Constructing a Ring-like Self-Aggregation SERS Sensor with the Coffee Ring Effect for Ultrasensitive Detection and Photocatalytic Degradation of the Herbicides Paraquat and Diquat

Abstract

A strategy for building ring-like deposit surface-enhanced Raman scattering (SERS) sensors with the coffee ring effect through the functional modification of the silica nanoparticle surface encapsulated by free-tagged Ag nanoparticles is addressed along with their applications in the SERS-based detection and degradation of target species, including paraquat, diquat, and their free radicals. The nanogap formed by two interparticles with SERS hotspots provides a gigantic amplification signal for the Raman scattering intensity of the analyte molecule located approximately at the hotspots. The enhanced Raman spectrum signals of these target analytes were achieved through the hotspot region of the surface plasmon resonance (SPR) located on the embankment formed by self-aggregation of SiO2@Ag nanoparticles due to the coffee ring effect. Meanwhile, the intrinsic properties of Ag nanoparticles embedded onto the silica surface were applied to photocatalytically degrade the target analytes by harvesting energy from sunlight. The SERS sensor detected the analytes down to 10–9 M in the aqueous solution.

Meso-Au/BN Nanosensor for Trinitrotoluene Based on Fluorescence Resonance Energy Transfer and Surface-Enhanced Raman Spectroscopy Mechanisms

“…Taking TNT as an example, the characteristic band of TNT at 1357 cm –1 was chosen to calculate the EF of the meso-Au/BN/MEA NPs, and the I SERS and I NR of TNT were directly obtained, as shown in Figure S15A. The calculation of N SERS and N NR is based on previous studies, , and the detailed description of “Calculation of the Enhancement Factor (EF)″ is provided in the Supporting Information. The Raman enhancement factors EFs of the target analytes TNT, DNT, TNP, and DNP using SERS (meso-Au/BN/MEA and meso-Au) and non-SERS substrates are shown in Table , and the corresponding EFs for TNT, DNT, TNP, and DNP are 8.68 × 10 5 , 5.23 × 10 5 , 2.40 × 10 5 , and 5.43 × 10 5 using meso-Au/BN/MEA NPs as SERS substrates, respectively.…”

“…44 One milliliter of meso-Au/BN NPs was mixed with 1 mL of TNT, DNT, TNP, and DNP solutions at different concentrations from 10 −3 , 10 −4 , 10 −5 , 10 −6 , 10 −7 , 10 −8 , 10 −9 , to 10 −10 mol•L −1 and incubated in the dark at room temperature for 1 h. One hundred microliters of the mixed solution above was dropwise added onto a glass slide and then dried naturally to achieve the meso-Au/BN NP sensor with an enhanced Raman signal, which detected the target analytes above recorded by the enhancing Raman signal using Raman spectroscopy. 45 2.6. Characterizations.…”

Surface-enhanced Raman scattering of a gold core–silver shell-sponge substrate for detection of thiram and diquat

“…The Raman characteristic peaks of diquat were mainly at 561 cm −1 (stretching vibration of the S–S bond), 735 cm −1 (C–H bending inside plane), 998 cm −1 (C–H bending out of plane) 1075 cm −1 (C–C ring stretching) 1287 cm −1 (ring bending), 1578 cm −1 , and 1613 cm −1 (symmetric ring stretching vibration). 42,43 The Raman shift of 1579 cm −1 was the main characteristic peak of diquat. In order to explore the relationship between the concentration of diaquat ethanol solution and its corresponding Raman signal intensity, the Raman signal at a Raman shift of 1579 cm −1 was selected for fitting.…”

Portable SERS-Based POCT Kit for Ultrafast and Sensitive Determining Paraquat in Human Gastric Juice and Urine

“…By dramatically boosting the electromagnetic fields and dense plasmonic hotspots that are constantly produced by the surrounding metal nanostructures, SERS platforms offer exceptional sensitivity and specificity . Given these attributes, SERS technology has been widely used in biomedicine , and stands out as a promising alternative for the analysis of paraquat (PQ) . While recent approaches have explored SERS detection of PQ, the predominant focus has been on environmental samples and food, such as apple juice, adzuki beans, and oily matrix .…”

“… 13 Given these attributes, SERS technology has been widely used in biomedicine 14 , 15 and stands out as a promising alternative for the analysis of paraquat (PQ). 16 While recent approaches have explored SERS detection of PQ, the predominant focus has been on environmental samples 17 and food, such as apple juice, 18 adzuki beans, 19 and oily matrix. 20 However, there are few studies on the SERS detection of PQ in body fluids.…”