A self-assembly hydrophobic oCDs/Ag nanoparticles SERS sensor for ultrasensitive melamine detection in milk

Qiu, Jianxiu; Chu, Yujin; He, Qihang; Han, Yingkuan; Han, Lin

doi:10.1016/j.foodchem.2022.134241

Cited by 25 publications

(9 citation statements)

References 38 publications

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“…The SERS enhancement factor (EF) was calculated using the following equation: EF = I SERS I NR × C NR C SERS where I SERS and I NR represent the Raman intensity of R6G on the PVA-Ag/Au/UiO-66 hybrid membrane and the PVA membrane, and C SERS and C NR represent the corresponding R6G concentration on the PVA-Ag/Au/UiO-66 hybrid membrane and the PVA membrane, respectively.…”

Section: Results and Discussionmentioning

confidence: 99%

UiO-66 Particles Decorated with Ag/Au Nanoparticles as SERS Sensors for Detecting Harmful Patina in Trace Analysis of Ancient Bronze Art

Zhang,

Huang,

Chen

et al. 2024

ACS Appl. Nano Mater.

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Quantitative analysis of harmful patina components on the surface of bronzeware is crucial as patina can corrode artifacts. Surfaceenhanced Raman spectroscopy (SERS) has a common application in surface analysis. However, there exists an absence of documented investigations concerning the quantitative analysis of detrimental patina, particularly the chloride patina. To achieve high sensitivity in targeting harmful patina, we report a fabrication method for constructing Ag/Au alloys in the pores and on the surface of UiO-66 (zirconium 1,4-dicarboxybenzene metal−organic framework) nanomaterials, resulting in Ag/Au/UiO-66 nanoparticle monolayers formed by self-assembly at the oil−water interface. By incorporating them onto the surface of PVA hydrogel, we obtained SERS sensor devices with excellent flexibility, outstanding optical transparency, and ultrahigh activity. These sensor devices efficiently sample irregular surfaces and detect micrometer-scale specimen. They significantly enhance the Raman characteristic peaks of measured objects, facilitating precise analysis of the patina composition on the surface of bronze artifacts. The Raman peak at 118 cm −1 was boosted from 367 to 11,909 for detecting harmful patina, and the enhancement factor of the SERS substrate was calculated to be 3.6 ×10 10 for detecting the Raman peak of rhodamine 6G (R6G), which could be easily detected at 610 cm −1 at a concentration of 10 −13 mol/L (M). The Raman peaks at 610 cm −1 from the SERS substrate could also be readily detected. By grafting the organic fluorescent group amino-MQAE onto the surface of Ag/Au/UiO-66 nanoparticles (NPs), the content of harmful patina on the surface of bronze artifacts treated for different durations was indirectly determined. These results indicate the successful construction of the Ag/Au alloy on the surface of UiO-66 NPs, resulting in SERS sensor devices with excellent flexibility, optical transparency, and ultrahigh sensitivity.

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Section: Results and Discussionmentioning

confidence: 99%

UiO-66 Particles Decorated with Ag/Au Nanoparticles as SERS Sensors for Detecting Harmful Patina in Trace Analysis of Ancient Bronze Art

Zhang,

Huang,

Chen

et al. 2024

ACS Appl. Nano Mater.

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“…As shown in Figure e and f, the monolayer can efficiently detect the 10 –12 M and 10 –11 M of 4-MBA and 4-BPT, respectively, which verify the excellent SERS sensitivity. , Moreover, the open-gap Au/AgAu monolayer also achieves the SESR detection of melamine (10 –8 M), which is much lower than the limit of 2.5 ppm (2 × 10 –5 M) set by the European Union (Figure S7). To evaluate the qualitative analysis ability in complex components, an open-gap Au/AgAu monolayer was used to detect the mixed solution of CV, MB, RhB, and 4-BPT. As shown in Figure g, the SERS spectrum of mixed solution matches well with the SERS spectra of CV, MB, RhB, and 4-BPT, respectively.…”

Section: Resultsmentioning

confidence: 99%

Open-Nanogap-Induced Strong Electromagnetic Enhancement in Au/AgAu Monolayer as a Stable and Uniform SERS Substrate for Ultrasensitive Detection

Zhao,

Liang,

Chen

et al. 2024

Anal. Chem.

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Nanogap-based plasmonic metal nanocrystals have been applied in surface-enhanced Raman scattering detection, while the closed and insufficient electromagnetic fields as well as the nonreproducible Raman signal of the substrate greatly restrict the actual application. Herein, a highly uniform Au/AgAu monolayer with abundant nanogaps and huge electromagnetic enhancement is prepared, which shows ultrasensitive and reproducible SERS detection. Au/AgAu with an inner nanogap is first prepared based on Au nanotriangles, and the nanogap is opened from the three tips via a subsequent etching process. The opengap Au/AgAu displays much higher SERS efficiency than Au and Au/ AgAu with an inner nanogap on detecting crystal violet due to the opengap induced electromagnetic enhancement and improved molecular absorption. Furthermore, the open-gap Au/AgAu monolayer is prepared via interfacial self-assembly, which shows further improved SERS due to the dense and strong hotspots in the nanocavities induced by the electromagnetic coupling between adjacent open gaps. The monolayer possesses excellent signal stability, uniformity, and reproducibility. The analytic enhancement factor and relative standard deviation reach to 2.12 × 10 8 and 4.65% on detecting crystal violet, respectively. Moreover, the monolayer achieves efficient detection of thiram in apple juice, biphenyl-4-thiol, 4mercaptobenzoic, melamine, and a mixed solution of four different molecules, showing great promise in practical detection.

