Determination of Trace Amount of Cadmium in Real Water And Baby Food Samples By Microinjection Flame Atomic Absorption Spectrometry After Cloud Point Extraction Using Selective Synthesis Ligand

Abstract

A cloud point extraction procedure was used for preconcentration and determination of trace amount of cadmium ion in real water and baby food samples by microinjection flame atomic absorption spectrometry and with using new synthesis dithiocarbamate ligand. The method is based on cloud point extraction of cadmium using triton X-114 as nonionic surfactant. A certain amount of ligand (Complexing Agent) and surfactant was added to samples and after pH adjustment; the sample was heated in a water bath. A hydrophobic complex was formed between cadmium and
[N-(2-phenylethyl) dithiocarbamate] ligand and followed by its extraction into triton X-114 surfactant-rich phase.The surfactant-rich phase was diluted with suitable solvent and was separated with using centrifugation, and then measurements were performed with a micro-injection flame atomic absorption spectrometry. Extraction conditions such as pH, amount of Ligand (Complexing Agent) and Surfactant, equilibrium temperature and time, diluent volume and type were optimized. Also ionic strength effect and limit of interferences were studied. Under the optimum conditions, the limit of detection (3Sb/m) of 0.2 µg L^-1, an enhancement factor of 116 and the relative standard deviation (5 µg L^-1, n=5) of 4.5% were obtained. The calibration curve was linear for the concentration range of 0.5 to 20 µg L^-1 with correlation coefficient of 0.9992. The proposed method was applied to determination of cadmium ion in water samples including tap water, mineral water, river water and sea water also baby food samples including infant formula powder (milk-based) and infant cereal Powder (wheat and milk-based).