Philip Smith

ABSTRACT High temperatures are frequently used to disperse 2-chlorobenzylidene malononitrile (CS) riot control agent. We examined airborne CS degradation products heat-dispersed together with CS from canisters of a type used by law enforcement personnel for crowd and riot control. Air contaminants derived from CS were trapped using a polytetraflouroethylene filter. Analysis was by open tubular gas chromatography coupled to mass spectrometry. Compounds observed in addition to CS included 2-chlorobenzaldehyde, 2-chlorobenzonitrile, quinoline, 2-chlorobenzylcyanide, 1,2-dicyanobenzene, 3-(2-chlorophenyl)propynenitrile, cis and trans isomers of 2-chlorocinnamonitrile, 2,2-dicyano-3-(2-chlorophenyl)oxirane, 2-chlorodihydrocinnamonitrile, benzylidenemalononitrile, cis and trans isomers of 2-cyanocinnamonitrile, 2-chlorobenzylmalononitrile, 3-quinoline carbonitrile, and 3-isoquinoline carbonitrile. © 2001 John Wiley & Sons, Inc. J Micro Sep 13: 186–190, 2001

ABSTRACT Occupational air concentration ceiling standards should not be exceeded during any part of a working exposure. Air sampling with pumps, and filters or sorbent tubes may be coupled to methods such as gas chromatography for definitive identification of occupational air contaminants. With such methods, 15-minute sample durations are common for ceiling standard comparisons (to trap sufficient analyte for detection) giving a 15-minute time-weighted average, and not an instantaneous concentration. We used 2-minute duration solid phase microextraction (SPME) field sampling, followed later by gas chromatography with a nitrogen-phosphorous detector (GC/NPD) to detect, identify, and quantify airborne hydrogen cyanide (HCN) concentrations encountered in a field setting. The presence of HCN was confirmed in the atmosphere sampled by SPME field sampling followed by gas chromatography with mass spectrometric detection. The HCN-contaminated atmosphere was from two CS riot control canisters actuated in an enclosed building. With four simultaneous SPME field samples and GC/NPD analysis, the coefficient of variation associated with the HCN peak areas for the samples was 17%, and the HCN concentrations measured ranged from about 12 to 19 ppm. Acetonitrile and acrylonitrile were also detected as volatile nitrogen-containing air contaminants dispersed along with the CS, although their concentrations were not determined.

Suitable detectors are needed to support survey needs of incident responders and health care personnel who may receive patients from an incident with exposures to hazardous chemicals. In the health care setting, such a detector would avoid cross-contamination to workers, patients, and to the treatment facility and associated equipment. An ideal survey detector would be sensitive, hand-held, capable of extended battery operation, and would provide a nearly immediate detector response on exposure to a broad range of high-concern chemicals. For responders, important capabilities would include quantitative measurement of gas/vapor contamination, and for both response and health care settings, qualitative detection of contaminated people and objects. In this study, the operating characteristics of photoionization detector (PID) instruments were examined using O-isopropyl methylphosphonofluoridate (sarin) in a laboratory setting. Instrument response factors were calculated for quantitation of airborne sarin, and speed of detector response and recovery were examined with point-contaminated cloth material. By sampling a range of sarin-contaminated air, calculated isobutylene unit response factors for high-and moderate-sensitivity commercial PID instrument types were 11.3 and 14.0 (dry air) and 20.1 and 44.4 (50% relative humidity), respectively. Response of the PID systems was highly correlated to concentration sampled, with R(2) values greater than or equal to 0.997 for all combinations of PID detector type and humidity. While not sensitive enough to warn the unprotected public against a chemical with an extremely low "safe" exposure concentration, quantitation with available PID instruments could be useful to quickly prioritize corrective measures for a PID-detectable chemical. Qualitative survey characteristics were examined for the more sensitive PID tested using a piece of cloth material contaminated by a 1.0 micro L droplet of liquid sarin. Rapid response and recovery times (seconds) were observed when the sampling inlet was moved close to and away from the point of contamination. Within the health care setting, hand-held PID instruments could fill an important and currently unmet need as a point source detector for liquid contamination from extremely dangerous chemicals to help identify contaminated surfaces and limit secondary contamination and exposures.

