Abstract

SOLVENT EXTRACTION, SPECTROPHOTOMETRIC DETERMINATION OF SELENIUM (IV) AT MICROGRAM LEVEL USING O-METHYLPHENYL THIOUREA AS A SENSITIVE REAGENT: ANALYSIS OF PHARMACEUTICALS, SYNTHETIC MIXTURES AND REAL SAMPLES

Shashikant Kuchekar*, Shivaji Pulate, Vishvas Gaikwad, Pradeep Dighe, Ponnadurai Ramasami

ABSTRACT

A simple and rapid method has been developed for solvent extraction and spectrophotometric determination of selenium (IV) using o-methylphenyl thiourea (OMPT) as a sensitive reagent. The basis of proposed method is formation of selenium (IV)-OMPT complex. Selenium (IV) was extracted with 0.015 mol L-1 OMPT in chloroform from aqueous solution in 3.6 mol L-1 hydrochloric acid. The absorbance of complex was measured at 335 nm. Beer’s law was obeyed up to 800.0 μg mL-1 for selenium (IV). The molar absorptivity and Sandell’s sensitivity of the complex were 4.066 × 102 L mol-1 cm-1 and 0.1942 μg cm-2 respectively. The Stiochiometry of selenium (IV)-OMPT complex was 1:2 established from slope ratio method, mole ratio method and job’s continuous variation method. The stability of selenium (IV)-OMPT complex was >48 h. The proposed method is free from interferences from foreign ions and suitable masking agents were used wherever necessary to enhance selectivity of method. The proposed method was successfully applied for separation and determination of selenium (IV) from pharmaceuticals, synthetic mixtures and real samples. Precision of method was checked by finding relative standard deviation for 10 determinations was 0.44%.

Keywords: Solvent extraction, Analysis, Pharmaceuticals and Vegetable, Selenium (IV).