Sudy On The Detection Of Pesticides,Veterinary Drugs And Mycotoxin Residues Based On The Functionalized Gold And Silver Nanoparticle Probes

Food safety is a global issue.Therefore,developing a series of rapid detection methods for harmful substance plays an important role in food safety control and management.The traditional chromatographic techniques and immunoassay technology have shortcomings,suche as high cost,time-consuming,needing professional operator and complex operation,which restricts the development of detecting techniques.So,it is important to develop a series of quick,acurate,sensitive methods for food safety analysis.Because of their unique structure and optical property,gold and silver nanoparticles get more and more attention in envirment,food,chemical,pharmacy,life of science.In this paper colorimetric and fluorescence are established to determine the harmful ingredients of food based on surface plasmon resonance and catalytic ability of AuNPs/AgNPs.For instance,acetamiprid,kanamycin and ochratoxin A.?1?.The colloidal gold particles were synthesized by the classical method of reducing hydrogen tetrechloroaurate with sodium citrate.The particle size was characterized by TEM,which are about 13 nm and have good dispersibility,the color is red.It's color and SPR absorption is changed in the presence of a high concentration of salt.As aptamer show specific adsorption on the surface of AuNPs by electrostatic interation,modified AuNPs would remain stable in the presence of aptamer,even if NaCl was added.When acetamiprid was added,the aptamer would react specifically with the acetamiprid,which induced the color of the solution changed from red to blue and the SPR absorption was also changed.Under optimal conditions,it is proved the optimality conditions.The reaction time between aptamer and acetamiprid is 10 min.Under the optimal conditions,for example,the concentration of aptamer,NaCl were 40 nM,20 mM,respectively,the limit of detection is 1.2 nM.The RLS intensity of AuNPs was linearly correlated with the acetamiprid concentration in the range of 0-100 nM.The recovery rate was in the range of 92.2%-112.6%.This established colorimetric method showed strong specificity,high sensitivity,rapid response,simple operation,and has good application prospect.?2?.In this work,we demonstrated that kanamycin could enhance the peroxidaselike activity of citrate-capped AuNPs to realize the detection of kanamycin.The result showed that reaction could be divided into two steps: the attachment of kanamycin onto AuNPs through-NH₂?on anamycin?and –COOH?on AuNPs?interactions;and the specifically interaction between glucoside on kanamycin and Au NPs which change the surface property of AuNPs,and produced ·OH radicals and Au³⁺ in the solution,and catalyzed the chromogenic reactions between 3,3',5,5'-tetramethylbenzidine?TMB?and H₂O₂.It is proved the optimality conditions,for example,the value of pH is 7.5,the concentration of TMB and H₂O₂ were 0.56 mM and 0.17 M respectively.The reaction time between kanamycin and AuNPs is 45 min.Under the optimal conditions,as low as 0.1 nM kanamycin could be detected.The spiked recovery rate in milk,pork,chicken were 100.3%-119.5%?99.6%-113.2% and 98.6%-102.7% respectively.?3?.Established a rapid and sensitive fluorescence resonance energy transfer?FRET?method to detect of ochratoxin A?OTA?based on the AgNPs and C-dots.The AgNPs and C-dots were functionalied by-SH-aptamer?probeI?and-NH₂-cDNA?probeII?.Complementary reactions between probeI and probe II shortened the distance between AgNPs and C-dots,and fluorescence intensity decrease.When OTA was added,the probeI would react with OTA specifically,which induced the fluorescence intensity increase.Therefore,this method could use to quantitatively determine of OTA.Under the optimal conditions,a linear calibration curve in the concentration range of 0 nM-5000 nM was displayed and the limit of detection?LOD?was down to 8.7 nM?S/N =3?.By the proposed method,the selective detection of OTA in real samples?flour and beer?was accurately achieved.This new biosensor detection of OTA with the characteristics of simplicity,rapid response and sensitivity,and provides a new approch for real-time detection of OTA.