DETERMINATION OF SULFATE IN ENVIRONMENTAL WATER BY SPECTROPHOTOMETRICFLOW-INJECTION ANALYSIS

Sulfate ion in environmental water was determined by flow injection an alysis using barium-dimethylsulfonazo-III complex as the reagent at a rate of 12 samples per hour. The linearity and sensitivity were invest igated using ethanol - or dimethyl sulfoxide (DMSO) - water as solvent , respectively. DMSO - water medium was beneficial in the determinatio n of a low concentration of sulfate below 3mg 1(-1). The calibration c urve was linear in the range of 0.1-7mg 1(-1) with the correlation coe fficient of 0.999. The detection limit was 0.1mg 1(-1). The relative s tandard deviation for 10 injections of SO42-(5mg 1(-1)) was 1.8%. The results of actual sample analysis agreed satisfactorily with those obt ained by ion chromatography.