title: Determination of the natural abundance δ15N of taurine by gas chromatography-isotope ratio measurement mass spectrometry.
abstract: The measurement of the nitrogen isotope ratio of taurine (2-aminoethanesulphonic acid) in biological samples has a large number of potential applications. Taurine is a small water-soluble molecule which is notoriously difficult to analyze due to its polarity and functionality. A method is described which allows the determination of the natural abundance δ(15)N values of taurine and structural analogues, such as 3-amino-1-propanesulphonic acid (APSA), by isotope ratio mass spectrometry interfaced to gas chromatography (GC-irm-MS). The one-step protocol exploits the simultaneous derivatization of both functionalities of these aminosulphonic acids by reaction with triethylorthoacetate (TEOA). Conditions have been established which ensure quantitative reaction thus avoiding any nitrogen isotope fractionation during derivatization and workup. The differences in the δ(15)N values of derivatized and non-derivatized taurine and APSA all fall within the working range of 0.4‰ (-0.02 to 0.39‰). When applied to four sources of taurine with various δ(15)N values, the method achieved excellent reproducibility and accuracy. The optimized method enables the determination of the natural abundance δ(15)N values of taurine over the concentration range 1.5-7.84 µmol.mL(-1) in samples of biological origin.
authors.affiliation: Elucidation of Biosynthesis by Isotopic Spectrometry Group, Unit for Interdisciplinary Chemistry: Synthesis-Analysis-Modelling (CEISAM), University of Nantes-CNRS UMR6230, 2 rue de la Houssinière, BP 92208, F-44322 Nantes, France. illa.tea@univ-nantes.fr
authors.forename: Illa
authors.initials: I
authors.lastname: Tea
authors.forename: Ingrid
authors.initials: I
authors.lastname: Antheaume
authors.forename: Jorick
authors.initials: J
authors.lastname: Besnard
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Robins
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D009587:Nitrogen Isotopes / Q000032:analysis*; D013654:Taurine / Q000032:analysis* / Q000097:blood; D014867:Water / Q000032:analysis
chemical_list: D009587:Nitrogen Isotopes; D014867:Water; D013654:Taurine