Low-blank isotope ratio measurement of small samples of lithium using multiple-collector ICPMS

A new method is presented for separation of lithium from silicate rocks and high precision MC-ICPMS analysis. A relatively small (3.57 meq) resin volume is able to separate lithium from all silicate rocks in a single step using only 16 ml of nitric acid mixed with methanol. Some advantages of the method are high sample throughput, low blanks and elution parameters that are insensitive to lithology. Elution schemes are presented for a range of igneous rocks and minerals. delta(7)Li values for standards from the U.S. Geological Survey (USGS) for BCR-1, BHVO-2 and AGV-2 are 2.4parts per thousand, 4.6parts per thousand and 7.9parts per thousand, respectively. Reference materials from the Geological Survey of Japan (GSJ) JB-2 and JR-2 give delta(7)Li values of 4.7parts per thousand and 3.8parts per thousand, respectively. The data for most reference rocks reproduce to within better than 0.5parts per thousand. This column method can also be used for the direct separation of high-field-strength elements (Ti, Zr, Hf, Nb, Ta) from silicate rocks. (C) 2004 Elsevier B.V. All rights reserved.