A method is proposed for the determination of tin in silicates by atomic absorption spectrometry after extracting tin (IV) iodide with benzene. Take 0.1 to 0.5g of sample in a platinum dish, add 10 ml of HF, 5ml of HClO
4, and 3 ml of HNO
3, and evaporate the solution to dryness. Dissolve the residue by heating with 5 ml of HCl (1+1). Transfer the solution into a separatory funnel, add 10 ml of HClO
4, 0.5 ml of 50% sodium hypophosphite, 5 ml of 5M NaI, and extract tin for 3 min with 10 ml of benzene. Wash the organic phase with 16 ml of 5.5M HClO
4-0.3M NaI solution. Shake the organic phase for 3min with 10 ml of 0.6M HCl-0.004M MgCl
2, and withdraw the aqueous phase into a beaker. Cover the beaker, immerse in boiling water for about 15 min to remove the dissolved benzene, and introduce this solution into a premix type slot burner. The sensitivity is 0.02 μg/ml/1% abs., and the limit of detection 0.4 ppm of tin in rock samples. The relative standard deviation in the determination of 2 to 100μg tin is 2 to 9%. The time required for 10 samples is about 4 hours. The method is satisfactorily applied to the standard silicate samples.
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