Estimation of Thiosemicarbazide and Its Metal Complexes with Lead Tetra Acetate

Department of  Post-Graduate Studies and Research in Chemistry, University of Mysore,

Manasa Gangotri, Mysore-570006.

Manuscript received 14 June 1976, revised 12 December 1976, accepted 30 December 1976.

A simple but accurate method for the estimation of thiosemicarbazide (TSC) and it, 'ionic' and ‘neutral' complexes with Zn, Cd, Hg, Co, Ni, Pt and Pd, by lead tetra acetate, in aqueous or pH 4 buffer medium containing  KBr and sodium acetate has been developed. The direct titration with a visual or potentiometric end point involves generally a 11 electron change per molecule of the TSC in the pure state and in its complexes. The platinum complexes are however oxidized with a 9-electron change per molecule of the ligand. A back titration procedure in which TSC and  its complexes in aqueous or pH 4 buffer medium are oxidized by lead tetra acetate with a 10-electron change per ligand molecule has also been developed. The proposed analytical methods are useful for a rapid estimation of  TSC and its complexes on a macro scale and also for computing the number of ligand molecules in a TSC metal complex.