Dynamic measurements of Henry's law constant of aromatic compounds using proton transfer reaction mass spectrometry

Henry's law constants (HLC) of volatile aromatic compounds were determined using a dynamics approach by coupling a stripping cell directly to a homemade proton transfer reaction mass spectrometry (PTR-MS). The intensity of C6H6H+ ion dependence on liquid height of benzene solution was explored in order to ensure the equilibrium of aromatic compound components between the gas-bubbles and water. The HLC of benzene measured at 25 degrees C is in agreement with the reported value in literature, showing that this method is valid. HLC values were presented for benzene, toluene, ethylbenzene, chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1,2dimethylbenzene, 1,3-dimethylbenzene, 1,4-dimethylbenzene, and 1,2,4-trimethylbenzene. Compared to the conventional techniques, the dynamics extraction combination with PTR-MS is simple, fast, and less prone to artifacts in the HLC measurement.