scholarly journals Biomimetic synthesis of Ag-coated glasswing butterfly arrays as ultra-sensitive SERS substrates for efficient trace detection of pesticides

2019 ◽  
Vol 10 ◽  
pp. 578-588 ◽  
Author(s):  
Guochao Shi ◽  
Mingli Wang ◽  
Yanying Zhu ◽  
Yuhong Wang ◽  
Xiaoya Yan ◽  
...  

In this work, we report a biomimetic synthesis route of 3D Ag nanofilm/glasswing butterfly wing hybrids (Ag-G.b.) by magnetron sputtering technology. The 3D surface-enhanced Raman scattering (SERS) substrate is fabricated from an original chitin-based nanostructure, which serves as a bio-scaffold for Ag nanofilms to be coated on. The novel crisscrossing plate-like nanostructures of 3D Ag-G.b. nanohybrids with thick Ag nanofilms provide a substantial contribution to SERS enhancement. Measuring the SERS performance with crystal violet (CV), the Ag-G.b. nanohybrids with the sputtering time of 20 min (Ag-G.b.-20) shows the highest enhancement performance with an enhancement factor (EF) of up to 2.96 × 107. The limit of detection (LOD) for CV was as low as 10−11 M, demonstrating the ultrahigh sensitivity of the Ag-G.b.-20 substrate. In addition, the Ag-G.b.-20 substrate has an outstanding reproducibility across the entire area with the maximum value of relative standard deviation (RSD) of less than 10.78%. The nanohybrids also exhibit a long-term stability regarding Raman enhancement, as suggested by a duration stability test over a period of 60 days. Importantly, the high-performance Ag-G.b.-20 substrate is further applied as an ultra-sensitive SERS platform for the trace detection of acephate, showing its great potential application in biochemical sensing and food security.

Nanophotonics ◽  
2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Yanlin Mi ◽  
Yinzhou Yan ◽  
Mengyuan Wang ◽  
Lixue Yang ◽  
Jing He ◽  
...  

Abstract Surface-enhanced Raman spectroscopy (SERS) has been widely investigated and employed as a powerful optical analytical technique providing fingerprint vibrational information of molecules with high sensitivity and resolution. In addition to metallic nanostructure, dielectric micro-/nano-structures with extraordinary optical manipulation properties have demonstrated capability in enhanced Raman scattering with ultralow energy losses. Here we report a facile cascaded structure composed of a large microsphere (LMS) and a small microsphere array with Ag nanoparticles as a novel hybrid SERS substrate, for the first time. The cascaded microsphere-coupled SERS substrate provides a platform to increase the molecular concentration, boost the intensity of localized excitation light, and direct the far-field emission, for giant Raman enhancement. It demonstrates the maximum enhancement factor of Raman intensity greater than 108 for the limit of detection down to 10−11 M of 4-nitrothiphenol molecules in aqueous solution. The present work inspires a novel strategy to fabricate cascaded dielectric/metallic micro-/nano-structures superior to traditional SERS substrates towards practical applications in cost-effective and ultrahigh-sensitive trace-detection.


Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2371
Author(s):  
Lu Liu ◽  
Shuting Hou ◽  
Xiaofei Zhao ◽  
Chundong Liu ◽  
Zhen Li ◽  
...  

Graphene–metal substrates have received widespread attention due to their superior surface-enhanced Raman scattering (SERS) performance. The strong coupling between graphene and metal particles can greatly improve the SERS performance and thus broaden the application fields. The way in which to make full use of the synergistic effect of the hybrid is still a key issue to improve SERS activity and stability. Here, we used graphene as a chemical mechanism (CM) layer and Ag nanoparticles (AgNPs) as an electromagnetic mechanism (EM) layer, forming a CM–EM unit and constructing a multi-layer hybrid structure as a SERS substrate. The improved SERS performance of the multilayer nanostructure was investigated experimentally and in theory. We demonstrated that the Raman enhancement effect increased as the number of CM–EM units increased, remaining nearly unchanged when the CM–EM unit was more than four. The limit of detection was down to 10−14 M for rhodamine 6G (R6G) and 10−12 M for crystal violet (CV), which confirmed the ultrahigh sensitivity of the multilayer SERS substrate. Furthermore, we investigated the reproducibility and thermal stability of the proposed multilayer SERS substrate. On the basis of these promising results, the development of new materials and novel methods for high performance sensing and biosensing applications will be promoted.


