HPLC of acetyl-L-carnitine in human plasma by derivatization with p-bromophenacyl bromide

A high performance liquid chromatographic method is developed for the determination of acetyl-L-carnitine (ALC), an endogenous carnitine derivative, in human plasma, e-Carnitine, which is the structural analogue of ALC, was used as an internal standard. The human plasma samples were treated with ninhydrin solution for the removal of amino acids and then extracted with methanol. After solid phase extraction on silica columns, samples were derivatized with p-bromophenacyl bromide in the presence of 18-crown-6. The derivative of ALC was quantified by high-performance liquid chromatography with UV detection at 260 nm. The retention time of ALC and e-carnitine was about 27.5 and 22.3 min, respectively. The limit of quantitation was 0.22 nmol/mL, based on signal to noise ratio of 3. The accuracy deviation of assay was less than 12.86%, and the intra-day and inter-day coefficients of variation (CV, %) were lower than 5.18 and 5.06%, respectively.