Determination of silicon in biological tissue by electrothermal atomic absorption spectrometry using slurry sampling of original and pre-ashed samples

Two methods for the determination of silicon in biological tissue by electrothermal atomic absorption spectrometry using the slurry sampling technique are described. In one of them, a slurry of the tissue and, in the second, a slurry of the ash obtained by separate thermal pre-treatment in an ashing furnace vas introduced into the graphite furnace. The second method proved to be superior regarding the elimination of matrix interferences. Optimum sensitivity was obtained by using a mixture of palladium nitrate and magnesium nitrate as modifier. The silicon contents determined were between about 3 and 14 mu g g(-1) and they were compared with results obtained by other methods and laboratories. The limits of detection of the direct method and the method involving pre-ashing were found to be 0.2 and 0.03 mu g g(-1), respectively.