针对当前痕量Hg2+检测大多是借助于大型化学分析仪器在实验室条件下完成而无法满足现场检测需求的现状, 基于量子点荧光淬灭原理设计了一种反射式痕量Hg2+检测传感器, 主要包括荧光感知和电信号处理两个模块。 荧光感知模块主要由激光光源、 光路准直及光电探测器构成, 实现了荧光信号的激发和感知。 电信号处理模块完成了对感知信号放大滤波等处理, 最终在linux系统的QT界面中显示Hg2+浓度。 该传感器系统实现了仪器的小型化与低成本。 试验表明Hg2+浓度在15.0×10-9～1.8×10-6 mol·L-1范围内, 传感器检测结果具有很好的线性关系, 回归拟合方程为V0/V=1.309 13+3.37ｃ, 其中ｃ为Hg2+浓度, 单位为μmol·L-1; V0为空白检测值, 单位为mV）, 线性度为0.989 26。 离子抗干扰实验中, Ca2+, Mn2+, Pb2+对Hg2+检测结果有微弱影响(4％～7％), 其他常见离子的影响(＜3％)可以忽略, 表明传感器具有优越的选择性。 传感器响应时间为35 s, 并具有良好的重复性和选择性, 实现了痕量Hg2+的现场快速有效检测。

The detection of Hg2+ ions usually requires large laboratory equipment, which encounters difficulties for rapid field test in most applications. In this paper, we design a reflective sensor for trace Hg2+ analysis based on the fluorescent quenching of Quantum dots, which contains two major modules, i.e. the fluorescent sensing module and the signal processing module. The fluorescence sensing module is composed of a laser source, a light collimated system and a photo-detector, which enables the realization of the fluorescence excitation as well as its detection. The signal processing module realized the further amplification of the detected signal and hereafter the filtering of noises. Furthermore, the Hg2+ concentration will displayed on the QT interface using a Linux embedded system. The sensor system is low cost and small, which makes it available for rapid field test or portable applications. Experimental results show that the sensor has a good linear relationship for the Hg2+ concentration range from 15.0×10-9 to 1.8×10-6 mol·L-1. The regression equation is V0/V=1.309 13+3.37ｃ, where c is Hg2+ concentration, and V0 is the voltage value for the blank case. In our work, the linearity is determined as 0.989 26. The experiments exhibit that Ca2+, Mn2+ and Pb2+ ions have small influence on the Hg2+ detection, and the interfere of other common ions can be neglected, which indicates a good selectivity of the sensor. Finally, it shows that our sensor has a rapid response time of 35 s and a good repeatability, thus it is potential for field test of trace Hg2+.