Determination of Arsenic(III) by Anodic Stripping Method Using Co-deposition with Copper

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Abstract
The determination of arsenic(III) by anodic stripping using co-deposition with copper was worked out. A 0.24 M hydrochloric acid containing arsenic(III) and copper(II) was electrolyzed with a rotating platinum electrode (rpm=800) at a constant current. The deposit on the electrode was stripped by linear potential sweep method in 4 M hydrochloric acid. The stripping voltammogram was recorded in the span voltage −0.2–+1.2 volt vs. SCE. The stripping voltammogram showed two peaks, at zero volt and 0.5 volt vs. SCE. The area of the second peak was proportional to the concentration of arsenic. Linear dynamic range was 1–20 microgram per milliliter. The method was rapid and simple, the time required for analysis being about 35 minutes (electrolysis temperature, 25°C). X-ray and electron diffractions indicate that the second peak in the stripping voltammogram results from the dissolution of Cu3As.