Pencil and Gold Electrode Materials for the Electrochemical Study and Analysis of Dinitrotoluene

The aim of our work was to investigate practical and robust methods for the electrochemical analysis of DNT. Using gold WEs, we differentiated between the nitro substituents in 2,4- and 2,6-DNT in organic electrolyte systems. Switching to an aqueous electrolyte (2 M H₂SO₄), a limit of detection (LOD) of 0.158 ppm (0.87 μM) and a limit of quantitation (LOQ) of 0.48 ppm (2.64 μM) were observed for 2,4-DNT. Subsequent simplification to wooden craft pencils as WEs in aqueous 2 M H₂SO₄ electrolyte achieved a LOD of 4.8 ppm (26.48 μM) and a LOQ of 14.6 ppm (80.54 μM) for 2,4-DNT. Alongside this easily renewable WE choice, 2 M H₂SO₄ was found to improve the solubility of DNT in aqueous media and has not been previously reported as an electrolyte in DNT electroanalysis. On testing a range of pencil grades from 4H to 8B, it was found that 4B gave the best sensitivity. The work serves as a preliminary study into materials that, through their simplicity and availability, may be suitable for the development of a robust and portable instrumental method through the electrochemical work presented here.