Development of a pre-concentrator-thermo-desorber/ micro-gas chromatograph/mass spectrometer coupling for on-site analyses of emissions of volatile organic compounds from landfills

摘要

The development and use of a pre-concentrator-thermo-desorber/micro-gas chromatograph/ mass spectrometer (μTD/μGC/MSD) coupling for the on-site analysis of VOCs in landfill gases are presented. The coupling has the advantage of analysing compounds with two detectors operated in series: the TCD (of the μGC) initially analyses the gas without destroying it, and then the MSD identifies the compounds. Due to the TCD response, the results were quantified with reference to toluene. The reliability of the analytical chain for quantitative analysis was validated by sampling two gaseous standards, including the EPA TO14 mixture, containing 39 compounds. With the OV1 μGC column, 24 compounds were identified and 16 correctly quantified. The repeatability of the measures estimated by their standard deviation was in the order of 1-2%. The detection limit was evaluated at 0.1 ppbv, for a 40min pre-concentration on the Tenax of the μTD. The results of VOC analyses in the air of a landfill site obtained with the μTD/μGC/MSD coupling show its potential for on-site analyses: immediate results, high sensitivity, no storage for the samples, and measurements of pollution peaks.