Method for detecting trace trivalent arsenic through two-signal anodic stripping voltammetry

Abstract

The invention relates to a method for detecting trace trivalent arsenic through two-signal anodic stripping voltammetry, wherein a working electrode is a gold electrode, a reference electrode is a saturated calomel electrode (SCE) or a silver / silver chloride electrode; and a counter electrode is a platinum, carbon or gold inert electrode; supporting electrolyte solution includes neutral phosphate buffer solution, B-R buffer solution with pH 1.81 to 8.95, or sulphuric acid solution with 0.1 to 0.5 mol.L-1; under the negative potential (-1.1 to -0.1 VvsSCE), test solution is mixed for enrichment for 300 to 600s, so that As (III) is reduced to As (0) to be enriched to the surface of the working electrode; the solution is on standing for 10 to 20s; when forward scanning reaches a certain electric potential point between 1 to 1.6 VvsSCE, the enriched As (0) is electro-oxidized and stripped into the As (III), and the As (III) is further electro-oxidized into As (V); and the trivalent arsenic in the test solution is calculated by the prior art according to the oxidation current double-response signals generated through detection. The method has more accurate detection result, high sensitivity, better property for resisting interference of materials as copper ion, obtains satisfactory result by being applied to the sample detection, is simple and quick, and can be widely applied in fields as environmental monitoring, food safety and bioelectrochemistry.

Description

technical field [0001] The invention relates to the field of electrochemistry, in particular to a method for detecting trace trivalent arsenic by double-signal anode stripping voltammetry. Background technique [0002] Drinking water monitoring, environmental monitoring, food monitoring, or bioelectrochemical fields all need to detect trace arsenic. At present, the rapid detection methods for trace trivalent arsenic mainly include stripping voltammetry and nano-silver-based spectrophotometry, among which Stripping voltammetry has high sensitivity, simple instrument, simple steps, rapid method, and the ability of rapid field testing; it has been used for the detection of trace arsenic [G. Forsnerg, J. W. O'Laughlin, R. G. Megargle, Anal. Chem., 1975 , 47, 1586-1592]. The current anodic stripping voltammetry mainly uses nano-gold modified glassy carbon electrode, platinum nanoparticle-modified glassy carbon electrode and gold nanoparticle-modified indium tin oxide (ITO) elect...

AI Technical Summary

Problems solved by technology

The current anodic stripping voltammetry mainly uses nano-gold modified glassy carbon electrode, platinum nanoparticle-modified glassy carbon electrode and gold nanoparticle-modified indium tin oxide (ITO) electrode as working electrodes; saturated calomel electrode as reference Specific electrode, using low scan rate linear sweep voltammetry, square wave pulse voltammetry or differential pulse voltammetry, but no high scan rate linear sweep voltammetry and high scan rate cyclic voltammetry, and the reports are all A single signal appears. The disadvantage of this single-signal anodic stripping voltammetry is that there is interference from copper ions or other impurity ions in the monitoring, resulting in low accuracy and large errors in the detection results.

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