Separation and determination of carnitine and its esters in human serum

A colorimetric method for the determination of carnitine and its derivatives is described. Free carnitine, acetylcarnitine and palmitoylcarnitine were extracted with chloroform-methanol. After evaporation, the residue was dissolved in n-butanol and water; palmitoylcarnitine in the organic phase, and free carnitine and acetylcarnitine by passing the aqueous phase through a column of Amberlite CG-120 (H+). Separated carnitine derivatives were hydrolyzed to free carnitine which was followed by the Amberlite column chromatography. After eluting with 2N NH4OH solution, the samples were esterified and determined colorimetrically.