Molecularly imprinted polymer capped Au@HKUST−1 nanocapsules-based electrochemical sensing platform for monitoring isoproturon herbicide in water at sub−nanomole level

In this context, an innovative design of a molecularly imprinted polymer (MIP) capped Au@HKUST− 1 nanocapsules−based electrode was described for highly sensitive and selective detection of isoproturon herbicide. The Au@HKUST− 1 nanocapsules were constructed by in−situ growth of nanoscaled HKUST− 1 crystals on Cu2O core materials and subsequent encapsulation of Au nanoparticles inside the hollow HKUST− 1 walls via galvanic replacement reaction between AuCl4− and Cu2O. After a further surface imprinting−directing polymerization process in the presence of hydrophobic Au@HKUST− 1, a high−performance electrochemical sensing platform was obtained and used for recognition and quantification of isoproturon. Under the optimal experimental conditions, a linear relationship was observed covering the linear range of 0.0010 − 45 μM with an ultra−low detection limit of 0.45 nM. In addition, the Au@HKUST− 1 @MIP modified electrode had higher sensing specificity for isoproturon in the application of water samples with recoveries in the range of 99.07 − 105.8% and a relative standard deviation of < 4%.