###### Abstract  
In the present study, we report a highly effective electrochemical sensor for detecting 2,4-dinitrotoluene (2,4-DNT). The amperometric determination of 2,4-DNT was carried out using a gold electrode modified with zinc-metal organic framework-8 and silver quantum dot (Zn-MOF-8@AgQDs) composite. The synthesized nanomaterials were characterized by using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD). The synthesized nanocomposite proved to be efficient in electro-catalysis thereby reducing the 2,4-DNT. The unique combination present in Zn-MOF-8@AgQDs composite offered an excellent conductivity and large surface area enabling the fabrication of a highly sensitive (\(-0.238\)\(\mu\)A \(\mu\)M\({}^{-1}\) cm\({}^{-2}\)), selective, rapid and stable 2,4-DNT sensor. The dynamic linear range and limit of detection (LOD) was about 0.0002 \(\mu\)M to 0.9 \(\mu\)M and 0.041 \(\mu\)M, respectively. A 2,4-DNT reduction was also observed during the linear sweep voltammetry (LSV) experiments with reduction peaks at \(-0.49\) V and \(-0.68\) V. This is an unprecedented report with metal organic framework (MOF) composite for sensing 2,4-DNT. In addition, the presence of other species such as thiourea, urea, ammonia, glucose, and ascorbic acid displayed no interference in the modified electrode suggesting its practicability in various environmental applications. napthalene-2,6-dicarboxylic acid; silver quantum dot particles; electrochemical sensor; 2,4-dinitrotoluene 201999249520199924952019  
2,4-DNT as a carcinogen [6] and considering its destructive potential, significant efforts have been devoted for the development of reliable, innovative, simple and efficient sensing devices. In recent years, various researchers have attempted to detect explosives using strategies including fluorescence, liquid chromatography, mass spectrometry, ion mobility spectrometry, infrared absorption spectroscopy and electron capture detection [7; 8; 9; 10; 11; 12; 13; 14; 15; 16]. However, these techniques are both expensive and time-consuming. The electrochemical technique has been extensively utilized to detect explosives due to its simplicity, high sensitivity and quick response time [17; 18]. The electroactive nature of the nitro groups present in 2,4-DNT is responsible for the electrochemical sensing which can be performed by a stepwise 4-electron reduction for each NO\({}_{2}\) group into NHOH followed by a further 2-electron reduction of the NHOH group into NH\({}_{2}\)[19; 20]. Recently, nanomaterials have also attracted remarkable interest, owing to their unique features [21; 22; 23; 24] and are represented by conductive polymers, metal oxides, natural semiconductors and carbon nanomaterials for sensing toxic materials [25; 26] with electrocatalytic frameworks for reduction of 2,4-DNT. In an earlier study, reduced graphene fabricated on a glassy carbon electrode (GCE) surface was used to detect 2,4-DNT via a stripping voltammetry technique in which the detection limit was 42 nmol L\({}^{-1}\) and a carbon-screen-printed electrode for trace 2,4-DNT detection in field applications [1; 27], including electrochemical sensing in sea water [28]. In another study, a GCE-rGO/SrTiO3 modified glassy carbon electrode (MGCE) showed rapid electronic communication for the electrochemical sensing of nitro-substituted 2,4-DNT [29] and a carbowax/PPy-based system [30]. A carbon nanotube (CNT)-based flexible sensor was developed for the trace detection of 2,4-DNT, displaying good response at 0.22 ppm concentration; such composite conducting materials provide a fast electron exchange between the electrode and the electrolytic solution. Yet, the production of these materials is complex, with a low yield thus necessitating a need to develop novel materials for the rapid detection of 2,4-DNT.