(423f) Zero Valent Silver-Based Electrode for 2, 4-Dinitrotoluene Detection

Zero Valent Silver-based Electrode for 2,
4-Dinitrotoluene Detection

Mbah J. C.-Tuskegee University

Moorer K. - Tuskegee University

Vahdat N. - Tuskegee University

                                          Hernandez-Rivera
S.-University of Puerto Rico-Mayaguez

The prevalent
use of nitro-aromatic materials including, 2, 4, 6-trinitrotoluene (TNT) for
explosive devices has made their detection crucial in the fight against act of
terrorism and detection of military explosives. But rather than attempting to
detect TNT, researchers focus on detecting 2, 4-dinitrotoluene (DNT) which is a
common impurity in TNT ?based explosive. DNT has a higher vapor pressure than
TNT, allowing for more sensitivity and easy detection. In the production
of munitions and explosives, DNT is used as a gelatinizing and waterproofing
agent. Furthermore, it can be found in
landmines, contaminated water, waste sites, and a variety of other locations
making it readily accessible to terrorists. High
sensitivity and selectivity, combined with the ability to lower the deployment
cost of sensors using mass production, is essential in winning the war on explosives-based
terrorism.

In this
study, the donor based electrode for the detection of DNT was synthesized by
modifying the surface of carbon fiber material with zero valent
silver (Ag) via chemical deposition. DNT detection was conducted
electrochemically in aqueous media of pH 6.0. The cyclic voltammetric
oxidation of DNT is diffusion controlled with detection sensitivity increasing
with Ag loading of the electrode. The only oxidation product is benzoic
acid, which suggests that the difference in performance of Ag-C electrode
compared to other available materials is directly ascribable to the electrode fabricated
in this study. Detection limit of
DNT was 5μM with the electrode showing no
signs of degradation after several cycles, and supported by surface
behavior of characterized Ag-C electrode. Kinetic study was also investigated. In another study, the
fabricated Ag nanoparticle on carbon fiber substrate was used as an efficient surface
enhanced Raman spectra (SERS) substrate to detect the adsorbed DNT molecules
with a detection limit of 50 ppm. In advent, our developed SERS substrates could
have great potential in detecting other nitro-aromatic based-explosive
materials, such as TNT molecules.

The objective of this research is to engineer an efficient
surface for rapid detection of trace quantities of nitro-aromatic based
explosives with particular emphasis on DNT with the following specific aims:

1.      Deposit
zero valent silver nanoparticles on carbon fiber surface
which provide higher surface area-to-volume ratio that can lead to enhanced
reactivity with environmental contaminants that degrade through adsorption
mechanism.

2.      Detect
and splits DNT with high selectivity, linearity, and reversibility to a more
benign material by electroanalytical means.

3.      Modify
material surface for surface enhanced Raman spectra with excellent response
time and dynamic range.