DETERMINATION OF PHENYLALANINE IN SERUM USING REVERSED-PHASE LIQUID-CHROMATOGRAPHY AND FLUORESCENCE DETECTION

A liquid chromatography procedure is reported for determining phenylalanine in small volumes of serum. A 10-μl volume of serum was deproteinized with ethanol and an aliquot was derivatized with dansyl chloride reagent. The dansylated phenylalanine and the norleucine internal standard were separated using reversed-phase chromatography and measured with a fluorescence detector. Linearity was excellent over the range 50-800 mg/l. Within-run precision was better than 4%. Total analysis time including chromatography was approximately 40 min. As little as 300 pg of dansylated phenylalanine was detected. © 1979.