INFLUENCE OF IRON ON THE DETERMINATION OF TOTAL SELENIUM IN SEWAGE-SLUDGE BY ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY

The determination of total selenium by ETAAS in complex matrices such as sewage sludge has always been a challenge offing to the problems en countered with the solubilization of selenium species and the interfer ences observed during their determination. The use of a microwave oven in order to shorten the digestion step can lead to the solubilization of larger amounts of elements that can behave as interferents in the determination of Se by ETAAS, This study has shown the particular infl uence of Fe on the determination of Se by ETAAS, A correction procedur e was developed and applied successfully to different digested samples of sewage sludge.