A Novel Genistein Electrochemical Sensor Based on Molecularly Imprinted Polycarbazole/Carboxylated Multiwalled Carbon Nanotubes Nanocomposite

Genistein is an important isoflavone that has been widely used to prevent blood disease and cancer. In this work, a novel genistein electrochemical sensor was developed based on the composite of molecularly imprinted polymer (MIP) and carboxylated multiwalled carbon nanotubes (cMWCNTs). The MIP layer was electropolymerizated on the cMWCNTs modified electrode using carbazole as functional monomer and genistein as template molecule. The morphology and electrochemical performance of MIP/cMWCNTs were characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV), respectively. A series of experimental conditions were optimized, including the pH value of supporting electrolyte, electropolymerization potential range, molar ratio of functional monomers to template molecules, numbers of cycle, accumulation potential and accumulation time. Under the optimal conditions, the resulting electrochemical sensor (MIP/cMWCNTs/GCE) showed high performance, such as high sensitivity and selectivity towards genistein, a wide linear range (0.02–7.00 μM) and a low limit detection of 0.006 μM (S/N = 3). The electrochemical sensor was applied to determination of genistein in tablets and human urine samples with satisfactory recoveries (97.9%–102.8%), and the accuracy of the sensor was demonstrated with the HPLC method.