High-performance liquid chromatography with amperometric determination of plasma tyramine

A method for the measurement of tyramine in human plasma is described. It is based on tetraphenylboron ion-pair extraction and reversed-phase ion-pairing liquid chromatography with amperometric detection. Tyramine can be reliably measured in the range 5-200 ng/ml with an absolute limit of detection of 0.50 ng/ml at a signal-to-noise ratio of 2.0. Correction for variable recovery is made by using a tritiated tyramine internal standard. This assay is suitable for studies on the bioavailability of ingested tyramine and should thus have a role in the development of safer monoamine oxidase inhibitor drugs.