Detection of thiazide-based diuretics in equine urine by liquid chromatography/mass spectrometry.
Thiazide-based diuretics are included in the list of banned drugs in the horse-racing industry. One effect of their misuse is increased urine flow, contributing to dilution of other doping agents. Their determination is essential in ensuring compliance to horse-racing regulation. This study evaluates the feasibility of using liquid chromatography/mass spectrometry (LC/MS) with electrospray and atmospheric pressure chemical ionization interfaces to analyze thiazidic diuretics in equine urine samples. Existing LC and gas chromatography/MS methods are limited in their applicability to thiazide analysis. Sample preparation, analyte extraction, chromatographic separation, ion-source collision induced dissociation, solvent composition, ionization mode, and ion polarity are discussed. The practicality of LC/MS for this analysis is demonstrated with actual equine administration samples collected at specified time intervals. Detection limits were 270 ng/mL for chlorothiazide, 131 ng/mL for hydrochlorothiazide, and 384 ng/mL for trichlormethiazide.
Garbís
S D
SD
Illinois Racing Board Laboratory, Chicago 60612, USA.
Hanley
L
L
Kalita
S
S
D000818:Animals; D001581:Benzothiadiazines; D002853:Chromatography, Liquid; D004232:Diuretics; D005240:Feasibility Studies; D006736:Horses / Q000652:urine*; D016014:Linear Models; D013058:Mass Spectrometry; D015203:Reproducibility of Results; D049993:Sodium Chloride Symporter Inhibitors / Q000652:urine*
D001581:Benzothiadiazines; D004232:Diuretics; D049993:Sodium Chloride Symporter Inhibitors