of 201510633166 Portable heavy metal ions of patent CN are fast
Speed detector and application process；The least a portion of analytical technology using potentiometric stripping, such as patent CN201120372877.5
For the device of field trace heavy metals detection.
In stripping voltammetry and potentiometric stripping both common analysis methods, according to detection mechanism
A is working electrode area), the electrochemical area of working electrode is directly proportional to detection electric current in stripping voltammetry, this is also glass
Carbon electrode needs one of the reason of polishing treatment after each, also and electrode surface electric double layer diffusion coefficient phase
It closes.In contrast, the area of working electrode is unrelated with voltage signal in potentiometric stripping, only and the electric double layer of electrode surface
Diffusion coefficient is related, this is also that the working electrode of different manufacturers leads to the source of testing result difference.Therefore, screen printing electrode
Prepare to ensure printing process it is consistent, in particular for for stripping voltammetry, the working electrode area discrepancy of preparation
Want very little.This has strict demand in itself during printing to technique and material, in contrast, for the silk screen of potentiometric stripping
It prints electrode and does not just have the harshness of stripping voltammetry.
And time-measuring electric potential leaching theoretically for, the similary advantage with potentiometric stripping, if it is possible to and screen printing
Brush technology is combined, and the area of working electrode similarly should be only related to the diffusion coefficient of the electric double layer of electrode surface.
Therefore, while studying time-measuring electric potential leaching and being applied to heavy metal analysis field, how by itself and screen printing technique phase
With reference to also the same extremely important.However, it is desirable to it is appreciated that time-measuring electric potential leaching and volt-ampere leaching and potentiometric stripping
Working mechanism it is different, therefore, above-mentioned two method is also necessarily different from suitable for the screen printing electrode of time-measuring electric potential leaching.
Specifically, the factor of Electrochemical Detection on the electrode, the mainly property of working electrode surface are influenced, because of working electrode
The property on surface determines bilayer property of the working electrode in electrolyte, affects diffusion coefficient.And working electrode surface
Property largely determined by electrode surface hydrophilicity and hydrophobicity.The working electrode surface that stripping voltammetry is suitble to is parent
It is aqueous relatively good, and the working electrode surface of potentiometric stripping then requires hydrophobic performance.Time-measuring electric potential leaching is from reaction
It is seen in mechanism, the hydrophilicity and hydrophobicity of used working electrode surface should be between two methods.Therefore, using which kind of silk
Wire mark brush electrode, and be combined with time-measuring electric potential leaching for detecting heavy metal, it is current important research direction and sheet
The emphasis of application.
In addition, the heavy metal of electrochemical method detection is free state, there are many sample needing the heavy metal to be prepared into can be with
The free state of detection needs to pre-process.Conventional preprocess method is the strong acid or nitration mixture using strong oxidizing property, in high temperature height
Pressure is handled, and many substances are processed into small molecule, avoid interfering, in a kind of detection tealeaves of patent CN200710164548.X
The method of lead content, a kind of methods that lead, cadmium are quickly detected using scan anode stripping voltammetry of patent CN 201310574732
This method using this obtained treatment fluid that pre-processes since oxidisability is strong, is not suitable for the detection of potentiometric stripping, is only applicable in
Stripping voltammetry, while preprocessing process is cumbersome, is not suitable for onsite application；And the pretreatment of potentiometric stripping is mostly using metal
Replacement technique, such as the measure reagent of patent CN200410027136.8 trace content of beary metal, patent CN 201,310,058,742 1
The method of lead content in the quick detection blood of kind is that heavy metal ion displacement in sample dissociates into treatment fluid, will not change
Liquid oxidation is detected, meets the experiment condition of potentiometric stripping, also is adapted for the analysis detection of stripping voltammetry, but this pretreatment is only
To heavy metal ion, be not suitable for the processing of the heavy metal of other valence states.Therefore, if detecting a huge sum of money using time-measuring electric potential leaching
Belong to, the pretreatment to sample is also the place that emphasis is needed to think deeply.
