Direct Estimation of Total Arsenic Using A Novel Metal Side Disk Rotating Electrode

• Published in: Electroanalysis (New York, N.Y.) N.Y.), 2003-09, Vol.15 (17), p.1410-1414
• Main Authors: Prakash, Rajiv, Srivastava, R. C., Seth, P. K.
• Format: Article
• Language: English
• Subjects: Anodic stripping voltammetry; As(III) and As(V) toxicity; Differential pulse voltammetry; Electrochemical technique; Rotating disk electrode; Three electrode system
• ISSN: 1040-0397; 1521-4109
• DOI: 10.1002/elan.200302658

A special type of metal side disk rotating electrode has been demonstrated for the direct estimation of total arsenic [As(III) and As(V)] at low ppb (μg/L) level using anodic stripping differential pulse voltammetry (ASDPV). A conventional three electrodes cell is used equipped with side disk rotating gold electrode as working, graphite/platinum electrode as auxiliary and Ag/AgCl/3M KCl as reference electrodes. Arsenic is estimated in various acidified samples without any digestion, containing a trace amount of copper at low ppb level. The major problems associated with ASDPV of high acidic condition (acid hazards), irreproducible results due to the interference of hydrogen bubbles, evolved at the cathode during the deposition of arsenic in acidified samples and poor detection level are overcome with the help of the specially designed gold side disk rotating electrode and modified electrolyte. The presence of a trace amount of copper(II) salt in the electrolyte is found to enhance the sensitivity of the technique. The shape and position of the metal disk at the electrode, rotation speed of the electrode and electrolyte are optimized to have less hydrogen gas bubbles interference and high reproducibility in the detection of arsenic up to 2 ppb±15% level in various samples. The electrode has been found very stable and reproducible even for more than 200 estimations.