Modification of a high-performance liquid chromatographic method for assay of homocysteine in human plasma

A modification of a previously published method for analysis of total homocysteine in human serum is presented. The modification was implemented to allow use of a different derivatizing agent (i.e., 7-fluorobenzo-2-oxa-1,3-diazole-4-sulfonamide) which reacts much faster than the original derivatizing reagent and at a lower temperature. Shorter reaction time and lower temperature lead to less destruction of some biological thiols. In order to retain an isocratic mobile phase with the new derivatizing agent, a different concentration of acetonitrile was found that affords a 7-8 min retention time.