Abstract

On-line cITP-NMR with chiral selectors separates and concentrates analytes and identifies host-guest interactions of analytes with selectivity enhancers in the electrolyte. An NMR microcoil designed for a 200 μm i.d. capillary creates a high-mass-sensitivity 30 nL NMR cell and is used as an on-line detector for cITP. Using a mixture of 2 nmol racemic alprenolol in acetate buffer with α-cyclodextrin and sulfated β-cyclodextrin at pD 6.0, cITP-NMR successfully separates and concentrates both R- and S-alprenolol. The concentration enhancement for the R isomer is 224-fold and for the S isomer is 200-fold. The estimated concentration at peak maximum for R-alprenolol is ~28 mmol L-1 and a slightly lower concentration, 25 mmol L-1 is achieved for S-alprenolol. These concentrations convert to placing 76% of the injected S-alprenolol and 84% of the R-alprenolol into the 30 nL detection cell at peak maximum. With on-flow cITP-NMR, intermolecular interactions between the cyclodextrins and the alprenolol are observed in the NMR spectra. Aromatic and methyl moieties of R- and S-alprenolol are identified as two important sites that bind with these particular cyclodextrins.

Original languageEnglish (US)
Pages (from-to)1528-1535
Number of pages8
JournalAnalytical and bioanalytical chemistry
Volume378
Issue number6
DOIs
StatePublished - Mar 2004

Keywords

  • Capillary isotachophoresis
  • Chiral separation
  • Microcoil NMR
  • On-flow

ASJC Scopus subject areas

  • Analytical Chemistry
  • Clinical Biochemistry

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