Combing Of Solid Phase Microextraction And Surface Enhanced Raman Spectroscopy For In-situ Detection Of Environmental Organic Pollutants

Surface enhanced Raman spectroscopy (SERS), a kind of molecular vibration spectrum, can provide the molecule structure characteristics. It can amplify the Raman signal of the measured molecular, even the detailed vibration modes of molecules adsorbed on noble metal surface can be offered. Surface enhanced Raman spectroscopy, a simple and fast analysis method, has a high sensitivity, and has been widely used in environmental monitoring, food analysis, material science, biomedical inspection and combined detection techniques, etc.The principle of solid phase microextraction (SPME) is based on the like-dissolves-like rule, which makes the analytes transfer from sample matrix to the coating of the solid phase microextraction and reaches equilibrium between the two phases. Solid phase microextraction has been widely used in environmental analysis, food analysis, biological analysis and drug analysis. In addition, the combined methods that solid phase microextraction coupled with various modern analytical instruments have been developed, which broadened the application of solid phase microextraction.In this dissertation, we developed a method that combing SPME with SERS, SERS-active fibers were fabricated for the rapid in-situ detection of organic pollutants.1. The SERS-active SPME fiber was prepared by coating silver nanoparticles on Ag-Cu fiber. The SERS-active SPME fiber not only has high stability and uniformity, but also has good SERS effect, hence, the fibers could meet the requirements for routine analysis. The SERS-active SPME fiber was immersed into water directly to extract polycyclic aromatic hydrocarbons (PAHs) and then detected by a portable Raman spectrometer. The ananlytes on the fiber could also be further confirmed by GC-MS. The SERS-active SPME fibers combining of the advantages of both SPME and SERS may be extended to more widespread fields including on-site and nondestructive analysis.2. We developed a new solid phase microextraction coating for organic sulfide preconcentration by depositing gold nanoparticles on rough silver fiber. Due to noble metals (Au, Ag) and sulfur elements can form the covalent bond (Au-S bond, Ag-S bond), the AuNPs/Ag fiber can preconcentrate organic sulfideand produce Raman signal. The porous silver fiber was performed by electrochemical corrosion and deposited gold nanopartilces by chemical reduction. We also evaluated the SERS enhancement with different reaction time. The gold nanoparticles modified porous silver fiber has good stability, uniformity and reproducibility. Gold nanoparticles coating for solid-phase microextraction has good extraction effect on the detection of organic sulphur. The method is simple and fast, especially suitable for in situ analysis of the wild field.