CN113092564A

CN113092564A - Method for rapidly detecting heavy metals in water

Info

Publication number: CN113092564A
Application number: CN201911335685.4A
Authority: CN
Inventors: 汪劲能; 陈菲菲
Original assignee: Shanghai Xiongtu Biotechnology Co ltd
Current assignee: Shanghai Xiongtu Biotechnology Co ltd
Priority date: 2019-12-23
Filing date: 2019-12-23
Publication date: 2021-07-09

Abstract

The invention relates to the technical field of environmental monitoring, in particular to a method for rapidly detecting heavy metals in water quality, which comprises the following steps: the method comprises the following steps: preparing a high-performance working electrode: putting conductive carbon black or superconducting carbon black and ionic liquid in a certain mass proportion into a mortar, grinding for more than 50 minutes, fully and uniformly mixing, then putting into a pipe, compacting and molding, and taking a copper column as a lead at the rear end; the ionic liquid is N-octyl pyridine hexafluorophosphate, N-octyl pyridine tetrafluoroborate, N-octyl pyridine nitrate and N-hexyl pyridine hexafluorophosphate, and the mass ratio of the conductive carbon black to the ionic liquid is 2: 1-3: 1; the three electrodes of the sensor are all solid, and can be used in a static state or in a certain shaking or vibrating condition. The conductive carbon black ionic liquid paste electrode is used for replacing a mercury-based working electrode in the prior art, so that the use of mercury is avoided, the safety is good, and the potential risks of health and environmental pollution are avoided.

Description

Method for rapidly detecting heavy metals in water

Technical Field

The invention relates to the technical field of environmental monitoring, in particular to a method for rapidly detecting heavy metals in water quality.

Background

The functionality that water resources can perform is severely limited by its environmental quality status. Heavy metal pollution has been a serious concern many times. The method can monitor the content of heavy metal elements in water timely and accurately, and is vital to effective assessment and early warning of pollution.

The method for analyzing the heavy metals in water needs to ensure high sensitivity and good selectivity. At present, generally accepted heavy metal analysis methods include ultraviolet spectrophotometry (UV), Atomic Absorption Spectroscopy (AAS), Atomic Fluorescence (AFS), X fluorescence spectroscopy (XRF), inductively coupled plasma mass spectrometry (ICP-MS), Immunology (IA), test paper method (TP) and electrochemical method (ES), wherein ICP-MS and AAS have better detection limits, and part of elements are PPT-grade, but instruments are expensive, have high requirements on environmental conditions, are complex to operate and have high cost, so the instruments are mostly used for standard measurement at present; AFS is mostly used for analyzing and determining mercury and arsenic elements in environment and food, can be quantified, but is complex to operate and high in cost; the UV sensitivity is low, the requirement on the transparency of the analysis liquid is high, and the automation is not easy. The above methods also have a common problem: can only be carried out in a laboratory and cannot be used in a test field. The water sample is sampled on site and then sent to a laboratory for analysis, so that the cost is high, the timeliness is poor, and the objectivity of the detection result can be influenced by changes in the midway and pollution in the water sample transmission process due to the fact that the water sample is not detected in time. In addition, rapid and accurate reporting is required in the case of sudden pollution events, and the speed of the existing laboratory analysis method cannot meet the requirement of emergency monitoring. IA. TP offers the possibility of on-site analysis for the recently developed rapid detection methods, but much effort remains for sensitivity, precision and automation.

