Electrothermal atomic absorption spectrometric determination of chromium,iron and nickel in lithium metal

Graphite-furnace atomic absorption spectrometry is applied to the determination of traces of Cr, Fe and Ni in lithium metal, after dissolution as lithium chloride. Direct determination is applied to lithium samples containing higher levels of impurities, but determination in pure lithium samples requires preliminary separation by lanthanum hydroxide coprecipitation. With this enrichment, detection limits of 0.02–0.25 μg g^-1 are obtained using 0.5-g samples of lithium. The accuracy of the procedure was checked by analysis of lithium samples by the proposed coprecipitation method, by direct determination, and by determination after extraction, atomic absorption spectrometry being used in all cases.