Utility model content
Purpose of utility model：The utility model aim is to overcome technological difficulties, with reference to time-measuring electric potential leaching and silk screen
It prints electrode and detects the detecting system of trace heavy metal；
The another object of the utility model is to provide a kind of fast using said detecting system progress trace heavy metal scene
The detection method of speed detection.
Technical solution：Trace heavy metal detecting system described in the utility model based on time-measuring electric potential leaching, including meter
When potential digestion instrument and screen printing electrode；
The time-measuring electric potential digestion instrument is included housing, the work mainboard in the housing and is made with the housing
Electrode slot, built-in power, input unit and the output unit being loaded into respectively for platform on the housing；
The work mainboard includes I/O unit control module, D/A and A/D modules, constant potential module, constant current
Module and the power module to each module for power supply；The I/O unit control module and the input unit and output are single
Member connect respectively, D/A the and A/D modules respectively with I/O unit control module, constant potential module and constant current module
Connection；
The screen printing electrode includes substrate, working electrode is printed on the substrate, to electrode and reference electrode, and three
Covered with a layer insulating on electrode, wherein one end of three electrodes is exposed on the outside of insulating layer, as electrode contact, the other end with
The trepanning opened up on the insulating layer forms electrolysis cell cavity together, and the sample of detection is added dropwise in the electrolytic cell intracavitary；
The screen printing electrode is inserted into the electrode slot of the housing, the perseverance of reference electrode and the work mainboard
Current potential module connects, D/A the and A/D modules are controlled by the I/O unit control module, acquire the constant potential mould
Potential data on block；Working electrode is connect with the constant current module, and the constant current module is by D/A and A/D module controls
System inputs constant current in the dissolution stage to the working electrode.
Further preferably technical solution is the utility model, and the substrate of the screen printing electrode is the white of strip
PET film, thickness are more than 0.15mm, and three electrode of surface printing of substrate, the blue or green PET film of covering is as insulation on three electrodes
Layer, empty formation trepanning is cut out with being electrolysed cell cavity corresponding position on insulating layer, a face gluing of the insulating layer is suppressed described in being covered in
On substrate and three electrodes.
Preferably, in three electrodes, the working electrode is carbon electrode, is printed using electric conductive carbon printing ink；
It is carbon electrode to electrode, is printed using electric conductive carbon printing ink；
Reference electrode is silver-silver chloride electrode, is printed using conductive silver-AgCl ink.
Preferably, described be working electrode is carbon electrode, and carbon electrode component includes 20% graphite, 40% carbon black and 40% tree
Fat binding agent, production method are：Hydrophily processing is done to graphite, graphite is heated to 80 DEG C in 5% periodic acid solution, leaching
Bubble is stood overnight after 2 hours, and drying is washed with water after filtering, prepares the rich carboxylic graphite of hydrophily；By obtained graphite with
Carbon black and resinoid bond mixing, use three-roll grinder grinding slurry, it is desirable that fineness is in 1um hereinafter, carbon printing ink is made, and print
It is made as the working electrode of time-measuring electric potential digestion instrument.
Preferably, the input unit is to have both the touch display screen for outputting and inputting function.
Preferably, the output unit is touch display screen, data-interface, bluetooth communication port one or more of which.
Preferably, switch key is additionally provided on the housing, the switch key is connect with the power module, control
The switch of the power module.
Preferably, the I/O unit control module is based on Embedded micro- place that ARM family chips are core
Manage device.
