Method development for on-site monitoring of volatile organic compounds via portable TD-GC-MS: evaluation of the analytical performances of HAPSITE ER instrumentation and thermal desorption sampling media.

Determining worker exposure to hazardous volatile organic compounds (VOCs) in air at levels exceeding the Permissible Exposure Limits and Recommended Exposure Limits established by the U.S. federal agencies of Occupational Safety and Health Administration (OSHA) and the National Institute for Occupational Safety and Health (NIOSH), respectively, will continue to be an important part of environmental and occupational health risk assessments. The purpose of this work was to develop a reliable analytical method for rapid and on-site assessments of occupational VOC exposures using field-capable thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) instrumentation (i.e. the HAPSITE ER). The experiments involved in this study included determining TD-GC-MS parameters suitable for efficient analyte separation and quantitation on the HAPSITE ER, determinations of analyte mass loadings that cause mass spectrometer detector saturations, generation of calibration curves, estimations of the limits of detection (LODs) and quantification (LOQs), as well as desorption efficiency and relative response factor repeatability. The LODs using Carbopack B and Tenax TA sampling media were estimated and ranged from 0.2-1.9 ng and 0.045-0.3 ng, respectively. The LOQs using Carbopack B and Tenax TA sampling media were estimated and ranged from 1.0-6.3 ng and 0.2-1.1 ng, respectively. We have developed a reliable analytical method for chloroform, benzene, trichloroethylene, and heptane using field-portable HAPSITE ER instrumentation and Tenax TA sorbent media. Reliable and accurate methods were developed for chloroform and trichloroethylene using Carbopack B sorbent media, however, this particular sorbent hadlow desorption efficiency and insufficient repeatability in relative response factors for many analytes. Our current and ongoing work in determining the uptake rates for analytes on Tenax TA sorbent media will make the methods described herein applicable for on-site occupational VOC exposure assessments of chloroform, benzene, trichloroethylene, and heptane using either passive or active air sampling techniques.