Determination of the enantiomeric purity of L-carnitine and acetyl-L-carnitine by chiral liquid chromatography

摘要

A chiral liquid chromatographic method for determination of the enantiomeric purity of both L-carnitine and acetyl-L-carnitine is described. Separation of the enantiomers of DL-carnitine and acetyl-DL-carnitine was achieved on a commercial chiral column (Chiralcel CD-R) after derivatization with (alpho-bromo)methyl phenyl ketone. Introduction of this lipophilic UV chromophoric group to the carnitine and acetylcarnitine molecules improved their retention, resolution, and UV detection. The mobile phase was 74:26 (v/v) 0.5 mol L-1 sodium perchlorate-acetonitrile, pH 3.8, and the flow rate was 0.4 mL min(-1). Detection was performed at 235 nm. The method is selective and reliable for determination of the enantiomeric purity of bulk drug substances L-carnitine and acetyl-L-carnitine.