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Document Type

Dissertation - University Access Only

Award Date

2015

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry and Biochemistry

First Advisor

Brian A. Logue

Abstract

Several methods for the bioanalysis of nerve agents or their metabolites have been developed for the verification of nerve agent exposure. However, parent nerve agents and known metabolites are generally rapidly metabolized from biological matrices typically used for analysis (i.e., blood, urine, and tissues), limiting the amount of time after an exposure that verification is feasible. In this study, hair and nails were evaluated as a long-term repositories of nerve agent hydrolysis products. Pinacolylmethylphosphonic acid (PMPA) and isopropylmethylphosphonic acid (IMPA) were extracted from hair and nail samples with N,N-dimethylformamide and subsequently analyzed by liquid chromatography-tandem mass spectrometry (LC-MS-MS). For the analysis of the nerve agent methylphosphonic acid metabolites from hair, the analysis technique produced limits of detection for PMPA and IMPA of 0.15 g/kg and 7.5 g/kg and linear ranges of 0.3-150 g/kg and 7.5-750 g/kg, respectively. To evaluate the applicability of the method to verify nerve agent exposure well after the exposure event, rats were exposed to soman, hair was collected after approximately 30 days, and stored for up to 3.5 years prior to initial analysis. PMPA was positively identified in 100% of the soman-exposed rats (N=8) and was not detected in any of the xv saline treated animals (N=6). The hair was reanalyzed 5.5 years after exposure and PMPA was detected in 5 of 7 (one of the soman-exposed hair samples was completely consumed) rat hair samples (with no PMPA detected in the saline exposed animals). The approach presented here is complementary to current nerve agent exposure verification, and should allow for extremely long-term determination of nerve agent poisoning. For analysis of nerve agent methylphosphonic acid metabolites from nails, an additional LC-MS-MS method was developed. Similar to hair, the nail matrix protects the nerve agent markers from further metabolism and excretion after an exposure. Limits of detection for PMPA and IMPA extracted from nail clippings were 0.3 g/kg and 7.5 g/kg and linear ranges were 0.75-300 g/kg and 30-1500 g/kg, respectively. Precision was less than 10% and 8% relative standard deviation for PMPA and IMPA, respectively, and accuracy was ±12% for both analytes. Two techniques for the analysis of nerve agent markers for extremely long periods of time following exposure were developed as a result of this study. The approach presented here is complementary to current short-term nerve agent exposure verification, filling a critical need in the window of detection following nerve agent exposure.

Library of Congress Subject Headings

Nerve gases
Liquid chromatography
Mass spectrometry
Chemical warfare
Toxicology

Description

Includes bibliographical references (pages 69-74)

Format

application/pdf

Number of Pages

89

Publisher

South Dakota State University

Rights

In Copyright - Educational Use Permitted
http://rightsstatements.org/vocab/InC-EDU/1.0/

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