Author(s):  
Mingli Wang ◽  
Guochao Shi ◽  
Yanying Zhu ◽  
Yuhong Wang ◽  
Wanli Ma

Rapid sampling and multicomponent analysis are vital in the analysis of pesticide residue detection. In this work, we proposed a SERS platform to simultaneously detect three kinds of pesticides on apple peels by a straightforward “press and peel off” method. The flexible Au/dragonfly wing (Au/DW) substrate was obtained from sputtering Au nanoislands on dragonfly wing bioscaffold arrays by a simple DC magnetron sputtering system. The high-performance substrate exhibited a low limit of detection (LOD) to 4-aminothiophenol (4-ATP) (10-9 M), outstanding reproducibility (less than 12.15%), good stability and suitability in multifold pesticide residues detection. Considering its excellent sample collection efficiency, the Au/DW substrate was employed to solve critical pesticide residues problems for detection of acephate (APT), cypermethrin (CPT), tsumacide (MTMC) and their multiple components on apple peels. The results show that the LOD was 10-3 ng/cm2 for APT obtained on the apple surface with a calculation equation of y=0.26x+6.68 and a correlation coefficient (R2) of 0.970. Additionally, the LOD values for CPT and MTMC were 10-3 ng/cm2 and 10-4 ng/cm2, respectively. The finding in this work may provide a promising biomimetic SERS platform for on-spot detection of other organic pollutants in the food industry and the environmental protection.


NANO ◽  
2020 ◽  
Vol 15 (09) ◽  
pp. 2050122
Author(s):  
Chenyan Li ◽  
Chengxiang Yang ◽  
Weijun Li ◽  
Mingming Cheng ◽  
Yingkai Liu

Surface-enhanced Raman scattering (SERS) substrates with low cost, high sensitivity and good reproducibility are still challenging in practical application. Herein, we propose a facile method to prepare monolayer ZnS@Ag nanospheres (NSs) by sputtering Ag nanoparticles (NPs) on the surfaces of the monolayer ZnS NSs produced by self-assembly. The monolayer ZnS@Ag NSs have rough surface and nanoscale gaps, which can produce large SERS effect. The dye molecules, Rhodamine 6G (R6G) and Rhodamine B (RhB), were used as probe to evaluate the SERS performance on the monolayer ZnS@Ag NSs. It was found that the monolayer ZnS@Ag NSs showed the high SERS sensitivity in the detection of R6G and RhB, the limit of detection (LOD) down to 9.12×10−13 M and 8.55×10−11 M, respectively. The corresponding enhancement factors (EF) are 3.01×108 and 8.2×106, respectively. Furthermore, the ordered structure makes the monolayer ZnS@Ag NSs substrate with high signal reproducibility and stability, and the relative standard deviation (RSD) values are less than 15%. Therefore, the monolayer ZnS@Ag NSs is a candidate for detecting organic dyes in the environment.


Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3250
Author(s):  
Juanjuan Guo ◽  
Yang Xu ◽  
Caili Fu ◽  
Longhua Guo

Surface-enhanced Raman spectroscopy (SERS) has been proven to be a promising analytical technique with sensitivity at the single-molecule level. However, one of the key problems preventing its real-world application lies in the great challenges that are encountered in the preparation of large-scale, reproducible, and highly sensitive SERS-active substrates. In this work, a new strategy is developed to fabricate an Ag collide SERS substrate by using cetyltrimethylammonium bromide (CTAB) as a connection agent. The developed SERS substrate can be developed on a large scale and is highly efficient, and it has high-density “hot spots” that enhance the yield enormously. We employed 4-methylbenzenethiol(4-MBT) as the SERS probe due to the strong Ag–S linkage. The SERS enhancement factor (EF) was calculated to be ~2.6 × 106. The efficacy of the proposed substrate is demonstrated for the detection of malachite green (MG) as an example. The limit of detection (LOD) for the MG assay is brought down to 1.0 × 10−11 M, and the relative standard deviation (RSD) for the intensity of the main Raman vibration modes (1620, 1038 cm−1) is less than 20%.


