Matrix modification for the determination of thallium by graphite furnace AAS

Abstract

A mixture of nickel nitrate and EDTA tetraammonium salt was very suitable as a matrix modifier for the determination of thallium by graphite furnace AAS. The chloride interference could be eliminated because chloride formation of thallium and other metal cations was prevented by EDTA. Addition of nickel nitrate suppressed the EDTA-caused sensitivity loss in atomic absorption of the analyte thus permitting the addition of a large amount of EDTA to the sample solution. This effect depends on the EDTA complex of nickel acting as a thermal stabilizer for the analyte during the ashing step in the furnace.