In this paper, we report a green, ultrafast and facile aqueous preparation of highly luminescent core–shell CdTe/CdS with significant stability under atmospheric pressure. The surface topography, size, physical shape as well as crystalline structures were studied fully and in depth by adopting a variety of analytical methods such as transmission electron microscopy (TEM) and X-ray diffraction (XRD). The possible mechanism involved in the core growth was proposed and the relevant processes were conjectured too. In this study, we presented a convenient label-free fluorescence nanosensor for the rapid determination of trace mercury, which exhibited many advantages, such as a high sensitivity, excellent selectivity, a rapid response time, a wide linear range and a low limit of detection (LOD). The LOD is down to 1.7 × 10−9 mol L−1, which is lower than that of most other detection methods for mercury.
Xinyi Wang,Liubing Kong,Ying Gan,Tao Liang,Shuqi Zhou,Jiadi Sun,Hao Wan,Ping Wang
Cadmium ions (Cd 2+ ) greatly threat human health and the environment due to its extremely severe toxicity. Therefore, it is of paramount importance to establish a sensitive and portable platform for monitoring Cd 2+ on site. In this work, a novel microfluidic-based fluorescent electronic eye (E-eye) combined with tetrasodium iminodisuccinate (IDS)-etched CdTe/CdS quantum dots (QDs) was developed for portable and sensitive detection of trace Cd 2+ in water environment. The fluorescent E-eye consists of a microfluidic chip for miniaturized flow analysis, an ultraviolet light excitation module for fluorescent excitation, an optical lens for device miniaturization and a smartphone for portable photographing and analysis. The IDS was added in the CdTe/CdS QDs to cause fluorescence quenching due to the chemical etching. Subsequently added Cd 2+ will be recognized by etched QDs, thus inducing the fluorescence changes that can be directly captured by the E-eye for quantitative detection of Cd 2+ . With the optimization of all parameters including pH, reaction time and the concentration of IDS, the proposed platform could detect Cd 2+ with a low detection limit of 0.26 μg/L in the range of 1–250 μg/L. It is worth noting that the performance of the developed fluorescent E-eye is quite comparable to a commercial microplate reader with a detailed comparison in linearity, sensitivity and detection limit. In summary, the proposed microfluidic-based fluorescent E-eye provides a promising platform for portable and high sensitive detection of trace cadmium in water environment.
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