Abstract
A distillation method was used to separate arsenic trichloride from interfering substances in the presence of hydrochloric acid, hydrobromic acid, and hydrazine sulfate. Arsenic in distillate was determined by flameless graphite furnace atomic absorption spectrophotometry (GFAAS) and inductively coupled plasma atomic emission spectrometry (ICP-AES). Liberation of arsenic trichloride by distillation was not inhibited by , Ni+2, or other substances encountered in geological, biological, and water samples. Free nitric acid must be neutralized with potassium carbonate or removed by evaporation in the presence of sulfuric acid at 160°C (320°F) before arsenic trichloride distillation. Geochemical reference samples, U.S. Environmental Protection Agency (EPA) water standards, geological samples, and water samples were analyzed. Results of distilled arsenic trichloride in all reference samples agreed with the reported values. Without distillation, agreement with reported values was obtained only in water samples containing low matrix substances.