The Detection Of Poisonous And Harmful Material Based On PVP Coating Au Core-Shell Nanoparticles As SERS Substrate

Surface enhanced Raman（SERS）is a nanoscale metal rough surface（such as Au,Ag）or particle system with the abnormal phenomenon of optical enhancement,it can be adsorbed on molecules surface,the Raman signal amplification of 10⁶¹0¹¹,because of its high sensitivity,simple operation and don’t need to samples pretreatment,etc.So the surface enhanced Raman has very good prospects in trace analysis applications.This paper the main work is to use the SERS detection of poisonous and harmful substances malachite green,benzidine mercury and heavy metal ions.1.The core-shell nanopaticles of Au@PVP of uniform and shell-thickness controllable have been prepared by the hydrothermal method.The core-shell nanoparticles can be assembled to be the monolayer array on Si substrate relying on the dispersion of core-shell nanoparticles arising from PVP shell.The MG and Benzidine absorbed by H bond can be detected on the array under the electromagnetic enhancement of inner-core Au nanoparticles.Under the condition of the optimium shell-thickness of Au@PVP and the appropriate absorbed time of MG,the detection of MG can be realized in the linear range from 10^-1010 mol/L to 10^-55 mol/L with the linear coefficient R² of 0.98.The detection limit was 10^-1212 mol/L,which was much lower than the current national method HPLC fluoresecence test two orders of magnitude lowers detection limit.Because of benzidine symmetrical amino,it absorbed by H bond can be detected on the array under the electromagnetic enhancedment of inner-thickness Au nanoparticles.Under the condition of the optimium adsorption ratio,time,pH solution,and the excitation wavelength of laser,the detection of benzidine can be realized,the detection limit could reach 10^-99 mol/L.2.Gold nanoparticles and malachite green isothiocyanate（MGITC）interact with each other used as SERS substrate indirect detection of mercury ion.MGITC can very good adsorption Au nanoparticles surface,the formation of Au-MGITC polymer,utilize Au nanoparticles surface plasmon realize MGITC surface-enhanced Raman detedction.After joining the Hg²⁺,it can be break MGITC reunited with Au nanoparticles,reduce MGITC Raman signal,Hg²⁺concentration higher,MGITC surface-enhanced Raman singal is obvious lower.Under the condition of the optimizing MGITC quantity,used in the uniform colloidal sol SERS substrate for detecting the heavy metal of mercury ion high sensitivity analysis,the detection of Hg²⁺can be realized in the linear range from 10^-1010 to 10^-44 mol/L with the linear coefficient R² of 0.974.The detection limit was 10^-1111 mol/L,which was much lower than the current national method atomic fluorescence spectrum test three orders of magnitude lowers detection limit.