Simulation of atomic absorption signals: A kinetic model with two independent sources

A kinetic model of atomization processes based on the solution of one-dimensional diffusion equation with two independent sources is proposed. One of the sources describes the atomization of atoms from the graphite furnace surface, while another one describes the atom formation inside the walls of the furnace and their subsequent outflow into the analytical zone. This mechanism is used to describe electrothermal atomization of Cu and Ag. The simulations show that the form of atomic absorption signal of Cu is determined to the great extent by the processes of desorption from the graphite surface and diffusion inside the graphite. The tailing of the back edge of absorption profile can be explained by the rather slow diffusion process of copper atoms in the graphite. At the same time, for the atomization of Ag, the process of separation of single atoms from clusters is the limiting process. A new interpretation for the shift of absorbance maximum as the initial mass of Ag increases is proposed.