Surface oxidation of carbon dots enables highly selective and sensitive chemiluminescence detection of hydroxyl radical

The rapid quantification of hydroxyl radical (·OH) in real samples is a great challenge due to its highly reactive nature and the potential interferences from other coexisting reactive oxygen species (ROS). Herein, a chemiluminescence (CL) probe (ox-CDs) was rationally developed for the detection of ·OH through controlled oxidation treatment of original CDs (o-CDs) with H₂O₂. Post-oxidation of CDs can reduce the surface defects or functional groups on the CDs, exposing reactive sites capable of effectively reacting with ·OH. The chemical energy generated from redox reaction between ·OH and the ox-CDs can be efficiently utilized to generate strong and selective CL responses to ·OH without interferences from other ROS. Thus, a highly selective and sensitive CL method with a linear range from 0.01 to 150 µM and a detection limit of 3 nM was developed, which was successfully applied for monitoring the ·OH production from cigarette and mosquito coil smoke.