Journal of High Resolution Chromatography vol:22 issue:8 pages:465-468
In order to study protein digestibility by means of noninvasive tracer techniques (stable isotopes), a representative oral tracer, Le. a stable isotope labeled protein, is needed. Therefore, egg white containing L-[ring-H-2(5)]phenylalanine and L-[ring-H-2(4)]tyrosine was prepared. The aim of this study was to measure the isotopic enrichment of the labeled amino acids in the egg white. The use of a standard GC-MS, based on ion trap technology was found to be a reliable technique. The enrichment of L-[ring-H-2(4)]phenylalanine and L-[ring-H-2(4)]tyrosine, expressed in Molar Percent (MP) amounted to 23.2 MP and 2.8 MP respectively.