Plasma L-Ergothioneine Measurement by High-Performance Liquid Chromatography and Capillary Electrophoresis after a Pre-Column Derivatization with 5-Iodoacetamidofluorescein (5-IAF) and Fluorescence Detection

Two sensitive and reproducible capillary electrophoresis and high-performance liquid chromatography-fluorescence procedures were established for quantitative determination of L-egothioneine in plasma. After derivatization of L-ergothioneine with 5-iodoacetamidofluorescein, the separation was carried out by HPLC on an ODS-2 C-18 sperisorb column by using a linear gradient elution and by HPCE on an uncoated fused silica capillary, 50 mu m id, and 60 cm length. The methods were validated and found to be linear in the range of 0.3 to 10 mu mol/l. The limit of quantification was 0.27 mu mol/l for HPCE and 0.15 mu mol/l for HPLC. The variations for intra-and inter-assay precision were around 6 RSD%, and the mean recovery accuracy close to 100% (96.11%).