Abstract

Surface-enhanced Raman scattering (SERS) is a promising technique for rapid detection of pesticide residues. However, conventional SERS substrates require extraction processes which are time consuming and they also lack selectivity, stability and reproducibility. Herein, we present a multifunctional stable zero-valent iron based core-shell substrate. It combines magnetic separation, selective adsorption by molecular imprinting technique and sensitive detection of carbaryl by SERS. The core-shell substrate was successfully prepared by immobilizing silver on the surface of zero-valent iron microspheres. Subsequent molecular imprinting on the bimetallic magnetic silver microspheres ensured selective removal and detection. The substrate exhibited magnetization saturation of 8.89 emu/g providing efficient analyte separation. It showed high sensitivity and selectivity toward carbaryl detection to nanomolar concentration level. Linear regression models for peaks at Raman shift 1599 cm⁻¹ and 2233 cm⁻¹ demonstrated a good linear fit with R²=0.9738 and R²=0.8952 respectively. The composite was successfully applied on spiked water samples resulting in average recovery rate of 89%. The findings of this study demonstrate great substrate potential for application in separation and detection of trace quantities of chemical contaminants for environment safety and protection.

摘要

表面增强拉曼散射（SERS）是一种用于快速检测农药残留的有前途的技术。然而，常规的SERS底物需要费时的提取过程，并且它们还缺乏选择性，稳定性和可再现性。在这里，我们提出了一种多功能的稳定的零价铁基核壳基体。它结合了磁分离，通过分子印迹技术的选择性吸附和通过SERS灵敏检测西维因的方法。通过将银固定在零价铁微球的表面上，成功制备了核-壳基质。随后在双金属磁性银微球上的分子印迹确保了选择性去除和检测。底物的磁化饱和度为8.89 emu / g，可实现有效的分析物分离。它对纳摩尔浓度水平的西维因检测具有很高的灵敏度和选择性。拉曼位移1599 cm处峰的线性回归模型^-1和2233 cm ^-1表现出良好的线性拟合，分别为R ² = 0.9738和R ² = 0.8952。该复合材料已成功应用于加标水样，平均回收率为89％。这项研究的结果表明，在分离和检测痕量化学污染物以保护环境安全和保护方面，有很大的应用潜力。