High-performance liquid chromatographic analysis of beta-phenylethylamine for the estimation of in vivo protein synthesis.

A rapid, sensitive, and automated reversed-phase liquid chromatographic method was developed for the analysis of phenylalanine as beta-phenylethylamine, for the measurement of in vivo protein synthesis. beta-Phenylethylamine was derivatized with o-phthaldialdehyde (OPA) to form a fluorescent derivative that was successfully measured in tissue cell fluids and hydrolysates as the decarboxylation product of phenylalanine. The system was extremely sensitive enabling the accurate determination of 0.5 pmol in biological samples. Analysis time was less than 11 min, so that 130 samples can be analysed per day. The method eliminates the need for time-consuming column extraction procedures. This method offers substantial advantages over existing methods for the isolation and determination of beta-phenylethylamine.