PARTITIONING OF SEMIVOLATILE ORGANIC-COMPOUNDS BETWEEN AIR AND LOLIUM-MULTIFLORUM (WELSH RAY GRASS)

The kinetics and steady-state partitioning of semivolatile organic compounds between the gas phase and Lolium multiflorum were investigated using a solid-phase fugacity meter. This method proved to be very useful, providing precise measurements of the partitioning behavior and information on the size of the different storage compartments in the leaf. A fugacity model of the air/leaf exchange was assembled and applied to the data. A two-compartment model consisting of a small surface compartment and a large interior reservoir was employed. The two-compartment structure was necessary to describe the short-term kinetics in the leaf. A good correlation was obtained between the leaf/air partition coefficient and the octanol/air partition coefficient.