title: The measurement of theophylline in human serum or plasma using gas chromatography and isotope dilution-mass spectrometry (GC-IDMS) taking other substituted xanthines into consideration.
abstract: A method is described which uses a combination of gas chromatography and isotope dilution-mass spectrometry (GC-IDMS) to determine the concentration of theophylline (1,3-dimethyl xanthine) in human plasma or serum samples. The effects of similar substituted xanthines - namely theobromine (3,7-dimethyl xanthine), paraxanthine (1,7-dimethyl xanthine) 1,3-dimethyl-7-(2-hydroxyethyl) xanthine (internal standard HPLC) and caffeine (1,3,7-trimethyl xanthine) were tested to confirm the specificity of the method. The derivatisation of all xanthines was performed with N-methyl-N-trimethylsilyl trifluroacetamide (MSTFA). The internal standard used was 2-(13)C ,1,3-(15)N2-theophylline. The extraction and derivatisation procedures were examined in detail and optimised stepwise during the development of the method. High-performance liquid chromatography (HPLC) was used for comparison.
authors.affiliation: Instand Reference Laboratories Instand e.V., Düsseldorf, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Kress
authors.forename: Dieane
authors.initials: D
authors.lastname: Meissner
authors.forename: Patricia
authors.initials: P
authors.lastname: Kaiser
authors.forename: Rainer
authors.initials: R
authors.lastname: Hanke
authors.forename: William Graham
authors.initials: WG
authors.lastname: Wood
mesh_terms: D000081:Acetamides; D002851:Chromatography, High Pressure Liquid; D005463:Fluoroacetates; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods* / Q000592:standards; D006801:Humans; D012015:Reference Standards; D012680:Sensitivity and Specificity; D013806:Theophylline / Q000097:blood*; D014297:Trimethylsilyl Compounds; D014970:Xanthines / Q000097:blood
chemical_list: D000081:Acetamides; D005463:Fluoroacetates; D014297:Trimethylsilyl Compounds; D014970:Xanthines; C086665:N-methyl-N-(trimethylsilyl)trifluoroacetamide; D013806:Theophylline