Quantum dot induced phototransformation of 2,4-dichlorophenol, and its subsequent chemiluminescence reaction

Abstract

We have studied the CdTe quantum dot-induced phototransformation of 2,4-dichlorophenol (2,4-DCP) and its subsequent chemiluminescence (CL) reaction. Quantum dots (QDs) of different size and capped with thioglycolic acid were prepared and characterized by molecular spectroscopy, X-ray diffraction and transmission electron microscopy. In the presence of QDs, 2,4-DCP is photochemically transformed into a long-living light emitting precursor which can react with N-bromosuccinimide to produce CL with peak wavelengths at 475 and 550 nm. The formation of singlet oxygen during the phototransformation process was confirmed by the enhancement effect of deuterium oxide on the CL reaction and the change in the UV spectrum of a chemical trap. The CL intensity is linearly related to the concentration of 2,4-DCP in the range from 0.36 to 36 μmol L −1 , and the detection limit (at 3σ) is 0.13 μmol L −1 .

Luminescence enhancement by deuterium

“…81 These same technical concepts were also used to explore the photochemical properties of the two dyes, lumazine (7) 82 and methylene blue, 49 demonstrating their ability to generate singlet oxygen. Additionally, the D 2 O chemiluminescence enhancement effect was employed to prove the generation of singlet oxygen by CdTe quantum dots 83 as well as to reveal a singlet oxygen photodegradation pathway (or not) in an aquatic environment. [84][85][86]…”