Characterization of a Thermally Induced Irreversible Conformational Transition of Amylose Tris(3,5-dimethylphenylcarbamate) Chiral Stationary Phase in Enantioseparation of Dihydropyrimidinone Acid by Quasi-Equilibrated Liquid Chromatography and Solid-State NMR

Fang Wang, Robert M. Wenslow, Thomas M. Dowling, Karl T. Mueller, Ivan Santos, Jean M. Wyvratt

Research output: Contribution to journalArticle

37 Scopus citations

Abstract

A thermally induced irreversible conformational transition of amylose tris(3,5-dimethylphenylcarbamate) (i.e., Chiralpak AD) chiral stationary phase (CSP) in the enantioseparation of dihydropyrimidinone (DHP) acid racemate was studied for the first time by quasi-equilibrated liquid chromatography with cyclic van't Hoff and step temperature programs and solid-state (13C CPMAS and 19F MAS) NMR using ethanol and trifluoroacetic acid (TFA)-modified n-hexane as the mobile phase. The conformational transition was controlled by a single kinetically driven process, as evidenced by the chromatographic studies. Solid-state NMR was used to study the effect of the temperature on the conformational change of the solvated phase (with or without the DHP acid enantiomers and TFA) and provided some viable structural information about the CSP and the enantiomers.

Original languageEnglish (US)
Pages (from-to)5877-5885
Number of pages9
JournalAnalytical chemistry
Volume75
Issue number21
DOIs
StatePublished - Nov 1 2003

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry

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