Synthesis and Characterization of a Polypyrrole-Based Molecularly Imprinted Polymer Electrochemical Sensor for the Selective Detection of Phosphate Ion

In this study, polypyrrole-based molecularly imprinted polymer (MIP) containing phosphate selective site as a conductive polymer material for phosphate ion sensor was successfully synthesized and characterized. The synthesis of MIP-phosphate was carried out using pyrrole as a functional monomer by cyclic voltammetry on the surface of gold wire electrode. The MIP-phosphate electropolymerization was performed in potential range from −0.8 to 0.6 V at a scan rate of 100 mV/s for 10 cycles. According to the FTIR spectra and visual observation of SEM images, the MIP-phosphate was successfully synthesized as a homogenous and well-ordered porous structure. The MIP electrode response to phosphate was examined by potentiometry method, showing an excellent linear response for $${\text{PO}}_{4}^{{3 - }}$$ , $${\text{HPO}}_{4}^{{2 - }}$$ , and $${{{\text{H}}}_{{\text{2}}}}{\text{PO}}_{4}^{ - }$$ within the concentration range of 1 × 10–7 to 0.1 M with good sensitivity. The selectivity coefficient result also indicates good selectivity toward phosphate ions against the interfering anions (Cl–, $${\text{NO}}_{3}^{ - }$$ , and $${\text{SO}}_{4}^{{2 - }}$$ ).