The analysis of soil and sediment samples using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS ) was studied. Solution-based calibration was used for the quantification of trace elements in these samples. In most cases, the measured concentrations were within ±20% of the certified values using 60Ni or 107Ag as the internal standard. Measurements with Ag were carried out to investigate whether an internal standard could be spiked into soils for quantification purposes. The influence of particle size on the applicability of sample spiking was briefly studied, and it was demonstrated that particle size could significantly influence measurements if only the surface constituents of the particle were ablated. Use of 43Ca or 44Ca as an internal standard produced poorer results owing to interferences at these masses. In some cases, such as with Sr, Ba, Y and Rb, the measured concentrations were low by a factor of 2-3. This could be remedied by using one of these elements as an internal standard for the others. The effects of elemental speciation, organic content and particle size were investigated. Elemental speciation and organic content of the soils did not appear to significantly affect the LA-ICP-MS measurements. Particle size, however, was found to influence the precision and sensitivity of the measurements. Samples with smaller particle sizes yielded higher signal levels and better precision.

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A method for the determination of trace element concentrations by laser ablation inductively coupled plasma mass spectrometry (ICP-MS) using solution calibration and an internal standard has been studied and evaluated by analyzing NIST soil and glass samples. In most cases, the measured element concentrations were within ±10% of the certified values. The internal standard was chosen on the basis of investigations of the proper signal intensity of certain isotopes and the homogeneity of their distribution in the sample. For soil samples, a matrix element, Mg, was chosen to be the internal standard. For glass samples, a trace element, Sr, was used as the internal standard. The results indicated that in both cases the internal standard was effective. Ni and Cu in soil gave poor results, while good results were obtained for Ni and Cu in glass samples. Time-resolved studies show that Ni gave many more signal spikes than other elements when the ablating laser moved across the surface of the soil sample. This observation indicates that one possible reason for the poor results was caused by the heterogeneity of the Ni distribution in the matrix.

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