Spectrophotometric determination of cobalt in biological samples using 2-acetylpyridine semicarbazone

Department of Chemistry, Sri Krishnadevaraya University, Anantapur-515 003, Andhra Pradesh, India E-mail : khussainreddy@yahoo.co.in Department of Chemistry, Sri Venkateswara University, Tirupati-517 502, Andhra Pradesh, India Manuscript received 5 May 2008. revised 22 September 2008. accepted 23 October 2008 Analytical application of 2-acetylpyridine thiosemicarbazone (APT) and 2-acetylpyridine semicarbazone is described for the direct non-extractive spectrophotometric determination of cobalt. The reagents react with cobalt in acidic medium (pH 6.0, sodium acetate-acetic acid buffer) to form orange yellow colored 1 : 2 (M : L) complexes. The colour reactions are instantaneous and absorbance values remain constant for over 24 b. The molar absorptivity and Sandell's sensitivity of APT and APS methods are found to be 1.25 x 104 and 1.45 x 104 L mol-1 cm-1 and 0.0047 and 0.004 µg cm-2 of Coll respectively. The systems obey Beer's law in the range of 0.236-2.357 µg/ml of Coll . Since APS method is more sensitive it was applied for the determination of cobalt in biological samples