Electrochemical detection of chemical warfare agent simulants
Date
2009-11
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
Type
Degree Level
Masters
Abstract
This work attempted to detect chemical warfare agent (CWA) simulants via electrochemistry utilizing two approaches. The first approach consisted of a ferrocene (Fc) amino acid derivative film on Au surfaces. The molecule [(BocHN)Fc(CO)CSA]₂ was electrodeposited onto Au microelectrodes through a S–Au bond. Once immobilized, the Fc amino acid derivative was Boc deprotected allowing for the amino group to react with the target molecule. Detection of the target simulant was monitored by cyclic voltammetry (CV) while following the formal potential of the Fc molecule, which is influenced by its immediate electronic microenvironment. Reaction with either 1 mM diethyl cyanophosphonate (DECP) or 2 chloroethyl ethyl sulfide (2 CEES), both effectively simulants for the CWAs Tabun nerve agent and blistering sulfur mustard respectively, was not observed. However, detection of 1 mM acetyl chloride was achieved by observing a potential anodic shift from 217 ± 6 mV, for the Boc deprotected form, to 388 ± 7 mV for the reacted state of the molecule. The lack of reactivity with the Fc amino acid system was hypothesized as a kinetic issue.
In the second approach, the electrochemistry of gas generated naked Ag nanoparticles (NPs) deposited on indium tin oxide covered glass plates is compared to bulk polycrystalline Ag. The nano specific electrochemistry of Ag NPs has been identified and includes the preferential formation of β-oxides. In 100 mM KOH supporting electrolyte, disruption of β-oxide formation is exploited to test for the presence of 1 mM DECP resulting in the dissolution of Ag via cyanide complexes leading to a CV signal decrease. While in 8.0 M KOH, β-oxide formation is enhanced leading to testing capabilities for 1 mM 2 CEES resulting in the disappearance of the β-oxide peak and the appearance of surface oxide peak during CV. Analogous electrochemistry is not observed on polycrystalline bulk Ag.
Description
Keywords
silver nanoparticles, ferrocene amino acid derivative, chemical detection
Citation
Degree
Master of Science (M.Sc.)
Department
Chemistry
Program
Chemistry