Arrhenius plots for activation energy of atomization in graphite-furnace atomic-absorption spectrometry
1Centre for Analytical and Environmental Chemistry, Chemistry Department, Carleton University, Ottawa, Ontario, Canada K1S 5B6.
Abstract:
Activation energy plots drawn by use of various Arrhenius-type equations for atomization reactions in graphite-furnace atomic-absorption spectrometry (GFAAS) do not give reliable kinetic information about the atomization mechanism of the analyte element beyond a few data-points located near the very beginning of the absorbance signal profile. These plots are non-linear if they are drawn with data points near the maximum of the absorbance signal profile. This paper presents two Arrhenius-type equations which give linear plots over a long range of data-points, and hence reliable values for the activation energy. Also, a simple method is proposed for calculating the activation energy from the data-points anywhere from the initial appearance of the absorbance signal to its maximum. Activation energy values given by these two equations and by the method of calculation are compared with each other and with those given by the commonly used methods. The calculated activation energy values obtained can be used to verify those obtained experimentally. The three proposed methods also provide reliable kinetic information on atom-formation reactions in GFAAS. A mechanism for the atomization of copper, based on the experimentally determined activation energy and reaction order is proposed.
Related Concept Videos
Arrhenius Plots
The Arrhenius equation can be used to...
Atomic Absorption Spectroscopy: Atomization Methods
Atomic Absorption Spectroscopy: Lab
Solutions containing organic solvents, such as low-molecular-mass alcohols, esters, or ketones, enhance absorbances by increasing nebulizer...
Temperature Dependence on Reaction Rate
Atoms, molecules, or ions must collide before they can react with each other. Atoms must be close together to form chemical bonds. This premise is the basis for a theory that explains many observations regarding chemical kinetics, including factors affecting reaction rates.
The collision theory is based on the postulates that (i) the reaction rate is proportional to the rate of reactant collisions, (ii) the reacting species collide in an orientation allowing contact between...
Atomic Emission Spectroscopy: Lab
Atomic Emission Spectroscopy: Instrumentation


