Oxovanadium–salen and –salan complexes as effective labels for electrochemical immunosensing: a case study for estradiol detection

Oxovanadium complexes are presented as new labels for the development of electrochemical immunosensors. The concept was successfully applied to the accurate detection of estradiol, an emerging environmental pollutant, at concentrations ranging from 4 ng L−1 to 5 μg L−1.