Original Articles: 2011 Vol: 3 Issue: 3
Simple and sensitive spectrophotometric determination of Zn (II) in Biological and Pharmaceutical samples with 2-Benzoylpyridine thiosemicarbazone(BPT)
A simple, rapid and sensitive spectrophotometric method was developed for the determination of Zn(II) using 2-benzoylpyridine thiosemicarbazone (BPT) as an analytical reagent. The metal ion in aqueous medium forms yellow colored complex with BPT at pH 6.0 showing maximum absorbance at 430 nm. At 430 nm the reagent itself does not show considerable absorbance. Hence, analytical studies were further carried out at 430 nm. Beer’s law was obeyed in the range of 0.26-2.61 μg/ml of Zn(II). The molar absorptivity and sandall’s sensitivity of the method were 1.8 x 104 L mol-1 cm-1 and 0.0035 μg/cm2 respectively. The detection limit of the method was achieved to be 0.064 μg/ml. The percentage of relative standard deviation was calculated to be less than 3% by replicate determinations of different concentrations. The composition of the Zn(II) complex with BPT was studied by the method of Job’s continuous variation, and molar ratio method. It has been satisfactorily applied for the determination of zinc(II), when present alone or in presence of diverse ions. The proposed methods were applied for the determination of Zn(II) in real samples such as pharmaceutical and biological samples. Various certified reference materials (NIST 1573, NBS 1572, and NIST SRM 8435) have been tested for the determination of zinc for evaluating the accuracy of the developed method. The results of the proposed method are in agreement with flame atomic absorption spectrophotometry.