Chiral separation of homocysteine by derivatization with 4-aminosulfonyl-7-fluoro-2,1,3-benzoxadiazole followed by capillary electrophoresis using γ-cyclodextrin

Homocysteine was derivatized with 4-aminosulfonyl-7-fluoro-2,1,3-benzoxadiazole (ABD-F) to form an inclusion complex with cyclodextrin and to facilitate UV detection. ABD-homocysteine showed interaction with β- and γ-cyclodextrin in capillary electrophoresis at pH 2.25 as indicated by the decreased migration time. However, chiral separation of d,l-ABD-homocysteine was observed using γ-CD only. Optimal separation was obtained at pH 2.25, 50 mM γ-CD concentration, and 20 kV applied voltage. l-ABD-Homocysteine migrated faster than the d-isomer as demonstrated by a spiking experiment using dithiothreitol-reduced l-homocystine.