In recent years, Anodic Stripping Voltammetry (ASV) based on ES technology has been gaining importance again. The principle is as follows: the first step is 'electroanalysis', namely under a constant potential, the ions to be detected are electrodeposited and concentrated on the working electrode; the second step is 'stripping', namely, a reverse voltage is applied to the working electrode after the enrichment is finished, the metal is re-oxidized into an ion regression solution by negative positive scanning to generate an oxidation current, and a voltage-current curve, namely a volt-ampere curve, is recorded. The curve is in a peak shape, the peak potential can be used as the basis of qualitative analysis, and the peak current is in direct proportion to the concentration of the detected ions in the solution and can be used as the basis of quantitative analysis. As is known, unlike spectroscopy, mass spectrometry, immunization, etc., electrochemical methods directly obtain electrical signals, so that the electrical signals can be conveniently output without conversion, and the electrochemical methods have the advantages of low energy consumption, convenience in automation, and simple and portable instruments, thereby having essential superiority. A plurality of reports at home and abroad prove that the ASV has convenient operation and low cost, can continuously measure a plurality of metal ions at one time, usually takes several minutes, and has high sensitivity. Therefore, the method provides possibility for 'high-timeliness, on-site, low-cost and accurate quantitative detection', and becomes one of important development directions of the heavy metal on-site rapid detection technology. However, the above-mentioned ASV methods and apparatuses do not rely on mercury-based working electrodes (static mercury, suspended mercury, mercury membrane, etc.) for achieving the desired performance, which presents a great obstacle to popularization and application: firstly, the use of mercury itself has an environmental hazard risk; secondly, mercury in the sample cannot be measured; and thirdly, the detection result is seriously influenced by vibration and shaking and is not suitable for being used on transportation equipment. Therefore, scientists are striving to develop environmentally friendly mercury free working electrodes. Bismuth is an environment-friendly metal element, has electrochemical properties similar to mercury, and has been reported and applied in relevant documents and patents for heavy metal detection by adopting bismuth membrane electrodes. The method mainly adopts a pre-bismuth-plating film method or a co-bismuth-plating film method to detect the heavy metal. However, the preplated bismuth film is unstable when exposed to air and is easily oxidized, which causes unstable detection signals and poor reproducibility. The co-plating bismuth film method is easy to hydrolyze, so that the method can be only used in an acidic medium, and the application of the method in field detection is limited.

Disclosure of Invention

The invention aims to solve the technical problem of providing a field rapid detection method for heavy metals such as copper, zinc, lead and cadmium in water, which can rapidly and accurately detect the contents of the heavy metals such as copper, zinc, lead and cadmium in water in a sampling field and overcome the defects of the existing detection method and technology for the heavy metals in water in field detection.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a method for rapidly detecting heavy metals in water quality comprises the following steps:

the method comprises the following steps: preparing a high-performance working electrode: putting conductive carbon black or superconducting carbon black and ionic liquid in a certain mass proportion into a mortar, grinding for more than 50 minutes, fully and uniformly mixing, then putting into a pipe, compacting and molding, and taking a copper column as a lead at the rear end; the ionic liquid is N-octyl pyridine hexafluorophosphate, N-octyl pyridine tetrafluoroborate, N-octyl pyridine nitrate, N-hexyl pyridine hexafluorophosphate, N-hexyl pyridine tetrafluoroborate or N-hexyl pyridine nitrate, the mass ratio of the conductive carbon black to the ionic liquid is 2: 1-3: 1, and the mass ratio of the conductive carbon black to the conductive carbon black is adjusted according to the type of the ionic liquid;

step two; assembling a three-electrode system sensor and connecting a portable electrochemical analyzer: the sensor comprises a counter electrode, a reference electrode, a fixed disk (3) and a working electrode (5), wherein the working electrode is a conductive carbon black-ionic liquid paste electrode, the counter electrode is a platinum or glassy carbon electrode, the reference electrode is an Ag/AgCl electrode, the counter electrode, the reference electrode and the working electrode (5) are arranged on the fixed disk (3), and the sensor is connected with a portable electrochemical analyzer (7) sold in the market;

step three: formulating a heavy metal detection working curve: firstly, removing heavy metals in water by adopting an electrolysis method, then taking the heavy metals as a blank solution, adding a heavy metal standard solution into the blank solution to prepare a series of standard detection solutions with gradient concentration, wherein the volume ratio of the series of standard detection solutions to a supporting electrolyte is 2:1 mixing to form measuring liquid, setting anode stripping voltammetry detection parameters of an electrochemical analyzer, sequentially measuring current response values of the measuring liquid to obtain a working curve, and pre-storing the working curve into the electrochemical analyzer (7);

step four: pretreatment of a water sample: and (3) manually filtering a water sample collected in an investigation site by combining a disposable syringe with a 0.45-micron water system filter, wherein the filtered water sample is mixed with a supporting electrolyte in a volume ratio of 3:1 mixing to form a sample solution to be detected;

step five: and (3) water sample detection: and (3) putting the sensor into an electrolytic cell (8) containing a sample liquid to be measured, starting an electrochemical analyzer, detecting the target heavy metal by adopting a parameter anodic stripping voltammetry method which is the same as the established working curve, and bringing the measurement result into the working curve to obtain the concentration of the heavy metal ions in the measurement liquid to be measured.

Preferably, the mortar is made of stainless steel.

