Study Of The Detection Of Organophosphine Molecules Based On Surface Enhanced Raman Scattering Effect

Organophosphine compounds,such as sarin and soman,belong to the nerve agents and the most toxic substances.Poisoning will take place within few hours even when the nerve agent enters the body through the skin or through consumption.So it is very important to quickly detect it in trace-level and on-site or portable way for protection of people's life and to maintain national defense security.The detection based on surface enhanced Raman scattering(SERS)effect could be a suitable and promising method for quick and trace measurement.However,the organophosphine nerve agents(including sarin and soman)have only very weak interaction(or even no affinity)with the highly SERS-activated noble metal substrates,and hardly adsorb on the substrates or could stay on them only for a very short time.In this case,it is very difficult to detect such molecules by the normal SERS technique.This thesis is SERS-based ultrasensitive detection of organophosphorus nerve agents.This thesis conludes design of the highly SERS-active substrates,highly efficient non-metal SERS-active materials and the SERS-substrates with surface modification.And it includes construction for a high-density nano-tip array SERS substrate,SERS-based ultrasensitive detection of organophosphine nerve agents via amide reaction and design of the highly efficient non-metal SERS-active materials.The aim of this study was to improve the interaction between the SERS substrate and the nerve agents and to achieve strong selective adsorption and high efficiency enrichment.And its final purpose is to realize the rapid and trace detection of the nerve agents based on the SERS effect.And the main innovative results are summarized as follows:(1)A high density nanotips array SERS substrate construction strategy has been presented.The ordered gold covered nanotips arrays have been constructed through sputtering deposition method on orderly the glass nanotips frames.Such frames are fabricated using reactive ion etching(RIE)based on polystyrene spheres(PS)monolayer colloidal crystal as mask,which can be used as substrate for trace analyses of triphenyl phosphine(TPP)based on surface enhanced Raman scattering(SERS)effect,and exhibits excellent SERS activity.The surface of the SERS substrate is clean and homogeneous,and it provides a simple method for constructing high SERS-active substrate.(2)A new strategy is presented to achieve the SERS-based ultrasensitive detection of sarin-simulated agent methanephosphonic acid(MPA)via the surface modification-chemical of SERS-substrates.The Au-coated Si nanocone array is surface-modified with 2-aminoethanethiol and used as SERS-substrate for detection of MPA.The Raman peak intensity versus the MPA concentration is subject to a linear double logarithmic relation from?1 ppb to?1000 ppm.And revealed the Freudlisch adsorption mechanism.This study provides a new effective way for the highly efficient SERS-based detection of some other target molecules weakly interacted with metal substrates.(3)A new idea of capturing organophosphine compounds effectively by using the surface active groups of hydroxide is proposed.It has been demonstrated that such nanosheets are of strong surface enhancement Raman scattering(SERS)effect to the organophosphine molecules(TPPPO)that can be captured by the hydroxyls on the nanosheets.The enhancement factor is up to 2.0×103.The Raman peak intensity shows a linear double logarithmic relation with TPPPO concentration.This work presents a new approach to design of the highly efficient non-metal SERS-active materials.And its also provides a basis for the next step of combining this materials with high SERS active metal nanostructure arrays to study high performance composite SERS substrates.