Development of an Electrochemical Sensor based on a Molecularly Imprinted Polymer for the Detection of Taggant Molecules

Whittaker, Nancy (2021) Development of an Electrochemical Sensor based on a Molecularly Imprinted Polymer for the Detection of Taggant Molecules. MRes thesis, University of Lincoln.

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Development of an Electrochemical Sensor based on a Molecularly Imprinted Polymer for the Detection of Taggant Molecules
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Abstract

The uses of molecularly imprinted polymers and electrochemical analysis are not new
technology, however, there are few entries in the literature that use a combination of the two
in order to create a highly selective, specific and sensitive technique – and thus, are of great
forensic interest. This study utilises these technologies to create a sensor for 2,3-dimethyl�2,3-di-nitrobutane (DMNB), a military-used taggant, commonly found in explosives.
The response of DMNB was analysed using cyclic voltammetry followed by differential pulse
voltammetry. Polymerisation was achieved following a computational approach using density
functional (B3LYP) and semi empirical (PM3) models. The favoured monomer and ratio were
determined as pyrrole at a 6:1 ratio to DMNB. The formation of the MIP was somewhat
successful, but requires changes to improve the signal, to identify the peak potentials for
DMNB and maintain the peak potential.
The current method outlined in this study cannot be used to create an MIP for DMNB and
requires some adjustments, such as derivatisation, using MTBSTFA as the derivatisation
agent. This would also include pyrrole at a 3:1 concentration ratio to DMNB, which was
determined as the optimal ratio. The use of derivatisation will lower the polarity of DMNB and
thus increases its solubility, lessening the impact of water in the buffer solution as well as
increasing the number and complexity of interactions for the MIP. This should also enable the
use of the buffer in the working solution to determine the peak potentials for DMNB under this
method.
It also attempts to apply 3D printing technology to this method, by printing a carbon electrode
as a cheaper alternative to glassy carbon electrodes routinely used in electrochemical
analysis. A conductive polylactic acid (PLA) filament was determined as the best option to use
in a rod-like shape for ease of application, however, implementing this would prove difficult for
this molecule at this stage.

Keywords:polymers, electrochemistry, Forensic science
Subjects:F Physical Sciences > F100 Chemistry
Divisions:College of Science > School of Chemistry
ID Code:48589
Deposited On:16 Mar 2022 15:06

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