scholarly journals Surface Imprinted Layer of Cypermethrin upon Au Nanoparticle as a Specific and Selective Coating for the Detection of Template Pesticide Molecules

Coatings ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 751
Author(s):  
Jaya Sitjar ◽  
Ying-Chen Hou ◽  
Jiunn-Der Liao ◽  
Han Lee ◽  
Hong-Zheng Xu ◽  
...  

The detection of specific pesticides on food products is essential as these substances pose health risks due to their toxicity. The use of surface-enhanced Raman spectroscopy (SERS) takes advantage of the straightforward technique to obtain fingerprint spectra of target analytes. In this study, SERS-active substrates are made using Au nanoparticles (NPs) coated with a layer of polymer and followed by imprinting with a pesticide–Cypermethrin, as a molecularly imprinted polymer (MIP). Cypermethrin was eventually removed and formed as template cavities, then denoted as Au NP/MIP, to capture the analogous molecules. The captured molecules situated in-between the areas of high electromagnetic field formed by plasmonic Au NPs result in an effect of SERS. The formation of Au NP/MIP was, respectively, studied through morphological analysis using transmission electron microscopy (TEM) and compositional analysis using X-ray photoelectron spectroscopy (XPS). Two relatively similar pesticides, Cypermethrin and Permethrin, were used as analytes. The results showed that Au NP/MIP was competent to detect both similar molecules despite the imprint being made only by Cypermethrin. Nevertheless, Au NP/MIP has a limited number of imprinted cavities that result in sensing only low concentrations of a pesticide solution. Au NP/MIP is thus a specific design for detecting analogous molecules similar to its template structure.

2020 ◽  
Vol 11 (18) ◽  
pp. 4563-4577 ◽  
Author(s):  
Ana Isabel Pérez-Jiménez ◽  
Danya Lyu ◽  
Zhixuan Lu ◽  
Guokun Liu ◽  
Bin Ren

Surface-enhanced Raman spectroscopy (SERS) is a vibrational spectroscopy technique with sensitivity down to the single molecule level that provides fine molecular fingerprints, allowing for direct identification of target analytes.


2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Wei Qi ◽  
Weigen Chen ◽  
Fu Wan ◽  
Jingxin Zou ◽  
Zhaoliang Gu

Furfural is an important chemical solvent and intermediate. Sensitive detection of this compound has attracted great interest in various fields. Surface-enhanced Raman spectroscopy (SERS) is a highly sensitive method for material detection because of its optical enhancement effect of plasmonic nanostructures. This study presents a simple and versatile method to synthesize a SERS substrate, where polyaminothiophenol (PATP) was used to realize the stable combination of Au nanoparticles (AuNPs) and Au film via self-assembly. The near-field electric field distribution was calculated using the finite difference time domain (FDTD) simulation to determine the parameters responsible for electric field enhancement. The simulation results show that SERS enhanced factors are sensitive to interparticle spacing and materials for solid support but insensitive to particle size. Moreover, the experimental results show that the optimized substrates with the highest Raman activity were formed by six layers of 60 nm AuNPs decorated on a 30 nm thick Au film, thereby validating the simulation results. The SERS factor of the optimal substrates is approximately 5.57 × 103, and thein situdetection limit is 4.8 ppm. The 3D Raman spectra, relative standard deviation values for major peaks, and changes in signal intensity with time show the good reproducibility and stability of the substrates.


1995 ◽  
Vol 49 (12) ◽  
pp. 1793-1795 ◽  
Author(s):  
Valentin R. Zhelyaskov ◽  
Elizabeth T. Milne ◽  
Jamille F. Hetke ◽  
Michael D. Morris

Electrode sites of a photolithographically fabricated microelectrode array have been demonstrated to function as surface-enhanced Raman Spectroscopy (SERS) microelectrodes. The 5 × 15 μm iridium electrodes on the substrate are electroplated with silver and activated by standard procedures. Working and counter-electrode functions are integrated onto the same assembly. The electrode is shown to yield adenosine and pyridine spectra at low concentrations and submilliwatt laser power.


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