DETERMINATION OF GALLIUM BY AAS USING A T ANTALUM CARBIDE-COATED GRAPHITE TUBE

Graphite atomizer tubes were treated-with tantalum (Ta) in order to co at the surface of the tubes with tantalum carbide (TaC), and were used for the determination of gallium by AAS. The measurement conditions w ere optimized and the effects of diverse coexisting substances (metal cations, anions and organic compounds) were examined. By this treatmen t, the sensitivity increased by a factor over 5 along with an improvem ent in the repeatability, The calibration curve of Ga obtained by usin g a TaC-coated tube and a matrix modifier (250 mg dm(-3) Al Al+500 mg dm(-3) Ni + l mol dm(-3) HNO3) was linear over the range of 0 similar to 300 mu g dm(-3), and the detection limit (3 sigma(0)) was 10 mu g d m(-3) (0.10 ng). The present method was applied to analyses of rock st andard materials.