| High-voltage spark ablation is used for the direct sampling of solids with subsequent analysis by ICP-MS. Separation of sample vaporization, excitation, and detection phenomena allows each event to be optimized independently, thereby facilitating enhanced sampling efficiency. A direct linear relationship between electron multiplier counts and concentration was observed for trace elements (ranging from 0.75 to 125 ppm) in a series of pure copper standards. It is significant that neither concentration normalization nor internal standardization procedures were required. This technique can be applied for the direct determination of conductive samples with little or no sample preparation. For such samples, spark ablation could serve as an alternative to laser sampling in cases where larger sampling sites can be tolerated. In contrast, this technique uses inexpensive instrumentation, is simple to operate, and shows good accuracy and precision, even in prototype form.;Various aspects of the spark ablation ICP-MS technique are investigated. It is observed that several parameters including cone condition, ion lens tuning, integration method, and spark repetition rates can affect the signal and consequently the results obtained. The spark repetition rate has an especially dramatic effect on signal intensity and background levels. These observations and resultant optimization have led to enhanced stability and detection limits. Precision of ;The feasibility of analyzing elemental constituents in non-conducting powders by spark ablation ICP-MS is evaluated. The samples are made conductive by mixing with graphite or copper and pressing the mixture into a pellet. Optimal parameters for the analysis were established. Quantitative analysis of samples is done using successive dilutions of known materials and by the preparation of synthetic standards. Precision ranges from 1-10% with accuracy between 5-20%. Detection limits are in the ppb range. |
