USE OF HYDROGEN IN ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY TO DECREASE THE BACKGROUND SIGNAL ARISING FROM ENVIRONMENTAL SLURRY SAMPLES

The use of hydrogen in electrothermal atomic absorption spectrometry (ETAAS) to reduce the effects arising from smoke and other non-specific absorption interference has been investigated. Introduction of the hydrogen as a 10% (v/v) mixture in argon during the cool down and autozero stage just prior to atomisation led to a very much reduced background signal for environmental samples such as soil and a sewage sludge. For many of the samples in the absence of hydrogen, the background correction system was incapable of removing the interference and unreliable results were obtained. The method was validated using certified reference materials Canmet SO-2 soil and BCR 145 sewage sludge. Reasonable agreement with the certified values was obtained.