Development of a Highly Sensitive Imprinted Electrochemical Sensor for the Detection of Hydrocortisone in Wastewater

The existence of hydrocortisone in water resources is a serious threat to human health. However, the rapid and sensitive detection methods for hydrocortisone in wastewater are still lacking. Meanwhile, due to the weak redox activity of hydrocortisone, electrochemical technique cannot be used to detect hydrocortisone directly. Therefore, molecularly imprinted technique combined with prussian blue nanoparticles was synthesized for detecting HC indirectly in this work. We fabricated a novel and highly sensitive molecularly imprinted sensor based on the polydopamine/electro-reduced graphene oxide, which was used for the specific recognition of hydrocortisone in water samples. The prussian blue nanoparticles were introduced as probes to reflect the concentration of the target. The morphology of the prepared sensors was characterized by the scanning electron microscopy. And the feature of the imprinted electrode was performed by the cyclic voltammetry and differential pulse voltammetry. Under the optimal experimental conditions, the relative current signal of prussian blue decreased linearly with the increase of hydrocortisone concentration with a limit of detection 0.006 nM. Moreover, the imprinted sensor had a much higher affinity towards hydrocortisone than other analogues. Then, this system was successfully applied to determine hydrocortisone in real wastewater samples with workable results.