title: Polystyrene/Ag nanoparticles as dynamic surface-enhanced Raman spectroscopy substrates for sensitive detection of organophosphorus pesticides.
abstract: We report the use of Polystyrene/Ag (PS/Ag) nanoparticles as dynamic surface-enhanced Raman spectroscopy (dynamic-SERS) substrates for sensitive detection of low levels of organophosphorus pesticides. The PS particles clearly observed using Raman microscopy provide the masterplate for in situ growth of Ag NPs, leading to multiple active sites for SERS measurements. Besides obtaining the fingerprints of target molecules and recording time-resolved Raman spectra, this dynamic-SERS method can be used as an ultra-sensitive analytical technique which can enhance 1-2 orders of magnitude the signals of analytes in comparison to that of the traditional methods. On the other hand, importantly, it shows much better correlations between concentration and intensity than does the conventional SERS technique so that it can build the foundation for quantitative analysis of analytes. The as-prepared individual PS/Ag nanoparticle has been demonstrated for the sensitive detection of organophosphorus paraoxon and sumithion. SERS spectra are acquired at different concentrations of each pesticide and linear calibration curves are obtained by monitoring the strongest intensity value of bands arising from stronger stretching mode as a function of analyte concentration. The limits of detection and limits of quantitation are reported for two pesticides. The limit of detection for paraoxon is 96 nM (0.026 ppm) and for sumithion is 34 nM (0.011 ppm). The limits of quantitation are 152 nM (0.042 ppm) and 57 nM (0.016 ppm) for paraoxon and sumithion, respectively. It can be seen that these two organophosphorus pesticides can be detected in the low nM range based on this dynamic-SERS analytical method. Also, in the real sample experiments of paraoxon and sumithion, the results confirm that this dynamic-SERS technique would have potential applicability for quantitative analysis with slight interference.
authors.affiliation: Department of Chemistry, University of Science & Technology of China, Hefei, Anhui 230026, China.
authors.forename: Pan
authors.initials: P
authors.lastname: Li
authors.affiliation: Department of Chemistry, University of Science & Technology of China, Hefei, Anhui 230026, China.
authors.forename: Ronglu
authors.initials: R
authors.lastname: Dong
authors.affiliation: Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031, China.
authors.forename: Yiping
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031, China.
authors.forename: Honglin
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Chemistry, University of Science & Technology of China, Hefei, Anhui 230026, China; Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031, China. Electronic address: ltkong@iim.ac.cn.
authors.forename: Lingtao
authors.initials: L
authors.lastname: Kong
authors.affiliation: Department of Chemistry, University of Science & Technology of China, Hefei, Anhui 230026, China; Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031, China. Electronic address: lbyang@iim.ac.cn.
authors.forename: Liangbao
authors.initials: L
authors.lastname: Yang
mesh_terms: D005278:Fenitrothion / Q000032:analysis* / Q000737:chemistry; D007306:Insecticides / Q000032:analysis* / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D010261:Paraoxon / Q000032:analysis* / Q000737:chemistry; D011137:Polystyrenes / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods
chemical_list: D007306:Insecticides; D011137:Polystyrenes; D012834:Silver; D010261:Paraoxon; D005278:Fenitrothion
keywords: Dynamic; Organophosphorus pesticides; Quantitative analysis; SERS