The detection side described in the utility model that trace heavy metal field quick detection is carried out using above-mentioned detecting system
Method includes the following steps；
(1) pretreatment of sample is detected：By the hypochlorite that sample to be detected and mass percentage are 0.5~2%
The acid solution mixing that solution and molar concentration are 1~5mol/L shakes up, and after standing 5-30min, takes intermediate treatment liquid and detection
Liquid is with 1：4 ratio mixing, forms test solution；
(2) screen printing electrode is inserted into the electrode slot of time-measuring electric potential digestion instrument, then test solution is dropped into silk-screen printing electricity
The electrolytic cell intracavitary of pole；
(3) parameter of sample to be detected is inputted on time-measuring electric potential digestion instrument, D/A the and A/D modules for the mainboard that works are every
The electric potential signal of a constant potential module is acquired every a period of time, and marks+1 at corresponding current potential herein, gathered data is completed
The differentiated data of dt/dE is generated afterwards；
(4) D/A and A/D modules export the data of generation by output unit.
Preferably, in step (1), when the sample to be detected is fluid sample, sample and quality percentage are contained
Measure for 0.5~2% hypochlorite solutions and molar concentration be 1~5mol/L acid solution using volume ratio as 5：4：1 ratio
Mixing, obtains intermediate treatment liquid；
When the sample to be detected is solid sample, take 0.5 gram of sample add in the mass percentage of 4ml for 0.5~
In 2% hypochlorite solutions and the acid solution that the molar concentration of 1ml is 1~5mol/L, after mixing is stood, supernatant conduct is taken
Intermediate treatment liquid.
Preferably, the working electrode of screen printing electrode described in step (2) is carbon electrode, and component includes 20% stone
Ink, 40% carbon black and 40% resinoid bond, the production method of working electrode are：Hydrophily processing is done to graphite, graphite is existed
80 DEG C are heated in 5% periodic acid solution, after impregnating 2 hours, stands overnight, drying is washed with water after filtering, prepare hydrophilic
Property rich carboxylic graphite；It, using three-roll grinder grinding slurry by obtained graphite and carbon black and resinoid bond mixing
Fineness is sought in 1um hereinafter, carbon printing ink is made, and is printed to for the working electrode of time-measuring electric potential digestion instrument.
Advantageous effect：(1) the time-measuring electric potential leaching that the utility model uses is the same with stripping voltammetry, and property belongs to main
Dynamic dissolution, is influenced small by SOLUTION PROPERTIES, and the potential range scanned is wide, can be measured in positive and negative potential range, than
Advantage more than the element of potentiometric stripping detection, SOLUTION PROPERTIES are small on the detection influence of time-measuring electric potential leaching, thus in sample not
Heavy metal with valence state may be used the acid of oxidisability and be processed into soluble heavy metal ion state, can expand separate sources
The heavy metal analysis of sample；Time-measuring electric potential leaching is in the dissolution stage for reading data, acquisition the same with potentiometric stripping simultaneously
It is voltage signal, circuit conversion caused by meeting is brought not when avoiding the noise jamming of current signal and reading current signal
Just；The structure of the time-measuring electric potential digestion instrument of the utility model can be similar using being designed simple as potentiometric stripping, consumes
Electricity is low, high sensitivity, is easy to be miniaturized, easy to operate with reference to screen printing electrode so that entire detection architecture portability,
It is more suitable for scene to be detected various heavy；
(2) detecting system composition is simple in the utility model, is easy to minimize, can be with data line and bluetooth approach and electricity
Brain or mobile communication realize the upload of data, adapt to live quick analysis and laboratory testing analysis；With the use of screen printing
Brush electrode avoids electrode pretreatment, easy to use；In combination with preprocess method, the type of detection sample has been expanded significantly,
It can be widely used for water quality, the detection of heavy metal in food, agricultural product and biological sample has easy to operate, heavy metal analysis spirit
Sensitivity is high, is with a wide range of applications in fields such as environmental monitoring, food security, clinical detections；
(3) time-measuring electric potential digestion instrument is combined with screen printing electrode in the utility model, screen printing electrode feature is
Directly by working electrode, reference electrode and electrode is integrated on a substrate, suitable for being used on portable detector, still