2020 ◽  
Vol 16 ◽  
Author(s):  
Nadereh Rahbar ◽  
Fatemeh Ahmadi ◽  
Zahra Ramezani ◽  
Masoumeh Nourani

Background: Sample preparation is one of the most challenging phases in pharmaceutical analysis, especially in biological matrices, affecting the whole analytical methodology. Objective: In this study, a new Ca(II)/Cu(II)/alginate/CuO nanoparticles hydrogel fiber (CCACHF) was synthesized through a simple, green procedure and applied for fiber micro solid phase extraction (FMSPE) of diazepam (DIZ) and oxazepam (OXZ) as model drugs prior to high-performance liquid chromatography-UV detection (HPLC-UV). Methods: Composition and morphology of the prepared fiber were characterized and the effect of main parameters on the fiber fabrication and extraction efficiency have been studied and optimized. Results: In optimal conditions, calibration curves were linear ranging between 0.1–500 µg L−1 with regression coefficients of 0.9938 and 0.9968. Limit of detection (LOD) (S/N=3) and limit of quantification (LOQ) (S/N=10) of the technique for DIZ and OXZ were 0.03 to 0.1 µg L−1. Within-day and between-day relative standard deviations (RSDs) for DIZ and OXZ were 6.0–12.5% and 3.3–9.4%, respectively. Conclusion: The fabricated adsorbent has been substantially employed to extraction of selected benzo-diazepines (BZDs) from human serum real specimens and the obtained recoveries were also satisfactory (82.1-109.7%).


Author(s):  
Dilshad Ahmad ◽  
Faisal A. Al Meshaiti ◽  
Yazeed K. Al Anazi ◽  
Osama Al Owassil ◽  
Alaa Eldeen B. Yassin

Anastrozole, an aromatase inhibitor drug, is used for the treatment of breast cancer in pre- and postmenopausal women. Anastrozole’s incorporation into nanoparticulate carriers would enhance its therapeutic performance. To perceive the exact loaded amount of drug in nanocarriers, a valid analytical method is required. The reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated by using the C18 column, 150 × 4.6 mm, 5 µm particle size, in isocratic mobile phase composed of 50:50 V/V (volume/volume) acetonitrile–phosphate buffer (pH 3) flowing at a rate of 1.0 mL/min, and a diode array detector (DAD) set at λmax = 215 nm. The validation parameters such as linearity, accuracy, specificity, precision, and robustness have proven the accuracy of the method, with the relative standard deviation percentage (% RSD) values < 2. The limit of detection of the method was found equal to 0.0150 µg/mL, and the limit of quantitation was 0.0607 µg/mL. The percent recovery of sample was in the range of 98.04–99.25%. The method has the advantage of being rapid with a drug retention time of 2.767 min, specific in terms of resolution of peaks void of interference with any of the excipients, and high reproducibility. This makes it highly applicable for quality control purposes.


