CORRELATION OF SPECTRAL EMISSION INTENSITY IN THE INDUCTIVELY-COUPLEDPLASMA AND LASER-INDUCED PLASMA DURING LASER-ABLATION OF SOLID SAMPLES

Spectral atomic emission intensity from laser-induced plasmas (LIPs) e xhibits excellent correlation with atomic emission intensity in the in ductively coupled plasma (ICP) for a wide variety of materials and las er powers. Laser ablation sampling with introduction into an ICP for c hemical analysis has, among other factors, a strong nonlinear dependen ce on laser energy, spot size, and material composition. The LIP emiss ion also has a similar nonlinear dependence and is shown to correspond with the ICP behavior. The correlation is demonstrated for several ho mogeneous metallic and oxide materials during laser ablation sampling over a range of power densities and incident laser beam spot sizes. Th e correlation is best for higher melting temperature materials and mod erate laser power density. The LIP and ICP emission intensities both s how similar dependence for mass ablation rate versus power density and laser beam spot size. A normalized ICP/area over LIP emission ratio s hows that a functional relationship can be found for changes in ICP in tensity with changes in laser power density. The correlation shows tha t the ICP intensity accurately reflects changes in the laser ablation process and that the LIP may possibly be used for internal monitoring during laser sampling with the ICP.