Highly Sensitive Electrochemical Detection of Paraquat in Environmental Water Samples Using a Vertically Ordered Mesoporous Silica Film and a Nanocarbon Composite

Herein, we demonstrate a sensitive and rapid electrochemical method for the detection of paraquat (PQ) using a glassy carbon electrode (GCE) modified with vertically ordered mesoporous silica films (VMSF) and a nanocarbon composite. The three-dimensional graphene-carbon nanotube (3DG-CNT) nanocarbon composite has a 3D network structure, a large electroactive area and oxygen-containing groups, promoting electron transfer between PQ and the underlying electrode and providing a suitable microenvironment for the stable growth of VMSF. This VMSF/3DG-CNT nanocomposite film could be prepared on the GCE's surface by a two-step electrochemical method with good controllability and convenience. Owing to the synergistic effect of the electrocatalytic ability of 3DG-CNT and the electrostatically enriched capacity of VMSF, the proposed VMSF/3DG-CNT/GCE has superior analytical sensitivity compared with the bare GCE. Furthermore, VMSF has excellent anti-fouling ability that makes the fabricated sensor exhibit satisfactory performance for direct analysis of PQ in environmental water samples.