为了满足对环境中重金属污染物汞离子的快速、现场及高灵敏度检测需求,利用汞离子对量子点产生荧光猝灭效应,结合光纤倏逝波传感原理,自主研发了一套可用于汞离子检测的全光纤传感器。其主要由光纤探针、光学系统和信号处理系统构成,实现了荧光信号的激发、探测以及光电信息的处理和获取。实验表明该传感器对汞离子的检出限可达到1 nmol/L,且在1 nmol/L至500 nmol/L的浓度范围内,量子点的荧光猝灭率随汞离子的浓度对数呈线性变化规律,线性相关度为0.9867。同时,离子抗干扰实验证实了该传感器对汞离子具有良好的选择性识别检测能力,将其应用于实际水样检测的加标回收率为90.1%~97.3%。该传感系统灵敏度高、响应速度快,可以实现远程探测和实时监测,且有利于仪器的集成和小型化,在重金属离子污染检测等领域具有广阔的应用前景。

To meet the requirements for the rapid, on-site and high-sensitivity detection of mercury ions (Hg 2+) existing as the environmental heavy metal pollutant, we have independently developed an all-fiber sensor for Hg 2+ detection based on the fluorescent quenching of quantum dots and optical fiber evanescent wave sensing. It is mainly composed of an optical fiber probe module, an optical module and a signal processing module, which realizes the excitation and collection of fluorescent signal and the processing and acquisition of photoelectric signal. The experimental results show that the detection limit of the sensor for Hg 2+ reaches 1 nmol/L. Moreover, the fluorescent quenching rate of quantum dots varies linearly with the logarithm of the Hg 2+ concentration in the range of 1 nmol/L to 500 nmol/L, and the linear correlation coefficient is 0.9867. Meanwhile, the ion anti-interference experiment confirms that the sensor has good selective recognition for Hg 2+ detection. The sensor is also applied to the environmental water sample detection with the recovery of 90.1%-97.3%. The sensor system not only has high sensitivity and fast response speed, but also can realize remote detection and real-time monitoring. It is also conducive to the integration and miniaturization of the instrument. Therefore, it has a broad application prospect in the detection of heavy metal ion pollution.