以表面增強拉曼光譜進行十溴二苯醚之快速檢測

Abstract

多溴二苯醚（polybrominated diphenyl ethers, PBDEs） 是一系列含溴原子的聯苯醚化合物，共有209種同源物，工業上常做為阻燃劑。PBDEs進入環境後，由於脂溶性強，且不易分解，可干擾生物體甲狀腺內分泌，對人類的威脅日益升高。PBDEs中又以十溴二苯醚 （BDE-209） 用量最大且可能成為環境之PBDEs中最大宗污染物，也是其他PBDEs之主要源頭，佔總PBDEs之85%~95%；而目前檢測BDE-209處理程序，須經長時間萃取及繁複的淨化程序，耗費時間、成本與人力。本研究利用表面增強拉曼散射研發更快速且靈敏性高的偵測方法，可大幅改善目前之檢測方法。 拉曼散射光譜是用來研究分子振動模式的技術，但其強度非常微弱，無法應用於微量物質偵測。直到有學者將待測分子置於銀的表面，得到增強數個數量級的拉曼散射光譜訊號，成為表面增強拉曼散射 （Surface-enhanced Raman scattering, SERS） 用於化學檢測分析的濫觴。本研究探討以SERS技術快速偵測BDE-209之可行性，目前以微流體晶片方式實驗室配製之BDE-209樣品，其檢量線之R2大於0.98；以SERS檢測環境樣品萃取液中BDE-209（n=3）並以細針型SERS基材來增強訊號時，與各樣品之氣相層析儀測值進行相關性比較，發現當使用PMMA為材料時，其決定R2值可達0.8以上。分析大量之樣品，細針型SERS基材的製備時間加上進行拉曼訊號偵測的時間比傳統方法所需時間，可縮短90%以上的時間。此研究證實SERS可用於快速檢測底泥中多溴二苯醚之可能性，基於本研究成果，SERS應該可以應用於環境介質中微量疏水性污染物之快速檢測。

polybrominated diphenyl ethers（PBDE）sare diphenylethers with one to ten bromine atoms. With different numbers and positions of the bromine atoms on the benzene rings, they formed 209 different congeners. For industrial applications, they are usually physically added into products as flame retardants. After being released into the environment, they can easily enter human bodies through food chain and affect thyroid endocrine. PBDEs are not very soluble in water and are difficult to degrade, and, thus, pose serious threat to human health. Among them, decabrominated diphenyl ether（BDE-209）accounts for the largest share, about 85-95% of total PBDEs. Under anaerobic conditions, BDE-209 could be a source for other lower brominated diphenyl ethers through biodegradation. Currently, for the detection of BDE-209, one has to go through complicated extraction and cleanup procedures. Therefore, we propose to apply surface-enhanced Raman scattering（SERS）to facilitate rapid detection of BDE-209. Raman spectroscopy was used to study molecular vibration modes, but its intensity is too weak to be used in detecting trace chemicals. Later, some researchers deposit the sample on the surface of silver and Raman scattering signals were enhanced for several orders of magnitude. This is the beginning of SERS. In this research, we study the feasibility of application of SERS to the rapid detection of BDE-209. For SERS detection of pure BDE-209 in solvents using microfluidic chips, the coefficient of determination, R2, is as high as 0.9826. When comparing signal intensity and values obtained from SERS and gas chromatographic detection of the extracted BDE-209, respectively, the R2 could be higher than 0.800. SERS detection can save more than 90% of assay time. These results lend the support to the feasibility of application of SERS to rapid detection of PBDEs in sediments. Moreover, these results also suggest that SERS could be a good candidate for rapid detection of hydrophobic organic compounds in environmental matrices.