2-Hydroxy-1-Naphthalidene-Salicyloylhydrazone as an Analytical Reagent for Extractive Spectrophotometric Determination of a Biologically and Industrially Important Metal Cobalt (II)Author(s): Swapnil G. Prabhulkar and R. M. Patil
2-Hydroxy-1-naphthalidene-salicyloylhydrazone (HNSH) was used as an analytical reagent for the extractive spectrophotometric determination of cobalt (II). The optimum extraction conditions were evaluated by studying parameters like pH, time, solvent, reagent concentration and stability of complex etc. 2-Hydroxy-1-naphthalidene-salicyloylhydrazone gave a golden yellow coloured complex with Co (II) and quantitatively extracted into iso-butyl methyl ketone in the pH range of 8.0 to 9.0. The absorption spectrum of Co-HNSH shows maxima at 430 nm and obeys Beer’s law in the range of 0.0 to 10.0 ppm. The molar absorptivity and Sandell’s Sensitivity were 1.616 × 103 L mol-1 cm-1 and 0.036 μg mL-1 cm-2, respectively. The composition of Co (II)-HNSH was determined by Job’s continuous variation method and confirmed by mole ratio method. The standard deviation and variation from mean at 95% confidence limit were 0.15 and ± 0.107, respectively. The effects of diverse ions have been studied. The proposed method is rapid, sensitive and precise. It has been applied for the determination of cobalt in synthetic and real samples.