Selective transport of cadmium(II) through hollow fiber-supported liquid membrane microextraction using diaza-18-crown-6 in ionic liquids as carrier

A hollow fiber-supported liquid membrane microextraction (HF-SLME) system using diaza-18-crown-6 (DA18C6) in ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM]PF6) as an efficient carrier for the selective transport of cadmium(II) is described. The Cd(II) is ion paired with chlorine ion as a suitable counter into the membrane phase and then complexed with DA18C6; sodium thiosulfate (Na2S2O3) is injected in the lumen of membrane as an acceptor phase to trap the Cd(II) into the acceptor phase. The influence of various experimental parameters in the extraction procedure is discussed using a three-level Box–Behnken experimental design with three factors to optimize. Under the optimum conditions, the selectivity and efficiency of Cd(II) transport from an aqueous sample containing different mixtures of Co2+, Ni2+, Fe3+, Cr3+, Mn2+, and Cd2+ are investigated. The enrichment factor of Cd2+ is 172, the limit of detection is 0.13 ng L−1, and the relative standard deviation is 5.1 %. The method has been successfully applied to the determination of Cd(II) in food and cosmetic samples.