High-Throughput Determination of 30 Veterinary Drug Residues in Milk Powder by Dispersive Solid-Phase Extraction Coupled with Ultra-High Performance Liquid Chromatography Tandem Mass Spectrometry

Abstract

A high-throughput method was established for the simultaneous determination of 30 β-agonists, fluoroquinolones, and cephalosporins in milk powder by dispersive solid-phase extraction (dSPE) and ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Samples were firstly dissolved in sodium acetate buffer, then extracted with formic acid-acetonitrile, and subsequently purified by dSPE. Thirty target analytes were separated on a C18 column by gradient elution, detected through electrospray ionization (ESI) source in the positive mode with multi-reaction monitoring (MRM) conditions. The developed method was validated in terms of linearity, accuracy, and precision. Results indicated that 30 target analytes displayed excellent linearity in their corresponding concentration ranges and that their correlation coefficients were all higher than 0.995. The limits of quantitation (LOQs) for these targets were in the range of 0.7–7.0 μg/kg. The mean recoveries for negative sample spiked at three concentration levels were calculated between 80.0 and 97.5% with the relative standard deviation (RSD, n = 6) values ranging from 2.8 to 10.8%. In addition, the inter-day precision (n = 5) of the second spiked concentration was less than 13% (4.4–12.4%). The established and validated method is accurate and rapid and suitable for the high-throughput analysis of β-agonist, fluoroquinolone, and cephalosporin multi-residues in milk powder.