| With the rapid development of society,the problem of food satety is becoming more and more serious,the development of pesticides and veterinary drugs detection technology in limnetic products has been continuously concerned by the public.As all we know,China is rich in limnetic resources like crayfish,crabs,shellfish and so on.Anhui province has played an important role in limnetic products breeding,consumption and export with the major export limnetic products of longsnout catfish,red swamp crayfish and hairy crab.But in recent years,some drugs are enriched in limnetic products through food chain transmission and natural circulation due to the illegal and abused ues of pesticides and veterinary drugs in the process of limnetic products breeding.In order to ensure the quality and safety of limnetic products in China,it is urgent to establish a high-throughput,rapid screening and detection technology for drug multi-residues in limnetic products.For drug multi-residue analysis,the technology of pretreatment and detection have been a difficulty of analysis.QuEChERS(quick,easy,cheap,effective,rugged,safe)has been widely utilized in drug multi-residue analysis,multi-walled carbon nanotubes as a new type of adsorbent,has a capacity with good chemical stability,high specific surface area,strong adsorption.As a high resolution mass spectrometry,gas chromatography-quadrupole time of flight mass spectrometry(GC-QTOF/MS)technology has the characteristics of fast analysis speed,high selectivity and quality resolution to satisfy the rapid screening of drug multi-residues.LC-Qq Q-MS/MS proved to be the first choice for quantification of known compounds in complex background with its superior sensitivity and the wider linear range.Therefore,this study focused on the aspects that modified QuEChERS will be combined with GC-QTOF/MS and LC-Qq Q-MS/MS,to established the rapid screening of 145pesticide residues and 39 veterinary drug residues in limnetic products.The main research contents and results are summarized as follows:1、A modified QuEChERS method based on multi-walled carbon nanotubes(MWCNTs)was established for the simultaneous determination of 145 pesticide residues in limnetic products by gas chromatography-quadrupole time of flight mass spectrometry(GC-QTOF/MS).The samples were extracted with water and acetonitrile,purified by QuEChERS with MWCNTs,determined by GC-QTOF/MS.The quantification analysis was performed with the external standard calibration.The extraction conditions,type and amount of adsorbents,acquisition rate and extraction window of GC-QTOF/MS were optimized.Under the optimal conditions,the results indicated that the calibration curves were linear(r~2>0.98)in the range of 5-200μg/kg.The recoveries for 145 pesticides were in the range of 69.4%-114.2%at three spiked levels of 10,20,100μg/kg,with relative standard deviation(RSD,n=6)of 2.2%-13.8%.The limits of quantitation were in the range of 1.1-40.0μg/kg.Compared to the original QuEChERS method,the proposed method was rapid,accurate and could significantly reduced matrix interference.2、A modified QuEChERS method based on graphitization multi-walled carbon nanotubes was established for the simultaneous determination of 39 veterinary drug residues in limnetic products by liquid chromatography-triple quadrupole tandem mass spectrometry(LC-Qq Q-MS/MS).The samples were extracted with 1%acetonitrile formic acid,purified by QuEChERS with MWCNTs,determined by LC-Qq Q-MS/MS.The extraction conditions,type and amount of adsorbents,chromatography and mass spectrometry conditions such as mobile phase,fragmentor and collision energy were optimized.Under the optimal conditions,the results indicated that the calibration curves of39 veterinary drug were linear(r~2>0.99)in the range of 0.25-100μg/kg.The recoveries were in the range of 69.2%-111.8%at three spiked levels,with relative standard deviation(RSD,n=6)of 2.5%-13.5%.The limits of quantitation were in the range of 0.11-5.16μg/kg.The method has been applied to three positive samples,and the results generally accord with the detection results by the method of national standards. |
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