CoFe2O4-MWCNTs Modified Screen Printed Carbon Electrode Coupled with Magnetic CoFe2O4-MWCNTs Based Solid Phase Microextraction for the detection of Bisphenol A

Background: Bisphenol A (BPA) is an important intermediate in the industrial manufacturing of either polycarbonate plastic or epoxy resins. Bisphenol A and its chemical derivatives are endocrine-disrupting chemicals. BPA is a potent endocrine-disrupting compound (EDC) and its toxicity is widely reported in the literature. Therefore, it is important to develop fast identification methods for the monitoring of BPA in the environment. Methods: In this work, multi-walled carbon nanotubes decorated with cobalt ferrites (CoF) nanoparticles were synthesized by a controlled co-precipitation reaction. The modified multi-walled carbon nanotubes decorated with CoF nanoparticles were applied as a magnetic solid-phase microextraction (M-SPME) sorbent for the extraction of trace levels of BPA from water samples. In detection step, the CoF/MWCNTs modified screen-printed carbon electrodes (CoF/MWCNTs/SPCEs) (named CoFsensor) were used for the electrochemical detection of BPA. The CoF/MWCNTs modified SPCEs are found to give stable and reproducibility responses to BPA and the sensor exhibited good stability. Finally, the established combined procedure was successfully applied to determine BPA in water samples. Results: In this work, the magnetic CoFe2O4/MWCNTs nanoparticles were used as the electrode modifier and sample pre-concentrator. Firstly, some important electrochemical parameters of the modified electrodes were optimized and the calibration curve of the sensor showed a good linearity in the range of 0.5-50 μM and the detection limit was 0.2 μM. Secondly, the important parameters that affect the extraction performance were optimized. Under combined conditions, the calibration graph for the determination of bisphenol A was linear in the range of 0.02-1.5 μM (4.56-342 μg/L) and the detection limit was 0.01 μM. Finally, the combined system was successfully used for the detection of bisphenol A in tap water, drinking water, mineral water with recoveries of 93-102%. Conclusion: A new determination system combined CoF-sensor with M-CoF-SPME was developed for rapid, sensitive and selective detection of traces BPA in aqueous samples. The CoF/MWCNTs exhibited high sensitivity toward BPA with a maximum adsorption capacity of 67.7 mg/g. The nanoparticles were collected using a magnet and reused at least 10 times without substantial degradation in the activity. The analytical method combined miniaturised systems both in sample preparation and in detection stage, with the major advantage of avoiding costly and bulky or unmovable instrumentation. Besides, the M-CoF-SPME-CoF-sensor combination detection system provided many benefits such as cheapness, ease of operation, good sensitivity and repeatability. The determination method developed in current study provides a new option for the determination of BPA in water sample.