A magnetic Fe3O4@SiO2@Ag@COOH nanoparticle (NPs)/Au film was fabricated as an effective surface-enhanced Raman scattering (SERS) substrate through a combination of a solvothermal reaction, the Stöber method and an in-situ reaction. The superparamagnetic
property of Fe3O4@SiO2@Ag and the decoration with –COOH groups allow efficient enrichment and capture of thiabendazole molecules. A large quantity of sub-10 nm gaps emerge when Ag NPs are decorated on the surface of the SiO2 shell, offering
a dramatic electromagnetic field enhancement induced by localized surface plasmon resonance (LSPR). Finite-difference time-domain (FDTD) simulations show that strong near-field enhancement around the gap areas between the Ag NPs and Au film occurs, which is caused by the coupling between the
LSPR of the Ag NPs and surface plasmon polaritons (SPPs) of the Au film. Due to the superparamagnetic property and high electromagnetic field enhancement, the Fe3O4@SiO2@Ag@COOH NPs/Au film as a SERS substrate can detect 1 μg/L thiabendazole in solution,
showing great potential for SERS detection of environmental pollutants.
The high sensitivity and long-term storage stability of a plasmonic substrate are vital for practical applications of the surface-enhanced Raman scattering (SERS) technique in real-world analysis. In this study, a rationally designed, ternary film-packaged, silver-coated gold-nanoparticle (Au@Ag NP) plasmonic array was fabricated and applied as a stable and high-performance SERS chip for highly sensitive sensing of thiabendazole (TBZ) residues in fruit juices. The ternary films played different roles in the plasmonic chip: a newborn poly(methyl methacrylate) (PMMA) film serving as a template for fixing the self-assembled closely packed monolayer Au@Ag NP array that provided an intensive hot spot, a fluorescent quantitative polymerase chain reaction adhesive film (qPCR film) acting as a carrier to retrieve the Au@Ag/PMMA film that was used to improve the robustness of the plasmonic array, and a polyethylene terephthalate (PET) film covered over the Au@Ag/PMMA/qPCR film performing as a barrier to improve the stability of the chip. The Au@Ag/PMMA/qPCR-PET film chip showed high sensitivity with an enhancement factor of 3.14 × 106, long-term storage stability without changing SERS signals for more than 2 months at room temperatures, and a low limit of detection for sensing TBZ in pear juice (21 ppb), orange juice (43 ppb), and grape juice (69 ppb). In addition, the procedure for fabricating the Au@Ag/PMMA/qPCR-PET film SERS chip was easy to handle, offering a new strategy to develop flexible and wearable sensors for on-site monitoring of chemical contaminants with a portable Raman spectrometer in the future.
Pesticides and additives, extensively used in the raw agriculture samples and processed food, have attracted tremendous interests owing to their latent menace to the surroundings and human health. Herein, a rationally designed multifunctional polymethyl methacrylate-silver/graphite-like carbon nitride/silver (PMMA–Ag/g-C3N4/Ag) hybrid substrate with plasmonic-enhanced intrinsic Raman signals was exploited and served as a recyclable and quantitative surface-enhanced Raman scattering (SERS) sensor. Especially, the as-prepared flexible substrate with an electromagnetic enhancement factor of 1.64 × 106 could realize the sensitive monitoring and in-situ degradation of thiabendazole (TBZ) and carmine acid (CA) on apple or in applesauce with limits of detection as low as 2.29 × 10–6 and 6.76 × 10–5 mg/mL. Furthermore, heightened linear correlations with coefficients of 0.996 and 0.997 were accurately acquired using the film peak of PMMA as an internal standard. It was proved that the proposed sophisticated substrate may present attractive superior-in-practice multiplexed quantitative monitoring and facile decomposing of harmful molecules. The resulting recovery values distributed from 60.9 to 126% for the deeply processed foods that were decorated by 10–4 to 1 mg/mL CA together with TBZ.
危险品化学品经营许可证（带存储）