Investigation of selected ferroin-type compounds as fluorometric reagents Determination of zinc with 2-(4-methyl-2-pyridyl)-5(6)-phenylbenzimidazole

In a search for new fluorometric reagents for trace metal determinations, forty different ferroin-type compounds and their silver, lead and zinc chelates were tested for luminescence in aqueous—ethanol solutions at various pH values. Twelve formed fluorescent chelates of potential analytical utility, and the results revealed some correlation between ligand structure and fluorescence. After identification of the most sensitive fluorometric reagent for zinc among those tested, a spectrophotofluorometric method for the determination of zinc was developed. Proper control of pH and reagent concentration allows determination of nanogram amounts of zinc.