title: Analyses of quaternary ammonium drugs in horse urine by capillary electrophoresis-mass spectrometry.
abstract: A capillary electrophoresis-mass spectrometry (CE-MS) method for the analysis of quaternary ammonium drugs in equine urine was developed. Quaternary ammonium drugs were first extracted from equine urine by ion-pair extraction and then analysed by CE-MS in the positive electrospray ionization (ESI) mode. Within 12 min, eight quaternary ammonium drugs, each at 1 ng/mL in horse urine, could be detected. The confirmation of these drugs in urine samples was achieved by capillary electrophoresis tandem mass spectrometry (CE-MS/MS). A direct comparison of this method was made with existing liquid chromatography/mass spectrometry (LC-MS) methods in the detection and confirmation of glycopyrrolate and ipratropium bromide in horse urine. While the two drugs could be detected within the same CE-MS run at 1 ng/mL in urine, they could only be detected in separate LC-MS runs at 5 ng/mL in urine. In addition, CE-MS consumed a much smaller volume of extract; the analyte peak widths, in some cases, were much narrower; and as the quaternary ammonium ions were well separated electrophoretically from the mainly neutral urine matrix, a much cleaner background in the CE-MS total ion trace was observed.
authors.affiliation: Racing Laboratory, The Hong Kong Jockey Club, Shatin, PR China.
authors.forename: F P
authors.initials: FP
authors.lastname: Tang
authors.forename: G N
authors.initials: GN
authors.lastname: Leung
authors.forename: T S
authors.initials: TS
authors.lastname: Wan
mesh_terms: D000818:Animals; D018680:Cholinergic Antagonists / Q000652:urine; D002853:Chromatography, Liquid / Q000379:methods; D004300:Doping in Sports; D019075:Electrophoresis, Capillary / Q000379:methods*; D006024:Glycopyrrolate / Q000652:urine; D006736:Horses / Q000652:urine*; D009241:Ipratropium / Q000652:urine; D008297:Male; D000644:Quaternary Ammonium Compounds / Q000652:urine*; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D018680:Cholinergic Antagonists; D000644:Quaternary Ammonium Compounds; D009241:Ipratropium; D006024:Glycopyrrolate