RADIOFREQUENCY POWERED GLOW-DISCHARGES FOR EMISSION AND MASS-SPECTROMETRY - OPERATING CHARACTERISTICS, FIGURES OF MERIT AND FUTURE-PROSPECTS

Progress in source design and analytical characterization of radiofrequency powered glow discharge (r.f. GD) devices is described with respect to the overall routine use of the sources for applications in atomic emission and mass spectrometries. Versatile source designs are presented for mass spectrometric analysis of flat and pin-type samples. Plasma stabilization times are shown to be of the order of 1 min or less. Temporal stability of approximately 3% relative standard deviation (RSD) is seen for time periods extending to 45 min, with sample-to-sample reproducibility of approximately 3% RSD. Detection limits for atomic emission spectrometry on a high-resolution instrument are <100 ppb, with values in the single ppm range obtained to date on a quadrupole mass spectrometer. The range of sample types amenable to r.f. GD analysis is very wide, with examples in areas of precious metals, alloys, glasses, fusions and depth resolved analyses. It is believed that the experience to date and the prospect of wide applicability bode well for the techniques.