Unknown Exposures: Gaps in Basic Characterization Addressed with Person-Portable Gas Chromatography-Mass Spectrometry Instrumentation

Abstract

A newly developed person-portable gas chromatography-mass spectrometry (GC-MS) system was used to analyze several solvent standards, contact cement, paint thinner, and polychlorinated biphenyl samples. Passive solid phase microextraction sampling and fast chromatography with a resistively heated low thermal mass GC column were used. Results (combined sampling and analysis) were obtained in <2 min for solvent, contact cement, and paint thinner samples, and in <13 min for the polychlorinated biphenyl sample. Mass spectra produced by the small toroidal ion trap detector used were similar to those produced with heavily used transmission quadrupole mass spectrometers for polychlorinated biphenyl compounds, simple alkanes, and cycloalknes, while mass spectra for benzene and the ketone compounds analyzed showed evidence for ion/molecule reactions in the ion trap. For one of the contact cement samples analyzed, no evidence was found to indicate the presence of n-hexane, although the relevant material safety data sheet listed this ingredient. Specific chemical constituents corresponding to a potentially wide range of petroleum distillate compounds were identifiable from GC-MS analyses. The possibility for an improved basic characterization step in the exposure assessment process exists with the availability of fast, person-portable GC-MS, although work is needed to further refine this tool and understand the best ways it may be used.

Keywords:

• exposure assessment
• gas chromatography
• mass spectrometry
• real-time analysis

ACKNOWLEDGMENTS

This work was financially supported by the U.S. Marine Corps Systems Command. The views presented are those of the authors, and do not represent those of their respective organizations.

Notes

^A MSDS last revised December 1999.

^B MSDS last revised August 1999.

^C MSDS last revised October 2005.

*MSDS lists concentration of 10.0–5.0%. This is likely an error as a related product MSDS lists n-hexane 10.0–15.0%.

^A Dimer ion = [2M+H]⁺.

^B Dimer ion = [2M–H]⁺.

^A Verified to be components of contact cement 1 by GC-TMS analysis (Figure 1) or listed in the relevant MSDS in error as a mixture component.

^B 2010 TLV-TWA ppm.^{( 31 )}

^C Vapor pressure at 25°C, mmHg.

^D VHR = [vapor pressure (mmHg) · 10⁶][TLV · 760 mmHg].

^E Determined by transmission quadrupole GC-MS and GC-TMS analyses to be listed as a component of contact cement 1 in error.