Determination of lithium-7/lithium-6 isotope ratios in geological materials by inductively coupled plasma mass spectrometery.

摘要

A method for the determination of Li isotope ratios in a variety of Li-minerals using Inductively Coupled Plasma Mass Spectrometry is described. Lithium isotope ratios are determined with a precision of better than 0.1% and with an absolute accuracy of greater than 0.6% in samples containing as little as 60 ppb Li. Sample material is digested with HF and HCl in sealed Teflon vials and then Li is separated from the matrix on Bio-Rad AG50W-X8, 100-200 mesh cation exchange resin, since concomitant elements in solution are shown to cause isotope patio shifts at concentrations above 100 ppm for several elements (Na, K, Ca, Cs, Sr, Mg). The measured isotope ratios (