State Key Laboratory of Marine Environmental Science, Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Center for Marine Environmental Chemistry & Toxicology, College of the Environment and Ecology, Xiamen University, Xiamen 361102, China.
The Institute of Forensic Science, Xiamen Public Security Bureau, Xiamen 361000, China.
Anal Chem. 2024 Apr 16;96(15):5968-5975. doi: 10.1021/acs.analchem.4c00229. Epub 2024 Apr 5.
Surface-enhanced Raman spectroscopy (SERS) is a powerful tool for highly sensitive qualitative and quantitative analyses of trace targets. However, sensitive SERS detection can only be facilitated with a suitable sample pretreatment in fields related to trace amounts for food safety and clinical diagnosis. Currently, the sample pretreatment for SERS detection is normally borrowed and improved from the ones in the lab, which yields a high recovery but is tedious and time-consuming. Rapid detection of trace targets in a complex environment is still a considerable issue for SERS detection. Herein, we proposed a liquid-liquid extraction method coupled with a back-extraction method for sample pretreatment based on the pH-sensitive reversible phase transition of the weak organic acids and bases, where the lowest detectable concentrations were identical before and after the pretreatment process. The sensitive (μg L level) and rapid (within 5 min) SERS detection of either koumine, a weak base, or celastrol, a weak acid, was demonstrated in different drinking water samples and beverages. Furthermore, target generality was demonstrated for a variety of weak acids and bases (2 < p < 12), and the hydrophilicity/hydrophobicity of the target determines the pretreatment efficiency. Therefore, the LLE-BE coupled SERS was developed as an easy, rapid, and low-cost tool for the trace detection of the two types of targets in simple matrices, which paved the way toward trace targets in complex matrices.
表面增强拉曼光谱（SERS）是一种用于痕量目标进行高灵敏度定性和定量分析的强大工具。然而，只有在与食品安全和临床诊断相关的痕量领域进行适当的样品预处理，才能实现灵敏的 SERS 检测。目前，SERS 检测的样品预处理通常是从实验室中借用和改进的，虽然回收率高，但繁琐且耗时。在复杂环境中快速检测痕量目标仍然是 SERS 检测的一个重要问题。在此，我们提出了一种基于弱酸碱相敏可逆相转变的液-液萃取（LLE）-反萃取（BE）样品预处理方法，其中预处理前后的最低检测浓度相同。在不同的饮用水样品和饮料中，均实现了弱碱库米宁和弱酸雷公藤红素的灵敏（μg L 级）和快速（5 分钟内）SERS 检测。此外，该方法还展示了对多种弱酸和弱碱（2 < p < 12）的通用性，并且目标的亲水性/疏水性决定了预处理效率。因此，LLE-BE 耦合 SERS 已成为一种简单、快速且低成本的工具，可用于简单基质中这两种类型目标的痕量检测，为复杂基质中的痕量目标检测铺平了道路。