Preferably, the sensor fixing disc in step 2 is provided with a stirrer, and the stirrer is used for stirring in order to further shorten the detection time during the detection of the water sample.

The invention achieves the following beneficial effects: the three electrodes of the sensor are all solid, and can be used in a static state or in a certain shaking or vibrating condition. The conductive carbon black ionic liquid paste electrode is used for replacing a mercury-based working electrode in the prior art, so that the use of mercury is avoided, the safety is good, and the potential risks of health and environmental pollution are avoided; bismuth is not required to be preplated or co-plated, so that the efficiency is improved, and the cost is reduced; corrosion resistance and pollution resistance, and is suitable for water sample detection with high salt content and complex components; the stability is good, and the use is not influenced when the glass is placed in the air for 2 months at room temperature; the updating is easy; the sensitivity is high, the stability is good, the reproducibility is good, the detection requirement of heavy metal pollution is met, and the method can also be applied to accurate quantitative analysis of trace copper, zinc, lead, cadmium, mercury and arsenic in conventional water quality monitoring; the equipment is simple and portable, the operation is simple, the energy consumption is low, the result is automatically and digitally output, and the quantitative detection requirement of low cost on site is met; the pretreatment of the sample is simple, the response is fast, the result is obtained within minutes, and the data has high timeliness.

Drawings

FIG. 1: a schematic structural diagram of a working electrode;

FIG. 2: a top view of the sensor inverted;

FIG. 3: side view of the sensor:

FIG. 4: working schematic diagram of electrochemical heavy metal detection;

FIG. 5: a working curve diagram of heavy metal lead sample detection;

FIG. 6: a working curve diagram of heavy metal cadmium sample detection;

FIG. 7: a working curve diagram of heavy metal copper sample detection;

FIG. 8: and (3) a working curve diagram of heavy metal zinc sample detection.

Description of the drawings: 1. the electrochemical analyzer comprises an external thread copper column, 2 an internal thread tube body, 3 a fixed disc, 4 a composite electrode, 5 a working electrode, 6 a stirrer, 7 a portable electrochemical analyzer, 8 an electrolytic cell.

Detailed Description

The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

Step one, preparing a high-performance working electrode: placing 1.5g of conductive carbon black and 1.2g of ionic liquid N-octyl pyridine hexafluorophosphate into an agate mortar, manually grinding for 50 minutes under the protection of nitrogen, uniformly mixing, then placing the mixture into 5 internal-thread polytetrafluoroethylene tubes 2 with the inner diameter of 6mm, compacting and forming, taking a threaded copper column 1 outside the rear end as a lead, and grinding the lead on weighing paper to be flat before use, wherein the structure is shown in figure 1. The copper column 1 with the external thread is twisted, the paste is extruded out about 0.5mm and then ground flat, and the paste can be regenerated. The electrode is not affected when placed in the air at room temperature for 2 months.

Step two, assembling a three-electrode system sensor and connecting the three-electrode system sensor with a portable electrochemical analyzer: as shown in fig. 2 and 3, the sensor comprises a counter electrode, a reference electrode, a fixed disk 3 and a working electrode 5, in order to shorten the detection time, a polytetrafluoroethylene stirrer 6 is further arranged on the fixed disk of the sensor, the platinum counter electrode and the Ag/AgCl reference electrode are combined together to form a composite electrode 4, the composite electrode, the polytetrafluoroethylene stirrer and the working electrode are symmetrically arranged in a straight line on the circular fixed disk, the sensor is connected with a portable electrochemical analyzer 7, and the working schematic diagram is shown in fig. 4.

Step three, formulating a heavy metal lead detection working curve: taking 100mL of water sample to be detected, manually filtering the water sample by combining a disposable syringe and a 0.45-micron water filter, putting the filtered water sample into a 150mL glass electrolytic cell, inserting a sensor, electrolyzing for 10min at a-1.5V potential, then taking down a working electrode, twisting a copper column, extruding paste by about 0.5mm, and grinding to update the electrode. Electrolyzing for 10min again by the same parameters and method for 4 times to obtain blank solutions with copper, zinc, lead and cadmium respectively lower than 0.04 μ g/L, 0.05 μ g L, 0.01 μ g L and 0.01 μ g/L. 10mL of blank solution was taken and added to the standard lead solution to prepare a series of standard test solutions of 0.1. mu.g/L, 0.2. mu.g/L, 0.4. mu.g/L, 0.8. mu.g/L, 1.6. mu.g/L, 3.2. mu.g/L, 6.4. mu.g/L and 12.8. mu.g/L. The standard test solution was mixed with 0.8mol/L phosphate buffer solution (pH 2.0) at a volume ratio of 1:1 to form a measurement solution. Setting square wave anodic stripping voltammetry detection parameters of an electrochemical analyzer: amplitude, 25 mV; potential increment, 4 mV; frequency, 15 Hz; the enrichment potential is-0.9V; enrichment time 480 s; the stirring speed is 150 r/min; rest time 20 s; the initial potential for dissolution is-0.8V, and the final potential is-0.4V. And sequentially measuring the current response value of each measuring liquid, obtaining and storing a working curve (as shown in figure 5). The established lead working curve can be used for a long time, and does not need to be established before an actual sample is detected every time.

