Solvent extraction and spectrophotometric determination of cerium(IV) by using o-methoxy phenylthiourea as an analytical reagent

Abstract

A solvent extraction spectrophotometric determination method was developed for cerium(IV) using o-methoxy phenylthiourea (OMePT) as a selective reagent. A ternary complex was formed after liquid-liquid extraction from 0.05 mol L-1 potassium iodide aqueous media using 2.0×10-4 mol L-1 OMePT in chloroform and is measured spectrophotometrically at 318 nm. The validity of Beer's law was in the concentration range up to 22.5 μg mL-1, with molar absorptivity and Sandell's sensitivity values of 3.38×103 L mol-1 cm-1 and 0.041 μg cm-2 respectively. The stoichiometry of the cerium(IV)-OMePT-iodide complex was determined by the slope ratio method and verified by the mole ratio method. The complex was stable for more than 48 h. The method is free from interferences from large number of cations and anions. The developed method was successfully employed for the determination of cerium(IV) from binary synthetic mixtures, ternary synthetic mixtures, soil, tap water and sea water samples.