Study On The Visual Methods For The Detection Of Anabolic-androgenic Steroids In Foods

Three visual methods for the rapid detection of five kinds of anabolic-androgenic steroids were developed,including immunochromatography strip,Quantum dot-based immunochromatography test strip and gel-based immunoassay.Colloidal gold particles with a mean diameter of 20 nm were prepared according to the sodium citrate reduction method.The detection limit was 300 ?g/L for 17?-NT,with a test time within 10 minutes.Five food samples(chicken,pork,fish,beef,milk)were prepared by a simple centrifugation and extraction.For 17?-NT,the LOD by immunoenzymatic assay were 1500 ?g/kg in animal derived food,and 2100 ?g/L in milk.Quantum dots-antibody conjugates were prepared by activated ester method.For 17?-NT,trenbolone,testobolin,stanolone and mestanolone,the detection limits by quantum dots immunoenzymatic assay were 10 ?g/L,60 ?g/L,80 ?g/L,200 ?g/L and 400 ?g/L,respectively.The test time was about 15 minutes.Five food samples(chicken,pork,fish,beef,milk)were prepared by a simple centrifugation and extraction.For 17?-NT,trenbolone,testobolin,stanolone and mestanolone,the LOD were 50 ?g/kg,300 ?g/kg,400?g/kg,1000 ?g/kg and 2000 ?g/kg in chicken,pork and fish;The LOD were 60 ?g/kg,360?g/kg,480 ?g/kg,1200 ?g/kg and 2400 ?g/kg respectively in beef;And were 70 ?g/L,420?g/L,560 ?g/L,1400 ?g/L and 2800 ?g/L respectively in milk.The gel-based immunoassay was developed with CNBr-activated Sepharose-4B as the solid phase support.The detection layer was prepared via coupling with CNBr-activated Sepharose-4B and antibodies.While the control layer was prepared via coupling with CNBr-activated Sepharose-4B and anti-HRP.The detection limits of the gel-based immunoassay for 17?-NT,trenbolone,testobolin,stanolone and mestanolone were 5 ?g/L,20 ?g/L,20 ?g/L,40 ?g/L and 60 ?g/L,respectively;The test time was about 4?5minutes.For the IATCA detection,five food samples(chicken,pork,fish,beef,milk)were prepared by a simple centrifugation and extraction.The detection limits of 17?-NT,trenbolone,testobolin,stanolone and mestanolone were 25 ?g/kg,100 ?/kg,100 ?/kg,200 ?/kg and 300 ?g/kg in chicken,pork and fish,respectively;The detection limits were 50 ?g/kg,200?g/kg,200 ?g/kg,400 ?g/kg and 600 ?g/kg in beef,respectively;And were 10 ?g/L,40?g/L,40 ?g/L,80 ?g/L and 120 ?g/L respectively in milk.