Spectrophotometric determination of V(V) in environmental, biological, pharmaceutical and alloy samples by novel oxidative coupling reactions

A Novel, rapid, sensitive and selective reactions are developed for spectrophotometric determination of trace amounts of vanadium (V) in environmental, biological, pharmaceutical and alloy samples was studied. The methods were based on interactions of 4-bromophenyl hydrazine (4-BPH) with N-(1-naphthyl ethylenediamine dihydrochloride (NEDA) in the presence of vanadium in acidic medium (acetate buffer of pH 3.0) to give violet colored derivative or on the oxidation of 4-bromophenyl hydrazine by vanadium in basic medium and coupling with chromotropic acid (CA) to yield red color derivative. The violet color derivative having an absorbance maximum at 570 nm which is stable for 7 days and the red derivative with λ max 495 nm for 5 days. Beer's law was obeyed for vanadium in the concentration range of 0.5-6.0 μg ml-1 (violet derivative) and 0.6-7.0 μg ml-1 (red derivative), respectively. The optimum reaction conditions and other important analytical parameters were established to enhance the sensitivity of the proposed methods. Interference due to various non-target ions was also investigated. The proposed methods were applied to the analysis of vanadium (V) in environmental, biological, pharmaceutical and steel samples. The performance of proposed methods were evaluated in terms of Student's t-test and Variance ratio F-test that indicates the significance of proposed methods over reported method