Development of fast thermal programs in electrothermal atomic absorption spectrometry using hot injection and removal of the ashing stage for determination of heavy metals in sequential extracts from sediments

Abstract

In this work, a fast thermal methodology is developed for the determination of leachable Cu, Cr, Ni and Pb in sediments by electrothermal atomic absorption spectrometry. Fast thermal programs were tried using hot injection, removal of the ashing stage and matrix modifier and their performance compared with that obtained under conventional thermal programs. For this purpose, the BCR three-stage sequential extraction scheme was applied for partitioning of Pb, Cu, Ni and Cr. CRM BCR 601 lake sediment, which is provided with certified values for the extractable contents of the above metals according this scheme, was used for validation. A shortening of the measurement time by a factor of 3–4 was attained without losing analytical performance. Additionally, other features for speeding up determinations such as calibration are considered. Thus, specifically designed fast thermal programs allowed calibration with matrix-matched standards with extractants to be performed for most metals and fractions instead of standard additions. Background signals, LODs, repeatability and sensitivity were generally similar with both types of programs, hence yielding a comparable analytical performance.