A study of nickel electrothermal atomization

Abstract

The kinetic order of generation of the atomic vapor of Ni is determined as a function of the initial mass of analyte. For masses up to 3.0 ng, a kinetic order equal to 1 is obtained, with atomization energy and pulse half-width independent of the analyte mass. However, for sample mass in the range 4.0–8.0 ng, a kinetic order equal to 2 is determined with a constant atomization energy and a pulse width that increases as the initial mass increases. Accordingly, a first-order kinetic model is employed to describe the atomization profiles of analyte masses up to 3.0 ng. To determine the vapor formation and dissipation rate constants k 1 and k 2, the rate equations for this model were solved using boundary conditions at t y, the time at which the rate of change of absorbance presents a minimum value and the temperature has already reached its maximum value. Employing the kinetic parameters of this model, a good description of the absorbance profiles is achieved and the theoretical behavior of the peak absorbance and the area of the pulse, as a function of the analyte mass, is predicted.