Towards the detection of 2,4,6-trinitrotoluene with ionic liquid/poly(ionic liquid) membranes

Catherine E Hay; Elena Gorenskaia; Juliette I Phillips; Adam Butterfield; David Mecerreyes; Debbie S Silvester

doi:10.1016/j.talanta.2026.129410

Towards the detection of 2,4,6-trinitrotoluene with ionic liquid/poly(ionic liquid) membranes

Talanta. 2026 May 15:302:129410. doi: 10.1016/j.talanta.2026.129410. Epub 2026 Jan 16.

Authors

Catherine E Hay¹, Elena Gorenskaia¹, Juliette I Phillips², Adam Butterfield¹, David Mecerreyes³, Debbie S Silvester⁴

Affiliations

¹ School of Molecular and Life Sciences, Curtin University, GPO Box U1987, Perth, 6845, Western Australia, Australia.
² School of Molecular and Life Sciences, Curtin University, GPO Box U1987, Perth, 6845, Western Australia, Australia; Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Victoria, Australia.
³ POLYMAT University of the Basque Country UPV/EHU, Avenida Tolosa 72, 20018, Donostia-San Sebastián, Spain; Ikerbasque, Basque Foundation for Science, E-48011, Bilbao, Spain.
⁴ School of Molecular and Life Sciences, Curtin University, GPO Box U1987, Perth, 6845, Western Australia, Australia. Electronic address: D.Silvester-Dean@curtin.edu.au.

PMID: 41564585
DOI: 10.1016/j.talanta.2026.129410

Abstract

In this work, we explore a range of membranes based on ionic liquids (ILs) and poly(ionic liquid)s (poly(IL)s), with varying cation/anion combinations, for the electrochemical detection of 2,4,6-trinitrotoluene (TNT) using gold thin-film electrodes. The influence of the IL anion/cation structure, as well as the incorporation of a polycation, on the TNT reduction behaviour was systematically examined through cyclic voltammetry (CV) measurements. Among the studied systems, [C₂mim][TFSI]:p[DADMA][TFSI] and [C₄mim][TFSI]:p[DADMA][TFSI], where [C₂mim]⁺ = 1-ethyl-3-methylimidazolium, [C₄mim]⁺ = 1-butyl-3-methylimidazolium, [TFSI]^- = bis(trifluoromethylsulfonyl)imide and p[DADMA]⁺ = poly(diallyldimethylammonium), demonstrated an optimal balance between excellent electrochemical performance and high mechanical integrity, maintaining quasi-reversible TNT reduction with distinct three-step cathodic features. Environmental studies under controlled oxygen (0-25 vol %) and humidity (up to 95 % RH) environments revealed that the TNT response in real conditions is dependent on the membrane composition. These results highlight how ion-pair selection and environmental conditions jointly govern the charge transport and electrochemical behaviour in IL/poly(IL) membranes, providing key design principles for electrolytes in next-generation portable explosive sensors. The analytical performance of the sensing platform was evaluated using [C₂mim][TFSI]:p[DADMA][TFSI] and [C₄mim][TFSI]:p[DADMA][TFSI] membranes employing an 'electrode surface-loaded with analyte' detection strategy in which defined masses of TNT were deposited onto the electrode via solvent evaporation prior to electrochemical measurement.

Keywords: 2,4,6-Trinitrotoluene; Cyclic voltammetry; Electrochemical sensors; Ionic liquids; poly(ionic liquids).