Derivatization with N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) was used for gas chromatography-mass spectrometry (GC-MS) analysis of citrulline and ornithine. Aqueous 50 microl aliquots at 1 and 10 mM concentrations were dried and derivatized separately, and 70 eV electron ionization or CH(4) positive chemical ionization were used. Ornithine produced a single GC peak. Physiological citrulline concentrations produced GC artifact peaks for the ornithine derivative, and a compound consistent with elimination of a water molecule from the tri-tert-butyldimethylsilyl (TBDMS) citrulline derivative. A third GC peak obtained using 10 mM citrulline concentrations gave a mass spectrum consistent with a mixture of true tri- and tetra-TBDMS citrulline. Analyses of (13)C-ureido-labeled citrulline confirmed the presence of the true TBDMS citrulline derivatives produced from 10 mM samples and provided evidence that the TBDMS ornithine artifact results from loss of TBDMS isocyanate from tetra-TBDMS citrulline. Linear-programmed temperature GC retention index data relative to n-alkanes are reported for observed GC peaks.

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.

A separation technique known as solvating gas chromatography (SGC), which utilizes packed capillary columns and neat carbon dioxide as mobile phase, was used for the separation of nitroglycerine (NG) and other nitrogen-containing explosives including 2,6-dinitrotoluene (2,6-DNT), 2,4-dinitrotolulene (2,4-DNT), 2,4,6-trinitrotoluene (2,4,6-TNT), and pentaerythritol tetranitrate (PETN). SGC was coupled for the first time to a selective chemiluminescence thermal energy analyzer (TEA) detector for nitro-functional group specificity and sensitive detection of these compounds. TEA calibration curve for NG showed linearity in the sub-microg ml(-1) range. Soil samples containing NG were used to test the validity of the technique. Detector response of SGC-TEA versus SGC-flame ionization detection for NG was also evaluated.

Unusually high levels of epidermal and liver cancer have been observed in brown bullhead catfish taken from a river in an industrialized area in Ohio. Four chemical class fractions isolated from a sediment extract in this area were analyzed by capillary column gas chromatography-mass spectrometry and tested for mutagenicity in the Ames assay and for induction of unscheduled DNA synthesis

A high-surface area solid phase microextraction (HSA-SPME) sampler is described for dynamic sampling at high air velocities (up to several hundred centimeters per second). The sampling device consists of a thin wire coated with carboxen/polydimethylsiloxane (carboxen/PDMS) material, wound in the annular space between two concentric glass tubes, providing a large trapping surface from which analytes may then be thermally desorbed with little power consumption upon resistive heating of the wire. Desorbed analytes are focused and reconcentrated on a microtrap that is subsequently resistively heated to introduce analytes for GC or GC/MS analysis. Benzene, toluene, ethylbenzene, and xylenes (BTEX) included in a 39-component toxic organics (TO-14) gas mixture were used to evaluate the efficiency of the HSA-SPME sampler. Quantitation of trace-level BTEX compounds present during weapons cleaning was completed using stepwise calibration. Detection limits of 0.2-6.9 pptr(v) were observed for these analytes using single ion monitoring GC/MS analysis, and an improvement in sensitivity of several orders of magnitude was achieved when compared to standard dynamic flow SPME with a commercially available 10 mm carboxen/PDMS fiber. The potential for rapid analyte uptake and improved sensitivity using the HSA-SPME design will make it possible to rapidly collect and analyze VOC samples in field settings using a portable hand-held pump and a small, low power GC/MS instrument. This system will be especially useful for situations involving forensics, public safety, and military defensive or intelligence needs where rapid, sensitive detection of airborne analytes is required.

The chemical warfare agent O-ethyl S-(2-diisopropylaminoethyl) methyl phosphonothiolate (VX) and many related degradation products produce poorly diagnostic electron ionization (EI) mass spectra by transmission quadrupole mass spectrometry. Thus, chemical ionization (CI) is often used for these analytes. In this work, pseudomolecular ([M+H](+)) ion formation from self-chemical ionization (self-CI) was examined for four VX degradation products containing the diisopropylamine functional group. A person-portable toroidal ion trap mass spectrometer with a gas chromatographic inlet was used with EI, and both fixed-duration and feedback-controlled ionization time. With feedback-controlled ionization, ion cooling (reaction) times and ion formation target values were varied. Evidence for protonation of analytes was observed under all conditions, except for the largest analyte, bis(diisopropylaminoethyl)disulfide which yielded [M+H](+) ions only with increased fixed ionization or ion cooling times. Analysis of triethylamine-d(15) provided evidence that [M+H](+) production was likely due to self-CI. Analysis of a degraded VX sample where lengthened ion storage and feedback-controlled ionization time were used resulted in detection of [M+H](+) ions for VX and several relevant degradation products. Dimer ions were also observed for two phosphonate compounds detected in this sample.