A high-accuracy antimony water quality analysis detection process

Abstract

The application provides a reagent for testing antimony in water by an anodic voltammetric stripping method, comprising an electrolyte; the electrolyte comprises ascorbic acid, potassium iodide, hydrochloric acid and water; the concentration of the ascorbic acid is 0.06-0.6 mol / L; the concentration of the potassium iodide is 0.09-1.5 mol / L; and the concentration of the hydrochloric acid is 0.01-1.0 mol / L. The application also provides a process for detecting the content of antimony in water by an anodic voltammetric stripping method. The electrolyte formula provided by the application and the ASV method antimony water quality analysis and detection process can effectively test the content of antimony in water, film plating is performed each time for testing, normal operation of the instrument is ensured, the maintenance cost is low, and the indication error and repeatability of data can meet the detection of antimony water samples.

Description

Technical Field

[0001] This invention belongs to the field of antimony water quality analysis and detection technology, and relates to a reagent for testing antimony in water by anodic voltammetric stripping method, a process for testing antimony content in water by anodic voltammetric stripping method, and particularly to a reagent for testing antimony in water by anodic voltammetric stripping method and a highly accurate antimony water quality analysis and detection process. Background Technology

[0002] Antimony is a specific indicator for centralized drinking water surface water sources and is not a conventional indicator of drinking water quality. Currently, there is a need for monitoring it in areas rich in non-ferrous metal minerals in China. Although antimony is one of the parameters for evaluating surface water quality, its online monitoring is quite difficult. The main reasons are: 1) Spectrophotometric testing procedures are complex, reagents are prone to deterioration, and subsequent cleaning is difficult.

[0003] Spectrophotometric Determination of Antimony: SL 92-1994 Determination of Antimony (5-Br-PADAP Spectrophotometric Method), this standard was abolished on May 7, 2020. This method uses organic solvents, making subsequent cleaning difficult and instrument maintenance challenging. Acetone is used as a solubilizer. In the presence of potassium iodide and in hydrochloric acid medium, trivalent antimony reacts with 2-(5-bromo-2-pyridiniazo)-5-diethylaminophenol (5-Br-PADAP) to form a stable purple-red complex, with absorbance measured at 600 nm. The core reagent is 5-Br-PADAP, which reacts with antimony in a strongly acidic environment, with potassium iodide acting as a reducing agent to allow antimony to exist in its trivalent ionic form. However, this method requires acetone or other easily manufactured toxic reagents as a solubilizer, resulting in significant pollution.

[0004] Therefore, finding a more suitable way to test the antimony content in water and solving the problems mentioned above in existing testing methods has become one of the urgent problems to be solved by many front-line researchers in the industry. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a reagent for testing antimony in water by anodic voltammetric stripping spectroscopy, a process for detecting antimony content in water by anodic voltammetric stripping spectroscopy, and particularly a highly accurate antimony water quality analysis and detection process. The antimony water quality analysis and detection process provided by the present invention, using a unique electrolyte formulation and testing method, can effectively test the antimony content in water, and the indication error and repeatability of the data can meet the requirements for antimony water sample detection.

[0006] This invention provides a reagent for testing antimony in water using an anodic voltammetric stripping method, comprising an electrolyte;

[0007] The electrolyte comprises ascorbic acid, potassium iodide, hydrochloric acid, and water;

[0008] The concentration of ascorbic acid is 0.06~0.6 mol / L;

[0009] The concentration of potassium iodide is 0.09~1.5 mol / L;

[0010] The concentration of the hydrochloric acid is 0.01~1.0 mol / L.

[0011] Preferably, the reagent further includes a digestion solution;

[0012] The digestion solution includes a nitric acid solution;

[0013] The reagents also include electroplating solutions;

[0014] The electroplating solution includes a mercury standard solution.

[0015] Preferably, the concentration of the nitric acid solution is 0.03~0.3 mol / L;

[0016] The concentration of the mercury standard solution is 0.0003~0.0025 mol / L;

[0017] The electrolyte is used to clean the mercury film on the working electrode;

[0018] The electrolyte is used to coat the working electrode with a mercury film.

[0019] The electrolyte is used to test the voltammetric dissolution curve of antimony standard solution.

[0020] This invention provides a process for determining the antimony content in water using an anodic voltammetric stripping method, comprising the following steps:

[0021] 1) Place the antimony standard solution and electrolyte in an electrolytic cell, clean the electrodes by applying a positive potential under ultrasonication, and then drain the water;

[0022] 2) Place the electroplating solution and electrolyte in the electrolytic cell after the above steps to electroplat the electrodes with a mercury film;

[0023] 3) Place the antimony standard solution and electrolyte into the electrolytic cell after the above steps, react to obtain the first voltammetric dissolution curve, then add the correction solution into the electrolytic cell, react again to obtain the second voltammetric dissolution curve;

[0024] 4) Empty the electrolytic cell after the above steps, place the antimony standard solution and electrolyte in the electrolytic cell, react, and obtain the third voltammetric dissolution curve. Then add the digested sample to be tested into the electrolytic cell, react again, and obtain the fourth voltammetric dissolution curve.

