A potentiometric chiral sensor for l-Phenylalanine based on crosslinked polymethylacrylic acid–polycarbazole hybrid molecularly imprinted polymer

A novel chiral molecularly imprinted polymer (MIP) sensor for l-Phenylalanine has been developed, which is constructed by electrochemically driven cross-linking a pendant polymer precursor, poly[2-(N-carbazolyl)ethyl methacrylate-co-meth-acrylic acid]s (PCEMMAs). In this MIP sensing material, the recognition sites, the insulating polymethylacrylic acid (PMAA), were covalently bonded to the conducting polycarbazole which could be used as signal transfer interface between recognition layer and electrode. The mole ratio of copolymerizing monomers, 2-(N-carbazolyl) ethyl methacrylate:methylacrylic acid (CE:MAA), and the scanning cycles of electropolymerization were adjusted during the preparation of MIP sensing material. The optimized conditions, CE:MAA = 3:2 and 20 scanning cycles, were obtained. And then the properties of MIP films were characterized by atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS) and water contact angle. Open circuit potential–time technique was used to estimate the enantioselectivity of the MIP sensor. The results indicate that the promising sensor preferentially responses l-Phenylalanine (l-Phe) over d-Phenylalanine (d-Phe) with a selectivity coefficient KDL=5.75×10−4 and the limit of detection (LOD) is 1.37 μM, which reveals its good enantioselectivity and sensitivity.

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► We have fabricated a hybrid chiral MIP sensor in one step.
► The electropolymerization begin with a pendant polymer precursor to form MIP.
► The hybrid MIP gives better adhesion for sensitive layer to contact with electrode.
► The adjustable structure of MIP improved the selectivity and stability of sensor.
► The sensor has good sensitivity and highly selectivity for l-Phenylalanine detection.