title: Evaluation of a multi-class, multi-residue liquid chromatography-tandem mass spectrometry method for analysis of 120 veterinary drugs in bovine kidney.
abstract: Traditionally, regulatory monitoring of veterinary drug residues in food animal tissues involves the use of several single-class methods to cover a wide analytical scope. Multi-class, multi-residue methods (MMMs) of analysis tend to provide greater overall laboratory efficiency than the use of multiple methods, and liquid chromatography-tandem mass spectrometry (LC-MS/MS) of targeted drug analytes usually provides exceptional performance even for complicated sample extracts. In this work, an LC-MS/MS method was optimized and validated in a test of 120 drug analytes from 11 different classes in bovine kidney. The method used 10 ml of 4/1 acetonitrile/water for extraction of 2 g samples and cleanup with hexane partitioning. Quantitative and qualitative performance was assessed for the analytes at fortification levels of 10, 50, 100, and 200 ng/g. With the method, 66 drugs gave 70-120% recovery with ≤ 20% RSD at all levels over the course of 3 days. At the 200 ng/g level, 89 drugs met these same standards. Limits of detection were ≤ 10 ng/g for 109 of the analytes in the kidney matrix in validation experiments. Qualitatively, MS/MS identification criteria were set that ion ratios occur within ± 10% (absolute value) from those of the analyte reference standards. At the 10 ng/g level, 57% of the drugs met the identification criteria, which improved to 84% at the 200 ng/g level. The method serves as an efficient and useful additional option among the current monitoring methods available.
authors.affiliation: US Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, USA. marilyn.schneider@ars.usda.gov
authors.forename: Marilyn J
authors.initials: MJ
authors.lastname: Schneider
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Lehotay
authors.forename: Alan R
authors.initials: AR
authors.lastname: Lightfield
mesh_terms: D000097:Acetonitriles; D000818:Animals; D002417:Cattle; D002853:Chromatography, Liquid / Q000379:methods; D004350:Drug Residues / Q000032:analysis* / Q000302:isolation & purification; D007668:Kidney / Q000737:chemistry*; D057230:Limit of Detection; D008460:Meat / Q000032:analysis*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D019155:Veterinary Drugs / Q000032:analysis* / Q000302:isolation & purification
chemical_list: D000097:Acetonitriles; D019155:Veterinary Drugs; C032159:acetonitrile