New LASER fluorometric HPLC detection for ortho-tyrosine in gamma-irradiated phenylalanine solution and pork

New analytical procedure for o-tyrosine was studied to investigate effects of gamma irradiation on aqueous phenylalanine solution and pork. The process includes extraction and hydrolysis of protein, derivatization of the free amino acid by fluororeagent, and finally separation and detection by LASER fluorometric HPLC. The detection limit was 25 ng.To study how the procedure works, irradiated phenylalanine solution and pork were analyzed. The samples were irradiated at doses up to 10kGy at room temperature.Three tyrosine isomers were detected in phenylalanine solution, and 2 isomers (o-and p-tyrosine) were found in pork. Dose response was found in the formation of the isomers both in phenylalanine solution and in pork. O-tyrosine peak obtained from irradiated pork was separated from interference successfully. Those findings illustrate the procedure may be applicable to detection of irradiated food.