Spatial and temporal profiles of indium in a furnace atomization plasma excitation spectrometry source

Spatially resolved emission and absorption intensities from the indium 303.93-nm resonance line were measured in a furnace atomization plasma excitation spectrometry (FAPES) source. These measurements show that the spatial structure observed in the analyte emission is due to two effects, The first is the spatial distribution of analyte atoms in the source. The absorption measurements show that this spatial distribution is fairly uniform. There is a slight gradient, with analyte concentrations increasing from the cuvette wall to the center electrode. The fine structure in the emission intensity profiles must therefore be caused by the dependence of the degree of analyte excitation on position within the cuvette. This structure suggests that the FAPES source operates as an atmospheric-pressure radio-frequency glow discharge. Negative glows are seen adjacent to the graphite cuvette wall and center electrode.