title: Simultaneous determination of stable isotopically labelled L-histidine and urocanic acid in human plasma by stable isotope dilution mass spectrometry.
abstract: A capillary gas chromatographic-mass spectrometric method for the simultaneous determination of stable isotopically labelled L-histidine (L-[3,3-2H2,1',3'-15N2]histidine, L-His-[M + 4]) and urocanic acid ([3-2H,1',3'-15N2]urocanic acid, UA-[M + 3]) in human plasma was developed using DL-[2,3,3,5'-2H4,2'-13C,1',3'-15N2]histidine (DL-His-[M + 7]) and [2,3,5'-2H3,2'-13C,1',3'-15N2]urocanic acid (UA-[M + 6]) as internal standards. L-Histidine and urocanic acid were derivatized to alpha N-(trifluoroacetyl)-imN-(ethoxycarbonyl)-L-histidine n-butyl ester and imN-(ethoxycarbonyl)urocanic acid n-butyl ester. Quantification was carried out by selected ion monitoring of the molecular ions of the respective derivatives of L-His-[M + 4], DL-His-[M + 7], UA-[M + 3] and UA-[M + 6]. The sensitivity, specificity, precision and accuracy of the method were demonstrated to be satisfactory for measuring plasma concentrations of L-His-[M + 4] and UA-[M + 3] following administration of trace amounts of L-His-[M + 4] to humans.
authors.affiliation: Department of Medicinal Chemistry and Clinical Pharmacy, Tokyo College of Pharmacy, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Furuta
authors.forename: M
authors.initials: M
authors.lastname: Katayama
authors.forename: H
authors.initials: H
authors.lastname: Shibasaki
authors.forename: Y
authors.initials: Y
authors.lastname: Kasuya
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry; D006639:Histidine / Q000097:blood*; D006801:Humans; D013058:Mass Spectrometry; D011865:Radioisotope Dilution Technique; D014560:Urocanic Acid / Q000097:blood*
chemical_list: D006639:Histidine; D014560:Urocanic Acid