Step four, water sample pretreatment: the sample solution to be measured was obtained by manually filtering the mixture with a disposable syringe and a 0.45 μm water filter in combination, and mixing 10mL of the filtrate with 0.8mol/L of a phosphate buffer solution (pH 2.0) in a 25mL plastic electrolytic cell 8 at a volume ratio of 1: 1.

Step five, water sample detection: and putting the sensor into an electrolytic cell containing a sample liquid to be detected, starting an electrochemical analyzer 7, analyzing the sample liquid to be detected by adopting a square wave anodic stripping voltammetry with the same parameters as the formulated working curve, and substituting the result into the working curve to obtain the lead ion concentration of 0.88 mu g/L. The replicates were 11 times and the relative standard deviation of the readings was 6.5%.

The working curve making step is not counted, and the time from sampling to reading out the lead ion concentration value is about 15 min.

Example 2 in-situ determination of heavy metal cadmium in Water samples

Step one, preparing a high-performance working electrode: placing 5g of superconducting carbon black and 3g of ionic liquid N-hexyl pyridine tetrafluoroborate into a stainless steel mortar, mechanically grinding for 120 minutes under the protection of nitrogen, uniformly mixing, then placing the mixture into 5 internal-threaded polytetrafluoroethylene tubes with the inner diameter of 10mm, compacting and forming, wherein the external-threaded copper column at the rear end is a lead, and the structure is shown in figure 1. Before use, the paper is ground flat. The copper cylinder is twisted, the paste is extruded about 0.5mm and then ground flat, thus being renewable.

Step two, assembling a three-electrode system sensor and connecting the three-electrode system sensor with a portable electrochemical analyzer: as shown in fig. 2 and 3, the sensor comprises a counter electrode, a reference electrode, a fixed disk 3 and a working electrode 5, in order to shorten the detection time, a polytetrafluoroethylene stirrer 6 is further arranged on the fixed disk of the sensor, the platinum counter electrode and the Ag/AgCl reference electrode are combined together to form a composite electrode 4, the composite electrode, the polytetrafluoroethylene stirrer and the working electrode are symmetrically arranged in a line shape, and the sensor is connected with a portable electrochemical analyzer (the schematic diagram is shown in fig. 4).

Step three, formulating a heavy metal cadmium detection working curve: 100mL of water sample is manually filtered by a disposable syringe and a 0.45-micron water filter, the water sample is put into a 150mL glass electrolytic cell, a sensor is inserted, electrolysis is carried out for 10min at a-1.5V potential, then a working electrode is taken down, a copper column is twisted, and paste is extruded out by about 0.5mm and then ground flat to renew the electrode. Electrolyzing for 10min again by the same parameters and method for 4 times to obtain blank solutions with copper, zinc, lead and cadmium respectively lower than 0.04 μ g/L, 0.05 μ g/L, 0.01 μ g/L and 0.01 μ g/L. 10mL of blank solution is taken respectively, and added with cadmium standard solution to prepare 0.1. mu.g/L, 0.2. mu.g/L, 0.4. mu.g/L, 0.6. mu.g/L, 0.8. mu.g/L, 1.0. mu.g/L, 1.2. mu.g/L and 1.4. mu.g/L series standard detection solutions. The standard test solution was mixed with 0.2mol/L acetic acid-sodium acetate buffer solution (pH 4.0) at a volume ratio of 1: 1. Setting square wave anodic stripping voltammetry detection parameters of an electrochemical analyzer: amplitude, 25 mV; potential increment, 4 mV; frequency, 15 Hz; the enrichment potential is-1.0V; the enrichment time is 600 s; the stirring speed is 150 r/min; rest time 20 s; the initial dissolution potential is-1.0V, and the final dissolution potential is-0.8V. And sequentially measuring the current response value of each measuring liquid, obtaining and storing a working curve (as shown in figure 6). The established cadmium working curve can be used for a long time, and does not need to be established before an actual sample is detected every time.

