Evaluation of tetraglyme for the enrichment and analysis of volatile organic compounds in air

A recently developed method for the sampling and analysis of volatile organ ic compounds in air has been evaluated. The system is based on the enrichme nt of analytes in tetraethylene glycol dimethyl ether or tetraglyme, a wate r-soluble organic liquid. The subsequent analysis consists of dispersion of a sample aliquot in water followed by purge-and-trap and gas chromatograph ic separation. Physico-chemical data were investigated for 10 volatile orga nic compounds, providing information on the possibilities and limitations o f the tetraglyme method. The target analytes included chlorinated alkanes a nd alkenes, and monocyclic aromatic hydrocarbons. Air/tetraglyme partition coefficients K-at were determined over an environmental relevant temperatur e range of 2-25 degreesC to evaluate sorption efficiencies and estimate bre akthrough volumes at the sampling stage. At 2 degreesC breakthrough volumes (allowing 5% of breakthrough) ranged from 5.8 (1,l-dichloroethane) to 312 l (1,1,2-trichloroethane) for 20 mi of tetraglyme. With regard to the desor ption stage, the effect of tetraglyme on the air/water partition of organic compounds was investigated through the measurement of air/tetraglyme-water partition coefficients Kat-w for 2-31% (v/v) tetraglyme in water. Finally a clean-up procedure for tetraglyme was evaluated. Analysis of a blank tetr aglyme-water (17:83, v:v) mixture by gas chromatography-flame ionization de tection/mass spectrometry showed minor background signals. None of the targ et compounds were detected. (C) 2001 Elsevier Science B.V. All rights reser ved.