TY - JOUR
T1 - Chiral separation of nanomole amounts of alprenolol with cITP/NMR
AU - Jayawickrama, Dimuthu A.
AU - Sweedler, Jonathan V.
N1 - Funding Information:
Acknowledgments We gratefully acknowledge Professor Barry L. Karger and Dr Roger A. Kautz (Department of Chemistry, Northeastern University, USA) for supplying PVA-coated capillaries. We thank Andrew Wolters (Department of Chemistry, University of Illinois, Urbana-Champaign, USA) and Professor Andrew G. Webb (Department of Electrical and Computer Engineering, University of Illinois, Urbana-Champaign, USA) for technical support. We greatly appreciate the assistance of Dr Paul F. Molitor and the Varian Oxford Instruments Center for Excellence in NMR (VOICE Lab) in the School of Chemical Sciences at the University of Illinois, Urbana-Champaign, USA. We gratefully acknowledge financial support from the National Institute of Health (EB002343).
PY - 2004/3
Y1 - 2004/3
N2 - 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.
AB - 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.
KW - Capillary isotachophoresis
KW - Chiral separation
KW - Microcoil NMR
KW - On-flow
UR - http://www.scopus.com/inward/record.url?scp=14744276970&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=14744276970&partnerID=8YFLogxK
U2 - 10.1007/s00216-003-2421-0
DO - 10.1007/s00216-003-2421-0
M3 - Article
C2 - 15214413
AN - SCOPUS:14744276970
SN - 1618-2642
VL - 378
SP - 1528
EP - 1535
JO - Analytical and bioanalytical chemistry
JF - Analytical and bioanalytical chemistry
IS - 6
ER -