Abstract:In the present work, we report a practical fabrication method of gold-aluminium substrates for surface enhanced Raman spectroscopy. A commercial aluminium-foil was used to fabricate SERS substrates by depositing gold nanocuboids and faceted particles onto their surfaces using the drop-drying method. The gold nanoparticles were characterized by ultraviolet-visible spectroscopy, while the size and morphology were determined by field emission scanning electron microscopy. The performance of the substrates was inv… Show more
“…37 The results show that the AuNPs prepared using the automated loop flow-reactor technology as SERS substrates have comparable EFs and detection limits for the RG6 detection compared to laboratory methods. 38 The actual minimum concentration of the AuNPs prepared by the ring-flow analysis method for the RG6 solution was 1 × 10 −9 M, which is similar to that of the AuNPs of similar shape and size mentioned in the literature. 39…”
This study used automatic control methods to prepare gold nanoparticles (AuNPs) as the substrate and rhodamine 6G molecule as the probe to investigate the enhancement effect, stability, and consistency of surface-enhanced Raman spectroscopy (SERS). The gold nanosols were prepared via automatic control using loop flow-reactor technology, and the synthesis of nanoparticles with different sizes was precisely controlled by optimizing the ratio of the solution required for the reaction between sodium citrate and chloroauric acid during the preparation process. The morphology, structure, and optical properties of the prepared AuNPs were investigated using field-emission scanning electron microscopy, transmission electron microscopy, and ultraviolet visible spectroscopy. Using the proposed method, AuNPs with average particle sizes of 72, 85, 93, and 103 nm were synthesized in a precisely controlled manner. The 93 nm particles exhibited good SERS activity for rhodamine 6G under 785 nm excitation with a detection limit of 2.5 × 10−10 M. The relative standard deviation of the SERS spectra synthesized multiple times was <3.5%, indicating their good sensitivity and reproducibility. The results showed that the AuNPs prepared by the automatic control of the loop-flow method have high sensitivity, stability, and reproducibility. Moreover, they exhibited notable potential for in situ measurement and quantitative analysis using SERS.
“…37 The results show that the AuNPs prepared using the automated loop flow-reactor technology as SERS substrates have comparable EFs and detection limits for the RG6 detection compared to laboratory methods. 38 The actual minimum concentration of the AuNPs prepared by the ring-flow analysis method for the RG6 solution was 1 × 10 −9 M, which is similar to that of the AuNPs of similar shape and size mentioned in the literature. 39…”
This study used automatic control methods to prepare gold nanoparticles (AuNPs) as the substrate and rhodamine 6G molecule as the probe to investigate the enhancement effect, stability, and consistency of surface-enhanced Raman spectroscopy (SERS). The gold nanosols were prepared via automatic control using loop flow-reactor technology, and the synthesis of nanoparticles with different sizes was precisely controlled by optimizing the ratio of the solution required for the reaction between sodium citrate and chloroauric acid during the preparation process. The morphology, structure, and optical properties of the prepared AuNPs were investigated using field-emission scanning electron microscopy, transmission electron microscopy, and ultraviolet visible spectroscopy. Using the proposed method, AuNPs with average particle sizes of 72, 85, 93, and 103 nm were synthesized in a precisely controlled manner. The 93 nm particles exhibited good SERS activity for rhodamine 6G under 785 nm excitation with a detection limit of 2.5 × 10−10 M. The relative standard deviation of the SERS spectra synthesized multiple times was <3.5%, indicating their good sensitivity and reproducibility. The results showed that the AuNPs prepared by the automatic control of the loop-flow method have high sensitivity, stability, and reproducibility. Moreover, they exhibited notable potential for in situ measurement and quantitative analysis using SERS.
