A novel electrochemical sensor for estradiol based on nanoporous polymeric film bearing poly{1-butyl-3-[3-(N-pyrrole)propyl]imidazole dodecyl sulfonate} moiety

Using 1-butyl-3-[3-(N-pyrrole)propyl]imidazolium tetrafluoroborate ionic liquid as functional monomer, a nanoporous polymeric film modified glassy carbon electrode was fabricated with potential step from 0 V to 1.2 V. Followed by anionic exchanging, a hydrophobic electrochemical interface bearing poly{1-butyl-3-[3-(N-pyrrole)propyl]imidazolium dodecyl sulfonate} moiety was achieved. The obtained nanoporous polymeric hydrophobic film modified glassy carbon electrode, which denoted as BPIDS/GCE, was characterized with scanning electron microscopy and electrochemical impedance spectrum. Voltammetric behavior of estradiol at the BPIDS/GCE was investigated, and an irreversible oxidation peak was observed in the potential range from −0.2 V to 1.0 V. In comparison with the unmodified electrode, slightly positive shift of peak potential and dramatic increasing of peak current were observed obviously at the BPIDS/GCE. Experimental conditions for estradiol determination were optimized. Under optimal conditions, the oxidation peak current was linearly related to estradiol concentration in the range of 1.0 × 10−7–1.0 × 10−5 mol L−1. The detection limit was estimated to be 5.0 × 10−8 mol L−1 (S/N = 3). The recoveries for the determination of estradiol in human serum samples demonstrated that an accurate method has been developed.