Standard Article

Field-Based Analysis of Organic Vapors in Air

Field-portable Instrumentation

  1. Richard E. Berkley

Published Online: 15 SEP 2006

DOI: 10.1002/9780470027318.a0910

Encyclopedia of Analytical Chemistry

Encyclopedia of Analytical Chemistry

How to Cite

Berkley, R. E. 2006. Field-Based Analysis of Organic Vapors in Air. Encyclopedia of Analytical Chemistry. .

Author Information

  1. US Environmental Protection Agency, Research Triangle Park, NC, USA

Publication History

  1. Published Online: 15 SEP 2006

Abstract

Volatile organic compounds (VOCs) exist in the vapor phase in ambient air at partial pressures ranging from less than 1 part per billion to a few parts per million. Some of them are toxic and potentially harmful to the environment and to human health. The threshold concentrations at which individual compounds become harmful is often not well defined, and less is known about mixtures. Accurate assessment of health risk requires analytical methods that are accurate, affordable, convenient, fast, and sensitive enough to detect each compound at a concentration below the threshold of harmful effect. The usual approach to identification and quantitation of them has been to collect samples and submit them to laboratory analysis. United States Environmental Protection Agency (USEPA) Method TO-14 is a standard procedure for analyzing a group of 41 potentially harmful nonpolar and semipolar organic compounds, which is in widespread use and has been found to detect and measure target compounds reliably under most conditions. However, more rapid delivery of data is often needed, and samples can deteriorate during storage pending analysis. Alternative analytical methods that produce immediate data are needed. Analysis of samples at the time and place of collection has seldom been done because of the lack of suitable equipment and the vicissitudes of operating it under field conditions. Portable or field-deployable gas chromatographs (PGCs) have, with cause, been regarded as less accurate than laboratory equipment, and a perception remains that analyses done in the field are less useful than those done in the laboratory. In fact, laboratory- and field-based analyses each have inherent advantages and disadvantages, and using them together can finesse the disadvantages of both. A high-speed gas chromatograph (GC) using a time-of-flight mass spectrometer (TOFMS) detector can mitigate the problem of delayed data.