Study And Application Of The Determination Of Nitrofurans And Metabolites In Aquaculture Products By LC-MS/MS

A new method was established for the determination of AOZ,AMOZ,SEM,AHD,DNSAH,PSH,NPIR and NSTY in aquaculture products by liquid Chromatography-Tandem Mass Spectrometry(LC-MS/MS).The method was applied to the detection of nitrofurans in aquaculture products in Shenzhen market,providing fundamental data for the establishment of relevant standards and providing the guarantee for the safe aquaculture products.The sample was added with the mixed isotope internal standard solution,after hydrolyzed with hydrochloric acid and derivatized with2-nitrobenzaldehyde.The mixture was adjusted to the pH 7.2(+0.2).then extracted with ethyl acetate twice,evaporated to dryness under nitrogen,reconstituted with acetonitrile/water(1:9,v/v),and then defatting using n-hexane.The analytes were quantified by LC-MS/MS operating in both positive and negative ion multiple monitoring modes(MRM),and quantitatively determined by isotope internal calibration method for quantitative analysts.The results showed that limits of AOZ,AMOZ,PSH and DNSAH were0.1?g/kg,and the quantitative limits were 0.2 ?g/kg;the detection limits of AHD,SEM and NPIR were 0.2 ?g/kg,and the quantitative limits were 0.4?g/kg;the detection limit of NSTY was 1.0 ?g/kg and the quantitative limit was 2.0 ?g/kg.All analytes to be tested had good linearity,AOZ,AMOZ,PSH and DNSAH were in the range of 0.2 ~ 50.0 ?g/kg,AHD,SEM and NPIR were in the range of 0.4 ~ 100.0?g/kg,NSTY was in the range of 2.0 ~ 200.0 ?g/kg,and all the correlation coefficients were greater than 0.999.The average recoveries of the four freshwater fishes were82.58 % ~ 115.95 %,and the relative standard deviations were0.97 % ~ 15.77 %.The average recoveries of the four shrimps were87.63 % ~ 110.88 %,and the relative standard deviations were1.39 % ~ 11.33 %.The average recoveries of the four marine fishes were 82.2 % ~ 109.75 %,and the relative standard deviations were0.82 % ~ 113.43 %.The average recoveries of the five shellfish were 83.07 % ~ 113.43 %,and the relative standard deviations were0.74 % ~ 14.36 %.Using the new method,280 samples were tested,and the results showed that none of the other nitrofuran analytes were detected except for the metabolite of nitrofurazone.Among them,SEM and nitrofurazone metabolites was detected in 45 samples,with adetection rate of 16.07%,but the detected concentration was low,with a content of 0.21 ~1.86 ?g/kg.Only 4 samples exceeded the national minimum required performance limit(1.0 ?g/kg)for SEM,which were 1.15,1.86,1.33 and 1.14 ?g/kg respectively.In this paper,a new method was developed which had high sensitivity and high throughput for detection nitrofurans and their metabolites in aquaculture products.