Analysis of Volatile Chemicals in the Workplace by Fourier Transform Infrared Spectroscopy

Abstract

Fourier transform infrared (FTIR) instrumentation was evaluated to determine if it has the capability to singly monitor mixtures of volatile organic chemicals (VOCs) at or below their threshold limit value. The system investigated to monitor work sites for the presence of VOCs was the Perkin-Elmer 1760x Fourier Transform Infrared Spectrometer equipped with a 20-meter Wilks/Foxboro gas cell. Six different work areas were chosen for this study: a photography lab, a dry-cleaning establishment, surgical operating rooms in a vivarium, a histology lab, a paint stripping shop, and a paint spraying facility. The contents of workplace air samples collected in Teflon^™ bags were identified by matching FTIR sample spectra against known VOC spectra stored in a computerized library and by manual spectral comparisons. The FTIR monitoring of the workplace air samples identified single volatile components in the photography laboratory (acetic acid), and the two medical operating rooms (forane, halothane). Air samples from the other work sites contained mixtures of VOCs: dry-cleaning facility—140°F petroleum naphtha; histology—ethanol, xylene, trioxane; paint stripping—ammonia, toluene, isopropanol, methylene chloride; paint spraying—methyl ethyl ketone, methyl isobutyl ketone, n-butyl acetate, toluene, 1, 1, 1-trichloroethane. Quantitation of the chemicals identified in the workplace was determined by linear regression analysis. Concentrations of the samples ranged from sub parts per million to nearly 1000 ppm. It was possible to identify and quantitate all workplace samples within 15 minutes to 2 hours using this FTIR method.