Simple and Sensitive Fluorescent and Electrochemical Trinitrotoluene Sensors Based on Aqueous Carbon Dots

Abstract

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.

Carbon Nanodots: A Review—From the Current Understanding of the Fundamental Photophysics to the Full Control of the Optical Response

“…The use of CDs as "raw" sensors is quite common in the literature [131]. Differently prepared CDs can be applied to detect various metal cations as Hg 2+ , Cu 2+ , Fe 3+ [23,26,[112][113][114][115]132], or small molecules or macromolecules in solution, even in a biological context [122,[133][134][135][136][137]. Typically, when CDs are dissolved in a solution with a specific analyte, their luminescence is quenched (decreases), allowing to detect the analyte with high sensitivity and, often, high selectivity, as obtained by a proper engineering of the surface functional groups, interacting only with a given type of metal cation.…”

Fluorescent carbon dots: rational synthesis, tunable optical properties and analytical applications

“…[145][146][147] Therefore, the development of practicable analytical platforms for monitoring ultra-trace levels of TNT is urgently necessary. Zhang et al 148 successfully synthesized Nrich CDs via a microwave-assisted pyrolysis method and employed them in both the uorescence and the electrochemical determination of TNT. The uorescence sensing platform was based on the strong interaction between TNT and amino groups, which can quench the PL of CDs via charge transfer.…”

Interfacial engineering of carbon dots with benzenediboronic acid for fluorescent biosensing

“…Besides low cytotoxicity, carbon dots have attracted much attention due to their simple preparation procedure and tunable surface functional groups compared with quantum dots. Therefore, CDs are extensively used in various elds including sensors, [10][11][12][13] optoelectronic devices 14 and biomedical imaging. 15 Specically, the unique optical features of CDs make them particularly attractive for biosensors.…”