[0025] 5) Based on the first, second, third, and fourth voltammetric dissolution curves obtained in the above steps, the antimony content in the sample to be tested is calculated.

[0026] The electrolyte, digestion solution, or electroplating solution includes the electrolyte, digestion solution, or electroplating solution among the reagents described in any one of the above technical solutions.

[0027] Preferably, in step 1), the concentration of the antimony standard solution is 0.01~0.1 mg / L;

[0028] In step 1), the volume ratio of antimony standard solution to electrolyte is (1~2):(5~1).

[0029] The cleaning potential is 200~800mV;

[0030] The cleaning time is 20~100s.

[0031] Preferably, in step 2), the volume ratio of the electroplating solution to the electrolyte is (1~2):(3~1);

[0032] The enrichment potential of the electroplated mercury film is -1500 ~ -900mV;

[0033] The electroplating time for the mercury film is 100~600s;

[0034] In step 2), the ratio of the total volume of the electroplating solution and the electrolyte to the total volume of the antimony standard solution and the electrolyte in step 3) is (1~3):(3~1).

[0035] Preferably, in step 3), the concentration of the antimony standard solution is 0.01~0.1 mg / L;

[0036] In step 3), the volume ratio of the antimony standard solution to the electrolyte is (1~2):(5~1).

[0037] In step 3), the enrichment potential of the reaction process is -1300~-300mV;

[0038] In step 3), the enrichment time of the reaction process is 100~600s;

[0039] In step 3), the resting potential of the reaction process is -400~-200mV;

[0040] In step 3), the resting time of the reaction process is 5~30s;

[0041] In step 3), the dissolution range of the reaction process is -200mV to +500mV;

[0042] In step 3), the step voltage of the reaction process is 1~5mV;

[0043] In step 3), the scanning speed of the reaction process is 200~800mV / s;

[0044] The calibration solution includes an antimony standard solution or a mixed solution of antimony, hydrochloric acid, and water.

[0045] The concentration of the calibration solution is 0.01~0.2 mg / L.

[0046] Preferably, in step 3), the total volume ratio of the antimony standard solution and the electrolyte to the volume ratio of the calibration solution is (20~1):(1~20).

[0047] In step 3), the enrichment potential of the second reaction process is -1300~-300mV;

[0048] In step 3), the enrichment time of the second reaction process is 100~600s;

[0049] In step 3), the resting potential of the second reaction process is -400~-200mV;

[0050] In step 3), the resting time for the second reaction process is 5-30 seconds;

[0051] In step 3), the dissolution range of the second reaction process is -200mV to +500mV;

[0052] In step 3), the step voltage for the second reaction process is 1~5mV;

[0053] In step 3), the scanning speed of the second reaction process is 200~800mV / s;

[0054] In step 4), the concentration of the antimony standard solution is 0.01~0.1 mg / L;

[0055] In step 4), the volume ratio of antimony standard solution to electrolyte is (1~2):(5~1).

[0056] Preferably, in step 4), the enrichment potential of the reaction process is -1300 to -300 mV;

[0057] In step 4), the enrichment time of the reaction process is 100~600s;

[0058] In step 4), the resting potential of the reaction process is -400~-200mV;

[0059] In step 4), the resting time of the reaction process is 5~30s;

[0060] In step 4), the dissolution range of the reaction process is -200mV to +500mV;

[0061] In step 4), the step voltage of the reaction process is 1~5mV;

[0062] In step 4), the scanning speed of the reaction process is 200~800mV / s;

[0063] In step 4), the enrichment potential of the second reaction process is -1300~-300mV;

[0064] In step 4), the enrichment time of the second reaction process is 100~600s;

[0065] In step 4), the resting potential of the second reaction process is -400~-200mV;

[0066] In step 4), the resting time for the second reaction process is 5-30 seconds;

[0067] In step 4), the dissolution range of the second reaction process is -200mV to +500mV;

[0068] In step 4), the step voltage for the second reaction process is 1~5mV;

[0069] In step 4), the scanning speed of the second reaction process is 200~800mV / s;

[0070] The electrode includes a working electrode.

[0071] Preferably, the digested sample to be tested is obtained by mixing and reacting the digestion solution and the sample to be tested in a closed heating system;

[0072] The temperature for the heating and mixing reaction is 90~120℃;

[0073] The heating and mixing reaction time is 300~900s;

[0074] The volume ratio of the digestion solution to the sample to be tested is (1~30):1;

[0075] The ratio of the volume of the digested sample to the total volume of the antimony standard solution and electrolyte is (20:1) to (1:20).

[0076] The calculation steps include peak height normalization;

[0077] The electrode material includes glassy carbon electrode or gold electrode.

