title: Simultaneous determination of [2-15N]- and [5-15N]glutamine with gas chromatography-mass spectroscopy: applications to nitrogen metabolic studies.
abstract: A gas chromatographic-mass spectrometric method for analysis of L-[2-15N]- and L-[5-15N]glutamine is described. The method is based on direct acylation of glutamine with trifluoroacetic anhydride and the formation of the N,N-bis-trifluoroacetyl-L-glutamine derivative. This simple and sensitive method is capable of detecting approximately 0.5 atom% excess 15N in as little as 10 microliter of plasma with a mean coefficient of variance of 11.6%. The method was applied to determine the appearance of 15N enrichment in plasma amino-N and amide-N of glutamine in a healthy adult volunteer during a constant infusion of 15NH4Cl. A plateau level of 3.7 and 2.6 atom% excess was observed in amide-N and amino-N, respectively, at 1 and 2 h after 15NH4Cl infusion was started.
mesh_terms: D000089:Acetic Anhydrides; D000215:Acylation; D000328:Adult; D000577:Amides; D000588:Amines; D055598:Chemical Phenomena; D002621:Chemistry; D005463:Fluoroacetates; D008401:Gas Chromatography-Mass Spectrometry; D005973:Glutamine / Q000032:analysis* / Q000097:blood; D006801:Humans; D008297:Male; D009584:Nitrogen / Q000378:metabolism*; D009587:Nitrogen Isotopes
chemical_list: D000089:Acetic Anhydrides; D000577:Amides; D000588:Amines; D005463:Fluoroacetates; D009587:Nitrogen Isotopes; D005973:Glutamine; C017958:trifluoroacetic anhydride; D009584:Nitrogen