Due to time-measuring electric potential leaching and volt-ampere leaching and potentiometric stripping the course of work and work based on mechanism there are different,
Therefore suitable for time-measuring electric potential leaching screen printing electrode also not with above-mentioned two method；Used by time-measuring electric potential leaching
The hydrophilicity and hydrophobicity of working electrode surface is between two methods, and the hydrophilicity and hydrophobicity of working electrode surface is mainly by working
What the material composition of electrode determined, as carbon electrode, mainly by graphite, carbon black and resinoid bond, graphite has hydrophobicity
Can, carbon black has hydrophilicity, and resinoid bond has hydrophobic performance, therefore in the utility model, graphite is done at hydrophily
Reason prepares the carbon printing ink for the carbon working electrode for being exclusively used in time-measuring electric potential leaching, is matched with this carbon printing ink printing screen printing electrode
The use of portable time-measuring electric potential digestion instrument is closed, does not have the harshness of stripping voltammetry in printing process, there is potentiometric stripping
Advantage, it is opposite to be more suitable for producing in batches；
(4) due to carrying out heavy metal analysis using time-measuring electric potential leaching in the utility model, to sample pretreatment
Cheng Zhong, detects that influence of the oxidisability of liquid to time-measuring electric potential leaching is small, and the sour pre-treatment of oxidisability can be used as time-measuring electric potential
The sample pretreating method of leaching, the detection for heavy metal, it is only necessary to which the treatment fluid for having strong oxidizing property will interfere heavy metal
The resolution of the organic matter with special functional group of detection, can carry out, such treatment conditions under conditions of strong acid is not needed to
Mildly, high temperature and pressure is not needed to, largely reduces detection difficulty, suitable for in-situ processing, operates entire detection process
Simply, detection is quick, is particularly suitable for the needs that scene heavy metal quickly detects.
Description of the drawings
Fig. 1 is constant potential system schematic in the utility model；
Fig. 2 is micro-current sensing circuit figure in the utility model；
Fig. 3 is the positive structure schematic of timing potential digestion instrument in the utility model；
Fig. 4 is the structure schematic diagram of timing potential digestion instrument in the utility model；
Composition schematic diagrams of the Fig. 5 for the mainboard that works in the utility model；
Fig. 6 is screen printing electrode structure chart in the utility model；
Fig. 7 is the stereogram of screen printing electrode in the utility model；
Fig. 8 is to the detection figure of heavy metal lead sample in the utility model embodiment 1；
Fig. 9 is to the detection figure of heavy metal cadmium sample in the utility model embodiment 2；
Figure 10 is to the detection figure of heavy metal zinc sample in the utility model embodiment 3；
Figure 11 is to the detection figure of heavy metal copper sample in the utility model embodiment 4；
Figure 12 is to the detection figure of heavy metal lead in soy sauce in the utility model embodiment 5；
Figure 13 is to the detection figure of Heavy Metals In Vegetables lead cadmium in the utility model embodiment 6；
Figure 14 is to the detection figure of heavy metal cadmium in rice in the utility model embodiment 7.
Specific embodiment
Technical solutions of the utility model are described in detail below by attached drawing, but the scope of protection of the utility model
It is not limited to the embodiment.
Embodiment 1：A kind of trace heavy metal detecting system based on time-measuring electric potential leaching, including time-measuring electric potential digestion instrument
And screen printing electrode.
Time-measuring electric potential digestion instrument includes housing 101, and 101 front of housing is touch display screen 102, and the setting of housing right edge is opened
Close button 103,101 lower backside of housing are battery case 104, and built-in rechargeable battery, there is silk-screen printing electricity in 101 side upper end of housing
The electrode slot 105 of pole, 101 side lower end of housing are respectively equipped with data-interface 106 and bluetooth communication port 107, in housing 101
Put work mainboard 108.Instrument is opened/closed to switch key 103, and touch display screen 102 sets running parameter in display unit
Confirmation is shown on (touch screen) 102.Power supply adaptor connects data-interface 106, is powered at this time by power supply adaptor, while to electricity
Rechargeable battery charging in pond box 104；When there is data-interface 106 without connection power supply adaptor, by filling in battery case 104
Electric battery powered ensures onsite application under no Power Supplies Condition.