[0078] This invention provides a reagent for testing antimony in water using the anodic voltammetric stripping method, comprising an electrolyte; the electrolyte includes ascorbic acid, potassium iodide, hydrochloric acid, and water; the concentration of ascorbic acid is 0.06~0.6 mol / L; the concentration of potassium iodide is 0.09~1.5 mol / L; and the concentration of hydrochloric acid is 0.01~1.0 mol / L. Compared with existing technologies, this invention addresses the problems of current methods for testing antimony content in water. Research suggests that the ASV method has superior research prospects compared to traditional spectrophotometric methods for antimony testing. Anodic stripping voltammetry (ASV) is an electrochemical detection method. After digestion, the water sample is uniformly oxidized to high-valence metal ions, which are then mixed with the electrolyte in a detection cell. A reduction voltage is applied to the working electrode to enrich and reduce the analyte ions in the mixture to the electrode surface. After a short resting period, the analyte is stripped in reverse using a linear scan. The concentrations of different metal ions are qualitatively and quantitatively analyzed by measuring the peak current and the peak voltage. Although some existing literature involves the ASV method for testing antimony content in water, publicly available literature shows that while the ASV method can be used to test antimony, it also has the following problems: the literature on this method for testing antimony is relatively old, and directly applying the method described in the literature results in the instrument failing to detect the peak correctly. Even using the commercially available ASV method GR-3600 online heavy metal monitoring instrument (Hangzhou Green Clean Technology Co., Ltd.) and its formulation, the target peak shape was not observed. Furthermore, the electrolyte reagent formulations in the literature are inconsistent, ranging from hydrochloric acid-anhydrous ethanol to malonic acid-hydrochloric acid solution, or the addition of organic matter. Moreover, when using the ASV method to test the formulations provided in the literature, the test results could not be reproduced. In addition, most of the formulations have the ability to erode the mercury film in the working electrode, and the coating needs to be re-coated after more than 4 complete tests.

[0079] Based on this, the present invention specifically designs an electrolyte formulation and corresponding testing method for testing antimony in water using the ASV method. The electrolyte formulation provided by the present invention exhibits strong mercury film ablation effect, ensuring normal testing of antimony in water and reducing the maintenance frequency of the working electrode. A new testing procedure has been designed accordingly, enabling the normal testing of antimony in water. The ASV method for antimony water quality analysis and detection provided by the present invention can effectively test the antimony content in water. Coating is performed for each test to ensure normal instrument operation, resulting in low maintenance costs. Furthermore, the data indication error and repeatability meet the requirements for antimony water sample detection.

[0080] Experimental results show that the electrolyte formulation and corresponding testing method for testing antimony in water using the ASV method provided by this invention are not significantly different from the existing ASV method GR-3600 online heavy metal monitoring instrument in terms of indication error, repeatability, and other indicators, and meet the instrument design requirements. Attached Figure Description

[0081] Figure 1 A simplified schematic diagram illustrating the process of detecting antimony content in water using the anodic voltammetric stripping method provided by the present invention.

[0082] Figure 2 A simplified schematic diagram of the electrolytic cell used in the anodic voltammetric stripping method for detecting antimony content in water provided by this invention. Detailed Implementation

[0083] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims.

[0084] There are no particular restrictions on the source of any raw materials used in this invention; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0085] There are no particular restrictions on the purity of any raw materials used in this invention. However, it is preferred to use analytical grade or conventional purity used in the field of water quality testing.

[0086] This invention provides a reagent for testing antimony in water using an anodic voltammetric stripping method, comprising an electrolyte;

[0087] The electrolyte comprises ascorbic acid, potassium iodide, hydrochloric acid, and water;

[0088] The concentration of ascorbic acid is 0.06~0.6 mol / L;

[0089] The concentration of potassium iodide is 0.09~1.5 mol / L;

[0090] The concentration of the hydrochloric acid is 0.01~1.0 mol / L.

[0091] In this invention, the concentration of ascorbic acid is 0.06~0.6 mol / L, which can be 0.1~0.5 mol / L, and preferably 0.2~0.4 mol / L.

[0092] In this invention, the concentration of potassium iodide is 0.09~1.5 mol / L, which can be 0.9~1.3 mol / L, and preferably 1.0~1.31 mol / L.

[0093] In this invention, the concentration of hydrochloric acid is 0.01~1.0 mol / L, which can be 0.1~0.8 mol / L, and preferably 0.3~0.5 mol / L.

[0094] In this invention, the reagent preferably also includes a digestion solution.

[0095] In this invention, the digestion solution preferably includes a nitric acid solution.

[0096] In this invention, the reagent preferably also includes an electroplating solution.

[0097] In this invention, the electroplating solution preferably includes a mercury standard solution.

[0098] In this invention, the concentration of the nitric acid solution is preferably 0.03~0.3 mol / L, more preferably 0.05~0.2 mol / L, and even more preferably 0.07~0.1 mol / L.

[0099] In this invention, the concentration of the mercury standard solution is preferably 0.0003~0.0025 mol / L, more preferably 0.0005~0.002 mol / L, and even more preferably 0.001~0.0015 mol / L.

[0100] In this invention, the electrolyte is preferably used to clean the mercury film on the working electrode.

[0101] In this invention, the electrolyte is preferably used to coat the working electrode with a mercury film.

[0102] In this invention, the electrolyte is preferably used to test the voltammetric dissolution curve of an antimony standard solution.

