磁性SERS基底的制备及在食品快检领域的应用

发布时间：2018-02-04 13:01

本文关键词： 表面增强拉曼散射样品前处理食品快检农残地沟油　出处：《吉林大学》2017年博士论文　论文类型：学位论文

【摘要】：传统实验室分析技术,如色谱、质谱技术可针对复杂体系进行多组分定性、定量分析,但分析周期较长、分析结果滞后,不能及时有效监控食品和环境的安全现状。所以,快速、高效、准确的食品分析技术是现阶段食品快速检测领域面临的十分棘手的问题。表面增强拉曼散射(SERS)是一种基于散射原理的指纹图谱技术,与其他测试技术相比,具有样品用量少、测试速度快、分辨率高、灵敏度高等特点,可用于溶剂体系下痕量物质的超灵敏检测,尤其在现场定性检测方面越来越受到人们的关注,发展一种简单有效的前处理方法与SERS检测技术结合是食品快检领域的当务之急。本课题基于表面增强拉曼散射技术,利用磁性材料发展高选择性、环境友好的样品前处理方法与小型化拉曼光谱仪有效结合,为发展快速有效的食品检测与监测提供新的技术手段,进而为食品安全保驾护航。研究内容主要包括以下三个方面:1、采用层层组装的方法制备了一种多功能磁性石墨烯基SERS基底:Fe_3O_4@GO@Ag。该基底同时具有固相萃取和SERS检测的功能,利用该基底发展了一种新型的预处理、检测方法称为:表面磁膜固相萃取-表面增强拉曼散射技术(Surface Magnetic Solid Phase Extraction-SERS:SMSPE-SERS),SMSPE-SERS技术集目标分子的表面萃取、分离与检测于一体。利用该基底对果皮、蔬菜表面农药残留的萃取、分离到检测整个过程仅需15 min,对福美双和噻菌灵两种农残的最低检出限分别达到:0.48 ng/cm2和4 ng/cm2。2、Fe_3O_4@GO@Ag三元复合材料可集萃取、分离、检测于一体,但是分步法制备该三元SERS基底,制备工艺复杂,制备时间较长,重复制备对工艺参数要求较高,不适合工艺放大,因此我们尝试使用一锅法的工艺制备三元SERS基底。以乙酰丙酮铁作为铁源,乙二醇为溶剂,NaAc为还原剂,聚乙烯亚胺为静电组装剂。分别探讨了NaAc和AgNO_3用量对Fe_3O_4和AgNPs在石墨烯表面的负载量,按照优化的实验配比进行了工艺放大研究。对一锅法制备的三元SERS基底进行了SERS活性研究,结果显示,一锅法制备的三元基底与多步自组装法具有同样的SERS活性。3、地沟油的甄别是分析化学和食品安全领域的重要难题,辣椒碱是目前鉴定地沟油的重要外源性标记物,辣椒碱的检测技术目前主要由HPLC-MS实现,本论文基于表面增强共振拉曼散射(SERRS)技术,利用分子的衍生化,建立了地沟油中的外源性标记物:辣椒碱的超灵敏检测方法。通过使用特殊的衍生化试剂,从SERRS机理出发,使目标分子的最大吸收波长与激发光波长最大程度重叠,再利用具有磁聚集功能的磁性纳米粒子作为SERS基底,可实现辣椒碱的超灵敏检测,检测限可达到1.0×10-9 M,该方法为地沟油的鉴定提供了一种简单、快速、超灵敏的分析方法。
[Abstract]:Traditional laboratory analysis techniques, such as chromatography and mass spectrometry, can be used for qualitative and quantitative analysis of complex systems, but the analysis period is longer and the analysis results lag behind. Not timely and effective monitoring of food and environmental safety status. So, fast, efficient. Accurate food analysis technology is a very difficult problem in the field of rapid food detection. Surface enhanced Raman scattering (SERS) is a fingerprint technology based on scattering principle. Compared with other testing techniques, it has the advantages of less sample consumption, faster testing speed, higher resolution and higher sensitivity. It can be used for the hypersensitive detection of trace substances in solvent system. Especially in the field of qualitative testing, people pay more and more attention to it. It is an urgent task to develop a simple and effective pre-processing method combined with SERS detection technology. Based on surface-enhanced Raman scattering technology, magnetic materials are used to develop high selectivity. The combination of environmentally friendly sample pretreatment method and miniaturized Raman spectrometer provides a new technique for the development of rapid and effective food detection and monitoring. And then for food safety escort. The research mainly includes the following three aspects: 1. A kind of multifunctional magnetic graphene base SERS substrate: Fe3O\ +\\%\%\\%\\\. A new kind of pretreatment was developed by using the substrate. The detection method is called surface magnetic film solid phase extraction-surface enhanced Raman scattering (. Surface Magnetic Solid Phase Extraction-SERS: SMSPE-SERS. The SMSPE-SERS technique integrates the surface extraction, separation and detection of the target molecules. The substrate is used to extract pesticide residues on the pericarp and vegetable surfaces. The detection time was only 15 minutes, and the minimum detection limits for Fumex and thiabendazole were 0. 48 ng/cm2 and 4 ng/cm2.2, respectively. Fe_3O_4@GO@Ag ternary composites can be extracted, separated and detected in one body, but the preparation process of the ternary SERS substrate is complicated and the preparation time is longer. The repeated preparation requires higher technological parameters and is not suitable for the process amplification. Therefore we try to prepare ternary SERS substrate by one-pot process with iron acetylacetone as Tie Yuan and ethylene glycol as solvent. NaAc was used as reducing agent and polyethylene imine as electrostatic assembler. The loading amount of NaAc and AgNO_3 on the surface of graphene was studied respectively. The SERS activity of ternary SERS substrate prepared by one-pot method was studied according to the optimized experimental ratio. The ternary substrate prepared by one-pot method has the same SERS activity as multi-step self-assembly method. The screening of gutter oil is an important problem in the field of analytical chemistry and food safety. Capsaicin is an important external marker for the identification of gutter oil. The detection technology of capsaicin is mainly realized by HPLC-MS at present. In this paper, surface enhanced resonance Raman scattering (SERRS) technique is used to detect capsaicin. A new method for the detection of capsaicin in gutter oil was established by molecular derivation. By using special derivatization reagent, the mechanism of SERRS was studied. The maximum absorption wavelength of the target molecule overlaps with the excitation wavelength to the greatest extent, and then the magnetic nanoparticles with magnetic aggregation function are used as the SERS substrate to realize the hypersensitive detection of capsaicin. The detection limit can reach 1.0 脳 10 ~ (-9) M. this method provides a simple, rapid and hypersensitive method for the identification of gutter oil.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TS207.3;O657.37

【相似文献】