title: A Quantum Dot Fluorescence Sensor System Design for Hg²⁺ Trace Detection.
abstract: 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 x 10⁻⁹ to 1.8 x 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⁺.
authors.forename: Wei
authors.initials: W
authors.lastname: Luo
authors.forename: Xin-hua
authors.initials: XH
authors.lastname: Zeng
authors.forename: Miao
authors.initials: M
authors.lastname: Li
authors.forename: Shou-guo
authors.initials: SG
authors.lastname: Zheng
authors.forename: Hua-long
authors.initials: HL
authors.lastname: Li
authors.forename: Shi-zhuang
authors.initials: SZ
authors.lastname: Weng
authors.forename: Shao-qi
authors.initials: SQ
authors.lastname: Wang