Recent advances in analytical spark source mass spectrometry

Abstract
Spark source mass spectrometry is an established technique for the chemical analysis of trace and minor inorganic constituents in many types of material. Its merits are its inherent high sensitivity with detection limits down to a few nanograms per gram and an extremely wide elemental coverage, i.e. essentially all the elements present in the sample. Drawbacks that explain its lesser popularity compared with other techniques result from (1) the complexity and cost of the apparatus, (2) the time-consuming operation when detection is performed with an ion emulsion, and (3) inaccuracies inherent in ion formation and the measurement process. A review will be given of the basic theory, the instrumentation and a few representative applications. Special reference will be made to recent advances in methodology (e.g. the development of multi-element isotope dilution) and instrumentation: the development of the understanding of the r.f. spark ion formation process, alternative mechanisms for ionization, and the exploitation of ion detectors other than the photographic plate (electrical detection with electron multipliers and position-sensitive detectors).