title: Hotspots engineering by grafting Au@Ag core-shell nanoparticles on the Au film over slightly etched nanoparticles substrate for on-site paraquat sensing.
abstract: Paraquat (PQ) pollutions are ultra-toxic to human beings and hard to be decomposed in the environment, thus requiring an on-site detection strategy. Herein, we developed a robust and rapid PQ sensing strategy based on the surface-enhanced Raman scattering (SERS) technique. A hybrid SERS substrate was prepared by grafting the Au@Ag core-shell nanoparticles (NPs) on the Au film over slightly etched nanoparticles (Au FOSEN). Hotspots were engineered at the junctions as indicated by the finite difference time domain calculation. SERS performance of the hybrid substrate was explored using p-ATP as the Raman probe. The hybrid substrate gives higher enhancement factor comparing to either the Au FOSEN substrate or the Au@Ag core-shell NPs, and exhibits excellent reproducibility, homogeneity and stability. The proposed SERS substrates were prepared in batches for the practical PQ sensing. The total analysis time for a single sample, including the pre-treatment and measurement, was less than 5min with a PQ detection limit of 10nM. Peak intensities of the SERS signal were plotted as a function of the PQ concentrations to calibrate the sensitivity by fitting the Hill's equation. The plotted calibration curve showed a good log-log linearity with the coefficient of determination of 0.98. The selectivity of the sensing proposal was based on the "finger print" Raman spectra of the analyte. The proposed substrate exhibited good recovery when it applied to real water samples, including lab tap water, bottled water, and commercially obtained apple juice and grape juice. This SERS-based PQ detection method is simple, rapid, sensitive and selective, which shows great potential in pesticide residue and additives abuse monitoring.
authors: College of Mechatronics Engineering and Automation, National University of Defense Technology, Changsha, Hunan 410073, PR China; Key Laboratory of New Molecular Diagnosis Technologies for Infectious Diseases, Institute of Radiation Medicine, Academy of Military Medical Sciences, Beijing 100850, PR China.
authors: Chaoguang
authors: C
authors: Wang
authors: College of Mechatronics Engineering and Automation, National University of Defense Technology, Changsha, Hunan 410073, PR China.
authors: Xuezhong
authors: X
authors: Wu
authors: College of Mechatronics Engineering and Automation, National University of Defense Technology, Changsha, Hunan 410073, PR China. Electronic address: ptdong@nudt.edu.cn.
authors: Peitao
authors: P
authors: Dong
authors: College of Mechatronics Engineering and Automation, National University of Defense Technology, Changsha, Hunan 410073, PR China.
authors: Jian
authors: J
authors: Chen
authors: Key Laboratory of New Molecular Diagnosis Technologies for Infectious Diseases, Institute of Radiation Medicine, Academy of Military Medical Sciences, Beijing 100850, PR China. Electronic address: ruixiao203@sina.com.
authors: Rui
authors: R
authors: Xiao
mesh_terms: D000327:Adsorption; D004784:Environmental Monitoring / Q000295:instrumentation*; D004785:Environmental Pollutants / Q000032:analysis; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006046:Gold / Q000737:chemistry; D008567:Membranes, Artificial; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D054802:Molecular Imprinting; D010269:Paraquat / Q000032:analysis* / Q000737:chemistry; D010316:Particle Size; D066330:Printing, Three-Dimensional; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012834:Silver / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000295:instrumentation*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*; D013499:Surface Properties
chemical_list: D004785:Environmental Pollutants; D008567:Membranes, Artificial; D012834:Silver; D006046:Gold; D010269:Paraquat
keywords: Hotspots engineering; Hybrid substrate; Paraquat; SERS