Detection of mercury ion based on quantum dots using miniaturised optical fibre sensor

Mercury ion (Hg2+) is one of the common pollutants which exists in the natural environment far and wide. The detection of Hg2+ usually requires large laboratory equipment, which limits their field applications. Here, a miniaturised optical fibre sensor based on quantum dots (QDs) for detection of Hg2+ is developed. The sensor is based on the principle of fluorescence quenching caused by Hg2+ and evanescent wave sensing. It is an all-fibre sensor which composed of an optical fibre probe module, an optical module and a signal acquisition module. Through miniaturisation design of optical system and the structure of the sensor, the sensor is reduced to the volume of 120x120x100mm. The experimental results show that in the miniaturised sensor both has high sensitivity and fast response speed. Meanwhile, the ion anti-interference experiment shows that the sensor has good selectivity for Hg2+ detection. In general, the proposed sensor has significant potential in the field of biochemistry, environmental monitoring, and food safety.