[0103] This invention provides a process for determining the antimony content in water using an anodic voltammetric stripping method, comprising the following steps:

[0104] 1) Place the antimony standard solution and electrolyte in an electrolytic cell, clean the electrodes by applying a positive potential under ultrasonication, and then drain the water;

[0105] 2) Place the electroplating solution and electrolyte in the electrolytic cell after the above steps, and electroplat the electrodes with a mercury film;

[0106] 3) Place the antimony standard solution and electrolyte into the electrolytic cell after the above steps, react to obtain the first voltammetric dissolution curve, then add the correction solution into the electrolytic cell, react again to obtain the second voltammetric dissolution curve;

[0107] 4) Empty the electrolytic cell after the above steps, place the antimony standard solution and electrolyte in the electrolytic cell, react, and obtain the third voltammetric dissolution curve. Then add the digested sample to be tested into the electrolytic cell, react again, and obtain the fourth voltammetric dissolution curve.

[0108] 5) Based on the first, second, third, and fourth voltammetric dissolution curves obtained in the above steps, the antimony content in the sample to be tested is obtained after calculation.

[0109] The electrolyte, digestion solution, or electroplating solution includes the electrolyte, digestion solution, or electroplating solution among the reagents described in any one of the above technical solutions.

[0110] The present invention first places an antimony standard solution and an electrolyte in an electrolytic cell, cleans the electrodes by applying a positive potential under the action of ultrasound, and then drains the electrolyte.

[0111] In this invention, in step 1), the concentration of the antimony standard solution is preferably 0.01~0.1 mg / L, more preferably 0.03~0.08 mg / L, and even more preferably 0.05~0.06 mg / L.

[0112] In this invention, in step 1), the volume ratio of antimony standard solution to electrolyte is preferably (1~2):(5~1), more preferably (1.4~1.6):(5~1), and even more preferably (1~2):(4~2).

[0113] In this invention, the cleaning potential is preferably 200~800mV, more preferably 300~700mV, and even more preferably 400~600mV.

[0114] In this invention, the cleaning time is preferably 20-100s, more preferably 35-85s, and even more preferably 50-70s.

[0115] In this invention, the electroplating solution and electrolyte are then placed in the electrolytic cell after the above steps to electroplat the electrodes with a mercury film.

[0116] In this invention, in step 2), the volume ratio of the electroplating solution to the electrolyte is preferably (1~2):(3~1), more preferably (1.4~1.6):(3~1), and even more preferably (1~2):(2.5~1.5).

[0117] In this invention, the enrichment potential of the electroplated mercury film is preferably -1500 ~ -900mV, more preferably -1400 ~ -1000mV, and even more preferably -1300 ~ -1100mV.

[0118] In this invention, the electroplating time for the mercury film is preferably 100-600s, more preferably 200-500s, and even more preferably 300-400s.

[0119] In this invention, in step 2), the ratio of the total volume of the electroplating solution and the electrolyte to the total volume of the antimony standard solution and the electrolyte in step 3) is preferably (1~3):(3~1), more preferably (1.5~2.5):(3~1), and even more preferably (3~1):(1.5~2.5).

[0120] The present invention then places the antimony standard solution and electrolyte into the electrolytic cell after the above steps, and after the reaction, obtains the first voltammetric dissolution curve. Then, the correction solution is added to the electrolytic cell, and after the reaction is repeated, the second voltammetric dissolution curve is obtained.

[0121] In this invention, in step 3), the concentration of the antimony standard solution is preferably 0.01~0.1 mg / L, more preferably 0.03~0.08 mg / L, and even more preferably 0.05~0.06 mg / L.

[0122] In this invention, in step 3), the volume ratio of antimony standard solution to electrolyte is preferably (1~2):(5~1), more preferably (1.4~1.6):(5~1), and even more preferably (1~2):(4~2).

[0123] In this invention, in step 3), the enrichment potential of the reaction process is preferably -1300~-300mV, more preferably -1000~-400mV, and even more preferably -700~-500mV.

[0124] In this invention, in step 3), the enrichment time of the reaction process is preferably 100-600s, more preferably 150-500s, and even more preferably 200-400s.

[0125] In this invention, in step 3), the resting potential of the reaction process is preferably -400~-200mV, more preferably -350~-250mV, and even more preferably -300mV.

[0126] In this invention, the resting time of the reaction process in step 3) is preferably 5~30s, more preferably 10~25s, and even more preferably 15~20s.

[0127] In this invention, in step 3), the dissolution range of the reaction process is preferably -200mV to +500mV, more preferably -150mV to +400mV, even more preferably -100mV to +300mV, or -250mV to +190mV.

[0128] In this invention, in step 3), the step voltage of the reaction process is preferably 1~5mV, more preferably 1.5~4.5mV, more preferably 2~4mV, and even more preferably 2.5~3.5mV.

[0129] In this invention, in step 3), the scanning speed of the reaction process is preferably 200~800mV / s, more preferably 250~700mV / s, more preferably 300~600mV / s, and even more preferably 400~600mV / s.

[0130] In this invention, the calibration solution preferably includes an antimony standard solution or a mixed solution of antimony, hydrochloric acid, and water.

