An internal normalization technique for unmixing total-spiked mixtures with application to MC-ICP-MS

Isotopic analyses of a total-spiked sample by multiple-collector inductively coupled plasma mass spectrometry (MCICP-MS) are often corrected for mass fractionation by doping the sample with an external tracer element of known isotopic composition and similar mass. However, because of the potential for elemental fractionation on the ICP-MS, internal normalization methods should be used whenever possible. Here, we present a weighted non-linear inversion of the mass spectra of a total-spiked sample, using linear, power, and exponential laws. This method was applied to the calibration of an Osmium tracer solution enriched in Os, and the results agree with iterative unmixing algorithms. # 2001 Elsevier Science Ltd. All rights reserved.