“…The estimated average sizes were (a) 36 ± 5 nm (90 μL), (b) 42 ± 5 nm (60 μL), (c) 46 ± 7 nm (40 μL), (d) 55 ± 9 nm (20 μL), (e) 63 ± 5 nm (10 μL), and (f) 85 ± 8 nm (5 μL) , respectively. 20–22 When a small volume of seeds is added to the growth solution, large-sized CGNCs grow, and conversely, smaller sized CGNCs were obtained using a large volume of seeds. The size of CGNCs as a function of seeds shows an exponential behavior (see Supplementary Figure S1 in the supplementary material).Figure 1.Micrographs and sizes histograms of the concave gold nanocubes: (a) 36 ± 5 nm, (b) 42 ± 5 nm, (c) 46 ± 7 nm, (d) 55 ± 9 nm, (e) 63 ± 5 nm, and (f) 85 ± 8 nm.…”
We report a simple preparation of surface enhanced Raman spectroscopy (SERS) substrates with gold concave nanocubes of different sizes, deposited onto aluminum slides. The SERS substrates were characterized using 4-Aminothiophenol. Resulting in that the substrate prepared with 55 nm nanocubes exhibits the higher analytical enhancement factor (AEF), 1.5 × 106. Moreover, the SERS substrates’ performance was also evaluated for thiram detection using a series of water and tomato juice samples spiked with the pesticide. Our results show that the excellent performance of the substrate allows the detection of thiram with high sensitivity. The substrates were able to detect thiram with a limit of detection of 7 ppm and 14 ppm, respectively, in water and tomato juice. Our preliminary results open the possibility of using our methodology to detect diverse pollutants of interest.
“…To prepare the SERS substrate, a thin film of AgNPs/AuNPs was deposited onto the polished surface of a square-sized Al plate by drop-casting (Martínez-Torres et al, 2015) of the aqueous solution of NPs followed by spontaneous evaporation of the solvent (Fig. 1).…”
Section: Preparation Of Samples For Sers Measurementsmentioning
confidence: 99%
“…Therefore, the thin film of AgNPs seems to be more efficient in producing the Raman enhancement of R6G in agreement with the hypothesis of superactive hotspots formation (Kleinman et al, 2013). Martínez-Torres et al (Martínez-Torres et al, 2015) reported enhancement factor as ~ 10 6 using a solution of R6G on Al-foil where Au nanocuboids have been drop cast and allowed to dry spontaneously. Martinez-Garcia et al (2016) measured EF in the order of ~ 10 7 using the drop-dry method to obtain dried concave gold nanocubes solution on Al-6063 slides on which the drop of the sample (R6G) had subsequently dried.…”
Section: Fig 3 Uv-vis Absorption Spectrum Of Chemically Synthesized Agnps (Red Line) Commercially Available Agnps (Black Line) and Aunps mentioning
We report herein an economically cheap and functionally stable surfaceenhanced Raman scattering (SERS) protocol of two photoactive pigments Rhodamine 6G (R6G) and Kiton Red (KR), implemented in thin films of silver (Ag) and gold (Au) nanoparticles (AgNPs and AuNPs). Both commercially available and chemically synthesized nanoparticles were used. The suitability of the nanoparticles toward SERS activity was tested through UV-visible absorption spectroscopy and scanning electron microscopy (SEM). The AgNPs and AuNPs based SERS substrates in the form of films were fabricated onto square-sized aluminum(Al) plates by simple drop deposition of colloidal nanoparticles solution onto their polished surfaces. The prepared nanoparticle films were sufficiently dried and coated further with the probe (R6G and KR) molecules by employing the identical deposition technique. The enhanced Raman signals of R6G and KR in such composite film structures were then recorded through a custom-built dispersive Raman spectrometer with He-Ne laser excitation at 632.8 nm. Our AgNPsfilm-based SERS protocol could yield the magnitude of the Raman signal enhancement up to 104 times for both R6G and KR. Moreover, AuNPs-based film was found to be less efficient toward the Raman enhancement of both compounds. Our SERS substrates can be easily fabricated, and SERS spectra are reproducible and stable, allowing one to consistently get a reproducible result even after 6 months.
J. Bangladesh Acad. Sci. 45(1); 1-11: June 2021
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