Zeng Jiaying, Zhang Ting, Liang Geyu, Mo Jingwen, Zhu Jianxiong, Qin Longhui, Liu Xiaojun, Ni Zhonghua
School of Public Health, Southeast University, Nanjing 210009, PR China.
Engineering Research Center of New Light Sources Technology & Equipment-Ministry of Education, Jiangsu Key Laboratory for Design & Manufacture of Micro/Nano Biomedical Instruments and School of Mechanical Engineering, Southeast University, Nanjing 210096, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2024 Apr 15;311:124002. doi: 10.1016/j.saa.2024.124002. Epub 2024 Feb 8.
Hexavalent chromium (Cr(Ⅵ)) is a significant environmental pollutant because of its toxic and carcinogenic properties and wide use in various industries. Hence, there is an urgent need to develop accurate and selective approaches to detect the concentration of Cr(Ⅵ) in agricultural and aquaculture products to help humans avoid potential hazards of indirectly taking in Cr(Ⅵ). In this work, we report a "turn off-on" fluorescent sensor based on citric acid coated, 808 nm-excited core-shell upconversion nanoparticles (CA-UCNPs) and self-assembled copper porphyrin nanoparticles (nano CuTPyP) for sensitive and specific detection of Cr(Ⅵ). Nano copper 5, 10, 15, 20-tetra(4-pyridyl)-21H-23H- porphine obtained by acid-base neutralization micelle-confined self-assembly method function as an effective quencher due to its excellent optical property and water solubility. Through electrostatic interactions, positively charged nano CuTPyP are attracted to the surface of negatively charged CA-UCNPs, which can almost completely quench the fluorescence emission. In the presence of Cr(Ⅵ), nano CuTPyP can discriminatively interact with Cr(Ⅵ) and form nano CuTPyP/Cr(Ⅵ) complex, which separates nano CuTPyP from CA-UCNPs and restores the fluorescence. The sensing system exhibits a good linear response to Cr(Ⅵ) concentration in the range from 0.5 to 400 µM with a detection limit of 0.36 µM. The sensing method also displays high selectivity against other common ions including trivalent chromium and is applied to the analysis of Cr(Ⅵ) in actual rice and fish samples with satisfactory results.
六价铬（Cr(Ⅵ)）因其毒性和致癌特性以及在各种行业中的广泛应用，是一种重要的环境污染物。因此，迫切需要开发准确且具有选择性的方法来检测农产品和水产品中Cr(Ⅵ)的浓度，以帮助人类避免间接摄入Cr(Ⅵ)带来的潜在危害。在这项工作中，我们报道了一种基于柠檬酸包覆、808 nm激发的核壳型上转换纳米颗粒（CA-UCNPs）和自组装铜卟啉纳米颗粒（纳米CuTPyP）的“关-开”荧光传感器，用于灵敏且特异性地检测Cr(Ⅵ)。通过酸碱中和胶束限域自组装法获得的纳米铜5, 10, 15, 20-四(4-吡啶基)-21H-23H-卟啉，由于其优异的光学性质和水溶性，可作为一种有效的猝灭剂。通过静电相互作用，带正电荷的纳米CuTPyP被吸引到带负电荷的CA-UCNPs表面，这几乎可以完全猝灭荧光发射。在Cr(Ⅵ)存在的情况下，纳米CuTPyP可以与Cr(Ⅵ)发生特异性相互作用并形成纳米CuTPyP/Cr(Ⅵ)络合物，该络合物将纳米CuTPyP与CA-UCNPs分离并恢复荧光。该传感系统对Cr(Ⅵ)浓度在0.5至400 μM范围内表现出良好的线性响应，检测限为0.36 μM。该传感方法对包括三价铬在内的其他常见离子也显示出高选择性，并应用于实际大米和鱼肉样品中Cr(Ⅵ)的分析，结果令人满意。
