A hemin-based molecularly imprinted polymer (MIP) grafted onto a glassy carbon electrode as a selective sensor for 4-aminophenol amperometric

Molecular imprinting technology is becoming a versatile tool for the preparation of tailor-made molecular recognition elements. This work investigates the performance of a hemin-modified molecularly imprinted polymer (MIP) used as an amperometric sensor for the detection of 4-aminophenol (4-APh). MIP particles were prepared by the precipitation polymerization method with hemin introduced as the catalytic center to mimic the active site of peroxidase. 4-APh was used as the template molecule, methacrylic acid (MAA) as the functional monomer, trimethylolpropane trimethacrylate (TRIM) as the cross-linker and 2,2′-azobisisobutyronitrile (AIBN) as the initiator. The synthesized polymer particles were characterized in terms of particle size, porosity and morphology. The amperometric sensor used for 4-APh detection was prepared by modifying a glassy carbon electrode surface with the hemin-based MIP. Under optimized operational conditions, a linear response was obtained in the range of 10.0-90.0 μmol L−1, with a sensitivity of 5.5 nA L μmol−1 and a detection limit of 3.0 μmol L−1. The sensor showed good repeatability (RSD = 2.7% for n = 7). It exhibited to be very selective for 4-APh even in the presence of structurally similar compounds (2-aminophenol, catechol, guaiachol, 2-cresol and chloroguaiachol). Recoveries in the range 93-111% were obtained using the sensor for the determinations of 4-APh in tap and river water samples.