多氯联苯是一种持久性有机污染物,它在环境中极难分解,并通过食物链可在生物体内富集,从而对生态系统和人类健康造成严重危害。目前,多氯联苯在土壤、垃圾处理厂、天然水域及水生生物体内仍广泛存在,所以,亟需建立一种快速、灵敏、抗干扰的痕量检测方法。本项工作以金包裹二氧化硅的球形纳米颗粒(SiO2@Au)为探针,采用表面增强拉曼光谱(Surface-Enhanced Raman Spectroscopy,SERS)技术对多氯联苯进行痕量检测。研究中,我们制备了不同大小、形状均一的金包裹二氧化硅球形纳米粒子(SiO2@Au)(粒径范围为200~310 nm),并将制备好的纳米粒子用于溶液中PCB-77的检测。结果发现,在红外激光激发下,所制备的SiO2@Au纳米粒子对PCB-77分子都显示了较好的SERS检测效果,而用200 nm 的SiO2@Au纳米颗粒检测PCB-77,其检测低限可达10-7 M。这项工作为环境中的有机污染物痕量检测提供了一种有效可行的方法。

Polychlorinated biphenyls(PCBs) is a kind of persistent organic pollutants which is difficult to degrade in the environment while easy to accumulate in organisms through the food chains,thus resulting in serious damage to ecosystems and humans.Presently,PCBs can be found in soil,waste treatment plants,natural water and aquatic organisms.So it is imminent to develop rapid,sensitive and anti-interference trace detection methods.In this work,spherical silica nanoparticles(SiO2@Au) coated with gold was used as a probe,and surface-enhanced Raman spectroscopy(SERS) was used to detect trace amount of PCBs.In the experiment,we fabricated gold-coated silica spherical nanoparticles(SiO2@Au) with well-controlled different sizes (with particle diameter in the range of 200-310 nm),and applied the as-fabricated well-dispersed nanoparticles for the measurement of PCB-77 in solutions with different concentrations.As a result,we demonstrated that the SiO2@Au nanoparticles exhibited considerable SERS detection ability on PCB-77 molecules under the excitation of infrared laser and the detection limit was as low as 10-7 M using 200 nm SiO2@Au nanoparticles.This work may provide an effective and feasible method for the trace detection of environmental organic pollutants in general.