Evaporation and Degradation of VX on Silica Sand

Brevett, Carol A.; Sumpter, Kenneth B.; Pence, John J.; Nickol, Robert G.; King, Bruce E.; Giannaras, Chris V.; Durst, H. D.

doi:10.1021/jp8111099

Cited by 38 publications

(42 citation statements)

References 15 publications

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“…In such a situation, hydrolytic degradation, once initiated, may proceed to completion (Yang et al, 1996;Brevett et al, 2009). …”

Section: Comment On Vx Stabilitymentioning

confidence: 99%

Stability Study for Ultra-Dilute Chemical Warfare Agent Standards

Leif¹,

Koester²,

Mulcahy³

2012

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Executive SummaryUltra-dilute (10 ppm) chemical warfare agent (CWA) standards are being supplied to the Environmental Response Laboratory Network (ERLN) laboratories to allow the use of authentic standards to assist in analyses required in the aftermath of a terrorist attack with CWAs. It is critical for the ERLN laboratories to be able to work with authentic CWA standards to allow the unambiguous identification and quantification of CWAs. The ultradilute standards are synthesized in-house for use in analytical method development by the ERLN laboratories. However, data regarding the long-term stability of the ultra-dilute standards are lacking. For this reason, a study was undertaken to monitor the concentrations of CWAs in ultra-dilute standards as a function of time, under normal conditions of storage and use. The data collected in such a study could then be used to estimate reliable holding times for the ultra-dilute standards.CWAs in single-component and five-component standard solutions, containing 510 ppm each CWA in hexane and dichloromethane (DCM), were studied. The CWAs studied included sarin (GB), soman (GD), cyclohexylsarin (GF), sulfur mustard (HD), and O-ethyl-S-(2-diisopropylaminoethyl) methylphosphonothioate (VX). The specific objectives were the following:1. Measure the stability, over the course of 12 months, of single-component ultradilute (10 ppm) CWA standards that were stored at 4 C in the dark, 2. Measure the stability over the course of 12 months of multiple-component ultradilute (510 ppm) CWA standards that were stored at 4 C in the dark, 3. Determine if CWA stability differs in single-and multiple-component mixtures, 4. Determine if solvent choice (hexane versus DCM) affected holding time, and 5. Compare the stabilities of CWA standards stored in flame-sealed amber glass ampoules versus CWA standards stored in amber glass vials closed with Teflonlined, silicone septa screw caps that were opened and closed periodically.After the CWA standards were prepared in the desired solvent, 1-mL aliquots were transferred to amber glass ampoules and flame-sealed or transferred to screw-capped vials. All ampoules and vials were stored at 4°C ± 2 °C in a refrigerator. Duplicate ampoules/vials were opened at predetermined times and CWA concentrations were measured using a gas chromatograph coupled with a flame photometric detector (GC-FPD). CWA concentrations were plotted as a function of time over the course of one year. Selected samples were also analyzed by gas chromatography/mass spectrometry (GC/MS) to identify contaminants/degradation products.Estimated holding times for CWA standards under different conditions were determined using Dunnett's Test (Hsu 1996) to identify the time point before which a statistically significant decrease in analyte concentration occurred; see Table 1. Results for individual standards stored in sealed ampoules showed that the CWA standards made in DCM were stable for a year. Individual standards of CWAs stored in hexane and in sealed ampoules showed varying stabili...

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“…In such a situation, hydrolytic degradation, once initiated, may proceed to completion (Yang et al, 1996;Brevett et al, 2009). …”

Section: Comment On Vx Stabilitymentioning

confidence: 99%

Stability Study for Ultra-Dilute Chemical Warfare Agent Standards

Leif¹,

Koester²,

Mulcahy³

2012

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“…In addition, this information can support the choice of the decontamination technology for a specific scenario. In recent years some data was published on the desorption characteristics of the persistent CWAs O ‐ethyl S ‐2‐( N , N ‐diisopropylamino)ethyl methylphosphonothiolate) (VX) and sulfur mustard (HD) from numerous surfaces using laboratory‐sized wind tunnel devices. The results showed that bitumen‐containing surfaces, such as asphalt blocks, conserve VX and slowly release it over a long period of weeks to months .…”

Section: Introductionmentioning

confidence: 99%

Evaporation of the Nerve Agent GB From Common Matrices: A Model‐System Study

Columbus

Marcovitch

Elias

et al. 2018

CLEAN Soil Air Water

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The measurement of a temperature‐dependent volatilization rate of the nerve agent GB (sarin) from various common matrices, using a laboratory‐designed wind tunnel (model system), is described. Small GB droplets are dispersed on the matrices surfaces, and samples are collected from the model system and analyzed utilizing a solid phase extraction/gas chromatography analytical method. Profiles demonstrating the vapor concentrations as a function of time are calculated. The results indicate that asphalt blocks relatively conserve GB, exhibiting a slow‐release mode of action over at least 2 weeks. Nevertheless, using standard decontamination procedures such as super tropical bleach may prevent this secondary evaporation risk. The concentration profile of commercial sidewalk bricks show a moderate decay, probably due to the existence of basic sites in the cement‐containing bricks. Fast clearance of GB is measured from smooth surface tiles, as these porous tiles both adsorb and/or degrade GB droplets very quickly.

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“…In general, chemical reactions between and within any of the solid, liquid, or gases present in the porous media may occur. Such phenomena can contribute to the fate of droplets …”

Section: Introductionmentioning

confidence: 99%

Fate of a sessile droplet absorbed into a porous surface experiencing chemical degradation

et al. 2014

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A general‐purpose multiphase and multicomponent computer model was developed for simulation of the spread, evaporation, and chemical reaction of sessile droplet(s) in porous substrates. In the model, chemical reactions were allowed in or between any of the liquid, gas, or solid phases present. The species mass and momentum conservation equations were solved on a finite difference mesh representing the domain. These equations were marched in time using the Runge–Kutta fourth‐order method. The model's function was studied via simulation of experiments, both those performed by the authors and found in the literature. These simulations demonstrated a quantitative match to the time history of product evolution and a similar spread of liquid reactants. The model may be particularly beneficial for predicting the extent of contamination and the possible threat outcomes of those chemical agents that are harmful when introduced into the environment. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2557–2565, 2014

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Evaporation and Degradation of VX on Silica Sand

Cited by 38 publications

References 15 publications

Stability Study for Ultra-Dilute Chemical Warfare Agent Standards

Stability Study for Ultra-Dilute Chemical Warfare Agent Standards

Evaporation of the Nerve Agent GB From Common Matrices: A Model‐System Study

Fate of a sessile droplet absorbed into a porous surface experiencing chemical degradation

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