Molecularly imprinted flexible sensor based on nitrogen-doped graphene for selective determination of formononetin.

Formononetin is an isoflavone compound found in many traditional Chinese medicines that has a wide range of pharmacological activities. It is critical to develop a sensitive, accurate, and rapid determination method for in-depth formononetin research. A molecularly imprinted electrochemical sensor was constructed in this study. After the flexible electrode (ITO-PET) was modified with nitrogen-doped graphene (NG), the molecularly imprinted polymer (MIP) was electropolymerized on the surface using o-phenylenediamine (OPD) as the functional monomer and formononetin as the template. Under optimized experimental conditions, the MIP sensor detected formononetin selectively in 0.1 M phosphate buffer solution (PBS) with the linear range of 3 ~ 120 μM, a detection limit as low as 1.14 μM (S/N = 3), and good anti-interference ability and reproducibility. The analytical performance of the proposed MIP/NG/ITO-PET was evaluated for the detection of formononetin in real samples such as methanol extract of Radix Astragali and mouse plasma with good accuracy and precision.