Simultaneous determination of mercury and arsenic by anodic stripping voltammetry

Abstract

An electrochemical method for the simultaneous determinations of Hg" concentration and total As"' and AsV concentration has been developed. The method does not require the additional preliminary step of the chemical reduction of AsV to As"', or oxidation of As"' to AsV before stripping analysis takes place. Also, the method for the simultaneous determination of Hg" concentration and As"' concentration is described. Measurements were performed in 0.1 M HCI using a gold-plated graphite electrode as sensor. Detection limits for both methods are below 0.4ppb. Relative standard deviation did not exceed 15 70. The possible interference by other trace metals was investigated. Analyses of natural water and industrial solutions were made using proposed methods and AAS. The t-test demonstrates that there was no significant difference between the results obtained with these methods. Proposed methods decrease the time of analysis because concentrations of the Hg" and arsenic ions were measured simultaneously. Also, the removal of the additional step of chemical reduction of AsV to AsIn or oxidation of As"' to AsV decreases analysis time, and also reduces the chance of contamination due to the use of additional reagents.

Especiação analítica de compostos de arsênio empregando métodos voltamétricos e polarográficos: uma revisão comparativa de suas principais vantagens e aplicações

“…Em geral, as técnicas voltamétricas de redissolução anódica para arsênio são realizadas empregando-se um eletrodo de ouro sóli-do 33,34,36,[67][68][69] ou um filme de ouro 32,35,37,[70][71][72][73] depositado por eletrólise sobre um eletrodo de carbono ou platina como eletrodos de trabalho. Entretanto, problemas freqüentes relacionados à ASV em eletrodos sólidos, como efeitos de memória e baixa reprodutibilidade e precisão na medida, limitam sua aplicação em análises de rotina 63 .…”

“…Na maioria das vezes, a determinação de As(III) por ASV é realizada empregando-se um filme de ouro depositado por eletrólise sobre eletrodos de carbono-vítreo, grafite ou pasta de carbono como eletrodo de trabalho 35,37,55,[71][72][73][74][75][76] . Nos trabalhos publicados mais recentemente por Feeney e Kounaves 2,68 , um ultramicroeletrodo de ouro (Au-UME) foi desenvolvido e aplicado na determinação de traços de As(III).…”

Determination of Ultra-trace Mercury(II) by Flow-injection/ Anodic Stripping Voltammetry Using a Track-etched Microporous Membrane Electrode

“…In fact, ASV, which uses inexpensive and portable instruments, is widely recognized as a powerful tool for measuring trace metals. 10 Many reports have described the detection and quantification of mercury by ASV, [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] which are usually conducted after its electrolytic deposition on rotating, [19][20][21][22][23][24] flow-through, [22][23][24] or microwire [25][26][27] gold electrodes. In these methods, the convective transport of the analyte to the electrode surface greatly benefits the enhancement of a substantial stripping signal.…”

Mercury(II) Ion-Selective Polymeric Membrane Sensors for Analysis of Mercury in Hazardous Wastes

“…Methods in common use for mercury analysis include cold vapor atomic absorption spectrometry, 1,2 fluorometry, 3 X-ray fluorescence, 4 voltammetry, 5 inductively coupled plasma/mass spectrometry, 6,7 and spectrophotometry. 8 Direct potentiometry with chemical sensors provides a selective, precise and fast method for monitoring of various metal ions including Hg 2+ at low concentrations.…”