背景:表面增强拉曼光谱(SERS)由于其无标签的优点而被广泛用于生物医学和食品安全检测,原位和指纹图谱。然而,开发具有所有这三个特性(包括灵敏度)的优秀SERS基底是具有挑战性的。重复性和稳定性。
结果:在这项工作中,开发了特定的海藻酸钠水凝胶柔性SERS基底包封的金-银核-壳纳米颗粒(Au@AgNPs)来解决上述问题。具有SERS“热点”结构的Au@AgNPs均匀分散在水凝胶中,实现了对复杂样品基质中农药残留的直接、高效检测。以锡兰为目标,该SERS基板具有高灵敏度(检测极限约为1×10-10mol/L),良好的稳定性(7周后保持SERS活性的78.35%以上)和出色的重复性(在一个底物中的RSD低至3.56%)。此外,柔性水凝胶SERS基底可用于分析真实样品中的各种小分子(果汁,蔬菜和水果),无需费力的预处理过程。
结论:鉴于上述益处,功能性柔性水凝胶SERS基底为来自复杂样品的化学污染物的准确和现场测量提供了可靠的平台。
BACKGROUND: Surface-enhanced Raman spectroscopy (SERS) has been extensively used in biomedical and food safety detection due to its advantages of label-free, in situ and fingerprint spectrum. However, it is challenging to develop an excellent SERS substrate that possesses all three of these characteristics including sensitivity, repeatability and stability.
RESULTS: In this work, a specific sodium alginate hydrogel flexible SERS substrate encapsulated gold-silver core-shell nanoparticles (Au@Ag NPs) was developed to address the aforementioned issue. The Au@Ag NPs with SERS \"hot spot\" structure were evenly dispersed in the hydrogel, which achieved the direct and high efficiency detection of the pesticide residues from complex sample matrix. Taking thiram as objective, this SERS substrates exhibit high sensitivity (detection limit of approximately 1 × 10-10 mol/L), excellent stability (maintain above 78.35 % of SERS activity after 7 weeks) and outstanding repeatability (RSD in one substrate as low as 3.56 %). Furthermore, the flexible hydrogel SERS substrates can be used to analyze a variety of small molecules in real samples (juices, vegetables and fruits), without the need for a laborious pretreatment process.
CONCLUSIONS: In light of the aforementioned benefits, the functional flexible hydrogel SERS substrates present a reliable platform for the accurate and on-site measurement of chemical contaminants from complex samples.