title: Large volume injection for the direct analysis of ionophores and avermectins in surface water by liquid chromatography-electrospray ionization tandem mass spectrometry.
abstract: A simple method for the direct determination of residues of ionophore antibiotics and avermectin antiparasitics in surface water is reported. Using a large volume injector, a mixture of methanol and surface water is injected into an analytical liquid chromatography (LC) column and subsequently screened for residues of these veterinary pharmaceuticals using electrospray ionization tandem mass spectrometry. On-line sample enrichment and chromatographic separation are achieved using a single, short (20mm) octadecylsilane LC column. The method permits the detection of four ionophores and two avermectins in surface water samples at low ng L(-1) concentrations. Minimal matrix effects were observed for a variety of surface water samples which permitted the use of reagent-based standards for quantitation.
authors.affiliation: Food Safety Division, Agri-Food Laboratories Branch, Alberta Agriculture and Rural Development, Edmonton, Alberta, Canada. tom.thompson@gov.ab.ca
authors.forename: T S
authors.initials: TS
authors.lastname: Thompson
authors.forename: D K
authors.initials: DK
authors.lastname: Noot
authors.forename: F
authors.initials: F
authors.lastname: Forrest
authors.forename: J P
authors.initials: JP
authors.lastname: van den Heever
authors.forename: J
authors.initials: J
authors.lastname: Kendall
authors.forename: J
authors.initials: J
authors.lastname: Keenliside
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis*; D000977:Antiparasitic Agents / Q000032:analysis*; D002853:Chromatography, Liquid / Q000379:methods; D007476:Ionophores / Q000032:analysis*; D007559:Ivermectin / Q000031:analogs & derivatives* / Q000032:analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D014867:Water / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D000900:Anti-Bacterial Agents; D000977:Antiparasitic Agents; D007476:Ionophores; D014874:Water Pollutants, Chemical; D014867:Water; D007559:Ivermectin; C019264:avermectin