Effect of temperature on the breakthrough of a charcoal tube during vinyl chloride monomer sampling

This study evaluated the effects of temperature on breakthrough of two stan dard collection media at various concentrations during vinyl chloride monom er (VCM) sampling. The National Institute for Occupational Safety and Healt h (NIOSH) and Occupational Safety and Health Administration (OSHA) methods were evaluated. To determine whether breakthrough of VCM would occur at the extremes of exposure and temperature that might be encountered in some wor kplaces, air samples containing 4 ppm (10.24 mg/m(3)), 8 ppm (20.45 mg/m(3) ), 16 ppm (40.98 mg/m(3)), and 32 ppm (81.80 mg/m(3)) of VCM were collected at temperatures of 4, 22, and 40 degrees C. Five liters of air was sampled at the rate of 0.05 L/min for 100 min using the activated charcoal tube re commended by NIOSH. A second tube was added to the sampling train to collec t any VCM that might not have been absorbed in the first tube. To collect V CM air samples by the OSHA method, two carbon molecular sieve tubes were co nnected serially and 3 L of air was sampled at the rate of 0.05 L/min for 6 0 min. A gas chromatograph with a flame ionization detector and ultra 2 cap illary column was used to analyze VCM. Significant breakthrough was found w hen sampling at higher temperatures with the NIOSH method. No breakthrough was found when samples were collected using the OSHA media at different tem peratures and concentrations. Therefore, under hot ambient conditions (>22 degrees C), the possibility of breakthrough should be considered when sampl ing VCM by the NIOSH method.