Schilt, Alfred Ayars, 1927-
M.S. (Master of Science)
Department of Chemistry
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.
Hillison, Thomas E., "Investigation of some selected ferroin-type reagents as fluorometric reagents and determination of zinc (II) by chelation with 2-(4-Methyl-2-pyridyl)-5(6)-phenylbenzimidazole" (1979). Graduate Research Theses & Dissertations. 3654.
Northern Illinois University
Rights Statement 2
NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.