Electrochemical sensors of octylphenol based on molecularly imprinted poly(3,4-ethylenedioxythiophene) and poly(3,4-ethylenedioxythiophene-gold nanoparticles)

Two novel molecularly imprinted polymer (MIP)-graphene nanoribbon (GNR) composite film coated glassy carbon electrodes (GCE) were presented. The GNRs were prepared by unzipping multiwalled carbon nanotubes through a microwave-assisted method in the presence of ionic liquid. The 4-tert-octylphenol (OP) imprinted polymers were electrochemically synthesized at the GNR modified electrodes (GNRs/GCE), using 3,4-ethylenedioxythiophene (EDOT) and gold nanoparticles (AuNPs)-captured EDOT (EDOT-Au) as monomers, and the resulting electrodes were MIPEDOT/GNRs/GCE and MIPEDOT-Au/GNRs/GCE, respectively. An EDOT-Au precursor solution was prepared by mixing EDOT and AuNPs. The imprinting process and test conditions were optimized. The resulting electrodes MIPEDOT/GNRs/GCE and MIPEDOT-Au/GNRs/GCE showed good performance when they were used for the voltammetric determination of OP due to the synergistic effect of GNRs, AuNPs and MIP. Under the optimized conditions, the peak currents of OP at the MIPEDOT/GNRs/GCE and MIPEDOT-Au/GNRs/GCE were linear with its concentration in the ranges of 0.04-8 mu M and 0.02-8 mu M with sensitivities of 4.87 mu A mu M-1 and 7.28 mu A mu M-1 respectively; the corresponding detection limits were 6 nM and 1 nM (S/N = 3). The MIPEDOT-Au/GNRs/GCE was more sensitive than the MIPEDOT/GNRs/GCE due to the enhancement of AuNPs. In addition, the sensors showed good selectivity to OP compared with nonimprinted electrodes. When they were applied to the electrochemical determination of OP in real samples, satisfying results were obtained.