Simultaneous determination of diaveridine, trimethoprim and ormetoprim in feed using high performance liquid chromatography tandem mass spectrometry

This study developed and validated a simple and reliable method for detecting and quantifying DVD, TMP and OMP in feed using dichloromethane extraction followed by HPLC-MS/MS. A matrix effect evaluation was performed using the post-extraction spiking method, and levels were less than +/- 15% in all three feeds with their corresponding concentrations. LOD and LOQ, CC alpha and CC beta were 20 mu g kg(-1) and 40 mu g kg(-1), 8.68-15.55 mu g kg(-1) and 10.61-18.92 mu g kg(-1) for all analytes, respectively. Calibration curves were linear for DVD, TMP and OMP with R-2 >= 0.990 and r >= 0.995, respectively. Recoveries of low, medium and high concentrations using the proposed method ranged from 74.4 to 105.2%. Repeatability and within-laboratory reproducibility were < 7.4% ( RSD). The chosen seven factors had no a significant influence on robustness. The method showed good performance when it was applied to analyze other laboratory-prepared or actual feed samples. (C) 2016 Elsevier Ltd. All rights reserved.