Polarographic determination of arsenic in steel

Abstract

A method for the polarographic determination of arsenic in steel is described. It consists of the reduction of arsenic(V) to arsenic(III) in 9·5 N hydrochloric acid solution by means of potassium iodide in the presence of ascorbic acid, and of the extraction of arsenic(III) with chloroform. Arsenic is then re-extracted from chloroform with 0·2 M ascorbic acid and determined polarographically with the same ascorbic acid solution as supporting electrolyte. The method was checked on NBS steel standards and synthetic mixtures. Arsenic contents greater than 0·01 per cent. can thus be determined easily without concentrating in the re-extraction step.