An eco-friendly, simple, and sensitive fluorescence biosensor for the detection of choline and acetylcholine based on C-dots and the Fenton reaction

• Carbon dots with excellent fluorescence properties were prepared with a simple method.
• It was firstly reported that the fluorescence of carbon dots was quenched by H2O2 in the presence of Fe2+.
• Carbon dots are successfully adopted as probes for the sensitive detection of H2O2.
• An eco-friendly, sensitive and simple biosensor for the choline and ACh detection is established using carbon dots as probes.

A simple and novel method is proposed for the preparation of Carbon dots (C-dots) with excellent properties. We firstly demonstrated that the fluorescence of C-dots decreased apparently in the presence of H2O2 and Fe2+. Based on the this finding, C-dots are successfully adopted as probes for the detection of H2O2. After the experimental conditions are optimized, the limit of detection (LOD) for H2O2 is found to be 0.1 μM. Furthermore, we established an eco-friendly, simple and sensitive biosensor for the detection of choline and acetylcholine (ACh) based on the detection of H2O2 using C-dots as probes. The detection limit for choline is 0.1 μM and the linear range is 0.1–40 μM. The detection limit for ACh is found to be 0.5 μM and the linear range is 0.5–60 μM. The excellent performance of the proposed biosensor shows that this method possesses the potential for practical application.