A fluorometric assay for beta-phenylethylamine in human urine.

A sensitive and specific method for the fluorometric determination of beta-phenylethylamine (PEA) in human urine is described. PEA in urine was separated from phenylalanine and 5-hydroxytryptamine by n-heptane extraction, and determined by the ninhydrin reaction in the presence of L-leucyl-L-alanine. Using this method, the amounts of free PEA in urine samples of normal subjects and schizophrenics were measured. Normal subjects excreted 15.9 +/- 6.4 microgarm/day of free PEA, and chronic schizophrenics 9.3 +/- 2.7 microgram/day of free PEA. In normal subjects, the highest excretion of free PEA was observed in the period from 4:00 p.m. to 12:00 p.m. in a day.