CHARACTERISTIC MASS AND ATOMIZATION EFFICIENCY OF GRAPHITE-FURNACE INATOMIC-ABSORPTION SPECTROMETRY

Measurements of characteristic masses for 8 elements (Ag, Bi, Cd, Cr, Ga, Ge, In and Tl) have been made using a Hitachi GA-3 graphite furnac e with the V-shaped boat over broad temperature intervals. The m(o)(ex p) values are compared with theoretical data, m(o)(cal), to assess the effect of temperature on the correction factor of theorization for va lue of characteristic mass (alpha = m(o)(cal)/m(o)(exp)) and the atomi zation efficiency (beta). The atomization efficiency (beta) was equal to the correction factor of theorization for characteristic mass value (alpha) times tau(D)/tau(R) value. The tau(R) was value experimentall y measured of atomic residence time and the tau(D) value calculated fr om tau(D) = 1(2)/8D. The beta value of element always is smaller than the alpha value because the tau(D)/tau(R) value is less than one for e lements in the operating conditions. Part of the analyte vapour is rea dsorbed by the heated tube wall at high temperature and reevaporation of the adsorbed analyte followed by diffusion account for the longer r esidence time, and it appeared that the tau(R) value was larger than t he tau(D) in graphite furnace.