Effect of polycyclic aromatic hydrocarbons on detection sensitivity of ultratrace nitroaromatic compounds.

Polycyclic aromatic hydrocarbons (PAHs) with different numbers of pi-electrons and geometric symmetry of pi-systems, including anthracene, phenanthrene, pyrene, triphenylene, perylene, benzo[ghi]perylene, and coronene, were chosen to modify glassy carbon electrodes (GCEs) by self-assembling. The self-assembled monolayer of PAHs was investigated by STM and was used in the electrochemical detection of nitroaromatic compounds (NACs). The results indicate that PAH-modified GCE shows higher sensitivity to NACs than an unmodified one. Among the seven different PAHs, coronene-modified GCE exhibits the highest sensitivity to 2,4,6-trinitrotoluene and 1,3,5-trinitrobenzene.