High-performance liquid chromatographic determination of N-acetylcysteine in human serum following acetaminophen overdosage.

An analytical method has been developed for the determination of N-acetylcysteine in human serum following acetaminophen overdosage in humans. Serum samples were treated with dithiothreitol and the protein-freed product was derivatized with 2,4-dinitrofluorobenzene. N-Acetylhomocysteine thiolactone was used as an internal standard. Following diethyl ether extraction, the components were separated on a reversed-phase column with retention times of 7.4 and 9.9 min for N-acetylcysteine and internal standard, respectively. Ultraviolet detection at 365 nm was employed and little interference was noted from other serum components. The method has been applied to quantitation of N-acetylcysteine given as treatment for acetaminophen intoxication.