Effect of Anode Dimensions and Location of the Discharge Gas Inlet Port on the Spatial Distribution of Copper Atoms in a Radio Frequency Glow Discharge Atomizer for Atomic Absorption Spectrometry

Abstract

The absorbance of Cu atoms sputtered from a Cu cathode in a laboratory-modified radio frequency glow discharge atomizer for atomic absorption spectrometry was measured at different regions within the atomizer chamber for different discharge parameters. The results show that not only the discharge gas flow rate and pressure but also the applied rf power and the degree of extension of the negative glow have significant effects on the atomization and on the distribution of sputtered atoms within the atomizer chamber. The influence of various diameters and thicknesses of the sampling orifice (anode) on the plasma atomization characteristics and the sample weight loss rates has been examined. By increasing the diameter of the sampling orifice, a larger area of the cathode surface (Cu) was allowed to be sputtered, thereby generating a larger number of atoms (higher absorbance) in the analysis volume, where the sputtered atoms were studied by atomic absorption spectrometry. The absorbance of Cu atoms was inverse...