Hexaacetatocalix(6)arene was used for the solvent extraction of iron(III). About 7.5 x 10-2 M extractant was used at pH 7.0 for the quantitative extraction of iron(III). The metal from the organic phase was stripped with 1.0 M hydrochloric acid and determined spectrophotometrically as its thiocyanate complex at 480 nm. Iron(III) was separated from large excesses of alkali and alkaline earths in the ratio 1:20. The transition and main group elements were tolerated in the ratio 1:10. The method was extended for the analysis of iron from its mineral, alloy and pharmaceutical preparation. The method is reproducible with SD ± 1.10%.
Khandwe, R. M., & Khopkar, S. M. (1998). Calix(6)arene carboxylate derivative for solvent extraction separation of iron(III). In Talanta (Vol. 46, pp. 521–525). Elsevier B.V. https://doi.org/10.1016/S0039-9140(97)00301-9