| Abstract: | Determination of selenium and arsenic in animal tissues is disturbed mainly by spectral interferences, uncorrectable with the dueterium arc. These interferences are produced by the calcium and magnesium phosphates always present in these matrixes. In animal tissue solution this disturbance may be avoided by addition of 20 micrograms of Ni (nitrate) for a 10 microliter sample. A lower amount of nickel does not allow a correct development of analyte absorbance signals whereas an excess induces a loss of sensitivity for the two elements studied. Measurement of peak-height proved to be most suitable, integrated absorbance being partially influenced by the matrix. The slope constants of working curves obtained with different animal matrixes are very close and direct calibration becomes possible. This was confirmed by analysis of several reference materials. |
