Determination of lithium traces in microliters of water, wine and high purity solvents by stable isotope dilution and field desorption mass spectrometry

Abstract

In this work, the applicability of field desorption mass spectrometry for the determination of lithium in mineral and tap water, wine and high-purity solvents has been examined. Because of the outstanding sensitivity of field desorption mass spectrometry for alkali cations and the high specificity of mass spectrometry, it was possible to determine lithium from microlitre samples by using the method of stable isotope dilution. Lithium, at levels of 10−7–10−4 mg/ ml, was determined in the samples without any pretreatment. The time required for one analysis was about 20–30 min. The results from quantitative analyses of mineral water were compared with others obtained by atomic-absorption spectrophotometry and were in good agreement. The very small concentrations of lithium in wine and high-purity solvents, which are too low to be measured by conventional atomic-absorption techniques, can be determined accurately without difficulty by field desorption mass spectrometry.