High sensitivity PIXE determination of selenium in biological samples using a preconcentration technique
The importance of selenium in biological and organic matrices is well established; a very sensitive and fast analytical method is necessary to investigate its role deeply. A preconcentration technique is described that allows selenium detecting at the ppb level in biological samples in a short time. It involves first the decomposition of the organic matrix and then the precipitation of selenium using tellurium both as the coprecipitant and as the internal standard. For serum samples the optimal range of volume to be used is 0.1-2 ml. The sensitivity is obtained at the ppb level after about 10 min irradiation time. The accuracy of the method is checked by comparison with the direct palletization method and by using a standard reference material.