Developments in glow discharge optical emission spectrometry

The historical background of glow discharge optical emission spectroscopy (GD-OES) is briefly discussed. The Grimm-type source is described, including some of the unique analytical characteristics. State-of-the-art analytical figures of merit for hulk analysis are RSD 0.1-1% for major and minor analytes and detection limits in the range 1-10 ppm. For surface and depth profile analysis, GD-OES is a technique with the capability of profiling 100 mu m thick surface layers, yet the minimum information depth is just 1 mm. Recent developments in methods for the quantification of depth profiles are presented. The current trends in the development of new glow discharge sources is discussed, with emphasis on rf technology for non-conducting materials. Some speculations regarding future trends in the technical development of GD-OES are given. It is argued that pulsed operation in combination with time-resolved detection should be utilized in order to improve further the analytical figures of merit.