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“…A value of the EF of an electromagnetic mechanism can be estimated, but because it is derived from the maximum field strength, it is generally greater than the actual value. 19 To gain a better understanding of the electric field distribution and "hot spots" of Ag nanoparticles on TiO 2 / Ag nano substrate, we employed the FDTD method to compare the simulation results with the actually calculated EF. The purpose of this theoretical investigation was to develop an improved SERS substrate and to enhance our comprehension of the SERS enhancement mechanism.…”

Section: Finite-difference Time-domain (Fdtd) Simulationmentioning

confidence: 99%

Two-Dimensional Amorphous Titanium Dioxide/Silver (TiO₂/Ag) Nanosheets as a Surface-Enhanced Raman Spectroscopy Substrate for Highly Sensitive Detection

Zhang,

Wu,

Zhang

et al. 2023

Appl Spectrosc

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For the purpose of investigating the chemical enhancement of amorphous semiconductors as well as increasing the sensitivity of the surface-enhanced Raman spectroscopy (SERS) substrate, titanium dioxide (TiO2) precursors were calcined at different temperatures to generate crystallized TiO2 (c-TiO2) and amorphous TiO2 (a-TiO2) nanosheets, respectively. Afterward, a two-dimensional (2D) a-TiO2/Ag nanosheet SERS substrate was successfully fabricated using electrostatic interaction between a-TiO2 and Ag nanoparticles. In order to demonstrate a greater SERS sensitivity on a-TiO2/Ag compared to either c-TiO2 or Ag nanoparticles alone, the SERS probe molecules rhodamine 6G (R6G) and malachite green (MG) were utilized. Based on the results of SERS detections for probe molecules and contaminants, it demonstrates that a-TiO2/Ag nanosheets produce highly sensitive and repeatable Raman signals. The detectable concentration limits for R6G and MG were found to be 10−11 M and 10–10 M, respectively. And it has been determined that the system exhibits an enhancement factor (EF) of up to 1 × 108. The limit of detection for 4-mercaptobenzoic acid and alizarin red can both reach 1 × 10–8. Furthermore, a finite-difference time-domain simulation is performed in order to evaluate the magnetic field strength generated by Ag nanoparticles. As a result of the simulation, it is evident that the actual EF is smaller than the calculated one, leading support to the view that a-TiO2 nanosheets have a beneficial effect on the chemical enhancement of SERS.

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A self-assembly hydrophobic oCDs/Ag nanoparticles SERS sensor for ultrasensitive melamine detection in milk

Cited by 25 publications

References 38 publications

UiO-66 Particles Decorated with Ag/Au Nanoparticles as SERS Sensors for Detecting Harmful Patina in Trace Analysis of Ancient Bronze Art

UiO-66 Particles Decorated with Ag/Au Nanoparticles as SERS Sensors for Detecting Harmful Patina in Trace Analysis of Ancient Bronze Art

Open-Nanogap-Induced Strong Electromagnetic Enhancement in Au/AgAu Monolayer as a Stable and Uniform SERS Substrate for Ultrasensitive Detection

Two-Dimensional Amorphous Titanium Dioxide/Silver (TiO₂/Ag) Nanosheets as a Surface-Enhanced Raman Spectroscopy Substrate for Highly Sensitive Detection

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A self-assembly hydrophobic oCDs/Ag nanoparticles SERS sensor for ultrasensitive melamine detection in milk

Cited by 25 publications

References 38 publications

UiO-66 Particles Decorated with Ag/Au Nanoparticles as SERS Sensors for Detecting Harmful Patina in Trace Analysis of Ancient Bronze Art

UiO-66 Particles Decorated with Ag/Au Nanoparticles as SERS Sensors for Detecting Harmful Patina in Trace Analysis of Ancient Bronze Art

Open-Nanogap-Induced Strong Electromagnetic Enhancement in Au/AgAu Monolayer as a Stable and Uniform SERS Substrate for Ultrasensitive Detection

Two-Dimensional Amorphous Titanium Dioxide/Silver (TiO2/Ag) Nanosheets as a Surface-Enhanced Raman Spectroscopy Substrate for Highly Sensitive Detection

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Two-Dimensional Amorphous Titanium Dioxide/Silver (TiO₂/Ag) Nanosheets as a Surface-Enhanced Raman Spectroscopy Substrate for Highly Sensitive Detection