Separation of carnitine and acylcarnitines by capillary electrophoresis

Free carnitine and specific acylcarnitines (carnitinyl esters) play an important role in the metabolism of long-chain fatty acids and many metabolic disorders. The optical properties of the carnitine molecule and the esters make a derivatization necessary to introduce ultraviolet or fluorescent chromophores into the molecule. The separation of carnitine and different acylcarnitines as derivatives of 9-anthryldiazomethane was performed with capillary electrophoresis successfully. An electrophoretic buffer system with very high methanol content (88%), phosphoric acid and sodium dodecyl sulfate has been optimized with respect to the best resolution of the derivatives. The separation of carnitine and its acyl esters up to the palmitoylcarnitine was achieved in aqueous standards as well as in standard plasma samples. For carnitine and most of the acylcarnitines detection limits below physiological concentrations were determined using laser induced fluorescence. (C) 1997 Elsevier Science B.V.