A differential strategy to enhance the anti-interference ability of electrochemical molecularly imprinted polymers sensors for the determination of sulfamerazine and 4-acetamidophenol

Abstract

Herein, we report a differential strategy to enhance the anti-interference ability of the electrochemical molecularly imprinted polymers (MIP) based sensors for the determination of 4-acetamidophenol (AP) and sulfamerazine (SMR). Polypyrrole MIP membranes for AP or SMR were grown independently on the surface of Ni2P/GCE, with the imprinting factors of 6.13 for MIPAP and 5.82 for MIPSMR. At the potentials of 0.42 V and 0.89 V (vs. Ag/AgCl), MIPAP/Ni2P/GCE and MIPSMR/Ni2P/GCE exhibit sensitive current responses to AP and SMR, respectively. However, the non-specific adsorption of various interferents on the surface of MIP suppresses the selectivity of the MIP sensors. For example, 20 μM ascorbic acid (AA) and sulfamethoxazole (SMZ) were determined falsely as 5.2 μM AP and 4.7 μM SMR, respectively. In the proposed differential strategy using the current differences between MIPAP/Ni2P/GCE and MIPSMR/Ni2P/GCE as the signal indicators, 20 μM of AA and SMZ are equivalent only to 0.25 μM AP and 0.33 μM SMR, respectively, enhancing significantly the anti-interference ability of MIP sensors. Moreover, the limit of detection for AP and SMR are 0.011 and 0.019 μM, respectively. AP and SMR in actual urine samples were determined with the recoveries from 94% to 105%.