Determination Of Multiple Residues In Animal Derived Foods By QuEChERS Coupled With Liquid Chromatography Tandem Mass Spectrometry

The widespread use of veterinary drugs originates from their prevention of animal diseases,the spread of infectious diseases,and the treatment and diagnosis of animal diseases in animal husbandry.The good therapeutic effect of veterinary drugs leads to the phenomenon of overuse,and then resulting in veterinary drug residue and serious threat to human health.Therefore,it is very important to develop an accurate,efficient and low-cost method for the detection of veterinary drug residues in animal-derived foods.The Qu ECh ERS method has been widely used in pesticide residue analysis firstly.In the process of exploration by researchers,the scope of the matrix applied has been continuously expanded.This study aims at the improvement of Qu ECh ERS pretreatment technology and the optimization of conditions for liquid chromatography-tandem mass spectrometry,and then combines the two to get a new method.A method for the determination of glucocorticoids and penicillins in milk and beef is established using commonly used glucocorticoids and penicillins as target substances.The method not only improves the detection efficiency and accuracy of two types of veterinary drug residues,but also expands the matrix application range of Qu ECh ERS pretreatment technology,and providing a scientific basis for the detection of veterinary drug residues in other animal-derived foods.The following are the main contents and results of this study:A HPLC-MS/MS analysis method for the determination of glucocorticoid in milk and beef combined with Qu ECh ERS was established.The samples were extracted with acetonitrile under different acidity,dehydrated and salted-out with anhydrous Na₂SO₄,Na Cl,cleaned up with adsorbent and then analyzed by HPLC-MS/MS.18 glucocorticoids were linear in the range of 0.1 to 100 ng/m L with good linearity.Matrix effects of milk and beef are between 0.81 to 0.96 and 0.82 to 1.10,respectively,with the limits of detection and limits of quantification and of between 0.1?0.3?g/kg?0.5?1.1?g/kg and0.1?0.3?g/kg,0.5?0.9?g/kg.The recoveries of the three levels were between73.7%?98.6%and 64.5%?91.5%with the relative standard deviation less than 20%.The method was simple,fast,accurate and reliable,and suitable for the determination of glucocorticoid in large quantities of milk and beef samples.A method for the determination of penicillins in milk and beef by modified Qu ECh ERS combined with HPLC-MS/MS was established.The linearity of the 10penicillins was good.The linear range of amoxicillin was 5 to 100 ng/m L;the oxacillin,cloxacillin,and azlocillin were 0.5 to 100 ng/m L;the others were 1.0 to 100 ng/m L.The matrix effect of milk detection method was between 0.81?0.96,he recoveries of 10penicillins in milk were between 75.3%?93.4%,the inter-day precision and within-day precision were between 2.0%?12.0%and 3.0%?12.8%,respectively;the detection limits were 0.2?2.5?g/kg,limits of quantification were 0.5?5.0?g/kg.The mean recoveries of10 penicillins in the beef were 69.5%?92.6%,the repeatability and reproducibility were less than 20%.The limits of detection was 0.3?3.5?g/kg,and the limits of quantification were 1.0?10?g/kg.The detection method is applied to the actual testing,and the results are accurate and reliable.