| Veterinary drug residues in animal-derived products pose a serious threat to environmental safety and human health,and the pretreatment technology is complicated to operate and the high-consumption of organic solvents,which cannot meet the requirements of actual detection.In this study,based on solid phase extraction technology and Fe3O4-MWCNTs materials,the method for the detection of commonly used antibiotic residues in broilers’tissues and feces was established,and satisfactory validation parameters were obtained,which providing a new methodological basis for related detection.At the same time,the reduction rule of flufenicol residues in broiler tissues and the risk assessment of antibiotic residues in feces were studied.The main research contents are as follows:（1）Through the improvement of the extraction process,water-5%ammoniated acetonitrile was determined as the extraction solvent.Compared with the acid hydrolysis method,this method was simple in operation,short in time,and effectively reduced the amount of organic solvent,and achieved satisfactory extraction effect.Combined with ultra performance liquid chromatography-mass spectrometry（UPLC-MS/MS）,a method for the determination of FF residues in broilers was established.The limits of detection（LODs）and limits of quantification（LOQs）of this method ranged from 0.3-0.6μg/kg and from 0.8-1.0μg/kg,with intra-day deviations of less than 15%.Based on this method,it was found that the residues of FF in muscle,kidney and sebum were lower than the national standard limit on the 5th,1st and 9th day after drug withdrawal,respectively,and the residue in liver was always lower than the national standard limit.The abatement rule and existence form of FF in broilers were clarified,and the safe withdrawal period of FF was recommended as 14 days.（2）Fe3O4-MWCNTs composites were synthesized by chemical precipitation method,compared with the traditional adsorption materials,the material has obvious advantages in enrichment multiple,extraction speed,reuse and so on.Using this material as purifying agent,combined with UPLC-MS/MS technology,a method for the determination of 15 sulfonamides residues in broiler feces was established.It has been verified that the LODs of this method is0.5-1.0μg/kg,LOQs and the relative standard deviation（RSD）of 1.0-3.0μg/kg,is less than10%.The recoveries of 15 sulfonamides were in the range of 89-119%,indicating that this method has certain applicability and reliability in the analysis and detection of sulfonamides in broiler feces.Based on this method,37 farms in Shandong Province were screened.The results showed that about 76%of the fecal samples were contaminated,of which about 89%had low drug residue concentrations and 35%had more than 2 kinds of SAs residues.The potential risk of residual antibiotics in broiler feces was evaluated by risk quotient method（HQ）.The results showed that there was a high risk of SD,SMM and SQ,and the detection rate of SBA was as high as 59%.Although the country has not yet established the maximum limit of veterinary drug residues in feces,the problems of high concentration residues and multi-veterinary drug residues are worthy of attention. |
