Molecularly imprinted electrochemical sensor based on multi-walled carbon nanotubes for specific recognition and determination of chloramphenicol in milk

A molecularly imprinted electrochemical sensor of chloramphenicol (CAP) with high sensitivity and good selectivity is introduced in this paper. Glassy carbon electrode (GCE) was modified by chitosan-multiwalled carbon nanotubes (CS-MWCNTs), the CS could improve the dispersion of MWCNTS, and the MWCNTS could significantly improve the current response of the sensor, thus improving the sensitivity. CAP was used as a template molecule and o-phenylenediamine (o-PD) was used as a functional monomer, respectively. Molecularly imprinted polymers (MIPs) were prepared on the surface of a GCE modified with CS-MWCNTs by electro-polymerization. The MIPs provided specific recognition sites for the detection of chloramphenicol. The experimental parameters such as polymerization cycle, concentration ratio of template molecule to functional monomer, supporting electrolyte pH and incubation time were optimized. Under optimized experimental conditions, the sensor has a linear range of 0.1–1000 ng/mL and the limit of detection (LOD) of 3.3 × 10−2 ng/mL (S/N = 3). The sensor had high selectivity, good stability and reproducibility for the detection of CAP, and it has been successfully used for the determination of CAP in real spiked milk samples.