Functionalized carbon nanotubes as sensitive materials for electrochemical detection of ultra-trace 2,4,6-trinitrotoluene.

This report demonstrates a novel electrochemical method for fast and sensitive detection of ultra-trace 2,4,6-trinitrotoluene (TNT) based on modified electrodes by functionalized MWCNTs. To fabricate new kind of functionalized MWCNTs material sensitive to TNT, our work first theoretically investigated the interaction between triphenylene (TP) and TNT by calculating their electrostatic potentials, and secondly characterized this interaction by the fluorescence spectra. The functionalized MWCNTs of TP-MWCNTs were thoroughly characterized by fluorescence and UV-visible spectra, and by analysing these results, the interaction between TP and MWCNTs was also examined. Electrochemical experiment suggests, compared to MWCNTs- and TP- modified electrodes, TP-MWCNTs-modified electrodes result in both fast response and enhanced sensitivity to TNT detection. These results show the attachment of TP on MWCNTs leads to better sensing unit with more receptor site to TNT, associated with the coordinative recognition of TP and MWCNTs to TNT, finally result in the improvement of response and sensitivity. And this improved recognition process is attributed to the geometric and electrostatic complementarity between TP and TNT. The present study demonstrates TP-MWCNTs-modified electrode holds promising and important implications for the detection of ultra-trace TNT.