Determination of Thallium at Ppm Levels in Rocks and Minerals by Flame Atomic Absorption Spectrometry

Central Chemical Laboratory, Geological Survey of India, Calcutta-700 016 Manuscript received 29 Match 1990, revised 19 October 1990, accepted 24 October 1990 A solvent extraction atomic absorption spectrometry (AAS) method for the determination of thallium at parts per million levels in rocks and minerals have been described. The method involves sample decomposition by heating with mixture of hydrofluoric-perchloric acid, followed by extraction of thallium as iodo-complex with TOPO-MIBK from dilute hydrochloric acid medium. Flame AAS measurements for thallium is made from the organic phase. The method has been applied to the determination of thallium in a number of granite rocks and manganese ore samples. Precision studies by replicate analysis of one sample (granite B-26) gave an RSD of 6 6%