Saturation of energy levels in analytical atomic fluorescence spectrometry—II. Experimental

Abstract

In Part I of this investigation, a theoretical model was proposed to describe the saturation of atomic energy levels under conditions of intense but brief irradiation by a suitable excitation source. The experimental verification of that model is presented herein. In this study, the effects of dye laser-induced saturation of analyte concentration, flame composition and atomic properties of the elements were all examined and quantitated in terms of a measurable parameter, the saturation spectral power density (SSPD). The results of those studies reveal that SSPD is relatively independent of analyte concentration and flame composition but is a strong function of the nature of each particular atomic transition employed. Moreover, because of strong quenching in most analytical flames, a simple steady-state model for saturation applies even for brief (5.6 ns) pulses from a nitrogen-laser pumped dye laser. Most importantly, it is shown that reliable values for the SSPD can be obtained only through careful experimental design; considerations important in such measurements are therefore carefully detailed.