Reagents for detection of carboxylate anion ligands after chromatographic separation of zinc carboxylato complexes

Reagents for detection of carboxylate anions as components of zinc carboxylato mixed-ligand complexes, after chromatographic analysis, is documented in this article. Because direct optical detection of the carboxylate ligands was not possible, in this work we present procedures for detection of the carboxylate anions by use of classical reagents on thin layers after separation of the complexes. It is important to know the positions of zinc(II) and the carboxylate anion for determination of the mechanism of separation of the whole zinc complex. Primary spot detection was achieved with bromphenol blue, bromcresol green, and thymol blue indicator solutions, directly on the wet layer. Bromcresol green resulted in most sensitive detection of the carboxylates tested. The detection limit for this reagent and butyrate anion was established as 0.03 mg L-1.