Recently, MIPs-based electrochemical sensors have attracted much attention because of their high selectivity, high sensitivity, small size and low prices. 23,24 Although MIPs prepared by the conventional method show high selectivity, they have some disadvantages, such as labor-intensive preparation process, complex preparation processes, low binding capacity, poorly available sites and slow kinetics. 25 Efforts to overcome these problems involvde the use of MIP-grafted GR-Ox sensors, which offer promising solutions for the research world of science. 26 For example, Mehdinia and colleagues have used GR-Ox as an electrochemically active substance and MIP as an element of identification in their sensor design. 27 In the last decade, metal nanoparticles have been used in the design of nanocomposites. 28,29 They have unique features including high adsorption capability, excellent electrical characteristics and small size. 30,31 Magnetic nanoparticles (MNPs) coated with 2019 In this study, a new molecularly imprinted polymer (MIP) based nanocomposite was synthesized then used to determine epinephrine (EPN) by the use of an electrochemical sensor modified by it. Typical techniques for the synthesis of MIP have disadvantages, such as weak binding sites, low mass transfer and low selectivity. One of the ways to improve electrochemical properties is the use of graphene oxide (GR-Ox) and modification of its surface. For this purpose, GR-Ox was initially magnetized (MGR-Ox), then its surface was coated with a silica layer, and gold nanoparticles (AuNPs) were coated on its surface. Subsequently, copolymerization of methacrylic acid (MAA) and N,N′-methylene-bis-acrylamide (MBA) in the presence of EPN was performed on the MGO-AuNPs surface. Afterwards, a selective carbon paste electrode (CPE) with synthetic nanocomposite was fabricated to detect EPN. Under optimal conditions, a linear range from 10 -8 to 5.0 × 10 -7 M was obtained for the measurement of EPN in urine and blood with a detection limit of 5 × 10 -9 M (S/N = 3).
