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 μg/L for 17β-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 17β-NT,the LOD by immunoenzymatic assay were 1500 μg/kg in animal derived food,and 2100 μg/L in milk.Quantum dots-antibody conjugates were prepared by activated ester method.For 17β-NT,trenbolone,testobolin,stanolone and mestanolone,the detection limits by quantum dots immunoenzymatic assay were 10 μg/L,60 μg/L,80 μg/L,200 μg/L and 400 μg/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 17β-NT,trenbolone,testobolin,stanolone and mestanolone,the LOD were 50 μg/kg,300 μg/kg,400μg/kg,1000 μg/kg and 2000 μg/kg in chicken,pork and fish;The LOD were 60 μg/kg,360μg/kg,480 μg/kg,1200 μg/kg and 2400 μg/kg respectively in beef;And were 70 μg/L,420μg/L,560 μg/L,1400 μg/L and 2800 μg/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 17β-NT,trenbolone,testobolin,stanolone and mestanolone were 5 μg/L,20 μg/L,20 μg/L,40 μg/L and 60 μg/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 17β-NT,trenbolone,testobolin,stanolone and mestanolone were 25 μg/kg,100 μ/kg,100 μ/kg,200 μ/kg and 300 μg/kg in chicken,pork and fish,respectively;The detection limits were 50 μg/kg,200μg/kg,200 μg/kg,400 μg/kg and 600 μg/kg in beef,respectively;And were 10 μg/L,40μg/L,40 μg/L,80 μg/L and 120 μg/L respectively in milk.