DETERMINATION OF TRACE AMOUNT OF BISMUTH IN SOME SEDIMENTS BY GRAPHITE-FURNACE ATOMIC-ABSORPTION SPECTROMETRY AFTER PRECONCENTRATION AS XANTHOGENATE COMPLEX ON ACTIVATED CARBON

This method is based on the direct heating of activated carbon (AC) adsorbed bismuth-potassium o-ethyldithio-carbamate [potassium xanthogenate (KetX)] complex: that is, AC is introduced directly as “AC-suspension” into a carbon tube atomizer, without the desorption of bismuth from the AC. To a sample solution (pH 6.5 - 8.0) containing less than 0.10 μg of bismuth, potassium tartrate as a masking agent, 120 mg of KetX and 50 mg of AC are added, and the mixture is stirred for 20 s. After separation of AC from the aqueous phase through a membrane filter, 5.0 ml of AC-suspension are prepared by adding water to the AC. Then, aliquots (10 μl) of AC-suspension are injected into the atomizer, and the bismuth peak-height is measured under optimal instrumental operating conditions. The determination limit was 0.005 μg/100 ml (S/N=3), and the relative standard deviation was 2.0% (n=8). This method was applied to the determination of bismuth in river-bottom and submarine sediments. © 1990, The Japan Society for Analytical Chemistry. All rights reserved.