Determination of total arsenic and selenium in soils and plants by atomic absorption spectrometry with hydride generation and flow injection analysis coupled techniques

A procedure has been developed for determination of total arsenic and selenium in soils and plants by atomic absorption spectrometry with hydride generation associated with flow injection analysis (FIA-AAS-HG). Samples were wet-digested by using 2 systems: heating in a metal digestion block with controlled temperature and time and heating in a microwave oven, Total arsenic and selenium were reduced with NaBH4 and concentrated HCl, respectively, In both digestion systems used for the 2 matrix types, detection limits below 1 mu g/L were found for both elements for an injection volume of 160 mu L, with relative standard deviations of 3-6%, Recoveries by the method ranged from 93 to 105%; with the reference materials FD8 and MRG-1, the values obtained in all cases were consistent with the certified data. The FIA-AAS-HG procedure is highly suitable for determination of total arsenic and selenium in soils and plants, and because of the coupled system used, it is an improvement over other procedures in terms of sample treatment, sample consumption, and automation.