DIRECT SOLID VS SLURRY ANALYSIS OF TOBACCO-LEAVES FOR SOME TRACE-METALS BY GRAPHITE-FURNACE AAS - A COMPARATIVE-STUDY

Graphite furnace atomic absorption spectrometry (GFAAS) is used to determine cadmium, lead, nickel and cobalt in two samples of tobacco leaves (candidate reference materials). Two techniques for the direct determination of these elements are investigated - direct solid sampling into a "ring chamber tube" specially designed for the Zeiss AAS-3 spectrometer and slurry sampling. For both investigated sampling methods the optimum parameters of temperature-time programs, influence of Pd modifier and calibration methods are discussed. There is acceptable agreement between the results obtained from direct solid, slurry and solution (after wet decomposition) sampling.