Voltammetric detection of nitroaromatic compounds using carbon-nanomaterials-based electrodes

The morphology of glassy carbon surfaces was investigated by the atomic force microscope (AFM) method. Multi-wall carbon nanotubes (MWCNTs) were purified and investigated with a scanning electron microscope (SEM) and a transmission electron microscope (TEM). An electrochemical technique based on the glassy carbon electrode (GCE) or MWCNT-modified GCEs was used for the detection of nitroaromatic compounds (NACs), namely 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitrobenzene (TNB), 2,4-dinitrotoluene (2,4-DNT), and 1,3-dinitrobenzene (1,3-DNB). MWCNT-modified GCEs were more sensitive than GCEs to TNB, 2,4-DNT, and 1,3-DNB, with the detection limit down to ppb level, whereas the modified GCEs showed lower sensitivity to TNT. In varying degrees, the accumulation of nitro compounds can be promoted by MWCNT-modified GCEs in the detection process, a property which can be attributed to the large surface area and graphene-sheet structure of MWCNTs.