Determination of alpha-tocopherolquinone in human serum samples by liquid chromatography with fluorescence detection and on-line post-column derivatization.

A HPLC/fluorescence method with on-line post-column derivatization by a photoreactor was developed, where alpha-, beta + gamma- and delta-tocopherolquinone (TQ) are separated on a 250 mm x 4.6 mm RP-18 column. The LOD is about 250 pg for all TQs.