State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics, and Physics, Chinese Academy of Sciences , 3888 East Nanhu Road, Changchun, Jilin 130033, P. R. China.
ACS Appl Mater Interfaces. 2013 Dec 26;5(24):13242-7. doi: 10.1021/am4042355. Epub 2013 Dec 2.
Chromium(VI) [Cr(VI)] is considered as a severe environmental pollutant, due to its highly toxic and carcinogenic properties. Therefore, low cost, highly sensitive sensors for the determination of Cr(VI) are highly demanded. It is well-known that highly luminescent carbon dots (CDs) have been successfully applied as fluorescent nanosensors for pH, ions, and molecular substances. In the present work, we have demonstrated an on-off fluorescent CD probe for detecting Cr(VI) based on the inner filter effect (IFE) because the absorption bands of Cr(IV) fully covered the emission and excitation bands of CDs. This CD-based nanosensor provides obvious advantages of simplicity, convenience, rapid response, high selectivity, and sensitivity, which have potential application for the detection of Cr(VI) in the environmental industry. In addition, because Cr(VI) can be reduced to low valent chromium species easily by reductant, resulting in the elimination of the IFE and recovery of CD fluorescence, the CD-Cr(VI) mixture could behave as an off-on type fluorescent probe for reductant. We employed ascorbic acid (AA) as an example molecule to demonstrate this off-on type fluorescent probe.
六价铬（Cr(VI)）因其高毒性和致癌性而被认为是一种严重的环境污染物。因此，人们对用于测定 Cr(VI)的低成本、高灵敏度传感器有很高的需求。众所周知，高发光的碳点（CDs）已成功应用于 pH 值、离子和分子物质的荧光纳米传感器。在本工作中，我们基于内滤效应（IFE），展示了一种用于检测 Cr(VI)的开-关荧光 CD 探针，因为 Cr(IV)的吸收带完全覆盖了 CDs 的发射和激发带。这种基于 CD 的纳米传感器具有简单、方便、快速响应、高选择性和灵敏度等明显优势，在环境工业中具有潜在的 Cr(VI)检测应用。此外，由于 Cr(VI)很容易被还原剂还原为低价铬物种，从而消除 IFE 并恢复 CD 荧光，因此 CD-Cr(VI)混合物可以作为还原剂的关-开型荧光探针。我们以抗坏血酸（AA）为例分子来证明这种关-开型荧光探针。
