| With the accelerating of the urbanization process, the environment problems have been along with the rapid development of industry. The environmental pollution did great harm to public health, natural environment and social development. It is necessary for us to on-site detect environmental pollutants in varieties of sample matrix. Sample pretreatment technology was needed for preconcentration of target pollutant. Solid phase microextraction (SPME), is a kind of sample pretreatment technique. It is easy to operate and has been widely used in the environmental sample preparation technique. The stationary phase on the SPME fiber has larger affinity with the analyte than the sample matrix, which could separate the analyte and the other interferent. SPME is usually applied to field sampling, which could be used in air, water or solid matrix. According to the ’similarity-intermiscibility’ theory, polar molecule was adsorbed by polar stationary phase while nonpolar molecule was adsorbed by nonpolar stationary phase. But it is little studied to extract ionic compounds which are sometimes extracted using electrochemically assisted SPME method.Surface Enhanced Raman Spectroscopy (SERS) could avoid the interference of fluorescent background and amplify the Raman signal. As research of SERS substrates continues, the enhancement factor of SERS could reach 1013-1014, which makes it possible for signal molecule detection. Due to its high sensitivity and weak interference, SERS has wide range of application in trace detection such as environmental monitoring, biomedical technology and catalytic monitoring. Various of SERS substrates have been fabricated to amplify the Raman intensity of molecules adsorbed on to them. However, it is different for them to enrich the analyte from a real sample matrix.This paper is involved in fabricating solid phase microextraction fiber to combine SPME and SERS, which could combine the advantage of SPME and SERS and realize the on-site detection in complex sample matrix. The main contents of this paper could be summarized as follows:(1) Diethyldithiocarbamate (DDTC) modified sliver nanoplates were fabricated on the copper wire to perform the on-site microextraction and detection of perchlorate. This fiber could be inserted into water or soil to extract perchlotare through electrostatic interaction and then detected by a portable Raman spectrometer owing to its surface enhanced Raman (SERS) activity. The DDTC modified Ag/Cu fiber showed high uniformity, good reusability and temporal stability under continuous laser radiation with the RSD lower than 10%. Qualitative and quantitative detection of perchlorate were also realized. A log-log plot of the normalized SERS intensity against perchlorate concentration showed a good linear relationship. The fiber could be also directly inserted into the perchlorate polluted soil and the perchlorate could be on-site detected. This hyphenated method of microextraction with direct SERS detection may find potential application for direct pollutants detection free from complex sample pretreatment.(2) Solid phase microextraction and surface enhanced Raman spectroscopy were combined to integrate the extraction and detection of pentachlorophenol. Cysteamine hydrochloride (Cys) was modified on the surface of electrochemically roughened silver fiber, pentachlorophenol was extracted onto the fiber through electrostatic interaction. The log-log plot of normalized SERS intensity against concentration of pentachlorophenol showed a good linear relationship. This SPME fiber could be detected by both portable Raman spectroscopy and HPLC. The solid phase microextraction fiber have potential application in on-site detection of ionic environmental pollutant. |
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