Step four, water sample pretreatment: filtration was performed manually by a disposable syringe in combination with a 0.45 μm water filter. Mixing 10mL of filtrate with 0.2mol/L acetic acid-sodium acetate buffer solution (pH 4.0) in a volume ratio of 1:1 in a 25mL plastic electrolytic cell to obtain a sample solution to be detected.

Step five, water sample detection: the sensor is put into an electrolytic cell 8 containing sample liquid to be measured, an electrochemical analyzer 7 is started, the sample liquid to be measured is analyzed by adopting the anodic stripping voltammetry with the same parameters as the formulated working curve, and the result is substituted into the working curve to obtain the cadmium ion concentration of 0.35 mug/L. The replicates were 11 times and the relative standard deviation of the readings was 7.1%.

The working curve making step is not counted, and the time from sampling to reading out the cadmium ion concentration value is about 15 min.

Example 3 in-situ determination of heavy Metal copper in Water samples

Step one, preparing a high-performance working electrode: placing 5g of conductive carbon black and 3.2g of ionic liquid N-hexyl pyridine nitrate into a ceramic mortar, mechanically grinding for 120 minutes under the protection of nitrogen, uniformly mixing, then placing the mixture into 5 internal-thread polytetrafluoroethylene tubes with the inner diameter of 6mm, compacting and forming, wherein the outer thread copper column at the rear end is a lead, and the structure is shown in figure 1. Before use, the paper is ground flat. The copper cylinder is twisted, the paste is extruded about 0.5mm and then ground flat, thus being renewable.

Step two, assembling a three-electrode system sensor and connecting the three-electrode system sensor with a portable electrochemical analyzer: as shown in fig. 2 and 3, the sensor comprises a counter electrode, a reference electrode, a fixed disk 3 and a working electrode 5, in order to shorten the detection time, a polytetrafluoroethylene stirrer 6 is further arranged on the fixed disk of the sensor, the platinum counter electrode and the Ag/AgCl reference electrode are combined together to form a composite electrode 4, and the composite electrode, the polytetrafluoroethylene stirrer and the working electrode are symmetrically arranged in a straight line shape to form the sensor. The sensor is connected to a portable electrochemical analyzer 7 (see figure 4 for a schematic).

Step three, formulating a heavy metal copper detection working curve: 100mL of water sample is manually filtered by a disposable syringe and a 0.45-micron water filter, the water sample is put into a 150mL glass electrolytic cell, a sensor is inserted, electrolysis is carried out for 10min at a-1.5V potential, then a working electrode is taken down, a copper column is twisted, and paste is extruded out by about 0.5mm and then ground flat to renew the electrode. Electrolyzing for 10min again by the same parameters and method for 4 times to obtain blank solutions with copper, zinc, lead and cadmium respectively lower than 0.04 μ g/L, 0.05 μ g/L, 0.01 μ g/L and 0.01 μ g/L. 10mL of blank solution was added to the copper standard solution to prepare a series of standard test solutions of 0.1. mu.g/L, 0.5. mu.g/L, 1.0. mu.g/L, 2.0. mu.g/L, 3.0. mu.g/L, 4.0. mu.g/L, 5.0. mu.g/L and 6.0. mu.g/L. The standard test solution was mixed with 0.1mol/L ammonium acetate-acetic acid buffer solution (pH 5.0) at a volume ratio of 1: 1. Setting square wave anodic stripping voltammetry detection parameters of an electrochemical analyzer: amplitude, 25 mV; potential increment, 4 mV; frequency, 15 Hz; the enrichment potential is-0.5V; the enrichment time is 360 s; the stirring speed is 150 r/min; rest time 20 s; the initial potential for dissolution was-0.25V, and the final potential was 0.3V. And sequentially measuring the current response value of each measuring liquid, obtaining and storing a working curve (as shown in figure 7). The established copper working curve can be used for a long time, and is not required to be established before an actual sample is detected every time.

Step four, water sample pretreatment: filtration was performed manually by a disposable syringe in combination with a 0.45 μm water filter. Mixing 10mL of filtrate with 0.1mol/L ammonium acetate-acetic acid buffer solution (pH 5.0) in a volume ratio of 1:1 in a 25mL plastic electrolytic cell to obtain a sample solution to be detected.

