基于电化学表面增强拉曼光谱技术的近海海洋环境中痕量抗生素的快速检测方法研究

The qualitative and quantitative detection of emerging organic pollutants in coast seawater is typically carried out in lab using large-scale facilities, due to the extraordinary variety and the trace amount of these organic compounds and the interference from the complicated matrix in marine environment. However, the long-distance shipping and long-time storage could deteriorate or contaminate samples and give negative effect on the experimental results with the misleading information. Meanwhile, it is difficult for the long-term periodic monitoring and the analyzable data is restricted by the sampler frequency of the random sampling. Therefore, developing onsite detection technique is lacking and highly demanded and is the research tendency of marine environmental detection. Characterizing by the fingerprint resolution and high sensitivity, Electrochemical Surface-enhanced Raman Spectroscopy (EC-SERS) has the potential for the on-site, fast detection of trace emerging organic pollutants in marine environment, facilitated by the portable Raman spectrometer. Therefore, we planned to develop the EC-SERS based detection technique towards the trace emerging organic pollutants in coast region, with the trace antibiotics detection as an example. The following work would be carried out: 1) By integrating the handhold electrochemical workstation, the plug & play SERS active electrode, the electrochemical in-situ flow cell and the portable Raman spectrometer, the EC-SERS system would be formed. 2) Taking the negative quinolones and positive sulfonamides as the target molecules, the quick sample pretreatment process under the marine environment was developed. 3) considering the high salt concentration of the marine environment, the preparation of SERS active electrode with high sensitivity, selectivity, reproducibility and stability was optimized by surface ensemble and potential modulation. 4) Integration of internal SERS standard and the recognition algorithm of weak signal, the onsite EC-SERS system and related method could be realized towards the trace antibiotics in the marine environment.

近海海洋环境中有机污染物种类多、含量低且基质复杂，其定性定量分析需在实验室中进行，但长途输运过程伴随的污染或变质将影响结果的准确性且难应对应急监测。因此，发展现场检测技术是海洋环境监测研究的趋势。电化学表面增强拉曼光谱（EC-SERS）技术能提供分子指纹信息且具有极高检测灵敏度，结合便携式拉曼光谱仪，可实现近海海洋环境中痕量有机物的现场快速检测。本项目拟：1）设计研制掌上型电化学仪、即插即用型SERS基底和电化学流动池，与便携式拉曼光谱仪集成，研制一体化船载式EC-SERS检测系统；2）发展海洋环境中典型痕量抗生素（负电性喹诺酮类和正电性磺胺类）的快速样品前处理方案；3）针对海洋环境高盐特点，结合纳米材料表面组装和电化学电位调控技术，发展灵敏稳定的固态SERS基底；4）引入内标并结合弱信号识别算法，实现海洋环境中痕量抗生素的快速定性定量分析，从而建立船载式EC-SERS现场检测系统和方法。

近海海洋环境中有机污染物种类多、含量低且基质复杂，其定性定量分析需在实验室中进行，但长途输运过程伴随的污染或变质将影响结果的准确性且难应对应急监测。因此，发展现场检测技术是海洋环境监测研究的趋势。本项目拟建立船载式EC-SERS现场检测系统和方法。.经过四年研究，取得如下五项成果：.1）以三种磺胺类分子（SD、SMR、SMT）作为目标分子，系统研究了溶液pH值、分子结构和团聚剂种类对于溶胶型SERS增强基底的检测灵敏度的作用，提出了目标分子、团聚剂和SERS增强基底之间的竞争和共吸附行为的协同作用决定了目标分子能否被检出。.2）以分子主体结构一致的16种喹诺酮类抗生素作为目标分子，系统探究了SERS技术对精细结构差异的同系物分子的定性定量分析能力。1）SERS技术可有效定性鉴定单原子水平的结构差异。2）SERS检测灵敏度的变化主要来自于基团电负性和空间位阻等分子结构的差异。.3）结合磁性固相萃取（MSPE）样品前处理和SERS技术，构建了一种基质简单的饮用水水样中痕量QNs抗生素的快速、灵敏且高效的快速检测方法。相比于无富集的直接检测方法，其最低可检出浓度降低了2个数量级，有望在应急监测中发挥作用。.4）搭建了集成流动注射仪和便携式拉曼光谱仪的一体化和自动化的船载式多环芳烃快速检测仪（FIA-SERS）。对不同水域的海水进行加标测定，表明方法和仪器具有良好的稳定性和重复性较好。在厦门近海流域验证了此仪器用于现场检测的可行性。FIA-SERS检测仪具有操作简便、自动化程度高和耗时短（<30 min）的优点，未来也有望将此方法应用于其他环境污染物的检测分析工作。.5）利用数据增强技术、随机森林算法以及特征放大器实现了纯物质和混合物的SERS谱图快速精准识别。通过可视化模型确证了模型所捕获的目标物SERS特征峰的可靠性，证明了模型良好的泛用性和鲁棒性。将本方法应用于痕量物质检测中，可有效提升极低浓度目标物定性分析的可靠性。本工作为机器学习方法在光谱分析中的可视化提供了有价值的参考。