THE SPECIATION OF ARSENIC(V) AND ARSENIC(III), BY ION-EXCLUSION CHROMATOGRAPHY, IN SOLUTIONS CONTAINING IRON AND SULFURIC-ACID

Arsenic(V) and arsenic(III) can be separated, by ion-exclusion chromatography, in solutions containing iron and sulphuric acid. Iron is removed by ion-exchange before the speciation of arsenic, with phosphoric acid as the eluent. The separated arsenic(V) and arsenic(III) are measured spectrophotometrically in the ultraviolet region at a wavelength of 195 nm. Arsenic(V) and arsenic(III) can be determined at concentrations greater-than-or-equal-to 3 mg/l. The relative standard deviations are 1.3% for arsenic(V) and 0.9% for arsenic(III), at the 10 mg/l. level. The time required for the separation of the inorganic arsenic species is 11 min.