Ratiometric electrochemical glucose sensor based on electroactive Schiff base polymers

In this work, a flexible electroactive Schiff base polymers (SBPThi) was prepared by p-benzaldehyde-thionine amine-aldehyde condensation reaction and applied for electrochemical sensing for the first time. The SBPThi was demonstrated to be two-dimensional crystal nanosheet with a thickness of 0.8 nm. N-2 adsorption/desorption isotherms illustrated that SBPThi was mesoporous material. The porous SBPThi could be used to load glucose oxidase (GOD) and be assembled on electrode surface firmly. The electrochemical behaviors of SBPThi were studied and the results indicated that SBPThi had two pairs of redox peaks at -0.05 V and -0.2 V. They were far away from the oxygen reduction peak and accordingly could be used as reference signal to construct ratiometric glucose electrochemical sensor based on SBPThi/GOD. The proposed ratiometric electrochemical glucose sensor showed linear range from 1.97 mu M-4.0mM with detection limit of 0.66 mu M when the peak at -0.2 V was used as reference signal and linear range from 0.82 mu M-4.0mM with detection limit of 0.27 mu M when the peak at -0.05 V was used as reference signal. The SBPThi could also be made into flexible electrode to determine glucose in sweat. The results indicated that SBPThi could be used for electrochemical sensors.