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- 摘要
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- 实验方案
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Xenobiotic Contamination of Water by Plastics and Pesticides Revealed Through Real-time, Ultrasensitive and Reliable Surface Enhanced Raman Scattering
摘要： Uncontrolled utilization and consequent ubiquitous percolation of carcinogenic and xenobiotic contaminants, such as plasticizers and pesticides, into ecosystem has created an immediate demand for robust analytical detection techniques to identify their presence in water. Addressing this demand, we uncover the presence of xenobiotic contaminants such as Bisphenol A (BPA), Triclosan (TC), and Dimethoate (DM) through a robust, ultrasensitive and reliable Surface Enhanced Raman Scattering (SERS) platform. Thereby, conclusive real-time evidence of degradation of polyethylene terephthalate (PET) leading to release of BPA in water is presented. Worryingly, the release of BPA occurs at ambient temperature (40 0C) and within realistic timescales (12 hours) that are regularly encountered during the handling, transport and storage of PET-based water containers. Complementary mass-spectrometric, surface-specific atomic force microscopy and surface selective X-ray Photoelectron spectroscopy confirms the nanoscale surface degradation of PET through loss of C=O and C-O surface functionalities. Such ultra-sensitive (ppm-level), spectroscopic detection is enabled by the bottom-up assemblies of metal nanoparticles (Soret Colloids, SCs) acting as SERS platform to provide high analytical enhancement factor (108) with high reliability (relative standard deviation, RSD <5%). Effective and rapid detection (30 s) of several other potential xenobiotic contaminants such as Triclosan (TC) and Dimethoate (DM) over a wide range of concentrations (10-5 to 10-1 M) has also been demonstrated. Finally, non-destructive real-time spectroscopic “sniffing” of organophosphorous pesticides from the surface of fruits is achieved, illustrating the multi-phasic versatility of this label-free, non-lithography-based SERS platform.
关键词： plastic degradation,Soret colloids,water and food contamination,real-time detection,nanoparticle assembly,surface enhanced Raman scattering,Xenobiotics
更新于2025-09-23 15:21:01
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Silver Soret Nanoparticles for Femtomolar Sensing of Glutathione in a Surface Plasmon-Coupled Emission Platform
摘要： Surface plasmon-coupled emission (SPCE) has emerged as an interdisciplinary, versatile sensing platform due to its highly directional, solid-state and polarized emission. Here, we report the distinct properties rendered by Ag-Soret Colloids (Ag-SCs) such as nanovoids and nanocavities to observe 104-fold enhancement in emission intensity of omnidirectionally radiating emitter dipoles. Unlike earlier reports utilizing templated Ag-nanoparticles in spacer or cavity architectures, here we employ template-free, linker-less Ag-SCs. Purcell factor (PF - maximum of 120.6) obtained using the finite-difference time-domain (FDTD) simulations for soret nanocavities are in excellent agreement with the trend in emission enhancements obtained experimentally. Thermal gradient created by adiabatic cooling of Ag nanoparticles (AgNPs) drives their thermo-diffusion resulting in monodisperse nanoparticle assemblies (Ag-SCs). In addition, we report an extended-cavity architecture with Ag-SCs, as a novel pseudo-metal-dielectric-metal (p-MDM) interface, for achieving 80-fold SPCE. This study also features the unique properties of Ag-SCs as interfacial nanomaterials in SPCE platform to achieve femtomolar detection of glutathione (GSH). The quenching of fluorescence from alizarin red S-boric acid (ARS-BA) complex upon addition of Cu2+ ions and the dequenching upon GSH addition studied with Ag-SCs as spacer layer remarkably increased the sensitivity of the analyte. The uniform and intense electromagnetic field-confinement provided by these intricate architectures and hybrid interfaces, along with its ease of fabrication and versatility for variety of analytes, is critical to achieve augmented SPCE. This is accomplished without compromising on the reliability of detection as demonstrated with the use of a cellphone camera, CIE color space and luminosity plots for the turn-on fluorescence. The emission images were acquired using an android phone camera by aligning it with its angular emission, making it amenable for point-of-care diagnostics.
关键词： Soret colloids,Surface plasmon-coupled emission,spacer engineering,smartphone-based detection,template-free approach,fluorescence enhancement,glutathione sensing
更新于2025-09-23 15:19:57