Corrective correlation method for the analysis of gases by plasma/laser-excited fluorescence spectrometry

Traces of gaseous impurities in permanent gases can be quantitatively determined by recording their fluorescence produced in a dual process of excitation in a plasma discharge combined with excitation in a resonant field of laser radiation. However, variations in the composition of the gas samples can cause systematic errors of determination. Such errors can be corrected using a correlation relationship established between the fluorescence intensity and concentrations of components of the sample. As an example, the possibility of accurate determination of low neon concentrations in a sample of helium containing an undetermined amount of argon is presented. The correlation relationship between the level of the saturated fluorescence of neon and the saturation parameter (spectral density of laser power required to reach the 50% level of neon fluorescence intensity relative to the level of the completely saturated fluorescence) over a broad argon content range in helium was established and used. The objective was to neutralize possible obscuring impacts of unknown uncontrolled impurities that may or may not be present in a gas sample on the analytical results.