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Sensitive determination of deuterated and non-deuterated phenylalanine and tyrosine in human plasma by combined capillary gas chromatography—negative ion chemical ionization mass spectrometry

1986; Elsevier BV; Volume: 380; Linguagem: Inglês

10.1016/s0378-4347(00)83652-x

1872-812X

Tokishi Hayashi, Yukiko Minatogawa, Satoru Kamada, Michio Shimamura, Hiroshi Naruse, Yoshio Iida,

Analytical Chemistry and Chromatography

A combined capillary gas chromatography—negative ion chemical ionization mass spectrometric method for the determination of deuterated and non-deuterated phenylalanine and tyrosine in plasma was developed. Phenylalanine and tyrosine were converted to pentafluorobenzyl—trifluoroacetyl (PFB—TFA) and PFB—TFA—trimethylsilyl (TMS) derivatives, respectively, after prepurification with a Bio-Rad AG 50W-X2 cation-exchange column. These derivatives showed good gas chromatographic separation properties and provided intense (M  PFB)− ions. These ions were ideal for the specific and sensitive determination of deuterated and non-deuterated phenylalanine and tyrosine by selected ion monitoring assay. [2,2′,3,3,3′,4′,5′,6′-2H8]l-Phenylalanine and [2,2′,3,3,3′,5′,6′-2H7] l-tyrosine were used as internal standards. This method was used to determine the plasma levels of deuterated and non-deuterated phenylalanine and tyrosine, after oral administration of [2′,3′,4′,5′,6′-2H5]l-phenylalanine to a healthy person.