The mainboard 108 that works includes I/O unit control module 201, D/A and A/D modules 202, constant potential module
203rd, constant current module 205 and the power module 204 to each module for power supply；I/O unit control module 201 is to be based on
ARM family chips are the Embedded microprocessor of core, can meet control, are acquired, the needs of data processing and display.
The substrate 301 of screen printing electrode selects white PET film, is strip, and thickness is more than 0.15mm.Working electrode
303 be carbon electrode, and component includes 20% graphite, and 40% carbon black and 40% resinoid bond, production method are：Parent is done to graphite
Graphite in 5% periodic acid solution is heated to 80 DEG C, after impregnating 2 hours, stands overnight, water is used after filtering by aqueous treatment
It is cleaned and dried, prepares the rich carboxylic graphite of hydrophily；By obtained graphite and carbon black and resinoid bond mixing, three rollers are used
Grinder grinding slurry, it is desirable that fineness is in 1um hereinafter, carbon printing ink is made, and be printed to for the work of time-measuring electric potential digestion instrument
Electrode.It is carbon electrode to electrode 304, is printed using electric conductive carbon printing ink.Reference electrode 305 is silver-silver chloride electrode, using conduction
Silver-silver chloride ink is printed.Covered with insulating layer 306 made of one layer of indigo plant or green PET film on three electrodes, three electrodes its
Middle one end is exposed in 306 outside of insulating layer, as electrode contact 302, the other end and the profiled holes being opened on insulating layer 306
307 form electrolysis cell cavity 308 together.
Screen printing electrode is inserted into the electrode slot 105 of housing 101, the perseverance electricity of reference electrode 305 and work mainboard
Position module 203 connects, and control unit 201 controls constant potential module 203 to work by D/A and A/D modules 202, acquires permanent electricity
Electric potential signal in the module 203 of position, D/A and A/D modules 202 acquire potential data at regular intervals, and+1 is remembered at this current potential,
The differentiated data of dt/dE can be automatically generated after the completion of gathered data, the differentiation processing of data is completed in gatherer process, is saved
Data calculate the workload of analysis after acquisition；Working electrode 303 is connect with constant current module 205, and constant current module 205 is by D/A
It is controlled with A/D modules 202, constant current is inputted to working electrode 303 in the dissolution stage.
It needs to pre-process sample to be detected before detection.It is 0.5 by sample to be detected and mass percentage
The acid solution mixing that~2% hypochlorite solutions and molar concentration are 1~5mol/L shakes up, and after standing 5-30min, obtains
Intermediate treatment liquid.When sample to be detected is fluid sample, by sample and hypochlorite solutions and acid solution using volume ratio as 5：
4：1 ratio mixing, obtains intermediate treatment liquid；When sample to be detected is solid sample, 0.5 gram of sample is taken to add in time of 4ml
In the acid solution of solution of chlorate and 1ml, after mixing is stood, supernatant is taken as intermediate treatment liquid.
Detecting step is described in detail for detecting heavy metal lead sample in the present embodiment：
The preparation of lead sample：The pretreated lead water intermediate treatment liquid of 0.2ml is added in 0.8ml detection liquid, mixing obtains
To lead test solution；It is 0.2M ammonium citrates and 0.5M hydrochloride buffers to detect liquid, includes 24mg/L mercury ions.
