Determination of lithium in wines by ion chromatography

Lithium ion can be added as a denaturing agent to wines unsuitable for cons umption. Accuracy of flame atomic emission spectroscopy with direct nebuliz ation, which is commonly adopted for discovering illegal use of denatured w ines, was found to be compromised by Na+, K+, NH4+, Mg2+, Ca2+ and ethanol contained in wine. Ion chromatography (IC) was tested in order to propose a n alternative method for legal controls. Experimental design was used to in vestigate the influence on the accuracy of the determination of Li+ at ppb levels, of Na+ and ethanol content of wine and of fluctuations of eluent fl ow-rate and composition. It turned out that IC quantification of Li+ can be affected by eluent parameters rather than by wine composition. Since the f ormer can be maintained under the operators control, while the latter canno t, IC was judged preferable to AES for legal controls of Li+ in wines. (C) 2000 Elsevier Science BN. All rights reserved.