Publication Date


Document Type


First Advisor

Schilt, Alfred Ayars, 1927-

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Chemistry


Fluorimetry; Chelates


This Investigation consisted of three related studies concerned with the fluorometric properties and applications of metal chelates. Forty compounds, selected as represen­tative of various distinct classes of ferroin-type compounds, were screened as fluorometric reagents for zinc, lead, cop­per, and silver. Those compounds which formed fluorescent metal chelates were examined in greater detail by fluoro­metric studies of their zinc chelates. Spectral properties and ligand to metal mole-ratios were studied. Finally, the most promising compound, 2-(4-methyl-2-pyridyl)-5(6)- phenylbenzimidazole, was utilized for developing a procedure for the fluorometric determination of zinc. The classes of compounds that fluoresced in the screen­ing evaluation were the benzimidazoles, quinoxalines, quino­lines, and phenazines. The non-fluorescing classes were the triazines, pyridines, pyridazines, pyrimidines, triazolines, azines, and triazones. Seven of the fluorescing compounds were examined fluorometrically to study their spectral properties and zinc chelate mole-ratios. Non-linearity and the lack of sharp changes in the mole-ratio slopes indicated that the zinc chelates are weak complexes, too weak for a reliable determination of their mole-ratios. Based on the fluorometric studies, one compound, 2-(4-methyl-2-pyridyl)-5(6)-phenylbenzimidazole or 2-MPPB, was selected as the most promising reagent-for the fluorometric determination of zinc. Optimum experimental conditions were established for the determination of zinc with 2-MPPB. The final solution prepared for measurement should be 8 x 10⁻⁵ M in 2-MPPB, 50% 1n ethyl alcohol, at pH 4, and contain 0 - 200 ppb zinc. The recommended procedure yielded a sensitivity of less than a ppb and a relative standard deviation of 12%. Fur­ther studies are recommended for future investigations of 2-MPPB as a fluorometric reagent for other metal ions.


Includes bibliographical references.||Includes illustrations.


138 pages




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