On-line microwave sample pre-treatment for hydride generation and cold vapour atomic absorption spectrometry. Part 2. Chemistry and applications

Abstract

A system for on-line treatment of liquid samples in a microwave oven digestor was evaluated for use with cold vapour (CV) and hydride generation (HG) atomic absorption spectrometry (AAS). Various oxidation mixtures were tested and those based on bromination (bromate–bromide–acid) and peroxodisulfate (persulfate–acid–complexing agent) were found to be compatible with and most appropriate for CVAAS and HGAAS. The composition of reagents and the analytical conditions were optimized for the determination of mercury, arsenic, bismuth, lead and tin in urine and environmental waters. The limits of detection were 0.01 and 0.2 µg l^–1 for mercury, with and without amalgamation, respectively, 0.5 µg l^–1 for arsenic, 0.07 µg l^–1 for bismuth and 0.1 µg l^–1 for tin and the sample throughput was between 13 and 30 h^–1.