Evaluation of a multi-class, multi-residue liquid chromatography-tandem mass spectrometry method for analysis of 120 veterinary drugs in bovine kidney

• Published in: Drug testing and analysis Vol. 4 Suppl 1; p. 91
• Main Authors: Schneider, Marilyn J, Lehotay, Steven J, Lightfield, Alan R
• Format: Journal Article
• Language: English
• Published: England 01.08.2012
• Subjects: Acetonitriles; Animals; Cattle; Chromatography, Liquid - methods; Drug Residues - analysis; Drug Residues - isolation & purification; Kidney - chemistry; Limit of Detection; Meat - analysis; Tandem Mass Spectrometry - methods; Veterinary Drugs - analysis; Veterinary Drugs - isolation & purification
• ISSN: 1942-7611
• DOI: 10.1002/dta.1359

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.