Transient pseudo-isotachophoretic stacking in analysis of plasma for homocysteine by capillary zone electrophoresis

An analytical procedure enabling routine analysis of human plasma for total homocysteine has been developed and validated. The method includes reduction of homocysteine disulfides to thiol with tris 2-carboxyethylphosphine, derivatization of the thiol with 2-chloro-1-methylquinolinium tetrafluoroborate, separation of homocysteine 2-S-quinolinium derivative from those of plasma endogenous and exogenous thiol derivatives by capillary zone electrophoresis, and quantitation with the use of ultraviolet detection based on acetonitrile stacking. Method performance characteristics, for example recovery, calibration, precision, limit of detection, and limit of quantitation, are presented. The procedure was applied to analysis of plasma samples donated by apparently healthy volunteers.