title: Gas chromatography-mass spectrometry method for determination of phenylalanine and tyrosine in neonatal blood spots.
abstract: In this paper we developed a simple, rapid and sensitive method for the quantitative analysis of phenylalanine (Phe) and tyrosine (Tyr) in dried blood spots of newborns by gas chromatography-mass spectrometry (GC-MS). Phe and Tyr in blood samples were reacted with N-methyl-N-(tert.-butyldimethylsilyl)trifluoroacetamide at 120 degrees C for 30 min and their corresponding single derivatives were obtained. Phe and Tyr were determined by measurement of their derivatives by GC-MS in the selected ion monitoring mode. Contents of Phe and Tyr in blood spots were calculated by external standard method. The ratio of Phe to Tyr was used for neonatal screening for phenylketonuria. The present method only took a few minutes to perform and required minimal sample preparation. In addition it provided low detection limits of 1.2 micromol l(-1) for Phe and 1.6 micromol l(-1)for Tyr.
authors.affiliation: Department of Chemistry, Fudan University, Shanghai 200433, China. dengchunhui@163.com
authors.forename: Chunhui
authors.initials: C
authors.lastname: Deng
authors.forename: Yonghui
authors.initials: Y
authors.lastname: Deng
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.forename: Xiuhan
authors.initials: X
authors.lastname: Yang
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D007231:Infant, Newborn; D015997:Neonatal Screening / Q000379:methods*; D010649:Phenylalanine / Q000097:blood*; D010661:Phenylketonurias / Q000097:blood / Q000175:diagnosis; D015203:Reproducibility of Results; D014443:Tyrosine / Q000097:blood*
chemical_list: D014443:Tyrosine; D010649:Phenylalanine