SPECTROPHOTOMETRIC DETERMINATION OF SELENIUM IN INDUSTRIAL AND ENVIRONMENTAL SAMPLES USING 5-METHYLTHIOPHENE–2-CARBOXALDEHYDE ETHYLENEDIAMINE (MTCED)

K. Deepa*, T. Vasantha, Cheera Prasad, N. V. V. Jyothi and Y. Lingappa

ABSTRACT

A simple, rapid and sensitive spectrophotometric method was developed for the determination of Se (IV) using 5-methylthiophene–2-carboxaldehyde ethylenediamine (MTCED) as an analytical reagent. The reagent has been synthesized and characterized using IR, 1H NMR and mass spectral data. The metal ion in aqueous medium forms light greenish yellow colored complex with MTCED at (pH= 4.0) (sodium acetate- acetic acid buffer solution) showing maximum absorbance at 390 nm. Hence, analytical studies were further carried out at 390 nm. The reagent reacts with selenium in acidic medium to form light greenish yellow colored 1:1 (M:L) complex. The color reactions are instantaneous and absorbance values remain constant for 24 hours. The composition of the Se (IV) complex with MTCED was studied by the method of job’s continuous variation and molar ratio method. Beer’s law was obeyed in the range 0.007-3.47 μg ml−1of Se (IV). The molar absorptivity and Sandell’s sensitivity of the method were found to be 6.67 x104 Lmol-1cm-1 and 0.0015 μg/cm-2 respectively. Since MTCED method is more sensitive, it was applied for the determination of selenium in environmental samples.

Keywords: Selenium determination, Non-extractive spectrophotometry, 5-methylthiophene–2-carboxaldehyde ethylenediamine (MTCED), Environmental samples.