title: Quantitative SERS detection of low-concentration aromatic polychlorinated biphenyl-77 and 2,4,6-trinitrotoluene.
abstract: This paper reports a simple label-free high-sensitive method for detecting low-concentration persistent organic pollutants and explosive materials. The proposed method combines surface-enhanced Raman spectroscopy (SERS) and magnetomotive enrichment of the target molecules on the surface of Ag nanoparticles (NPs). This structure can be achieved through self-assembling integration of Ag NPs with ferromagnetic Fe3O4 microspheres, forming a hybrid SERS nanoprobe with both optical and magnetic properties. Moreover, the magnetic response of ferromagnetic Fe3O4 microspheres can be used to dynamically modulate the optical property of Ag NPs through controlling their geometric arrangement on the substrate by applying an external magnetic field. It is also demonstrated from the full-wave numerical simulation results that the maximum electromagnetic field enhancement can be greatly increased by shortening the distance of neighboring Ag NPs and therefore resulting in an improved SERS detecting limit. More importantly, by using the prepared substrate, the SERS signals from organic pollution substances, i.e. aromatic polychlorinated biphenyl-77 and 2,4,6-trinitrotoluene, were quantitatively analyzed.
authors.affiliation: Department of Applied Physics, Hong Kong Polytechnic University, Hong Kong, China.
authors.forename: Zhi Yong
authors.initials: ZY
authors.lastname: Bao
authors.affiliation: Department of Applied Physics, Hong Kong Polytechnic University, Hong Kong, China; Key Lab of Advanced Transducers and Intelligent Control System of Ministry of Education and Shanxi Province, College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Applied Physics, Hong Kong Polytechnic University, Hong Kong, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.affiliation: College of Material Science and Engineering, Hefei University of Technology, Hefei, China.
authors.forename: Yucheng
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Applied Physics, Hong Kong Polytechnic University, Hong Kong, China.
authors.forename: Helen L W
authors.initials: HL
authors.lastname: Chan
authors.affiliation: Department of Applied Physics, Hong Kong Polytechnic University, Hong Kong, China. Electronic address: jiyan.dai@polyu.edu.hk.
authors.forename: Jiyan
authors.initials: J
authors.lastname: Dai
authors.affiliation: Department of Applied Physics, Hong Kong Polytechnic University, Hong Kong, China; Shenzhen Research Institute, Hong Kong Polytechnic University, Shenzhen, China. Electronic address: dylei@polyu.edu.hk.
authors.forename: Dang Yuan
authors.initials: DY
authors.lastname: Lei
mesh_terms: D058185:Magnetite Nanoparticles; D009574:Nitro Compounds / Q000032:analysis*; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D012834:Silver; D013059:Spectrum Analysis, Raman / Q000379:methods*; D014050:Toluene / Q000031:analogs & derivatives* / Q000032:analysis
chemical_list: C545368:2,4,6-trinitrenotoluene; D058185:Magnetite Nanoparticles; D009574:Nitro Compounds; D014050:Toluene; D012834:Silver; D011078:Polychlorinated Biphenyls; C028451:3,4,3',4'-tetrachlorobiphenyl
keywords: Ag nanoparticles; Magnetic self-assembling; Polychlorinated biphenyl-77; Surface-enhanced Raman spectroscopy; Trinitrotoluene