Stimuli-enabled reversible switched aclonifen electrochemical sensor based on smart PNIPAM/PANI-Cu hybrid conducting microgel

摘要

A composite sensing film (PNIPAM/PANI-Cu), comprising of thermoresponsive polymer poly(N-isopropylacrylamide), conducting polymer poly(aniline) and copper ion, was constructed and modified onto a glassy carbon electrode (GCE). The PNIPAM/PANI-Cu/GCE act as a temperature-reversible switch for the electrochemical detection of herbicide aclonifen (AFN). Cyclic voltammetry of AFN on the PNIPAM/PANI-Cu/GCE showed large cathodic peak current while the temperature of PNIPAM/PANI-Cu was beyond the lower critical solution temperature of PNIPAM. The higher cathodic peak current of AFN vanished at low temperature. Intriguingly, the fabricated sensor exhibited reversible "on/off" electrochemical performances, which are modified with a temperature-responsive polymer. These behaviors can be ascribed to the temperature-dependent phase transition of PNIPAM and the combined effectiveness of the two functional constituents such as PANI with Cu. The reproducible "on/off" sensing of the voltammetric behaviors of AFN at the PNIPAM/PANI-Cu/GCE were obtained by controlling the phosphate buffer temperature. Moreover, the proposed sensor displayed a two detection range (0.01-10 mu M and 18-76 mu M) with the low limit of detection was found to be 0.009 mu M. Also, the PNIPAM/PANI-Cu/GCE manifests an excellent selectivity towards the potentially co-interfering compounds. Finally, the composite film achieved good recovery results in lake water samples for the determination of AFN.