Biomedical subjects

Philip A Smith

Publications and source records attributed to Philip A Smith.

7 recordsLinked to original sources

PubMed2003

Detection of VX contamination in soil through solid-phase microextraction sampling and gas chromatography/mass spectrometry of the VX degradation product bis(diisopropylaminoethyl)disulfide.

A solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) sampling and analysis method was developed for bis(diisopropylaminoethyl)disulfide (a degradation product of the nerve agent VX) in soil. A 30-min sampling time with a polydimethylsiloxane-coated fiber and high temperature alkaline hydrolysis allowed detection with 1.0 microg of VX spiked per g of agricultural soil. The method was successfully used in the field with portable GC-MS instrumentation. This method is relatively rapid (less than 1 h), avoids the use of complex preparation steps, and enhances analyst safety through limited use of solvents and decontamination of the soil before sampling.

Chemical Warfare Agents↗

PubMed2002

Application of headspace solid-phase microextraction and gas chromatography-mass spectrometry for detection of the chemical warfare agent bis(2-chloroethyl) sulfide in soil.

A field expedient analytical method for detecting the chemical warfare agent (CWA) sulfur mustard as a soil contaminant was developed using solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS). Five commercially available SPME fibers were investigated to determine the optimal fiber, and extraction conditions. Polyacrylate and carbowax-divinylbenzene fiber coatings gave a statistically indistinguishable and best response compared to the other three types examined in a simple system studied without soil. The polyacrylate fiber coating was selected for study of a system in which sulfur mustard was spiked to an agricultural soil (Standard Reference Material 2709, San Joaquin type). With soil samples, the greatest sensitivity occurred by the addition of deionized water to spiked soil and extraction at ambient temperature for 20 min or longer. SPME sampling with GC-MS analyses afforded good reproducibility (relative standard deviation between 2 and 10%), and analyte concentrations as low as 237 ng/g were detected in soil (total ion chromatograms). As completed here, total time for sampling and analysis was just under 1 h, and use of organic solvents or special sample introduction equipment was avoided.

Chemical Warfare Agents↗

PubMed2002

Formation of 2-chlorobenzylidenemalononitrile (CS riot control agent) thermal degradation products at elevated temperatures.

2-Chlorobenzylidenemalononitrile (CS riot control agent) has been shown to produce a number of thermal degradation products when dispersed at high temperature. We hypothesized that these CS-derived compounds are formed by energy input from heating during the dispersion process. Here we identified organic CS-derived compounds formed from purified CS subjected to temperatures ranging from 300 to 900 degrees C in an inert atmosphere with analysis of tube furnace effluent by gas chromatography and mass spectrometry. We conclude that the production of many CS-derived compounds previously observed during high-temperature dispersion is likely to be heat related.

Gas Chromatography-Mass Spectrometry↗

PubMed2002

Acute pulmonary effects from o-chlorobenzylidenemalonitrile "tear gas": a unique exposure outcome unmasked by strenuous exercise after a military training event.

o-Chlorobenzylidenemalonitrile, more commonly called CS, is grouped with several other irritant agents referred to as "tear gas." It is a riot-control agent used frequently in military settings to test the ability and speed of personnel in donning their military gas masks. When personnel are exposed to CS without proper personal protective equipment, it has potent irritant effects. We report a unique cluster of hospitalizations of nine U.S. Marines who developed a transient pulmonary syndrome. All nine patients had symptoms of cough and shortness of breath. Five of the nine presented with hemoptysis, and four presented with hypoxia. Symptoms were associated with strenuous physical exercise from 36 to 84 hours after heavy exposure of CS in a field training setting. Four of the nine Marines required intensive care observation as a result of profound hypoxia. All signs and symptoms resolved within 72 hours of hospital admission. One week after CS exposure, all nine Marines demonstrated normal lung function during spirometry before and after exercise challenge using cycle ergometry.

Adolescent↗

PubMedDate not supplied

Traditional sampling with laboratory analysis and solid phase microextraction sampling with field gas chromatography/mass spectrometry by military industrial hygienists.

