Effect of oxygen addition to an argon glow-discharge plasma source in atomic emission spectrometry

Small amounts of oxygen gas greatly change the characteristics of the argon plasma light source in glow-discharge emission spectrometry. The influence of oxygen addition on the sputtering rate and the excitation of the analytes in the argon plasma was investigated by employing argon-oxygen binary mixed gases having well-defined compositions. Strong quenching by oxygen was observed from the intensity of the emission lines originating from the analyte element as well as the gas species. The negative effect caused by oxygen gas in analytical applications with the glow-discharge lamp should be noted.