Spatial Mapping of Analyte Distribution within a Graphite Furnace Atomizer

Abstract

A versatile diagnostic scheme based on the combination of the unique properties of a laser, such as collimation and monochromaticity, together with absorption spectroscopy and subsequent computer extraction of quantitative information from a video signal has been applied to acquire spatially and temporally resolved information in a graphite tube atomizer. Spatially resolved concentration profiles with a 256 × 240 array of intensities can be obtained in 1/60 second. This capability has been demonstrated in the study of sodium atom distribution within a graphite furnace. Spatially and temporally resolved absorbance profiles taken within the furnace show extreme nonuniformities throughout the lifetime of the sodium atom plume. Early in the absorbance signal, the distributions show absorbances which decrease in going from the bottom, where the sample was initially deposited, to the top of the furnace. A more uniform distribution of the free atoms can be seen after a majority of the analyte has been released from the surface of the graphite tube, i.e., after the absorbance peak.