Highly selective chemiluminescence detection of hydroxyl radical via increased π-electron densities of rhodamine B on montmorillonite matrix

•RhB–montmorillonite hybrids act as novel CL probe for OH.•High selectivity towards •OH is due to the electrophilic properties of •OH.•Increased π-electron densities of RhB molecules are responsible for ultrastrong CL.•This CL probe is validated for sensing •OH in mouse plasma samples.

The current chemiluminescence (CL) probes for hydroxyl radical (•OH) are poorly selective owing to a non-specific redox reaction. To the best of our knowledge, there have not been established on the CL probes for •OH using the strong electrophilicity of •OH. In this work, an ultrastrong CL emission is initiated by electrophilic attack of •OH towards rhodamine B (RhB) on the surface of montomorillonite (MMT). The improved CL emissions are attributed to the oriented H-type aggregation of RhB molecules on the surface of MMT by π–π stacking interactions, resulting in an increase in π-electron density of aromatic ring of RhB. The high π-electron density of benzene ring could facilitate the attack of electrophilic •OH towards RhB. In addition, a novel CL probe for •OH with high selectivity and high sensitivity has been established using the electrophilic properties of •OH rather than its common redox properties. The applicability of the proposed CL probe is evaluated by detecting •OH in untreated and gentamicin treated mouse fresh plasma samples. Our findings provide a new strategy to improve the selectivity of CL sensor of •OH.

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