Optimisation of tin determination in aqua regia-HF extracts from sediments by electrothermal atomic absorption spectrometry using experimental design

An experimental design was applied to optimise total tin (Sn) determination in aqua regia-HF extracts from sediments. Determination was performed by electrothermal atomic absorption spectrometry using palladium as chemical modifier. A full factorial design for screening and a central composite design for optimisation were used for evaluation of the effects of several variables. The results showed that the pyrolysis temperature, the atomisation temperature and the modifier concentration exerted an influence on the determination. Accuracy and precision were checked using the reference material PACS-2. The results obtained were statistically, at the 95% confidence level, indistinguishable from the certified values. The limit of detection was 0.048 mg kg(-1). The optimised method was applied to the analysis of estuarine superficial sediments from Gipuzkoa (Spain). The total tin in these samples ranged from 9 to 37 mg kg(-1).