An electrochemically enhanced solid-phase microextraction approach based on molecularly imprinted polypyrrole/multi-walled carbon nanotubes composite coating for selective extraction of fluoroquinolones in aqueous samples

In this study, an electrochemically enhanced solid-phase microextraction (EE-SPME) approach based on molecularly imprinted polypyrrole/multi-walled carbon nanotubes (MIPPy/MWCNTs) composite coating on Pt wire was developed for selective extraction of fluoroquinolone antibiotics (FQs) in aqueous samples. During the extraction, a direct current potential was applied to the MIPPy/MWCNTs/Pt fiber as working electrode in a standard three-electrode system, FQ ions suffered electrophoretic transfer to the coating surface and then entered into the shape-complimentary cavities by hydrogen-bonding and ion-exchange interactions. After EE-SPME extraction, the fiber was desorbed with desorption solvent for high-performance liquid chromatography (HPLC) analysis. Some parameters influencing EE-SPME extraction such as applied potential, extraction time, solution pH, ionic strength, and desorption solvent were optimized. EE-SPME showed good selectivity and higher extraction efficiency to FQs compared with that of traditional solid-phase microextraction. EE-SPME coupled with HPLC to determine FQs in water samples, the limits of detection (S/N = 3) for the selected FQs are 0.5–1.9 μg L⁻¹. The proposed method was successfully used to the analysis of FQs spiked urine and soil samples, with recoveries of 85.1–94.2% for the urine samples and 89.8–95.5% for the soil samples.