Study of high-voltage breakdown and material consumption in spark-source mass spectrometry and their significance in analytical applications

The breakdown voltage has been found to be dependent on the gap width between the electrodes and on the melting point of the sample elements in spark-source mass-spectrometry (SSMS). The number of discharges per pulse train and the time required to reach the first discharge depend only on the chosen breakdown voltage. The spark gap is proportional to the "radius" of the volume sampled (for a given element) and this radius is linearly related to the reciprocal of the melting point of the elements (23 different elements, metals or semiconductors), when fixed spark-parameters are used. The effect of electrode temperature on material consumption can be qualitatively explained by a fictive increase or decrease in melting point of the element. Knowledge of the relations between the different spark and instrumental parameters and the volume or weight of sample consumed can be applied to the study of the homogeneity of samples, to in-depth analysis by SSMS and to the analysis of microsamples.