Determination of chromium in airborne particulate matter by high resolution and laser ablation inductively coupled plasma mass spectrometry

This work presents an optimized sample digestion procedure for determining Cr in airborne particulate matter by inductively coupled plasma mass spectr ometry (ICP-MS). High resolution (HR) ICP-MS is utilized to examine how the added acid mixture and subsequent evaporation process influence spectrosco pic interference. Experimental results indicate that a two-step high pressu re bomb acid digestion (1st step with HNO3+HClO4, and 2nd step with HF) pro cedure without evaporation is the optimum pre-treatment procedure for deter mining Cr by ICP-MS. In addition, laser ablation (LA) ICP-MS is used direct ly to analyze for Cr in airborne particulate matter. Results obtained by LA -ICP-MS correlate well with certified values and values obtained from the c onventional acid digestion/HR-ICP-MS method. The detection limit for Cr in air particles by HR-ICP-MS with the proposed digestion method is<10 ng g(-1 ). Furthermore, LA-ICP-MS provides a rapid direct analytical technique with a detection limit of 0.05 mu g/filter. (C) 1999 Elsevier Science B.V. All rights reserved.