Microextraction technique based on ionic liquid for preconcentration and determination of palladium in food additive, sea water, tea and biological samples

Modified cold-induced aggregation microextraction (M-CIAME) is a fast and simple method for extraction and preconcentration of metal ions from samples with high salt content. Furthermore, this technique is much safer in comparison with the organic solvent extraction. The extraction of palladium (Pd) was performed in the presence of Michler thioketone (TMK) as the complexing agent. In this method, sodium hexafluorophosphate (NaPF6) was added to the sample solution containing small amounts of 1-hexyl-3-methylimidazolium tetrafluoroborate [Hmim][BF4]. Afterwards, the solution was placed in the ice bath and a cloudy solution was formed. After centrifuging, the extraction phase was settled. Under the optimum conditions, the limit of detection (LOD) was 0.2 ng mL−1. The relative standard deviation (RSD) was 1.7% for 40 ng mL−1 of palladium (n = 5).