[0131] In this invention, the concentration of the calibration solution is preferably 0.01~0.2 mg / L, more preferably 0.05~0.2 mg / L, and even more preferably 0.1~0.15 mg / L.

[0132] In this invention, the volume ratio of the total volume of the antimony standard solution and the electrolyte to the volume of the calibration solution is preferably (20~1):(1~20), more preferably (15~5):(1~20), even more preferably (12~8):(1~20), even more preferably (20~1):(5~16), and even more preferably (20~1):(9~12).

[0133] In this invention, in step 3), the enrichment potential of the secondary reaction process is preferably -1300~-300mV, more preferably -1000~-400mV, and even more preferably -700~-500mV.

[0134] In this invention, the enrichment time of the second reaction process in step 3) is preferably 100~600s, more preferably 150~500s, and even more preferably 200~400s.

[0135] In this invention, in step 3), the resting potential of the second reaction process is preferably -400~-200mV, more preferably -350~-250mV, and even more preferably -300mV.

[0136] In this invention, the resting time of the second reaction process in step 3) is preferably 5-30s, more preferably 10-25s, and even more preferably 15-20s.

[0137] In this invention, in step 3), the dissolution range of the second reaction process is preferably -200mV to +500mV, more preferably -150mV to +400mV, even more preferably -100mV to +300mV, or -250mV to +190mV.

[0138] In this invention, in step 3), the step voltage of the second reaction process is preferably 1~5mV, more preferably 1.5~4.5mV, more preferably 2~4mV, and even more preferably 2.5~3.5mV.

[0139] In this invention, in step 3), the scanning speed of the second reaction process is preferably 200~800mV / s, more preferably 250~700mV / s, more preferably 300~600mV / s, and even more preferably 400~600mV / s.

[0140] The present invention then empties the electrolytic cell after the above steps, places the antimony standard solution and electrolyte in the electrolytic cell, reacts, and obtains the third voltammetric dissolution curve. Then, the digested sample to be tested is added to the electrolytic cell, reacts again, and obtains the fourth voltammetric dissolution curve.

[0141] In this invention, in step 4), the concentration of the antimony standard solution is preferably 0.01~0.1 mg / L, more preferably 0.03~0.08 mg / L, and even more preferably 0.05~0.06 mg / L.

[0142] In this invention, in step 4), the volume ratio of antimony standard solution to electrolyte is preferably (1~2):(5~1), more preferably (1.4~1.6):(5~1), and even more preferably (1~2):(4~2).

[0143] In this invention, in step 4), the enrichment potential of the reaction process is preferably -1300~-300mV, more preferably -1000~-400mV, and even more preferably -700~-500mV.

[0144] In this invention, the enrichment time of the reaction process in step 4) is preferably 100~600s, more preferably 150~500s, and even more preferably 200~400s.

[0145] In this invention, in step 4), the resting potential of the reaction process is preferably -400~-200mV, more preferably -350~-250mV, and even more preferably -300mV.

[0146] In this invention, the resting time of the reaction process in step 4) is preferably 5~30s, more preferably 10~25s, and even more preferably 15~20s.

[0147] In this invention, in step 4), the dissolution range of the reaction process is preferably -200mV to +500mV, more preferably -150mV to +400mV, even more preferably -100mV to +300mV, or -250mV to +190mV.

[0148] In this invention, in step 4), the step voltage of the reaction process is preferably 1~5mV, more preferably 1.5~4.5mV, more preferably 2~4mV, and even more preferably 2.5~3.5mV.

[0149] In this invention, in step 4), the scanning speed of the reaction process is preferably 200~800mV / s, more preferably 250~700mV / s, more preferably 300~600mV / s, and even more preferably 400~600mV / s.

[0150] In this invention, in step 4), the enrichment potential of the second reaction process is preferably -1300~-300mV, more preferably -1000~-400mV, and even more preferably -700~-500mV.

[0151] In this invention, in step 4), the enrichment time of the second reaction process is preferably 100-600s, more preferably 150-500s, and even more preferably 200-400s.

[0152] In this invention, in step 4), the resting potential of the second reaction process is preferably -400~-200mV, more preferably -350~-250mV, and even more preferably -300mV.

[0153] In this invention, in step 4), the resting time of the second reaction process is preferably 5-30s, more preferably 10-25s, and even more preferably 15-20s.

[0154] In this invention, in step 4), the dissolution range of the second reaction process is preferably -200mV to +500mV, more preferably -150mV to +400mV, even more preferably -100mV to +300mV, or -250mV to +190mV.

[0155] In this invention, in step 4), the step voltage of the second reaction process is preferably 1~5mV, more preferably 1.5~4.5mV, more preferably 2~4mV, and even more preferably 2.5~3.5mV.

[0156] In this invention, in step 4), the scanning speed of the second reaction process is preferably 200~800mV / s, more preferably 250~700mV / s, more preferably 300~600mV / s, and even more preferably 400~600mV / s.