Step five, water sample detection: and putting the sensor into an electrolytic cell containing a sample liquid to be detected, starting an electrochemical analyzer, analyzing the sample liquid to be detected by adopting a square wave anodic stripping voltammetry with the same parameters as the formulated working curve, and substituting the result into the working curve to obtain the copper ion concentration of 2.08 mu g/L. The readings were taken in parallel 11 times with a relative standard deviation of 6.0%.

The working curve making step is not counted, and the time from sampling to reading out the concentration value of the copper ions is about 15 min.

Example 4 in-situ determination of heavy Metal Zinc in Water samples

Step one, preparing a high-performance working electrode: placing 5g of conductive carbon black and 4g of ionic liquid N-octyl pyridine tetrafluoroborate into a polytetrafluoroethylene mortar, mechanically grinding for 120 minutes under the protection of nitrogen, uniformly mixing, then placing the mixture into 5 internal-thread resin tubes with the inner diameter of 6mm, compacting and molding, wherein the rear end is provided with an external-thread copper column as a lead, and the structure is shown in figure 1. Before use, the paper is ground flat. The copper cylinder is twisted, the paste is extruded about 0.5mm and then ground flat, thus being renewable.

Step two, assembling a three-electrode system sensor and connecting the three-electrode system sensor with a portable electrochemical analyzer: the sensor comprises a counter electrode, a reference electrode, a fixed disk and a working electrode, wherein the platinum column counter electrode, the Ag/AgCl reference electrode and the working electrode are arranged on the fixed disk in a shape like a Chinese character pin, and the sensor is connected with a commercially available HM-3000P type portable electrochemical analyzer.

Step three, formulating a heavy metal zinc detection working curve: 100mL of water sample is manually filtered by a disposable syringe and a 0.45-micron water filter, the water sample is put into a 150mL glass electrolytic cell, a sensor is inserted, electrolysis is carried out for 10min at a-1.5V potential, then a working electrode is taken down, a copper column is twisted, and paste is extruded out by about 0.5mm and then ground flat to renew the electrode. Electrolyzing for 10min again by the same parameters and method for 4 times to obtain blank solutions with copper, zinc, lead and cadmium respectively lower than 0.04 μ g/L, 0.05 μ g/L, 0.01 μ g/L and 0.01 μ g/L. 10mL of the blank solution was added with the zinc standard solution to prepare a series of standard test solutions of 1.0. mu.g/L, 2.0. mu.g/L, 4.0. mu.g/L, 8.0. mu.g/L, 12.0. mu.g/L, 16.0. mu.g/L, 20.0. mu.g/L, 24.0. mu.g/L, and 28.0. mu.g/L. The standard test solution was mixed with 0.1mol/L ammonium acetate-acetic acid buffer solution (pH 5.0) at a volume ratio of 1:1 to form a measurement solution. Setting square wave anodic stripping voltammetry detection parameters of an electrochemical analyzer: amplitude, 25 mV; potential increment, 4 mV; frequency, 15 Hz; the enrichment potential is-1.35V; the enrichment time is 600 s; rest time 20 s; the initial dissolution potential was-1.15V and the final dissolution potential was-0.85V. And sequentially measuring the current response value of each measuring liquid, obtaining and storing a working curve (as shown in figure 8). The formulated zinc working curve can be used for a long time, and does not need to be formulated before an actual sample is detected every time.

Step five, water sample detection: and putting the sensor into an electrolytic cell containing a sample liquid to be detected, starting an electrochemical analyzer, analyzing the sample liquid to be detected by adopting a square wave anodic stripping voltammetry with the same parameters as the formulated working curve, and substituting the result into the working curve to obtain the zinc ion concentration of 9.2 mug/L. The replicates were 11 times and the relative standard deviation of the readings was 5.4%.

The working curve making step is not counted, and the time from sampling to reading out the concentration value of the copper ions is about 20 min.

The above is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.

Claims

1. A method for rapidly detecting heavy metals in water quality is characterized by comprising the following steps: the method comprises the following steps:

2. The method for rapidly detecting the heavy metal in the water quality according to claim 1, which is characterized in that: the mortar is made of stainless steel.

3. The method for rapidly detecting the heavy metal in the water quality according to claim 1, which is characterized in that: and 2, a stirrer is arranged on the sensor fixing disc in the step 2, and stirring is carried out in order to further shorten the detection time during the detection of the water sample.