Simple mathematical treatment for non-isothermal atomisation

Abstract

A simple mathematical treatment, based on the analysis of the atomisation pulse and its derivatives, is presented for the description of the atomisation in a graphite furnace. By observing that the absorbance rate presents a maximum and a minimum at times t_x and t_y, respectively, and that for all the experimental situations studied, the temperature had reached a plateau before t_y, the rate equations were solved using boundary conditions at t_y, rather than at the beginning of the pulse. Simple and physically valid equations were obtained for the determination of the rate constants (k₁ and k₂) for the formation and loss of the atoms. The maximum at t_x, where the temperature is a function of time, allowed us to determine the actual heating rate of the vapour temperature. As an example, this treatment is successfully applied to the description of the entire absorbance pulse of the non-isothermal atomisation of Ru.