The opinions or assertions contained herein are the private ones of the authors and are not to be construed as official or reflecting the views of the United States Department of Defense or the Uniformed Services University of the Health Sciences. Rapid on-site detection and identification of environmental contaminants to which personnel may be exposed is often needed during military deployment situations. The availability of military industrial hygienists with capabilities for "complete" on-site exposure assessment of chemical species should allow detection and identification of a number of important stressors almost immediately following sample collection. Portable gas chromatography/mass spectrometry (GC/MS) provides a rapid and efficient separation of volatile and semivolatile organic analytes, accompanied by sensitive electron impact ionization-mass spectrometry (EI-MS) detection. The use of GC/MS in the field is limited, however, by equipment cost, complexity of the equipment, and the analytical process. Additionally, a skilled operator is needed to obtain useful separations and to interpret mass spectral data. To demonstrate benefits and limitations of "complete" exposure assessment capabilities, a previously unidentified complex mixture, produced by thermal dispersion of riot control agents, was examined. Established active sampling methods were used with laboratory analyses. Solid phase microextraction, a passive sampling method that simplifies preparation for GC/MS analysis, also was used with a field-portable GC/MS system. Both sampling/analysis methods were used to detect CS riot control agent-derived air contaminants dispersed from riot control type canisters through oxidizer-supported combustion of a chemical fuel.

Chemistry Techniques, Analytical↗

PubMedDate not supplied

Liberation of hydrogen cyanide and hydrogen chloride during high-temperature dispersion of CS riot control agent.

High temperature dispersion (greater than 700 degrees C) of the riot control agent orthochlorobenzylidenemalononitrile (CS) has previously been shown to produce a number of organic thermal degradation products through rearrangements and loss of cyano and chlorine substituents present on the parent CS compound. Until now the possibility that HCN and HCl might also be air contaminants produced during high temperature CS dispersion has not been examined. Air samples were collected to detect HCN and HCl as air contaminants released during high-temperature CS dispersion indoors. Sampling and analysis based on National Institute of Occupational Safety and Health methods 7904 and 6010 for HCN, and 7903 for HCl, showed evidence that both compounds were present in air samples collected. A reassessment of human health risks associated with exposure to CS riot control agent dispersed at high temperature should be conducted, and should consider the full range of contaminants produced during the dispersion process.

Environmental Exposure↗

PubMedDate not supplied

Volatile organic compounds produced during irradiation of mail.

In 2001, Bacillus anthracis spores were delivered through the United States postal system in a series of bioterrorist acts. Controls proposed for this threat included sanitization with high-energy electrons. Solid phase microextraction was used with gas chromatography/mass spectrometry for field sampling and analysis of volatile compounds apparently produced from polymeric materials such as cellulose and plastics, immediately following processing of mail at a commercial irradiation facility. Solid phase microextraction and direct sampling of air into a cryogenically cooled temperature programmable inlet were used in the laboratory for gas chromatography/mass spectrometry analysis of air in contact with irradiated mail, envelopes only (packaged identically to mail), and air inside irradiated plastic mail packaging bags (with neither mail nor envelopes). Irradiated mail or envelope systems produced hydrocarbons such as propane, butane, pentane, hexane, heptane, methylpentanes, and benzene; and oxygen-containing compounds such as acetaldehyde, acrolein, propionaldehyde, furan, 2-methylfuran, methanol, acetone, 2-butanone, and ethanol. In addition to hydrocarbons, methyl and ethyl nitrate were detected in irradiated bags that contained only air, suggesting reactive nitrogen species formed from air irradiation reacted with hydroxy-containing compounds to give nitro esters. The similarities of volatile compounds in irradiated systems containing paper to those observed by researchers studying cellulose pyrolysis suggests common depolymerization and degradation mechanisms in each case. These similarities should guide additional work to examine irradiated mail for chemical compounds not detectable by methods used here.

Air Pollution, Indoor↗