Modified Quechers Methods For The Analysis Of Drug Residues In Aquatic Products

Recently, the issue of seafood safety has increasingly become one of the public concerns. The veterinary drug residue in aquatic product is one of the important issues of aquaculture products, which do seriously harm to the environment and human health. There are several shortages in some existing methods, such as complex pre-treatment, time-consuming, single type detection and low sensitivity. Therefore, it is important to focus on the research of the detection methods and supervision of the method implementation. As a method to detect multi-class veterinary residues, QuEChERS has advantages of simple, rapid and efficient. The main object in our research is to study the critical technologies of QuEChERS and discuss the critical factors affecting the procedure. By modifying and innovation, the method has been applied to the detection of multi-residues drug residues in aquatic products coupling with ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The main contents and results are as follows:1. The UPLC-MS/MS methods were developed to determine malachite (MG) and leucomalachite (LMG) in fish by using QuEChERS methods. The parameters of the QuEChERS method, such as extraction solvent, amount of salt and sorbent are optimized. The results showed that using acetonitrile as extraction solvent, anhydrous magnesium (4g) as dehydrating agent and primary secondary amine/octadecylsilyl (PSA/C18=50mg/150mg) as dispersive solid phase extraction (dSPE) adsorbent were the best conditions to purify. The use of internal standard quantitative technique of isotope dilution can reduce matrix effect. The average recoveries of the method were81.2%-101.4%, with the intra-day and inter-day precision less than12%. The limit of detection (LOD) and the limit of quantification (LOQ) for MG and LMG were0.15-0.18μg/kg and0.50-0.60μg/kg, respectively. The developed method was applied to the analysis of eight samples, and the mandarin fish was confirmed positive.2. The modified QuEChERS method based on multi-walled carbon nanotubes (MWCNTs) was developed for the quantification of macrolides and lincosamides in aquatic products coupling with UPLC-MS/MS. The amount of sample, extraction solvent and the amount of MWCNTs were optimized according to the special adsorption properties of MWCNTs. Compare to the original QuEChERS method, the established method significantly reduced matrix interference and showed good accuracy and reproducibility. The average recoveries of the method were60.65%～110.36%, with the intra-and inter-day less than8.5%. The LOD and LOQ for macrolides and lincosamides were in the range of0.30～2.68μg/kg and1.00～8.93μg/kg, respectively. The proposed method was applied to the analysis of10batches samples, all the samples were lower than the LOQ of method or non-positive detected.3. A rapid detection QuEChERS-LC-MS/MS method was developed for the quantification of28veterinary residues in fish samples, aiming at the lack of multi-class veterinary simultaneous analysis techniques. A novel material of graphene/MWCNTs was used as dSPE adsorbent of QuEChERS and showed the advantages of reducing co-extraction impurities and improving recoveries. The average recoveries of the method were60.2%～100.4%, with the intra-and inter-day less than13.5%. The LOD and LOQ were in the range of0.06～1.42μg/kg and0.20～4.72μg/kg, respectively. The developed QuEChERS-LC-MS/MS method was applied to the analysis of40samples, and two culter alburnus samples were confirmed positive.