Construction of Reusable PMMA–Ag/g-C₃N₄/Ag Hybrid Substrates with Plasmonic-Enhanced Intrinsic Raman Signals for Quantitative SERS Detection and Green Degradation

Abstract

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.

Facile Method to Fabricate Cactus-like Ag NPs/CuO/Cu2O Nanocomposites for Recyclable SERS Detection of Trace Carbendazim Residues

“…As shown in Figure A, the Cu foam exhibits three sharp peaks at 43.2, 50.3, and 74.2°, which correspond to the lattice planes of (111), (200), and (220) of cubic Cu (JCPDS: 00-004-0836), respectively . Additionally, a relatively weak diffraction peak at 36.6° in the XRD pattern of Cu foam is indexed to cubic Cu 2 O (JCPDS: 65-3288), which indicates the formation of Cu 2 O during the Cu foam electrodeposition process. , Compared with the Cu foam, several new diffraction peaks at 38.2, 44.3, 64.4, and 77.4° can be observed in the XRD pattern of CACNs, which correspond to the FCC structure of Ag . In addition, the diffraction peaks of CuO can also be found at 38.8 and 61.7° .…”

“…51,58 Compared with the Cu foam, several new diffraction peaks at 38.2, 44.3, 64.4, and 77.4°can be observed in the XRD pattern of CACNs, which correspond to the FCC structure of Ag. 29 In addition, the diffraction peaks of CuO can also be found at 38.8 and 61.7°. 55 It is worth mentioning that four new peaks at 29.9, 36.6, 42.4, and 78.1°increased with the increase in the concentration of Tollens' reagent, implying that Cu 2 O was formed during the galvanic replacement reaction.…”

“…Although the noble metal nanostructures have high sensitivity and enhancement factor, their main disadvantage is single use due to the difficulty of eliminating the adsorbed analyte molecules, limiting the practical application of SERS for the carbendazim residue detection with low cost. Metal oxides, such as TiO 2 , ZnO, and Cu 2 O, are able to decompose analytes adsorbed on SERS substrates due to their photocatalytic capability under visible light irradiation, and have been used to degrade carbendazim. − Benefitting from the EM field enhancement of the noble metals and high photocatalytic activity of semiconductor materials, the combination of the noble metal NPs and the semiconductor nanomaterials endows SERS substrates with both high sensitivity and self-cleaning capability. , …”

“…25−27 Benefitting from the EM field enhancement of the noble metals and high photocatalytic activity of semiconductor materials, the combination of the noble metal NPs and the semiconductor nanomaterials endows SERS substrates with both high sensitivity and self-cleaning capability. 28,29 Three-dimensional (3D) nanostructures can greatly improve SERS sensitivity due to their large specific surface area for adsorbing more analyte molecules and a lot of hot spots along the three-dimensional structure. 9,30,31 Therefore, the development of 3D metal/semiconductor nanocomposites is an effective strategy to obtain SRES substrates with high sensitivity and recyclability.…”

Constructing a Highly Sensitivity SERS Sensor Based on a Magnetic Metal–Organic Framework (MOF) to Detect the Trace of Thiabendazole in Fruit Juice

“…Nonetheless, plenty of pesticide applications can lead to environmental pollution and pesticide residues in food, which can cause harm to public health; even trace amounts of pesticide residues can be harmful. , Thiabendazole (TBZ) is a fungicide widely used in fruits and vegetables to prevent them from mold, rot, blight, and many other diseases. TBZ is also generally used in fruits to keep their freshness before a waxing procedure during storage and transportation. − Even though TBZ is a low-toxic compound compared with other pesticides, the U.S. Environmental Protection Agency (EPA) has classified it as one of the carcinogenic compounds as it could disturb the thyroid hormone balance and damage the liver at high doses. − The maximum residual limit (MRL) of thiabendazole in citrus fruit proposed in China is 20 ppm . The European Commission (EU) stipulates that the maximum allowed for apple is 4 ppm .…”