Bottle-in-Bag Technique for Gas Sampling with Analysis by Autoheadspace GC

A new (bottle-in-bag) method for sampling gases is presented, examined, and discussed. The bottle-in-bag (BiB) method has broad application in air pollution control, industrial hygiene, soil remediation, groundwater remediation, and biofiltration of industrial waste streams. The BiB method is more cost-effective than the Tedlar bag capture method and allows analysis by autoheadspace GC. The method entails pumping the gas source and injecting it into a standard 22-mL headspace vial, held within a Ziploc bag, followed by crimp sealing of the bottle through the sealed bag. Gases from three separate sources (isobutylene calibration gas and pilot- and field-scale biofilter gas) were sampled to test the accuracy and precision of the BiB method under different sampling conditions. The BiB method was compared to the Tedlar bag and manual gas syringe methods. Sampling with the BiB technique produced results that were more accurate (recoveries of 98% and greater) and precise (coefficients of variability as low as 0.006) than the other methods. Highly reproducible and accurate results, even when the samples were subjected to temperature extremes and the rigors of airplane travel, are a strength of the BiB method, which combined with its simplicity and cost-effectiveness give it the potential for wide use.