Cubic cobalt ferrite anchored on graphene sheets for non-enzymatic electrochemical detection of 17α-ethinyl estradiol in environmental and biological samples

Recently, the endocrine interference of endocrine disruptors on the environment and aquatic organisms has been a hot topic. Ethinyl estradiol (EE2) is an estrogen endocrine disruptor and one of the most widely used ingredients in oral contraceptives, resulting in high emissions and environmental pollution. Therefore, it is urgent to construct a non-enzymic, simple and low-cost sensor to detect EE2 in environmental and biological samples. We successfully prepared cobalt ferric oxide with anti-spinel structure and reduced graphene oxide composite (CoFe2O4/RGO) using hydrothermal synthesis, which decorated on the glass carbon electrode (GCE) to detect EE2. The morphological structure of CoFe2O4/RGO composites was studied by FESEM, HRTEM, EDX, FT-IR, XRD, and XPS techniques. Additionally, the experimental conditions were optimized and the oxidation mechanism of EE2 was explained theoretically and EE2 was detected by CV, EIS, and SWV, which displayed a fantastic current response of EE2. The electrochemical results illustrated that the prepared sensor has good selectivity, high sensitivity, a wide linear range of 0.05–100 μM, and a lower detection limit of 42 nM. Finally, the practicability of the sensor to detect EE2 in real samples was also studied and obtained a satisfactory recovery.