A method for the spectrophotometric determination of cobalt(II) is presented, with a comparison of the binary complexes formed by cobalt(II) with di-2-pyridyl ketone nicotinoylhydrazone (DPKNH), di-2-pyridyl ketone 2-thiophenoylhydrazone (DPKTH) and di-2-pyridyl ketone benzoylhydrazone (DPKBH) in 50% (v/v) ethanolic solution. Cobalt(II) forms 1: 2 complexes with the three reagents. Maximum absorbance is at 372 nm for Co(II)- DPKNH, at 389 nm for Co(II)-DPKTH and at 370 nm for Co(II)-DPKBH

Analytica chimica acta, 1992, vol. 259, no1, pp. 175-179 (17 ref.)