State Key Laboratory of Food Nutrition and Safety, Tianjin University of Science & Technology, Tianjin, 300457, China.
Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University, Tianjin, 300071, China.
Mikrochim Acta. 2021 Feb 16;188(3):89. doi: 10.1007/s00604-021-04747-8.
A simple dual-colour fluorescent nanoprobe has been designed composed of blue and yellow emission carbon quantum dots (CQDs). This system is inexpensive and easy to operate and was successfully employed for on-site measurements based on a smartphone app. The designed nanoprobe exhibited increased selectivity for Cr(VI), leading to a double stable response of the two CQDs. The dual-emission nanoprobe showed blue-violet fluorescence upon UV irradiation, and the fluorescent emission peaks were located at 418 nm and 552 nm. The blue light emission of CQDs was quenched with increasing Cr(VI) concentration due to the inner filter effect, whereas the yellow light emission was enhanced due to the aggregation-induced emission effect. The different responses of the dual emissions to Cr(VI) resulted in a fluorescent colour variation, thus enabling facile macroscopic visualization. With a smartphone, the change in the fluorescence colour could be observed more apparently than that of a single fluorescence nanoprobe, and the response increased linearly so that the nanoprobe could be applied to instantaneous measurements. Furthermore, the dual-emission nanoprobe was successfully employed for analysing food and water samples. Accurate concentrations were obtained by constructing a calibration plot using a fluorescence spectrometer and a smartphone app; the recoveries were 81.6% to 107.7%, and the relative standard deviation was below 3.6%. Therefore, this smartphone-integrated dual-emission detection system is promising as a new portable method for the on-site measurement of Cr(VI) ions. * Y-CQDs: yellow emission carbon quantum dots. B-CQDs: blue emission carbon quantum dots. B/Y-CQDs: a mixture of B-CQDs and Y-CQDs.
一种简单的双色荧光纳米探针由蓝、黄发射的碳量子点（CQDs）组成。该系统成本低廉，易于操作，并成功地基于智能手机应用程序进行了现场测量。所设计的纳米探针对 Cr(VI) 表现出增强的选择性，导致两种 CQDs 的双稳定响应。双发射纳米探针在紫外光照射下显示出蓝紫色荧光，荧光发射峰位于 418nm 和 552nm。随着 Cr(VI)浓度的增加，由于内滤效应，CQDs 的蓝光发射被猝灭，而由于聚集诱导发射效应，黄光发射增强。双发射对 Cr(VI)的不同响应导致荧光颜色变化，从而实现了简便的宏观可视化。使用智能手机，可以比单个荧光纳米探针更明显地观察到荧光颜色的变化，并且响应呈线性增加，从而可以应用于即时测量。此外，双发射纳米探针成功地用于分析食品和水样。通过使用荧光分光光度计和智能手机应用程序构建校准曲线，可以获得准确的浓度；回收率为 81.6%至 107.7%，相对标准偏差低于 3.6%。因此，这种集成智能手机的双发射检测系统有望成为现场测量 Cr(VI)离子的新型便携式方法。* Y-CQDs：黄色发射碳量子点。B-CQDs：蓝色发射碳量子点。B/Y-CQDs：B-CQDs 和 Y-CQDs 的混合物。
