Determination of 2,4-dichlorophenol in water samples using a chemiluminescence system consisting of graphene quantum dots, rhodamine B and cerium(IV) ion

We report that the presence of graphene quantum dots (GQDs) causes an ∼60-fold enhancement of the chemiluminescence (CL) caused by the reaction between rhodamine B (RhB) and Ce(IV) ion. A possible CL mechanism is established on the basis of fluorescence, CL and UV-vis spectra. It is suggested that the GQDs facilitate the oxidation of RhB and accelerate the generation of the CL emitting species, thus leading to stronger CL intensity. We further observed that 2,4-dichlorophenol at even trace levels exerts a diminishing effect on this CL system. This finding was exploited to design a CL method for determination of 2,4-dichlorophenol in the 0.1 to 5.0 μM concentration range, with a detection limit of 25 nM. The method was applied to the analysis of spiked real water and wastewater samples and gave satisfactory results. (author)