DETERMINATION OF KINETIC-PARAMETERS FOR ATOM FORMATION AT CONSTANT-TEMPERATURE IN GRAPHITE-FURNACE ATOMIC-ABSORPTION SPECTROSCOPY

A new method for the simultaneous determination of the kinetic order and activation energy for atom release under isothermal condition in a graphite furnace has been developed. Tungsten wire probe atomization was employed to examine the validity of the present method. By means of this model, the kinetic parameters for the atomization of Bi, Ge, Pb and Mn at constant temperatures were successfully determined. The values of the kinetic order and activation energy were found to be 0.67 +/- 0.01 and 302 +/- 8 kJ mol(-1) for Bi, 1.01 +/- 0.08 and 109 +/- 2 kJ mol(-1) for Ge, 0.46 +/- 0.01 and 159 +/- 2 kJ mol(-1) for Pb and 0.97 +/- 0.03 and 372 +/- 5 kJ mol(-1) for Mn, respectively. The atomization mechanism for these four elements from the tungsten probe surface was also discussed.