Determination of trace cadmium in nonalcoholic beverages by coupling cloud point extraction with spectrophotometry
A cloud-point extraction (CPE) process using the nonionic surfactant, Triton X-114 to extract Cd(II) ions from aqueous solutions was investigated. The method is based on the ion-pairing reaction of Cd(II) with Victoria blue B (VBB+) in presence of excess iodide at pH 4.0 and extraction of the complex formed. The chemical variables affecting CPE efficiency were studied, and the analytical characteristics of the method were obtained. The calibration curves were obtained in the ranges of 1.0-30 and 10-500 ?g/L for Cd(II) ion with the detection limits of 0.34 and 3.8 ?g/L at 608 and 634 nm, respectively. The selectivity study was also tested. The precision (N: 5, 25 ?g/L) was 2.85% relative standard deviation. The results obtained for two certified reference samples were in a good agreement with the certified values. The method was successfully applied to the determination of Cd(II) in beverage samples. © Copyright by Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences.