UNDERESTIMATION OF INDOOR AIR CONCENTRATIONS; COMPARISON OF TENAX-ADSORPTION/THERMAL DESORPTION WITH DIFFERENT SORBENTS/LIQUID EXTRACTION

摘要

Reference procedures for determining volatile polar and non-polar organic compounds using different sorbents are compared to additional measurements of air samples adsorbed on Tenax TA followed by thermal desorption (TD). Tendencies for a relationship between absolute concentrations and divergence of measurements could be found. Results differ remarkably within compound classes with higher air-concentrations obtained by TD-analysis. Concentrations of homogeneous groups as aldehydes or terpenes show little variability. In the glycol-derivatives there is a split in a less-polar group with a factor of 1 and a polar group (acetates) with factors around 2. For alkanes and aromates continuously distributed deviations were obtained due to compound structure. Conclusions can be drawn that ,,real" air-concentrations are underestimated when using the liquid desorption procedures: for example for styrene a loss by a factor of 3 was found. A discussion is needed about how far reference-values and TVOC are concerned from these findings.