Use of long chain alkylamines for preconcentration and determination of traces of molybdenum, tungsten and rhenium by atomic-absorption spectroscopy--III. Tungsten in geological samples.
Tungsten is determined by atomic-absorption spectroscopy after its reduction to the W(V)-thiocyanate complex with tin metal and extraction with Alamine 336 into chloroform. Atomic absorbance is measured on a final MIBK solution after evaporation of the chloroform and redissolution of the residue in MIBK. Interference effects are shown to be negligible for diverse cations and anions, including Fe, Cu, Cr, Co, Mo, Al and Bi. Analysis of geological samples with an exceptionally wide range of W content from 2.8 ppm to 10% is achieved with relative standard deviations better than 5%.
Kim
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CH
Department of Analytical Chemistry, University of New South Wales, P.O. Box 1, Kensington, N.S.W., Australia 2033.
Alexander
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PW
Smythe
L E
LE