A molecularly imprinted electrochemical sensor with dual functional monomers for selective determination of...

A molecularly imprinted electrochemical sensor was designed for the selective determination of gatifloxacin (GTX) based on dual functional monomers. Multi-walled carbon nanotube (MWCNT) enhanced the current intensity and zeolitic imidazolate framework 8 (ZIF8) provided a large surface area to produce more imprinted cavities. In the electropolymerization of molecularly imprinted polymer (MIP), p-aminobenzoic acid (p-ABA) and nicotinamide (NA) were used as dual functional monomers, and GTX was the template molecule. Taking [Fe(CN)₆]^3-/4- as an electrochemical probe, an oxidation peak on the glassy carbon electrode was located at about 0.16 V (vs. saturated calomel electrode). Due to the diverse interactions among p-ABA, NA, and GTX, the MIP-dual sensor exhibited higher specificity towards GTX than MIP-p-ABA and MIP-NA sensors. The sensor had a wide linear range from 1.00 × 10^-14 to 1.00 × 10^-7 M with a low detection limit of 2.61 × 10^-15 M. Satisfactory recovery between 96.5 and 105% with relative standard deviation from 2.4 to 3.7% in real water samples evidenced the potential of the method in antibiotic contaminant determination.