Determination of Physostigmine in Plasma by Liquid Chromatography with Dual Electrode Amperometric Detection

Abstract

Abstract Physostigmine in plasma is determined after solid phase extraction. Ion-pair liquid chromatography is used for the separation and dual electrodes in a series mode are used for the detection. Physostigmine is first oxidized at +1.0 V and the reaction product formed is determined by reduction at +0.10 V versus Ag/AgCl. The solid phase extraction gives a recovery of 62 ± 6% (n=5) from plasma spiked with physostigmine to a concentration of 14 ng/mL. A detection limit of 0.5 ng/mL is obtained from a sample of 2 mL plasma.