Sequential extraction procedure for speciation of inorganic selenium in emissions and working areas

A sequential extraction procedure for separating inorganic species of selenium in particulate matter of emissions and working areas, has been developed. The proposed procedure has been tested first on synthetic samples prepared in laboratory with the different selenium salts, then in the presence of atmospherical particulate matter sampled in a laboratory of the department of general chemistry, previously checked for the absence of selenium. Finally the speciation was tested on a reference material (urban particulate matter NIST SRM 1648), certified for the total selenium content. The sample was first treated with the proposed procedure, followed by an evaluation of matrix spiking and recovery analyses. The repeatability of the selenium speciation was assessed by performing multiple analyses of the spiked samples. Quantitative determinations have been made by AAS and voltammetry. The possible interferences of the most common ions have been investigated.