A rapid acid digestion method with ICP-MS detection for the determination of selenium in dry sediments

The baseline concentration of Se in sediments is low (0.05 μg g−1), meaning that very sensitive analytical methods with low detection limits are required. We developed a simple and rapid method based on a pre-treatment/digestion of dry sediment samples with aqua-regia and HCl and quantification by ICP-MS using 82Se. Obtained and certified Se concentrations for international certified reference materials MESS-1, MESS-2, BCSS-1 and 1646a, showed no statistically differences (α = 0.05) between obtained and certified values. Low detection limits (approximately 0.03 μg g−1), good repeatability (<1.5%) and recoveries (98-103%) made this method a useful tool for rapid selenium analyses in dry sediments. This method was applied to 50 surface sediments collected in the Tagus estuary giving a rapid image of the distribution of total selenium concentrations in the estuary.