Switch key opens time-measuring electric potential digestion instrument, and after instrument stabilizer, the parameter of lead, silk are set in touch display screen
Wire mark brush electrode is inserted into the electrode slot of time-measuring electric potential digestion instrument, lead test solution is dropped in the electrolysis cell cavity of screen printing electrode,
Start test program, after to be detected, discard and print electrode, be inserted into and newly print electrode, retest.Test analysis obtains
Figure it is as shown in Figure 8.As a result show the time-measuring electric potential leaching trace heavy metal detection method of the utility model to lead ion
Detection has good reproducibility.
Embodiment 2：Heavy metal cadmium sample is detected using detecting system and detecting step same as Example 1：
The preparation of cadmium sample：0.2ml cadmium water intermediate treatments liquid is added in 0.8ml detection liquid, mixing；It detects liquid and detection is grasped
Make step with embodiment 1, the parameter in addition to the setting of time-measuring electric potential digestion instrument to be changed to cadmium.The figure that test analysis obtains is as schemed
Shown in 9.Showing the time-measuring electric potential leaching trace heavy metal detection method of the utility model has well heavy metal cadmium ion
Response.
Embodiment 3：Metallic zinc sample is detected using detecting system and detecting step same as Example 1：
The preparation of zinc sample：0.2ml zinc water intermediate treatments liquid is added in 0.8ml detection liquid, mixing；It detects liquid and detection is grasped
Same embodiment 1 is walked, the parameter in addition to the setting of time-measuring electric potential digestion instrument to be changed to cadmium.The figure that test analysis obtains such as Figure 10
It is shown.Show the utility model time-measuring electric potential leaching trace heavy metal detection method have to heavy metal zinc ion it is good
Response.
Embodiment 4：Metal copper sample is detected using detecting system and detecting step same as Example 1：
The preparation of copper sample：0.2ml copper water intermediate treatments liquid is added in 0.8ml detection liquid, mixing；It detects liquid and detection is grasped
Make step with embodiment 1, the parameter in addition to the setting of time-measuring electric potential digestion instrument to be changed to cadmium.The figure that test analysis obtains is as schemed
Shown in 11.Showing the time-measuring electric potential leaching trace heavy metal detection method counterweight metal copper ion of the utility model has well
Response.
Embodiment 5：Heavy metal lead in soy sauce is examined using detecting system and detecting step same as Example 1
It surveys：
The preparation of sample：Soy sauce 5ml is taken, sequentially adds 1% liquor natrii hypochloritis's 4ml and 2M hydrochloric acid 1ml mixings, is stood
After 10min, supernatant 0.2ml is taken to add in 0.8ml detection liquid, mixing；Liquid and detection operating procedure are detected with embodiment 1.It surveys
The figure that examination analysis obtains is as shown in figure 12.Show the time-measuring electric potential leaching trace heavy metal detection method of the utility model
There is good effect to the lead detection of heavy metal in soy sauce.
Embodiment 6：Heavy Metals In Vegetables lead cadmium is examined using detecting system and detecting step same as Example 1
It surveys：
The preparation of sample：0.5 gram of Chinese cabbage is taken, fragment is cut into ceramic scissors, sequentially adds 1% liquor natrii hypochloritis 4ml
With 2M hydrochloric acid 1ml mixings, after standing 30min, supernatant 0.2ml is taken to add in 0.8ml detection liquid, mixing；Detect liquid and detection
Operating procedure is the same as embodiment 1.The figure that test analysis obtains is as shown in figure 13.Show the time-measuring electric potential dissolution of the utility model
Method trace heavy metal detection method has good effect to the detection of Heavy Metals In Vegetables lead cadmium.
Embodiment 7：Heavy metal cadmium in rice is examined using detecting system and detecting step same as Example 1
It surveys：
Cadmium content detects in rice, the preparation of sample：Take rice crush after 0.5 gram, sequentially add 1% liquor natrii hypochloritis
4ml and 2M hydrochloric acid 1ml mixings after standing 30min, take supernatant 0.2ml to add in 0.8ml detection liquid, mixing；Detect liquid and inspection
Operating procedure is surveyed with embodiment 1.The figure that test analysis obtains is as shown in figure 14.Show that the time-measuring electric potential of the utility model is molten
Go out method trace heavy metal detection method has good effect to the detection of heavy metal cadmium in rice.
