Determination of Sn(II) and Sn(IV) after mixed micelle-mediated cloud point extraction using α-polyoxometalate as a complexing agent by flame atomic absorption spectrometry

The cloud point extraction behavior of Sn(II) and Sn(IV) using α-polyoxometalate and mixed surfactants solution was investigated. The mixture of a nonionic surfactant (Triton X-100) and a cationic surfactant (CTAB) was utilized as a suitable micellar medium for preconcentration and extraction of tin complexes. Sn(II) in the presence of Sn(IV) was extracted with α-polyoxometalate, 0.3% (w/v) Triton X-100 and 3.5 × 10−5 mol L−1 CTAB at pH 1.2. Whereas the pH value of 3.7 were used for the individual determination of Sn(II) and Sn(IV) and also for total tin determination at the same conditions. Enrichment factors of 100 were obtained for the preconcentration of both metal ions. Under the optimal conditions, linearity was obeyed in the ranges of 55–670 μg L−1 of Sn(II) and 46–750 μg L−1of Sn(IV) ion concentration. The detection limit of the method was also found to be 12.6 μg L−1 for Sn(IV) and 8.4 μg L−1 for Sn(II). The relative standard deviation of seven replicate determination of 100 μg L−1 both metal ions were obtained about 2.4%. The diverse ion effect of some anions and cations on the extraction efficiency of target ions were tested. Finally, the optimized conditions developed were successfully utilized for the determination of each metal ion in various alloy, juice fruit, tape and waste water samples with satisfactory results.