Haddad, P. R. published the artcileSpectrophotometric and fluorometric determination of cobalt, Name: 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine, the publication is Talanta (1976), 23(4), 275-81, database is CAplus and MEDLINE.
Co(II) reacts with pyridine-2-aldehyde-2-pyridyl hydrazone (L) and eosine (L1) at pH 5.6 to give the ternary complex CoL(HL)L12 which is extracted by CHCl3-Me2CO (7:3) to give a strongly colored, fluorescent extract Linear calibration curves for absorption at 547 nm and fluorescence at 558 nm were obtained for 0.04-0.4 and 0.02-0.2 ppm Co, resp. Relative standard deviations were 2.2 and 6.1% and detection limits were 0.017 and 0.008 ppm Co for absorption and fluorescence, resp. Interferences from Cu(II) were eliminated by electrodeposition of Cu and from Ni, Fe(II), Pd(II), and Hg(II) by ion exchange, giving recoveries of >98%. The method was successfully applied to determination of Co in steels.
Talanta published new progress about 2215-33-0. 2215-33-0 belongs to pyridine-derivatives, auxiliary class Pyridine,Amine, name is 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine, and the molecular formula is C11H10N4, Name: 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine.
Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem