All‑solid‑state chip utilizing molecular imprinted polymer for erythromycin detection in milk samples: Printed circuit board‑based potentiometric system

Abstract

Detection of erythromycin (ERY) residues in commercial milk samples is crucial for the safety assessment. Herein, a printed circuit board was patterned as a feasible miniaturized potentiometric sensor for ERY determination in dairy samples. The proposed chip design fts to a 3.5-mm female audio plug to facilitate the potential measurements of working electrode versus reference one in this all-solid-state system. The sensor utilizes molecular imprinted polymer (MIP) for the selective recognition of the studied drug in such challenging matrix. The electrode stability is achieved through the addition of poly (3,4-ethylenedioxythiophene) nano-dispersion on its surface. The proposed device detects down to 6.6× 10−8 M ERY with a slope of 51 mV/decade in the 1× 10−7–1× 10−3 M range. The results display high accuracy (99.9%±2.6) with satisfac- tory relative standard deviation for repeatability (1.6%) and reproducibility (5.0%). The efect of common antibiotic classes, namely, amphenicols, beta-lactams, fuoroquinolones, sulfonamides, and tetracyclines, can be neglected as evidenced by their calculated binding capacities towards the proposed MIP. The calculated selectivity coefcients also show a good electrode performance in the presence of naturally present inorganic ions allowing its application to diferent milk samples.