title: Quantitation of the anaesthetic xylazine in ovine plasma by LC-MS/MS.
abstract: Removal of the wool-bearing skin around a young lamb's rump (mulesing) provides long term health benefits for the animal, and the use of a sedative and analgesic agent such as xylazine may assist with pain relief to reduce discomfort and stress. Sensitive analytical methods are essential for monitoring pharmaceuticals and their metabolites in animals destined for human consumption. The following work reports a method that is 200 times more sensitive for xylazine detection than previously published methods, with lower limits of quantitation for xylazine and its primary metabolite in animals of 0.5pg and 2pg on-column, respectively. The use of a square wave solvent gradient immediately prior to analyte elution resulted in larger MS/MS peaks and a reduction in baseline noise, allowing reliable detection of lower analyte concentrations. The method uses as little as 1mL of plasma which allows replication within a sample if required, and requires simple sample preparation, minimising the introduction of matrix components into the MS/MS.
authors.affiliation: Graham Centre for Agricultural Innovation, Charles Sturt University, School of Agricultural and Wine Sciences, Wagga Wagga, NSW 2678, Australia. Electronic address: gdoran@csu.edu.au.
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Doran
authors.affiliation: Graham Centre for Agricultural Innovation, Charles Sturt University, School of Animal and Veterinary Sciences, Wagga Wagga, NSW 2678, Australia.
authors.forename: Leah A
authors.initials: LA
authors.lastname: Bradbury
mesh_terms: D000777:Anesthetics / Q000097:blood*; D000822:Animal Husbandry; D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012756:Sheep; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014991:Xylazine / Q000097:blood*
chemical_list: D000777:Anesthetics; D014991:Xylazine
keywords: 2,6-dimethylaniline; Chromatography; LC–MS/MS; Ovine; Sheep; Xylazine