Hollow Polypyrrole Composite Synthesis for Detection of Trace-Level Toxic Herbicide.

In this work, we successfully demonstrated the fabrication of a chemical sensor for toxic 1,1-dimethyl-3-phenylurea (fenuron) by using a hollow polypyrrole composite film. Here, we studied the interaction between negatively charged phosphate anions enclosed in the film with positively charged nitrogen atoms present in the fenuron. The electrochemical response of the film was characterized by cyclic voltammetry in which, interestingly, we observed that the bigger alkyl aryl sulphonate ions were replaced by smaller phosphate ions with the creation of hollow/pore composite films. Confirmation for ion replacement in the film and porosity of the film were studied by elemental analysis and field emission scanning electron microscopy, respectively. The tuning of hydrophilic to hydrophobic nature of the hollow composite film was tested by the wettability test (contact angle measurement). The electrocatalytic materials, as well as the fenuron sensing conditions such as pH and film thickness, were wisely optimized on glassy carbon (GC) electrodes for better performance. We can enhance the fenuron sensitivity by over 5 times as compared to that on the GC substrate. To our knowledge, this is the first electrochemical fenuron sensor based on a hollow polymer film by differential pulse voltammetry which can detect lower concentrations and show quick response compared to other reports. This method has potential applications in the electrochemical sensing platform with good sensitive and selective analysis in agriculture groundwater samples.