Measuring partition coefficients of VOC's and their temperature dependence by dynamic stripping and Proton-Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-ToF_MS)

Air-water partition coefficients play a significant role in understanding processes like aroma release from food, for many environmental phenomena or in medical analysis (breath analysis). The equilibrium of gas dissolved in a liquid (e.g. water) can be described via Henry`s Law constant (HLC). We have developed and validated a dynamic approach using a stripping cell configuration coupled on-line to a PTR-ToF-MS to measure with high accuracy the HLC of VOCs. This methodology allows the rapid determination of water-air partition coefficients, even for molecules with low volatility, and over an extended temperature range (25-90°C)