title: Determination of succinylacetone and succinylacetoacetate in physiological samples as the common product 5(3)-methyl-3(5)-isoxazole propionic acid using an isotope dilution method and mass spectrometry.
abstract: A stable isotope dilution method was developed for the determination of succinylacetone and succinylacetoacetate in physiological samples. Succinylacetone and succinylacetoacetate were both converted to 5(3)-methyl-3(5)-isoxazole propionic acid by treating them with a solution of hydroxylamine-HCl at a pH less than 3 and at 80 degrees C. After extraction with diethyl ether tertiary butyldimethyl silyl derivatives were prepared using N-methyl-N-t. butyldimethyl silyl-trifluoro acetamide and analyzed by gas chromatography mass spectrometry. Selective ion monitoring was carried out at m/z 138.1 (M-131) and m/z 212.1 (M-57) for the natural, and at m/z 139.1 and 213.1 for the labelled compound. (15N)-5(3)-methyl-3(5)-isoxazole propionic acid was synthesized and used as internal standard for the isotope dilution analysis. Concentrations in physiological samples as low as 10 nmol/l could be accurately measured.
authors.affiliation: Department of Pediatrics, University of Groningen, The Netherlands.
authors.forename: H
authors.initials: H
authors.lastname: Schierbeek
authors.forename: R
authors.initials: R
authors.lastname: Berger
mesh_terms: D000090:Acetoacetates / Q000032:analysis* / Q000652:urine; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006537:Heptanoates / Q000032:analysis* / Q000652:urine; D006538:Heptanoic Acids / Q000032:analysis*; D006801:Humans; D007554:Isotopes; D007555:Isoxazoles / Q000032:analysis* / Q000378:metabolism; D013058:Mass Spectrometry / Q000379:methods; D009587:Nitrogen Isotopes; D010080:Oxazoles / Q000032:analysis*; D014443:Tyrosine / Q000097:blood
chemical_list: D000090:Acetoacetates; D006537:Heptanoates; D006538:Heptanoic Acids; D007554:Isotopes; D007555:Isoxazoles; D009587:Nitrogen Isotopes; D010080:Oxazoles; D014443:Tyrosine; C020804:succinylacetone; C030734:succinylacetoacetate; C062570:5-methyl-3-isoxazolepropionic acid