An Automated Technique for the Sub-Microgram Determination of Selenium and Arsenic in Surface Waters by Atomic Absorption Spectroscopy

Abstract

Fully automated method for the analysis of selenium and rsenic in surface water specimens by atomic absorption spectroscopy is described. The technique employs sodium borohydride for conversion of selenium and arsenic compounds in specimens to hydrogen selenide and arsine. To increase the efficiency of hydride recovery for analysis, the reacted specimen is stripped using a heated column. The hydride gas and hydrogen evolved from the chemical reaction is then combusted in a tube furnace placed in the optical path of an atomic absorption spectrophotometer. Seventy specimens can be analyzed per hour with a detection limit of 0.019 µg/liter for selenium and 0.011 µg/liter for arsenic.