Simple and sensitive fluorescent and electrochemical trinitrotoluene sensors based on aqueous carbon dots

Aqueous N-rich carbon dots (CDs), prepared by the microwave-assisted pyrolysis method, are applied as a dual sensing platform for both the fluorescent and electrochemical detection of 2,4,6-trinitrotoluene (TNT). The fluorescent sensing platform is established on the strong TNT-amino interaction which can quench the photoluminescence of amino functionalized CDs through charge transfer. The resultant linear detection ranges from 10 nM to 1.5 μM with a fast response time of 30 s. Glassy carbon electrode modified with CDs exhibits a fine capability for TNT reduction with the linear range from 5 nM to 30 μM, better than that obtained by the fluorescent method. Moreover, the minimum distinguishable response concentration with respect to these two methods is down to the nanomolar level with a high specificity and sensitivity.