[0157] In this invention, the enrichment potential and time, resting potential and time, dissolution range, step voltage, and scan rate are all reaction conditions for any one of the first to fourth voltammetric dissolution curves. That is, the reaction conditions for any one of the first to fourth voltammetric dissolution curves in this invention are independently selected using the above parameter combinations. Specifically, in this invention, the first to fourth voltammetric dissolution curves correspond to four peaks A, B, C, and D, respectively, where C is equivalent to A, D is the sample + C peak height, and B is equivalent to the standard solution + A peak height.

[0158] In this invention, the electrode preferably includes a working electrode.

[0159] In this invention, the digested test sample is preferably obtained by mixing and reacting the digestion solution and the test sample in a closed heating system.

[0160] In this invention, the temperature of the heating and mixing reaction is preferably 90~120℃, more preferably 95~115℃, and even more preferably 100~110℃.

[0161] In this invention, the heating and mixing reaction time is preferably 300-900s, more preferably 400-800s, and even more preferably 500-700s.

[0162] In this invention, the volume ratio of the digestion solution to the sample to be tested is preferably (1~30):1, more preferably (5~25):1, and even more preferably (10~20):1.

[0163] In this invention, the volume ratio of the digested sample to the total volume of the antimony standard solution and the electrolyte is preferably (20~1):(1~20), more preferably (15~5):(1~20), even more preferably (12~8):(1~20), even more preferably (20~1):(5~16), and even more preferably (20~1):(9~12).

[0164] Finally, based on the first, second, third, and fourth voltammetric dissolution curves obtained from the above steps, the antimony content in the sample to be tested is calculated.

[0165] In this invention, the calculation steps preferably include peak height normalization. Specifically, when using peak height normalization, the A / B and C / D ratios and conditions are assumed to be consistent;

[0166] ).

[0167] In this invention, the electrode material preferably includes a glassy carbon electrode or a gold electrode, more preferably a glassy carbon electrode. Specifically, the electrolyte is highly corrosive to the gold electrode; after continuous testing for more than a week, the gold electrode becomes unusable and needs to be replaced promptly.

[0168] To complete and refine the overall technical solution, and to better improve the accuracy and repeatability of anodic voltammetric stripping spectroscopy for detecting antimony content in water, while reducing data indication errors, the preferred specific steps of the anodic voltammetric stripping spectroscopy for detecting antimony content in water include the following:

[0169] The reaction process of the antimony water quality analyzer designed in this invention.

[0170] 1. Reagent formulation: Electrolyte (ascorbic acid 0.3mol / L, potassium iodide 0.5mol / L, hydrochloric acid 0.4mol / L); digestion solution (0.1% nitric acid); electroplating solution (mercury standard solution 100mg / L).

[0171] 2. Test principle:

[0172] ① Iodine ions react with the digested antimony ions in the water sample via a redox reaction, producing stable SbO at a pH between 1 and 3. ＋ The configuration allows antimony to be detected as a peak normally;

[0173] ②Ascorbic acid protects potassium iodide from deterioration in the short term and can maintain its properties for at least 2 weeks;

[0174] ③ Hydrochloric acid provides an acidic environment, allowing the reduced antimony ions to form stable SbO in the reaction system. ＋ The configuration exists.

[0175] ④ Potassium iodide and ascorbic acid can mask interfering ions such as copper and mercury.

[0176] 3. The testing process for the main body of the instrument is as follows:

[0177] The parameters for the anodic stripping method are set as follows: cleaning potential and time: 500mV, 60s; coating enrichment potential and time: -1300mV, 300s; (enrichment potential and time: -500mV, 200s; resting potential and time: -300mV, 20s. Stripping range: -250mV~190mV, step voltage 2.5mV, scan speed: 600mV / s). These are the overall conditions for the ABCD process.

[0178] ① Cleaning the mercury film: First, the instrument draws 10ml of spiked electrolyte into the electrolytic cell. Following the parameters above, a positive cleaning potential of 500mV is applied, accompanied by ultrasonic cleaning. This pretreatment of the working electrode removes residual mercury film and redox products from its surface. The mercury film is then dissolved and drained.

[0179] ②Automatic coating: Draw 5ml of electroplating solution and 5ml of electrolyte into the above electrolytic cell, and coat according to the set parameters. At this time, a clear silver-gray mercury film will appear on the surface of the working electrode, and the texture is uniform.

[0180] ③ The instrument draws 10 ml of the spiked electrolyte into the electrolytic cell and performs a mixing reaction according to the parameters above to obtain the voltammetric dissolution curve. The peak height at this time is recorded as A.

[0181] ④ Draw 5 ml of calibration solution (known concentration) into the above electrolytic cell, mix and react, and record the peak height at this time as B.

[0182] ⑤ Empty the electrolytic cell, draw 10 ml of the spiked electrolyte into the electrolytic cell, mix and react, and record the peak height at this time as C.

[0183] ⑥ Draw 5 ml of the digested sample into the electrolytic cell, mix and react, and record the peak height at this point as D. Calculate the concentration of the sample based on the peak heights ABCD mentioned above.

[0184] See Figure 1 , Figure 1 A simplified schematic diagram illustrating the process of detecting antimony content in water using the anodic voltammetric stripping method provided by this invention.

