title: Determination of 8-methyl ether of xanthurenic acid in human urine by high-performance liquid chromatography.
abstract: We developed a simple and sensitive assay for the urinary 8-methyl ether of xanthurenic acid (XA-OMe) by high-performance liquid chromatography with fluorescence detection (excitation at 340 nm; emission at 450 nm). Urine samples were diluted with 0.03 M potassium phosphate buffer (pH 6.0) and applied to an octadecylsilane-bonded column (Nucleosil 5C18, 150 x 4 mm I.D.). The mobile phase used was a mixture of this same buffer and acetonitrile (1000:140, v/v). Both direct injection of urine and solvent extraction prior to HPLC were tested and showed a good correlation and sensitivity, although the peak of XA-OMe was occasionally less distinguishable from close peaks in urine from normal controls by the direct injection method. The quantification limit was 5 x 10(-14) mol which was sensitive enough to detect XA-OMe in urine from normal subjects. The method was applied to samples from patients with a deficiency in tryptophan catabolism, xanthurenic acid/3-hydroxykynurenine-uria and showed a striking elevation in urinary XA-OMe excretion.
authors.affiliation: Gifu Prefectural Health and Environment Research Center, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Imai
authors.forename: K
authors.initials: K
authors.lastname: Murayama
authors.forename: M
authors.initials: M
authors.lastname: Kawai
authors.forename: S
authors.initials: S
authors.lastname: Yamaguchi
authors.forename: K
authors.initials: K
authors.lastname: Matsuura
mesh_terms: D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005260:Female; D005453:Fluorescence; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007223:Infant; D008297:Male; D008738:Methyl Ethers / Q000032:analysis / Q000652:urine*; D014977:Xanthurenates / Q000032:analysis / Q000652:urine*
chemical_list: D008738:Methyl Ethers; D014977:Xanthurenates