Investigations of self-absorption in a radio-frequency glow discharge device

The self-absorption behavior of a radio-frequency glow discharge atomic emission device has been studied with Fourier transform spectrometry. Using a resonant transition of a major element, it has been shown that for this device the potential for self-absorption is severe, and no analytically useful discharge conditions that significantly reduce that potential were found. In fact, it is unlikely that such conditions can be found, even with a more exhaustive study. Therefore, there is no compelling reason to alter the discharge conditions that would typically be employed for analyses with the device. Based on the potential for self-absorption, it is advisable to use non-resonant, rather than resonant, transitions of major elements for analytical purposes. On the other hand, the use of resonant transitions of minor or trace elements appears to be free from any significant danger of analytical error induced by self-absorption. However, further studies are needed to validate this conclusion over a wider range of analytes, transitions, sample types, and discharge conditions. Owing to the fact that self-absorption is influenced by the subtleties of the design of a glow discharge device, such as the placement of a vacuum port, these results should not be assumed to be wholly applicable to other glow discharge devices.