[0185] See Figure 2 , Figure 2 This is a simplified structural diagram of the electrolytic cell used in the anodic voltammetric stripping method for detecting antimony content in water provided by the present invention. In the diagram, 1-reference electrode; 2-electrolytic cell body; 3-working electrode (glassy carbon electrode); 4-ultrasonic transducer; 5-auxiliary electrode.

[0186] The present invention provides a reagent for testing antimony in water using the anodic voltammetric stripping method (ASV) and a highly accurate antimony water quality analysis and detection process. The present invention specifically designs an electrolyte formulation and corresponding testing method for testing antimony in water using the ASV method. The electrolyte formulation provided by the present invention has a strong effect on mercury film ablation, ensuring normal testing of antimony in water and reducing the maintenance frequency of the working electrode. A new testing procedure has been designed accordingly, enabling normal testing of antimony in water. The ASV method antimony water quality analysis and detection process provided by the present invention can effectively test the antimony content in water. Coating is performed for each test to ensure normal instrument operation, low maintenance costs, and the indication error and repeatability of the data meet the requirements for antimony water sample detection.

[0187] Experimental results show that the electrolyte formulation and corresponding testing method for testing antimony in water using the ASV method provided by this invention are not significantly different from the existing ASV method GR-3600 online heavy metal monitoring instrument in terms of indication error, repeatability, and other indicators, and meet the instrument design requirements.

[0188] To further illustrate the present invention, the following describes in detail, with reference to embodiments, a reagent for testing antimony in water by anodic voltammetric stripping and a process for detecting antimony content in water by anodic voltammetric stripping. However, it should be understood that these embodiments are implemented under the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operating procedures, only to further illustrate the features and advantages of the present invention, and not to limit the scope of protection of the claims of the present invention. The scope of protection of the present invention is not limited to the following embodiments.

[0189] Example

[0190] The parameters for the anodic stripping method were set as follows: cleaning potential and time: 500mV, 60s.

[0191] Coating enrichment potential and time: -1300mV, 300s.

[0192] Enrichment potential and time: -500mV, 200s; Resting potential and time: -300mV, 20s. Dissolution range: -250mV~190mV, step voltage 2.5mV, scan rate: 600mV / s. Overall conditions for the ABCD process.

[0193] ① Cleaning the mercury film: First, the instrument draws 10ml of spiked electrolyte into the electrolytic cell. Following the parameters above, a positive cleaning potential of 500mV is applied, accompanied by ultrasonic cleaning. This pretreatment of the working electrode removes residual mercury film and redox products from its surface. The mercury film is then dissolved and drained. The ultrasonic device inside the electrolytic cell is shown in Figure 4-2.

[0194] ②Automatic coating: Draw 5ml of electroplating solution and 5ml of electrolyte into the above electrolytic cell, and coat according to the set parameters. At this time, a clear silver-gray mercury film will appear on the surface of the working electrode, and the texture is uniform.

[0195] ③ The instrument draws 10 ml of the spiked electrolyte into the electrolytic cell and performs a mixing reaction according to the parameters above to obtain the voltammetric dissolution curve. The peak height at this time is recorded as A.

[0196] ④ Draw 5 ml of calibration solution (known concentration) into the above electrolytic cell, mix and react, and record the peak height at this time as B.

[0197] ⑤ Empty the electrolytic cell, draw 10 ml of the spiked electrolyte into the electrolytic cell, mix and react, and record the peak height at this time as C.

[0198] ⑥ Draw 5 ml of the digested sample into the electrolytic cell, mix and react, and record the peak height at this point as D. Calculate the concentration of the sample based on the peak heights ABCD mentioned above.

[0199] Antimony was tested with a standard solution of 0.04 mg / L and a calibration solution concentration of 0.10 mg / L. The parameters and conditions of ASV were set as above. The test results are shown in Table 1. Table 1 shows the numerical results of the detection of antimony content in water in the embodiment of the present invention.

[0200] Table 1

[0201]

[0202] As shown in Table 1, the indication error and repeatability of the data using this invention meet the requirements for the detection of antimony water samples. The unique electrolyte formulation and testing method of this invention can effectively test the antimony content in water.

[0203] The foregoing has provided a detailed description of a reagent for testing antimony in water using anodic voltammetric stripping spectroscopy and a highly accurate antimony water quality analysis and detection process provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are merely for the purpose of helping to understand the method and core ideas of the present invention, including the best mode, and also to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements that are not different from the textual description of the claims, or if they include equivalent structural elements that are not substantially different from the textual description of the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A method for determining antimony content in water using anodic voltammetric stripping spectroscopy, characterized in that, Includes the following steps: 1) Place the antimony standard solution and electrolyte in an electrolytic cell, clean the electrodes by applying a positive potential under ultrasonication, and then drain the water; 2) Place the electroplating solution and electrolyte in the electrolytic cell after the above steps to electroplat the electrodes with a mercury film; 3) Place the antimony standard solution and electrolyte into the electrolytic cell after the above steps, react to obtain the first voltammetric dissolution curve, then add the correction solution into the electrolytic cell, react again to obtain the second voltammetric dissolution curve; 4) Empty the electrolytic cell after the above steps, place the antimony standard solution and electrolyte in the electrolytic cell, react, and obtain the third voltammetric dissolution curve. Then add the digested sample to be tested into the electrolytic cell, react again, and obtain the fourth voltammetric dissolution curve. 5) Based on the first, second, third, and fourth voltammetric dissolution curves obtained in the above steps, the antimony content in the sample to be tested is calculated. The electrolyte comprises ascorbic acid, potassium iodide, hydrochloric acid, and water; The concentration of ascorbic acid is 0.06~0.6 mol / L; The concentration of potassium iodide is 0.09~1.5 mol / L; The concentration of the hydrochloric acid is 0.01~1.0 mol / L.

