Abstract
Inductively coupled plasma-source mass spectrometry (ICP-MS) is a powerful tool in multielemental analysis and has been used to find the composition of many diverse materials in recent years. Traditionally, samples are dissolved for introduction to the ICP by means of a pneumatic nebuliser. Laser ablation of solids for the direct introduction of sample material to the ICP is an attractive alternative to pneumatic nebulisation offering a number of analytical advantages, but particularly the speed and ease of working directly from the solid. In this work a ruby laser and the Surrey prototype ICP-mass spectrometer were used to assess the possibility of using a laser for solid sample introduction to ICP-MS. Systematic studies of the influence of parameters such as sample matrix composition, laser pulse energy, plasma gas flows, etc., on system response were undertaken with a view to optimising analytical performance. The feasibility of the analysis of metals, rocks, soils, sediments, leaf material, animal tissue, and some foodstuffs, has been investigated. This was achieved by the use of standard reference materials and intra and inter-analytical comparisons. For many matrices analyses can be obtained using integrations covering the full mass scan with calibration against matrix-matched standards. Such procedures allow the determination of analyte concentrations, in the mug g-1 range. Concentrations in the ng g-1 region can be detected using short mass scans. The main difficulty with the technique lies in the matrix dependent nature of the ablation process. Despite this, most of the anticipated advantages of the method are realised in practice. Laser ablation ICP-MS is likely to find increasing application for rapid trace analysis, particulary to high technology and biological materials.