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A new selective molecular imprinted polymer (MIP) was synthesized for the electrochemical sensing of aminophylline (AMI). The MIP was fabricated via the co-polymerization of different monomers (acrylamide and methacrylic acid) around the template (AMI) in the presence of a cross-linker (ethylene glycol dimethacrylate) and an initiator (potassium persulfate). The prepared polymers were characterized by CHN elemental analysis, Fourier-transform infrared spectroscopy, atomic force microscopy, and scanning electron microscopy. For electrochemical applications, a voltammetric sensor was constructed by dropping MIP on the glassy carbon electrode surface after modification with the graphene oxide. Electrochemical determinations were achieved using differential pulse voltammetry (DPV), which indicated a wide range (3.7 × 10-11-1 × 10-3 M) of AMI and a low detection limit (2.1 × 10-12 M). Alternatively, MIP was immobilized on a plasticized PVC membrane and deposited as one layer on the GCE to fabricate the potentiometric sensor. In the same context, a potentiometric sensor was constructed and exhibited a linear calibration curve in the concentration range of 2.6 × 10-9 M to 3.1 × 10-3 M, with a detection limit of 1.5 × 10-10 M. Additionally, the developed methods displayed great selectivity for AMI compared to other competing molecules, high repeatability, and stability. In addition, the proposed methods were successfully applied for AMI detection in pharmaceutical drugs with recovery values (98.2-99.6%). [ABSTRACT FROM AUTHOR]

The electrochemical behavior of rivaroxaban (RIV), a direct Factor Xa inhibitor, was investigated using a glassy carbon electrode (GCE) based on molecularly imprinted polymer (MIP). The MIP was developed by co-polymerization of different monomers (acrylamide and methacrylic acid) with the cross-linker (ethylene glycol dimethacrylate (EGDMA)) in the presence of initiator (potassium persulphate) and RIV as a template. Fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), energy dispersive X-ray (EDX), and scanning electron microscope (SEM) were used for the characterization of the fabricated polymers. To prepare the potentiometric sensor, the MIP was incorporated in polyvinyl chloride (PVC) in the presence of a plasticizer and coated on the GCE as one layer. While the voltammetric sensor was prepared by drop coating technique, in which the graphene oxide and MIP were deposited on the bare GCE, respectively. Linear response over RIV concentrations in the range of 1.2 × 10−9 – 1 × 10−3 mol L−1 and 5.4 × 10−11 – 3.1 × 10−3 mol L−1 with detection limits of 2.4 × 10−10 mol L−1 and 2.3 × 10−12 mol L−1 were achieved for potentiometric and voltammetric sensors, respectively. Both sensors have high precision, selectivity, and good stability. Due to the abovementioned merits, both sensors were successfully applied for the detection of RIV in different blood samples and in pharmaceutical tablets, and acceptable mean recoveries (99.3–100.3%) were obtained. [Display omitted] [ABSTRACT FROM AUTHOR]