VALIDATION OF THE ANALYTICAL LINEARITY AND MASS DISCRIMINATION CORRECTION MODEL EXHIBITED BY A MULTIPLE COLLECTOR INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETER BY MEANS OF A SET OF SYNTHETIC URANIUM ISOTOPE MIXTURES

A set of commercially available synthetically prepared mixtures of uranium isotopes (IRMM 072) were used to assess the linearity and mass discrimination exhibited by a multiple collector ICP-MS instrument. Measurements of eight uranium isotopic reference materials with U-233:U-235 isotope abundance ratios ranging from 1 to 0.01 were made. Linear, power law and exponential relationships between instrumental mass discrimination and mass difference were evaluated. The power law and exponential function resulted in the best correction. The corrected isotope abundance ratios for U-233:U-235 and U-233:U-238 did not differ significantly from the certified values at the 3 x 10(-4) level.