A selective molecularly imprinted electrochemical sensor with GO@COF signal amplification for the simultaneous determination of sulfadiazine and acetaminophen

In this work, the development of a simple and sensitive electrochemical sensor for the simultaneous determination of sulfadiazine (SDZ) and acetaminophen (AP) is described. The sensor harnessed a molecularly imprinted polymer (MIP) for selective recognition of SDZ and AP, and a graphene oxide@covalent organic framework (GO@COF) nanocomposite for signal amplification. The GO@COF nanocomposite was first immobilized on a glassy carbon electrode (GCE), after which a polypyrrole MIP was electrodeposited on the modified electrode. The resulting electrochemical sensor (denoted as MIP/GO@COF/GCE) showed a strong current response to both SDZ and AP in phosphate buffer at pH 7.0. Under optimal testing conditions, linear calibration curves were obtained over the concentration range 0.5-200 mu M for SDZ and 0.05-20 mu M for AP, with limits of detection being 0.16 mu M and 0.032 mu M, respectively. Beef and fodder samples spiked with SDZ and AP were extracted in ethyl acetate, then the SDZ and AP in the extracts quantified using the MIP/GO@COF/GCE sensor. Recoveries were excellent, ranging from 82.0 to 108.0%. The same method was also employed to determine SDZ and AP residues in pork and chicken samples, with the results correlating well with those obtained using high-performance liquid chromatography.