The first gas chromatographic resolution of carnitine enantiomers

Abstract

The enantiomers of carnitine are converted on-line in the injection port of a gas chromatograph into beta-hydroxy-gamma-butyrolactones and are separated on a derivatized beta-cyclodextrin chiral stationary phase.

Vibrational Circular Dichroism (VCD) Reveals Subtle Conformational Aspects and Intermolecular Interactions in the Carnitine Family

“…Several methods, including enantioselective chemical synthesis and transformations of chiral pool substrates, enzymatic kinetic resolutions, biotransformations of prochiral substrates, and resolutions by crystallization of diastereomeric salts have been described in the literature. Fast, accurate, and reproducible analytical methods capable to measure the enantiomeric excess of the final material are also highly desired: in this field it is nice to acknowledge the seminal contribution of Professor Gasparrini and his group . Carnitine and acyl carnitines being chiral molecules, optical rotation (OR) and circular dichroism in the UV range (electronic circular dichroism, ECD) were measured; in the latter case, ECD has been used as a detector of enantiomeric separation, down the line of HPLC separation protocol, without the accuracy required in a dedicated ECD experiment.…”

“…Fast, accurate, and reproducible analytical methods capable to measure the enantiomeric excess of the final material are also highly desired 6 : in this field it is nice to acknowledge the seminal contribution of Professor Gasparrini and his group. 7,8 Carnitine and acyl carnitines being chiral molecules, optical rotation (OR) and circular dichroism in the UV range (electronic circular dichroism, ECD) were measured 9 ; in the latter case, ECD has been used as a detector of enantiomeric separation, down the line of HPLC separation protocol, without the accuracy required in a dedicated ECD experiment. To the best of our knowledge, though, no one has ever measured vibrational circular dichroism (VCD); yet various forms of vibrational spectroscopy, including IR, Raman, and SERS (surface-enhanced Raman spectroscopy) have been carried out and demonstrated to be useful.…”