High-throughput Screening Method for Multiple Classes of Antibiotics in Milk Using Automated Sample Preparation and LC-MS/MS

Introduction Veterinary drugs are widely used to prevent the outbreak of disease in livestock and are commonly administered as feed additives or in drinking water. In addition, veterinary drugs are given to treat diseases, for drying-off purposes, or to prevent losses during transportation. Many countries, such as the United States and those in the European Union, have set maximum residue limits (MRLs) for different food products of animal origin. Japan has also set MRLs for compounds identified on the Japanese Positive List. Recently, China has defined some new national standards to monitor banned antibiotics in foods. As a response to this, new methods are being developed for the determination of these compounds in a cost-effective way. By using the Thermo Scientific Aria TLX system powered by TurboFlowTM technology a drastic reduction in sample preparation time can be achieved while minimizing matrix interferences. LC-MS/MS is a powerful tool in food analysis, especially when combined with automated sample preparation that reduces matrix interferences. In addition, minimizing sample handling improves the performance characteristics of the method, such as recovery, repeatability, and reproducibility. However, most analytical techniques developed for quantitative analysis of antibiotic residues in food have been based on off-line methods involving solid phase extraction (SPE) or liquid-liquid extraction (LLE) followed by LC-MS1,2. Only recently, methods employing automated sample preparation have been reported, but usually for a specific class of compounds, rather than a multi-class method3. We propose a quick, highthroughput, sensitive screening method for the determination of different classes of antibiotics in milk samples.