Analysis of 5-pyrrolidone-2-carboxylate ester by reverse phase high-performance liquid chromatography

A simple quantitative method for estimating nanomole concentrations of 5-pyrrolidone-2-carboxylic acid (PCA) in tissue homogenates from mouse has been developed using reverse-phase HPLC. PCA was detected as the 4-nitrophenacyl ester which has an absorption maximum at 263 nm, a relatively high stability, and excellent chromatographic separation and detectability. This method offers distinct advantages over other analytical procedures thus far employed for measuring PCA in that the 4-nitrophenacyl derivative of PCA can be readily prepared from deproteinized tissue homogenates and quantitated by HPLC within relatively short time intervals with good precision and specificity.