title: Gas chromatographic-mass spectrometric method for quantitation of phenylalanine and tyrosine in serum.
abstract: A validated gas chromatographic-mass spectrometric method for quantitation of phenylalanine and tyrosine in serum is described. Quantitation of phenylalanine and tyrosine with a non-labelled non-endogenous internal standard, L-2-chlorophenylalanine, compared favourably with isotope dilution mass spectrometric quantitation. The 95% reference ranges for phenylalanine. tyrosine and the phenylalanine-tyrosine molar ratio in neonate cord blood serum were determined by isotope dilution mass spectrometry and were found to be 77.1-144.7, 33.3-109.3 micromol/l and 1.1-3.0, respectively.
authors.affiliation: Department of Chemical Pathology, Faculty of Medicine, University of Pretoria, South Africa. jlaurens@medic.up.ac.za
authors.forename: J B
authors.initials: JB
authors.lastname: Laurens
authors.forename: X Y
authors.initials: XY
authors.lastname: Mbianda
authors.forename: J B
authors.initials: JB
authors.lastname: Ubbink
authors.forename: W J
authors.initials: WJ
authors.lastname: Vermaak
mesh_terms: D005312:Fetal Blood / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D007231:Infant, Newborn; D010649:Phenylalanine / Q000097:blood*; D012015:Reference Standards; D012016:Reference Values; D014443:Tyrosine / Q000097:blood*
chemical_list: D014443:Tyrosine; D010649:Phenylalanine