Mechanism of high sensitivity proton acids doped polypyrrole molecularly imprinted electrochemical sensor and its application in urea detection

Molecularly imprinted electrochemical sensor is a kind of convenient, fast, and stable analyzer, but the conductivity of electrode materials and their affinity with the analyte affect its performance. A proton acid (PSS, SA , SSA) doping method was proposed to improve the electrochemical performance of the polypyrrole molecularly imprinted polymer (PPy-MIP), which promoted the electropolymerization of pyrrole , reduced the charge transfer resistance, and increased the electrochemical surface area . In terms of both improving conductivity and affinity, the response of the proton acids doped the polypyrrole molecularly imprinted electrochemical sensors (PPy-MIECS) to urea was improved by 25-fold (PSS), 5-fold (SA), and 3-fold (SSA) over that of PPy-MIECS. In addition, the PSS-PPy-MIECS was validated for the practical application with a linear detection range from 0.1 mM to 100 mM, high selectivity (α = 39.73), reusability (RSD% = 4.54 %), reproducibility (RSD% = 0.93 %), and stability (11 days). The advantage of proton acid doping method in PSS-PEDOT-MIECS to urea and PSS-PPy-MIECS to glucose extended its application in the performance enhancement of MIECS design.