Trace analysis of high-purity graphite by LA-ICP-MS

Laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been established as a very efficient and sensitive technique for the direc t analysis of solids. In this work the capability of LA-ICP-MS was investig ated for determination of trace elements in high-purity graphite. Synthetic laboratory standards with a graphite matrix were prepared for the purpose of quantifying the analytical results. Doped trace elements, concentration 0.5 mug g(-1), in a laboratory standard were determined with an accuracy of 1% to 7% and a relative standard deviation (RSD) of 2-13%. Solution-based calibration was also used for quantitative analysis of high-purity graphite . It was found that such calibration led to analytical results for trace-el ement determination in graphite with accuracy similar to that obtained by u se of synthetic laboratory standards for quantification of analytical resul ts. Results from quantitative determination of trace impurities in a real r eactor-graphite sample, using both quantification approaches, were in good agreement. Detection limits for all elements of interest were determined in the low ng g(-1) concentration range. Improvement of detection limits by a factor of 10 was achieved for analyses of high-purity graphite with LA-ICP -MS under wet plasma conditions, because the lower background signal and in creased element sensitivity.