Synthesis and characterisation of 2-hydroxy-3-methoxy benzaldehyde thiosemicarbazone (HMBATSC) and its application of simultaneous second order derivative spectrophotometric method for determination of cobalt(II),nickel(II) and vanadium(V)

2-hydroxy-3-methoxy benzaldehyde thiosemicarbazone (HMBATSC) has been synthesized, characterized and employed as a simple simultaneous second order derivative spectrophotometric method for the analysis of a three-component system containing cobalt(II) nickel(II) and vanadium(V) without separation. The reagent (HMBATSC) reacts with cobalt(II), nickel(II) and vanadium(V) at pH 6.0, forming soluble brown, yellow and green coloured species, respectively. Cobalt, nickel and vanadium present in the mixture are simultaneously determined without solving the simultaneous equations by measuring the second derivative amplitudes at 460 nm, 450 nm and 430 nm, respectively. Further, the derivative amplitudes obey Beer’s law at 460 nm, 450 nm and 430 nm for Co(II), Ni(II) and V(V) in the range 0.059 – 3.535 μg ml⁻¹, 0.058 – 3.425 μg ml⁻¹ and 0.051 – 4.074 μg ml⁻¹, respectively. A large number of additional ions did not interfere with the method. The simultaneous method can be applied for the determination of cobalt(II) in pharmaceutical samples, nickel(II) in water and plant samples and vanadium(V) in biological samples.