Dramatic enhancement effect of carbon quantum dots on the chemiluminescence of Ru(bpy)32+-Ce(IV) reaction and application to the determination of 4-nitrophenol

We studied the effect of glucose-derived carbon quantum dots (CQDs), prepared by a facile microwave method, on the Ru(bpy)32+-Ce(IV) chemiluminescence (CL) reaction for the first time. It was found that the prepared CQDs enhance the CL intensity of this reaction by a factor of ~70. Possible mechanisms that lead to the effect were elucidated by recording the fluorescence and CL spectra. It was suggested that the phenomenon is probably due to the action of CQDs as reductive intermediates and also as accelerators of Ru(bpy)32+ and Ce(IV) reaction. It was also shown that 4-nitrophenol at even trace levels exerts a significant increasing effect on the Ru(bpy)32+-Ce(IV)-CQDs CL system. This was exploited to design a new CL sensor for selective determination of 4-nirteophenol in the concentration range from 0.1 to 2.5 μM, with a limit of detection of 0.03 µM. 4-Nitrophenol was determined by this method in water and wastewater samples with satisfactory results.