Reduced graphene oxide-platinum nanoparticles composites based imprinting sensor for sensitively electrochemical analysis of 17β-estradiol

A novel sandwich-type molecular imprinting electrochemical sensor (MIES) with enhanced sensitivity was prepared by using reduced graphene oxide (rGO) combined with platinum nanoparticles (PtNPs). Functional monomers were chosen with the aid of Gaussian 09 software. With the formation of Pt–S bond, 6-mercaptonicotinic acid (MNA) was fabricated at the surface of PtNPs/rGO composites modified glassy carbon electrode (GCE). 17β-estradiol (E2) was assembled by forming hydrogen bond with MNA. The polymer films were formed by electropolymerization of MNA and the specific recognition cavities were formed after the removal of templates. By using the differential pulse voltammetry (DPV), the resulting sensor exhibited good linear ranges of 0.004–0.060 μM (Ip (μA) = 57.872 C (μM) + 1.6678, R = 0.9977) and 0.060–50 μM (Ip (μA) = 0.7915 C (μM) + 6.6906, R = 0.9957). The limit of detection (LOD) of E2 was 0.002 μM (S/N = 3). Moreover, the MIES was successfully used in the analysis of E2 in makeups with good recoveries (>91.9%) with lower RSDs (<3.8%). The results revealed that the combination of molecular imprinting polymers (MIPs) with rGO/PtNPs composites could be applied to sensitive and selective determination of trace E2 in complex matrix.