2017 ◽  
Vol 9 (2) ◽  
pp. 34
Author(s):  
N. Balaji ◽  
Sayeeda Sultana

Objective: An efficient, high performance liquid chromatographic method has been developed and validated for the quantification of related substances in pioglitazone hydrochloride drug substance.Methods: This method includes the determination of three related substances in pioglitazone hydrochloride. The mobile phase A is 0.1% w/v triethylamine in water with pH 2.5 adjusted by dilute phosphoric acid. The mobile phase B is premixed and degassed mixtures of acetonitrile and methanol. The flow rate was 1 ml/min. The elution used was gradient mode. The HPLC column used for the analysis was symmetry C18 with a length of 250 mm, the internal diameter of 4.6 mm and particle size of 5.0 microns.Results: The developed method was found to be linear with the range of 0.006-250% with a coefficient of correlation 0.99. The precision study revealed that the percentage relative standard deviation was within the acceptable limit. The limit of detection and limit of quantitation of the impurities was less than 0.002%and 0.006% with respect to pioglitazone hydrochloride test concentration of 2000 µg/ml respectively. This method has been validated as per ICH guidelines Q2 (R1).Conclusion: A reliable, economical HPLC method was magnificently established for quantitative analysis of related substances of pioglitazone hydrochloride drug substance.


Author(s):  
Muhammad Fawad Rasool ◽  
Umbreen Fatima Qureshi ◽  
Nazar Muhammad Ranjha ◽  
Imran Imran ◽  
Mouqadus Un Nisa ◽  
...  

AbstractTh accurate rapid, simple and selective reversed phase high performance liquid chromatography (RP-HPLC) has been established and validated for the determination of captopril (CAP). Chromatographic separation was accomplished using prepacked ODSI C18 column (250 mm × 4.6 mm with 5 μm particle size) in isocratic mode, with mobile phase consisting of water: acetonitrile (60:40 v/v), pH adjusted to 2.5 by using 85% orthophosphoric acid at a flow rate of 1 mL/min and UV detection was performed at 203 nm. RP-HPLC method used for the analysis of CAP in mobile phase and rabbit plasma was established and validated as per ICH-guidelines. It was carried out on a well-defined chromatographic peak of CAP was established with a retention time of 4.9 min and tailing factor of 1.871. The liquid–liquid extraction method was used for extraction of CAP from the plasma. Excellent linearity (R2 = 0.999) was shown over range 3.125–100 µg/mL with mean percentage recoveries ranges from 97 to 100.6%. Parameters of precision and accuracy of the developed method meet the established criteria. Intra and inter-day precision (% relative standard deviation) study was also performed which was less than 2% which indicate good reproducibility of the method. The limit of detection (LOD) and quantification for the CAP in plasma were 3.10 and 9.13 ng/mL respectively. The method was suitably validated and successfully applied to the determination of CAP in rabbit plasma samples.


INDIAN DRUGS ◽  
2021 ◽  
Vol 58 (07) ◽  
pp. 59-65
Author(s):  
Vinita C. Patole ◽  
Shilpa P. Chaudhari ◽  

An attempt was made to develop a simple, selective, rapid and precise high-performance liquid chromatography (HPLC) method for simultaneous estimation of thymol and eugenol. Analysis was performed on a C18 column with the mobile phase consisting of solvent %A (water) and solvent %B (acetonitrile) with the following gradient: 0–1 min, 80 % A, 20 % B; 1–7 min, 40 % A and 60 % B; 7–12 min, 10 % A and 90 % B; and 12–15min, 80 % A and 20 % B at a flow rate of 0.6 mL/min. The compounds were well separated on a Thermo Scientific Hypersil BDS RP C18 column (4.6 mm × 150 mm, dp = 5 µm) and ultraviolet detection at 280 nm. The retention times of eugenol and thymol were 10.5 min and 11.6 min, respectively. Validation of the proposed method was carried out according to the guidelines of the International Council on Harmonization (ICH). The linearity of the method is good for thymol and eugenol over the concentration range of 1–50 ppm, and the r 2 values were 0.9996 for both thymol and eugenol. The calculated limit of detection (LOD) value was 0.5ppm and the limit of quantification (LOQ) value was 1ppm for both the analytes. The intra and interday relative standard deviation (RSD) of the retention time and peak areas was less than 3 %.The established method was appropriate, and the two markers were well resolved, enabling efficient quantitative analysis of thymol and eugenol.


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