As described above, although the utility model has been represented and described with reference to specific preferred embodiment, it must not
It is construed to the limitation to the utility model itself.In the spirit and scope for not departing from the utility model that appended claims define
Under the premise of, it can various changes can be made in the form and details to it.
Claims (7)
1. a kind of trace heavy metal detecting system based on time-measuring electric potential leaching, which is characterized in that dissolved out including time-measuring electric potential
Instrument and screen printing electrode；
The time-measuring electric potential digestion instrument include housing, the work mainboard in the housing and using the housing as put down
Platform is loaded into electrode slot, built-in power, input unit and output unit on the housing respectively；
The work mainboard includes I/O unit control module, D/A and A/D modules, constant potential module, constant current module
With the power module to each module for power supply；The I/O unit control module and the input unit and output unit point
It does not connect, D/A the and A/D modules connect respectively with I/O unit control module, constant potential module and constant current module
It connects；
The screen printing electrode includes substrate, is printed with working electrode on the substrate, to electrode and reference electrode, three electrodes
On covered with a layer insulating, wherein one end of three electrodes is exposed on the outside of insulating layer, and as electrode contact, the other end is with opening up
Trepanning on the insulating layer forms electrolysis cell cavity together, and the sample of detection is added dropwise in the electrolytic cell intracavitary；
The screen printing electrode is inserted into the electrode slot of the housing, the constant potential of reference electrode and the work mainboard
Module connects, D/A the and A/D modules are controlled by the I/O unit control module, acquired in the constant potential module
Potential data；Working electrode is connect with the constant current module, and the constant current module is controlled by D/A and A/D modules, to institute
State working electrode input constant current.
2. the trace heavy metal detecting system according to claim 1 based on time-measuring electric potential leaching, which is characterized in that institute
State screen printing electrode substrate be strip white PET film, thickness be more than 0.15mm, three electrode of surface printing of substrate,
Blue or green PET film is covered on three electrodes as insulating layer, empty formation trepanning, institute are cut out with electrolysis cell cavity corresponding position on insulating layer
A face gluing of insulating layer is stated, compacting is covered on the substrate and three electrodes.
3. the trace heavy metal detecting system according to claim 2 based on time-measuring electric potential leaching, which is characterized in that three
In electrode, the working electrode is carbon electrode, is printed using electric conductive carbon printing ink；
It is carbon electrode to electrode, is printed using electric conductive carbon printing ink；
Reference electrode is silver-silver chloride electrode, is printed using conductive silver-AgCl ink.
4. the trace heavy metal detecting system according to claim 1 based on time-measuring electric potential leaching, which is characterized in that institute
It is to have both the touch display screen for outputting and inputting function to state input unit.
5. the trace heavy metal detecting system according to claim 4 based on time-measuring electric potential leaching, which is characterized in that institute
Output unit is stated as touch display screen, data-interface, bluetooth communication port one or more of which.
6. the trace heavy metal detecting system according to claim 1 based on time-measuring electric potential leaching, which is characterized in that institute
It states and switch key is additionally provided on housing, the switch key is connect with the power module, controls opening for the power module
It closes.
7. the trace heavy metal detecting system according to claim 1 based on time-measuring electric potential leaching, which is characterized in that institute
It is based on the Embedded microprocessor that ARM family chips are core to state I/O unit control module.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108362753A (en) * | 2017-12-11 | 2018-08-03 | 南京晓庄学院 | Trace heavy metal detecting system and detection method based on time-measuring electric potential leaching |
| CN108362753B (en) * | 2017-12-11 | 2023-09-12 | 南京晓庄学院 | Trace heavy metal detection system and detection method based on chronopotentiometric dissolution method |
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