Electrochemical Sensor Based on Poly-L-Tyrosine/AuNCs/PDA-CNTs Nanocomposites for the Detection of 17β-Estradiol in Wastewater

Achieving direct electrochemical detection of 17β-estradiol (E2) at low concentrations remains a challenge due to the weak electrochemical activity of E2. In this study, we report a simple, cheap and sensitive electrochemical sensor based on nanocomposite for the direct detection of E2 in wastewater. The nanocomposite sensing electrode was developed by electrochemical in situ polymerization. Due to the π–π stacking and hydrogen bonding between poly-L-tyrosine (P(L-tyr)) with E2, we prepared P(L-tyr) electrode based on dopamine-modified multi-walled carbon nanotubes (PDA-CNTs) and gold nanoclusters (AuNCs). Then P(L-tyr)/AuNCs/PDA-CNTs/GCE sensing system was obtained. Meanwhile, the synergistic effect of fast electron transfer of AuNCs and the signal amplification effect of PDA-CNTs enables sensitive and direct detection of E2. The results showed that P(L-tyr)/AuNCs/PDA-CNTs/GCE sensor had a linear response to E2 concentration from 0.05 to 10 μmol·l−1 with a detection limit of 7.1 nmol·l−1. Then, the trace amount of E2 in pharmaceutical wastewater samples can be directly detected against several interferences from complex matrix, with recoveries from 91.0 to 107.5%. P(L-tyr)/AuNCs/PDA-CNTs/GCE showed good stability when placed at room temperature. Therefore, it can meet the requirements of the sensitive detection of E2 in complex matrix.