2. The method according to claim 1, characterized in that, The electroplating solution includes a mercury standard solution.

3. The method according to claim 2, characterized in that, The concentration of the mercury standard solution is 0.0003~0.0025 mol / L; The electrolyte is used to clean the mercury film on the working electrode; The electrolyte is used to coat the working electrode with a mercury film. The electrolyte is used to test the voltammetric dissolution curve of antimony standard solution.

4. The method according to claim 1, characterized in that, In step 1), the concentration of the antimony standard solution is 0.01~0.1 mg / L; In step 1), the volume ratio of antimony standard solution to electrolyte is (1~2):(5~1). The cleaning potential is 200~800mV; The cleaning time is 20~100s.

5. The method according to claim 1, characterized in that, In step 2), the volume ratio of the electroplating solution to the electrolyte is (1~2):(3~1); The enrichment potential of the electroplated mercury film is -1500 ~ -900mV; The electroplating time for the mercury film is 100~600s; In step 2), the ratio of the total volume of the electroplating solution and the electrolyte to the total volume of the antimony standard solution and the electrolyte in step 3) is (1~3):(3~1).

6. The method according to claim 5, characterized in that, In step 3), the concentration of the antimony standard solution is 0.01~0.1 mg / L; In step 3), the volume ratio of the antimony standard solution to the electrolyte is (1~2):(5~1). In step 3), the enrichment potential of the reaction process is -1300~-300mV; In step 3), the enrichment time of the reaction process is 100~600s; In step 3), the resting potential of the reaction process is -400~-200mV; In step 3), the resting time of the reaction process is 5~30s; In step 3), the dissolution range of the reaction process is -200mV to +500mV; In step 3), the step voltage of the reaction process is 1~5mV; In step 3), the scanning speed of the reaction process is 200~800mV / s; The calibration solution includes an antimony standard solution or a mixed solution of antimony, hydrochloric acid, and water. The concentration of the calibration solution is 0.01~0.2 mg / L.

7. The method according to claim 1, characterized in that, In step 3), the ratio of the total volume of the antimony standard solution and electrolyte to the volume of the calibration solution is (20~1):(1~20). In step 3), the enrichment potential of the second reaction process is -1300~-300mV; In step 3), the enrichment time of the second reaction process is 100~600s; In step 3), the resting potential of the second reaction process is -400~-200mV; In step 3), the resting time for the second reaction process is 5-30 seconds; In step 3), the dissolution range of the second reaction process is -200mV to +500mV; In step 3), the step voltage for the second reaction process is 1~5mV; In step 3), the scanning speed of the second reaction process is 200~800mV / s; In step 4), the concentration of the antimony standard solution is 0.01~0.1 mg / L; In step 4), the volume ratio of antimony standard solution to electrolyte is (1~2):(5~1).

8. The method according to claim 1, characterized in that, In step 4), the enrichment potential of the reaction process is -1300~-300mV; In step 4), the enrichment time of the reaction process is 100~600s; In step 4), the resting potential of the reaction process is -400~-200mV; In step 4), the resting time of the reaction process is 5~30s; In step 4), the dissolution range of the reaction process is -200mV to +500mV; In step 4), the step voltage of the reaction process is 1~5mV; In step 4), the scanning speed of the reaction process is 200~800mV / s; In step 4), the enrichment potential of the second reaction process is -1300~-300mV; In step 4), the enrichment time of the second reaction process is 100~600s; In step 4), the resting potential of the second reaction process is -400~-200mV; In step 4), the resting time for the second reaction process is 5-30 seconds; In step 4), the dissolution range of the second reaction process is -200mV to +500mV; In step 4), the step voltage for the second reaction process is 1~5mV; In step 4), the scanning speed of the second reaction process is 200~800mV / s; The electrode includes a working electrode.

9. The method according to claim 1, characterized in that, The digested test sample is obtained by mixing and reacting the digestion solution and the test sample in a closed heating system. The digestion solution includes a nitric acid solution; The concentration of the nitric acid solution is 0.03~0.3 mol / L; The temperature for the heating and mixing reaction is 90~120℃; The heating and mixing reaction time is 300~900s.

10. The method according to claim 9, characterized in that, The volume ratio of the digestion solution to the sample to be tested is (1~30):1; The ratio of the volume of the digested sample to the total volume of the antimony standard solution and electrolyte is (20:1) to (1:20). The calculation steps include peak height normalization; The electrode material includes glassy carbon electrode or gold electrode.

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