Factors affecting the relative sensitivity coefficients in spark and laser plasma source mass spectrometry

Abstract

Any a priori calculations of relative sensitivity coefficients (RSC) using empirical formulae which take into account only the analyte properties are shown to be fruitless. In a series of experiments with model samples, it has been possible to determine the contribution of each individual step of mass spectrum formation, viz. substance atomization, atom ionization, and recombination accompanying plasma expansion. Both matrix properties and the interaction conditions affect the relationship between RSC and the thermodynamic parameters of analytes and/or their ionization potentials. Unlike other physical analysis methods, in spark- and laser-source mass spectrometry the effect on the sample is rather strong. Thus, certain atoms may acquire an energy much higher than their bond energy in a solid and the ionization energy. Therefore, it is possible, in principle, to correlate the interaction conditions with the matrix composition and properties. Under optimum conditions, a standardless quantitative analysis may be possible.