Use of Ion-pairing for High Performance Liquid Chromatography of Alkaloids and Quaternary Ammonium Compounds
Thesis - Open Access
Master of Science (MS)
Department / School
Duane P. Matthees
The alkaloids have been used by mankind in potions, medicines, teas and poisons for at least 3000 years. They occur throughout the plant and animal kingdoms and display a diversity of structure unmatched by any other group of natural compounds. Because the alkaloids exhibit an extraordinary array of pharmacological activities they are widely used in medicine. The following 1ist is designed to indicate the degree of use of various alkaloids by U.S. physicians: Major: Atropine, Ergonovine, Morphine, Codeine Medium: Scopolamine, Ergotamine, Quinine, Cocaine Minor: Strychnine, Brucine general approach to the ion-pairing high performance liquid chromatography (HPLC) of alkaloids and quaternary ammonium compounds is described in the analysis of these ionized solutes. Over the years, a variety of different approaches have been developed to allow selectivity in liquid chromatographic separations whether based on permeation, ion-exchange, absorption or partitioning phenomena. The latter approach has gained wide usage recently due to the development of stable normal or reversed-phase systems. The application of reversed-phase systems certainly has become the most popular form of HPLC. HPLC has been used previously for analysis of alkaloids using normal-phase adsorption method. This often results in high solute retention coupled with very poor peak shape and solute resolution. One of the major advantages of liquid chromatography over gas chromatography arises from the participation of the mobile phase in the equilibria distribution of the sample eluate molecules. Besides this primary chemical equilibria distribution process between mobile and stationary phase, secondary chemical equilibria between the eluate molecules and components present in either the eluent or the stationary phase can be established conveniently by choice of chromatographic conditions. These secondary processes will influence a variety of kinetic and thermodynamic parameters including ionization state, reversible complex formation, etc. Consequently, these secondary equilibria can have ·dramatic effects on the retention characteristics of the compound. The desired qualities of the ion-pairing reversed-phase HPLC method for the analysis of ionized solutes are rapidity, sensitivity, efficiency and ability to resolve materials from complex systems without a prior solvent extraction step.
Library of Congress Subject Headings
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South Dakota State University
Chiu, Hsiao-Kuang, "Use of Ion-pairing for High Performance Liquid Chromatography of Alkaloids and Quaternary Ammonium Compounds" (1982). Electronic Theses and Dissertations. 4132.