Water-soluble pillar[6]arene functionalized nitrogen-doped carbon quantum dots with excellent supramolecular recognition capability and superior electrochemical sensing performance towards TNT

By combining the merits of water-soluble pillar[6]arenes (WP6s) and nitrogen-doped carbon quantum dots (N-CQDs), a sensitive electrochemical sensing platform was constructed by using the WP6-N-CQD nanocomposites as an electrode material for the detection of trinitrotoluene (TNT). N-CQDs were prepared via microwave route by using urea and citric acid as raw materials. Two kinds of macrocyclic hosts, β-CD and WP6, were incorporated on to the N-CQDs via hydrogen bonding and π   −   π interactions, respectively. The FTIR, TGA, and XPS characterizitions demonstrated that the β-CD-N-CQD and WP6-N-CQD composites were successfully prepared. The WP6-N-CQD-modified glass carbon electrode (GCE) indicated an enhanced electrochemical signal than the β-CD-N-CQDs/GCE in the reduction of 2,4,6-trinitrotoluene (TNT), which was attributed to the higher supramolecular recognition capability of the WP6 host than that of β-CD towards TNT. The linear ranges of 0.001   μM–1.0   μM and 1.0   μM–20.0   μM were obtained by using this electrochemical sensing platform. The detection limit was 0.95   nM (S/N   =   3). The developed electrochemical sensing technique was successfully applied for the detection of TNT in lake water samples. Therefore, WP6-N-CQD nanocomposites are promising for the construction of high performance electrochemical sensors for the detection of explosives.