Study On Rapid Determination Of Nitroimidazoles In Animal Derived Food

Nitroimidazoles have antiprotozoal and anti-anaerobic activity,and have been widely used to prevent and treat parasitic diseases in livestock and poultry and aquatic animals.Common nitroimidazoles and their metabolites including metronidazole(MNZ),dimeidazole(DMZ),ronidazole(RNZ)and Metronidazole-hydroxy(MNZOH).However,due to the carcinogenicity and teratogenicity of tnitroimidazoles,which may be harmful to human health,the drugs were banned in China in 2002 and cannot be detected in animal foods.Therefore,it is of great significance to strengthen the ability to detect and monitor the nitroimidazoles in food.This research focused on the rapid determination of nitroimidazoles including MNZ,DMZ,RNZ and MNZOH.The results were as follows.(1)The detection conditions of high-performance liquid chromatography-tandem mass spectrometry were optimized and confirmed.According to the structural characteristics of the targets,collision energy and declustering potential of the four kinds of nitroimidazoles were optimized.By comparing the peak shapes and response values of different mobile phase systems,the mobile phase system consisting of methanol(containing 0.1% formic acid)and water(containing 0.1% formic acid)was confirmed.(2)Comparing the purification effect of traditional Qu ECh ERS purification technology and the new solid phase extraction on nitroimidazoles,it was confirmed that the solid phase extraction Oasis Prime HLB was used as the purification agent for sample pretreatment.(3)Under the optimal conditions,four kinds of nitroimidazoles had good linear relationships in the range of 1.0?25 ng/m L in pork,and the correlation coefficients were more than 0.991.The recoveries at 3 spiked levels(0.25,0.5,2.5?g/kg)were76.7%?105.6%,84.0%?107.1%,87.8%?102.0%,respectively;The relative standard deviations were RSD?13.9%,RSD?4.2%,RSD?2.5%,respectively.In order to confirm the performance index of the method,we evaluate the method.The spiked sample had good uniformity and stability in pork.The p+?95%,p-?85%,pf+?15%,pf-?5%.The results met the requirements of ? Technical Specifications for the Evaluation of Rapid Food Testing Methods?.(4)The applicability of the method in different kinds of food was verified,including chicken,milk,shrimp and honey.The results showed that among the four kinds of bases,nitroimidazoles had good linear relationships in the range of 1.0?25 ng/m L,and the correlation coefficients were more than 0.990.The recoveries at 3 spiked levels(0.25,0.5,2.5?g/kg)were70.6%?112.9%,76.5%?108.6%,85.1%?106.1%,respectively;The relative standard deviations were RSD?15.4%,RSD?9.6%,RSD?6.1%,respectively,indicating that the method had good recovery rate and precision.(5)Quick experiment was conducted on samples of different bases.The results showed that the results of relative accuracy of the four kinds of nitroimidazoles drugs in eggs,milk,shrimp,and honey were ?96%.This showed that the rapid determination based on pork was also suitable for the determination of poultry,dairy products,aquatic products and bee products.