Electrochemical sensing membrane with enhanced mass transfer under flow-through detection mode for high sensitivity and low detection limit

To increase the sensitivity and decrease the detection limit, electrochemical sensing membrane under the flow-through detection mode with enhanced mass transfer during the electrochemical detecting process is developed in this study. The Cu/ZIF-8/Ag@Ti electrochemical sensing membrane with Cu/ZIF-8/Ag immobilized in Ti membrane pores has been fabricated and then as a novel sensor for sensing under the flow-through detection mode. Electrochemical impedance spectroscopy (EIS) indicates that the electron transport resistance can be reduced by 50 % with the flow rate of 1 mL min−1, compared with that of 0 mL min−1 (under conventional static mode). The limiting current analysis shows that the mass transfer coefficient of glucose increased by 18 % and the boundary layer thickness decreased by 15 %. The detection of glucose shows that the sensitivity increased from 3453 to 20,665 μA mM−1 cm−2, and the detection limit decreased from 0.26 to 0.04 μM. The Cu/ZIF-8/Ag@Ti sensing membrane under the flow-through mode has a well reliability of 88.6–110.9 % in real blood samples. In addition, the sensing membrane of MnO2@Ti for uric acid and Au/Ag@Ti for H2O2 detection also shows high sensitivity and low detection limit under the flow-through detection mode.