Ratiometric electrochemical sensing platform for mitomycin C based on bimetallic Ce-Ni-MOF/MWCNTs with polythionine and a molecularly imprinted interface

A sensitive ratiometric electrochemical strategy for MMC detection is developed. • Polythionine serves as an internal reference for improved response stability. • Ce-Ni-MOF/MWCNTs enhance interfacial electron transfer. • Molecular imprinting enables selective MMC recognition. • MMC detection is validated by UPLC-QTOF-MS in water samples. Mitomycin C (MMC) is a widely used antitumor antibiotic, and its rapid and selective detection is crucial for monitoring its occurrence in environmental water samples. In this work, a ratiometric electrochemical sensor was constructed by sequential modification of a bimetallic Ce-Ni-metal-organic framework (Ce-Ni-MOF)/multi-walled carbon nanotube (MWCNTs) composite, polythionine (pThi) and a molecularly imprinted polymer (MIP) on a glassy carbon electrode. The Ce-Ni-MOF/MWCNTs composite facilitated electron transfer, contributing to the enhanced sensitivity of the sensing platform. The pThi was electropolymerized onto the modified electrode surface to provide an internal reference signal, while the ratiometric response was achieved through two electrochemical channels, with the [Fe(CN)₆] 3−/4 − redox probe serving as the response signal and the pThi signal as the reference, enabling effective correction of measurement variations. Under optimized conditions, the sensor exhibited a linear response to MMC over the concentration range of 0.1–100 nM, with a low detection limit of 0.046 nM and a limit of quantification of 0.075 nM. Owing to the specific molecular recognition of the MIP layer and the internal reference function of pThi, the proposed sensor demonstrated satisfactory selectivity, repeatability, reproducibility and stability. Furthermore, the sensor was successfully applied to the determination of MMC in water samples, achieving recoveries of 87–112%. The analytical performance of the proposed sensor was further validated by comparison with the results obtained using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). This work presents a reliable and sensitive ratiometric electrochemical sensing strategy and demonstrates its feasibility through a proof-of-concept study for MMC detection in environmental water samples. Download: Download high-res image (304KB) Download: Download full-size image