Correlation of Spectral Emission lntensity in the lnductively Coupled Plasma and Laser-lnduced Plasma during Laser Ablation of Solid Samples

Abstract

Spectral atomic emission intensity from laser-induced plasmas (UPs) exhibits exceUent correlation with atomic emission intensity in the inductive)y coupled plasma (ICP) for a wide variety of materials and laser powers. Laser ablation sampling with introduction into an ICP for chemical ana)ysis has, among other factors, a strong nonlinear dependence on laser energy, spot size, and material composition. The UP emission also has a similar nonlinear dependence and is shown to correspond with the ICP behavior. The correlation is demonstrated for several homogeneous metallic and oxide materials during laser ablation sampling over a range of power densities and incident laser beam spot sizes. The correlation is best for higher melting temperature materials and moderate laser power density. The UP and ICP emission intensities both show similar dependence for mass ablation rate versus power density and laser beam spot size. A normalized ICP 1 area over UP emission ratio shows that a functional relationship can be found for changes in ICP intensity with changes in laser power density. The correlation shows that the ICP intensity accurate)y reflects changes in the laser ablation process and that the UP may possib)y be used for internal monitoring during laser sampling with the ICP.