Element analysis of inhomogeneous samples by laser ablation ICP mass spectrometry

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been used for the determination of selected elements in heterogeneous powdered soils. The precision of the method essentially depends on the homogeneity of the samples. Therefore the influence of sample inhomogeneity on the precision of analytical results has been checked. The statistical evaluation was carried out using a correlation function. In the context of the described experiments, it is necessary to analyze a volume of about 20 mm³ in order to obtain reliable information on the bulk composition of the heterogeneous samples. This corresponds to about 50 craters, each with a depth of 1 mm. The results can be used to calculate certain analytical parameters, particularly the sample homogeneity, depending on the necessary analytical volume and the representative mass for the quantitative analysis under previously defined conditions. In addition to these calculations, analytical experiments have been carried out which confirm the applicability of this approach.