DETERMINATION OF TRACE IMPURITIES IN URANIUM-OXIDES BY LASER ABLATION INDUCTIVELY COUPLED PLASMA MASS-SPECTROMETRY

Laser ablation inductively coupled plasma mass spectrometry was used to perform a semi-quantitative determination of 23 impurity elements in a U3O8 Certified reference material (CRM). Matrix-matched, single-point calibration was achieved by using another CRM from the same series of standards. Based on uncertainties derived from error propagation, most measured concentrations fell within one standard deviation of certified values. Under optimum laser sampling conditions, limits of detection (LODs) for low m/z elements were found to be about 1-mu-g g-1; high m/z elements had LODs approximately 100 times lower. Upper limits of quantification were generally in the low mg g-1 range. Median short-term signal reproducibility was 8% relative standard deviation when an internal reference isotope (U-234) was used. Reproducibility was poorer when the internal reference was not used or when the same area of the target was ablated in replicate.