Liquid Surface-Enhanced Raman Spectroscopy (SERS) Sensor-Based Au-Ag Colloidal Nanoparticles for Easy and Rapid Detection of Deltamethrin Pesticide in Brewed Tea

Abstract

Deltamethrin pesticides can cause inflammation, nephrotoxicity and hepatotoxicity as well as affect the activity of antioxidant enzymes in tissues. As a result of this concern, there is a rising focus on the development of fast and reliable pesticide residue testing to minimise potential risks to humans. The goal of this study is to use Au-Ag colloid nanoparticles as liquid surface-enhanced Raman spectroscopy (SERS) to improve the Raman signal in the detection of deltamethrin pesticide in a brewed tea. The liquid SERS system is fascinating to study due to its ease of use and its unlikeliness to cause several phenomena, such as photo-bleaching, combustion, sublimation and even photo-catalysis, which can interfere with the Raman signal, as shown in the SERS substrate. Our liquid SERS system is simpler than previous liquid SERS systems that have been reported. We performed the detection of pesticide analyte directly on brewed tea, without diluting it with ethanol or centrifuging it. Femtosecond laser-induced photo-reduction was employed to synthesise the liquid SERS of Au, Au-Ag, and Ag colloidal nanoparticles. The SERS was utilised to detect deltamethrin pesticide in brewed tea. The result showed that liquid SERS-based Ag NPs significantly enhance the Raman signal of pesticides compared with liquid SERS-based Au NPs and Au-Ag Nanoalloys. The maximum residue limits (MRLs) in tea in Indonesia are set at 10 ppm. Therefore, this method was also utilised to detect and improve, to 0.01 ppm, the deltamethrin pesticide Limit of Detection (LOD).

Comparison of Surface-Enhanced Raman Scattering in Colloidal Silver Nanostar ‎and Colloidal Silver Nanocubes

“…The SERS effect has two mechanisms: an electromagnetic (EM) and a chemical (CM) that work together to simultaneously boost the Raman signal. The localized surface plasmon resonances (LSPR) induced local rise in an electric field close to the nanoparticles has an impact on electromagnetic enhancement 17 . The CM results from charge-transfer interactions between the surface of the nanoparticles and the electronic states of the molecules, which will also result in an increase in Raman signals.…”

Novel Microneedle Patch-Based Surface-Enhanced Raman Spectroscopy Sensor for the Detection of Pesticide Residues

“…Conventional approaches, such as gas chromatography 4 and high-performance liquid chromatography, 5 frequently necessitate time-consuming sample processing and can hardly detect pesticide residues in situ. 6 In light of the aforementioned issues, a variety of detection approaches have been reported, including electrochemical methods, 7 surface-enhanced Raman spectroscopy (SERS), 8 and colorimetry. 9 SERS is a promising approach for pesticide residue detection 10 because of its benefits, including simple pretreatment, high sensitivity, rapid response, and great specificity.…”

“…In light of the aforementioned issues, a variety of detection approaches have been reported, including electrochemical methods, surface-enhanced Raman spectroscopy (SERS), and colorimetry . SERS is a promising approach for pesticide residue detection because of its benefits, including simple pretreatment, high sensitivity, rapid response, and great specificity .…”

A label-free and selective SERS-based sensor for determination of ampicillin contamination in water using a fabric gold–silver alloy substrate with a handheld Raman spectrometer

“…This is because Au and Ag provide strong electromagnetic field enhancement. 16 Moreover, a solid film platform results in higher sensitivity than that with a colloidal based platform because nanoparticles on a solid support can locate in close proximity compared to those in a colloidal system. Recently, flexible SERS substrates have been widely developed as promising SERS substrates instead of the conventional rigid ones because of their advantages including flexibility, foldability, large scale production, and low cost.…”