Simple permeation absorber for sampling and preconcentrating hazardous air contaminants.
A permeation absorber was developed and experimentally evaluated for sampling and preconcentrating vapors of a primary aromatic amine into a small volume (ca. 0.1 ml) of a liquid extractant that can be directly injected into a chromatograph or other analytical instrument. Starting with 1-l or 4-l samples containing dry or humidified air (0, 7% or 35% relative humidity) and 0.5-5 parts per million by volume of aniline, the measured collection efficiency (fraction of aniline recovered in the extractant) ranged between 60 and 100% when the samples were recirculated 3-6 times. For a single-pass non-recirculating mode, the collection efficiency is calculated to be 40-50%. The degree of preconcentration is directly proportional to the volume V of the sampled air. The collection method is simple and fast and should also be applicable to the sampling and preconcentration of other hazardous air contaminants.