Mechanism of atomization in a Massmann-type graphite furnace using the basic principles of thermodynamics

Abstract

A method has been developed to determine the enthalpy of atom formation in a graphite furnace without invoking the order of reaction. The method is based on the equation In (AT) = −ΔH0/RT + C, where A is the peak-height absorbance, T is the absolute temperature, ΔH0 is the enthalpy of atom formation which, for highly endothermic reactions, is considered to be equal to the activation energy, R and C are the universal gas constant and the constant of integration, respectively. The plot of In (AT) vs. 1/T is similar to an Arrhenius-type plot and should yield the activation energy. Atomization mechanisms for eight elements, Cu, Co, Ga, Au, Ni, Fe, Ag, and Al, are proposed by correlating the experimental enthalpy with a very limited set of possible primary reactions. One significant result of this work is that the experimentally observed enthalpy of reaction correlates well with the activation energy, this means no excess energy other than the enthalpy of atomization is involved in the reaction.