Highly sensitive electrochemical sensor for estradiol based on the signal amplification strategy of Cu-BDC frameworks

Using 1,4-Benzenedicarboxylic acid (H2BDC) as the ligand, a kind of copper-based metal-organic frameworks (MOFs) were prepared and characterized using transmission electron microscopy, scanning electron microscopy, infrared spectroscopy, and X-ray diffraction. After that, the prepared Cu-BDC frameworks were used to modify the carbon paste electrode, constructing a novel electrochemical sensor for estradiol (E2). The prepared Cu-BDC frameworks are much more active for the oxidation of E2, and greatly increase the oxidation signals of E2. The results from chronocoulometry indicate that the Cu-BDC frameworks modified electrode exhibit much higher accumulation efficiency toward E2. Based on the signal amplification strategy of Cu-BDC frameworks, a sensitive and rapid electrochemical method was developed for the determination of E2. The linear range was from 5.00 to 650.0 nM, and the detection limit was as low as 3.80 nM. It was used in different water samples, and the values of recovery were over the range from 96.5 to 101%. The practical applications reveal that this new sensing system is accurate and convenient, and has great potential applications in the environmental monitoring.