Influence of the Isotopic Composition of Standards on the Accuracy of Atomic Spectrometry for the Determination of Lithium

Abstract

Analysis by atomic spectroscopy depends on the comparison of the signal generated by the sample to the signal generated by a standard. If the isotopic distribution of the analyte element in the sample differs substantially from the isotopic distribution in the standards, then an error will result. The magnitude of the error depends on the differences in abundances and on the wavelength differences between the analysis lines of the isotopes. If the analysis is performed by atomic absorption spectrometry, the error is also influenced by the isotopic distribution in the hollow cathode lamp. In the determination of lithium by emission the relative errors can reach 6% for an enriched (40 atom% 6Li) sample. In atomic absorption, the relative errors in the lithium concentrations can reach 50% for an enriched sample.