A monitor for vinyl chloride monomer (VCM) in ambient air was constructed using commercially available components of a gas chromatograph (GC) coupled with a chemiluminescence ozone analyzer slightly modified to make it suitable for use as a GC detector. The specificity for VCM is enhanced by use of a chemiluminescence detector because saturated hydrocarbons do not chemiluminesce with ozone. A custom absorption trap capable of concentrating the VCM from one liter (or more) of ambient air was used to extend the lower detection limit. Using a custom trap heating circuit, the concentrated sample can be thermally eluted into the GC in a gas volume of 10 ml or less, providing a 100-fold increase in sensitivity compared to that obtained with a 10 ml sample loop. Preliminary system and final acceptance test results are reported in detail. These test results indicate that a monitor of this type can detect less than one part per billion (ppb) of VCM in ambient air operating on a 15-minute cycle. If the concentration trap is replaced by a 20 ml sample loop, the limit of detection is estimated to be about 35 ppb VCM when operating on a 5-minute cycle.

"EPA-600/2-78-008." EPA contract no. 68-02-1770; EPA project officer: Ralph Baumgardner.