First investigations for the development of a microwave-induced plasma atomic emission spectrometry system to determine trace metals in gases

Abstract

Up to now the direct analysis of reactive gases has not been investigated sufficiently. A continuously running sampling system has been developed for the direct determination of the iron concentration in hydrogen chloride. Atomic emission spectra were generated by using a medium power microwave induced plasma with a rectangular type cavity. Different parameters were optimized, e.g., the design of discharge tubes, gas flow, forward power and volume of sample gas. In order to characterize the plasma, the excitation and gas temperatures have been determined. The calibration was carried out by means of a certified gas reference sample containing pentacarbonyliron in argon. The detection limit was found to be 0.25 µg l^–1 of iron in argon (T= 25 °C) with a reproducibility of 6%(n= 10).