Millington D S, Bohan T P, Roe C R, Yergey A L, Liberato D J
Clin Chim Acta. 1985 Jan 15;145(1):69-76. doi: 10.1016/0009-8981(85)90020-8.
Urine samples from three children at different stages of chronic valproate therapy were partially purified using a cation exchange column. A signal consistent with either valproylcarnitine or octanoylcarnitine was observed in one of these extracts by direct fast atom bombardment-mass spectrometry analysis. These isomeric acylcarnitines were synthesized, separated and characterized by thermospray high performance liquid chromatography-mass spectrometry. This new technique was then employed to positively identify intact valproyl-carnitine in the patients' urine samples. The implications of this finding with regard to a mechanism to account for carnitine deficiency in patients receiving valproate are discussed.
