Determination of Ampicillin in Plasma by Paired Ion High Performance Liquid Chromatography

Abstract

A new, accurate, precise, and specific method has been developed for the assay of ampicillin in plasma. No extraction of ampicillin from plasma is called for. Plasma is treated with acetonitrile containing propiophenone as the internal standard, vortexed, centrifuged, and the supernate is injected. A C18 reverse phase column is used. The mobile phase consisted of a mixture of methanol and 0.02M phosphate buffer of pH 6.00, and contained alkyldimethylamine C10 as an ion pair ligand. Detection was by UV at 220 nm. A linear relationship between concentration and peak area ratio was obtained. Recovery, day-to-day, and within-day variation were determined.