title: Separation, pre-concentration, and HPLC analysis of methylxanthines in urine samples.
abstract: An SPE method, using RP18 phases, for the simultaneous extraction of caffeine, theobromine, theophylline, paraxanthine, 1-methylxanthine, 3-methylxanthine, 7-methylxanthine, 1-methyluric acid, 1,3-dimethyluric acid, 1,7-dimethyluric acid, and 1,3,7-trimethyluric acid from urine has been developed. Besides a gradient HPLC system for the analysis of the compounds of interest on a LiChrosorb RP-18 (7 microm) column with mobile phase containing 0.05% aq. solution of trifluoroacetic acid and acetonitrile has been elaborated. The procedure has been successfully applied to the analysis of methylxanthines and methyluric acids in urine of patients with chronic asthma treated with theophylline and in urine of healthy subjects.
authors.affiliation: Department of Analytical and General Chemistry, Silesian University of Technology, 44-100 Gliwice, Poland.
authors.forename: Mirosława
authors.initials: M
authors.lastname: Zydroń
authors.forename: Jacek
authors.initials: J
authors.lastname: Baranowski
authors.forename: Irena
authors.initials: I
authors.lastname: Baranowska
mesh_terms: D002110:Caffeine / Q000652:urine; D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D015394:Molecular Structure; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013805:Theobromine / Q000652:urine; D014527:Uric Acid / Q000652:urine; D014556:Urine / Q000737:chemistry*; D014970:Xanthines / Q000652:urine*
chemical_list: D014970:Xanthines; D014527:Uric Acid; C008514:methylxanthine; D002110:Caffeine; D013805:Theobromine