This International Standard specifies a silver diethyldithiocar-bamate spectrophotometric method for the determination of arsenic in water and waste water.
It is applicable for the determination of arsenic concentrations in the range from 0.001 to 0.1 mg/l. In the case of arsenic com-pounds which are difficult to decompose, a method of diges-tion is described in the annex, clause A.1. By appropriate dilu-tion of the test portion with arsenic-free water, higher concen-trations of arsenic may also be determined.
Antimony interferes with the determination (see the annex, clause A.2). Chromium, cobalt, molybdenum, nickel, mercury, silver and platinum, in concentrations up to 5 mg/l, do not in-terfere with the determination.