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.