Estimating octanol-air partition coefficients of nonpolar semivolatile organic compounds from gas chromatographic retention times.

Relative gas chromatographic retention times on a non-polar stationary phase can be used to determine the octanol-air partition coefficient (K(OA)) and the energy of phase transfer between octanol and the gas phase (delta(OA)U) for semivolatile, nonpolar organic compounds. The only prerequisites are knowledge of the temperature-dependent K(OA) of a standard reference compound and directly measured K(OA) values at one temperature for a sufficient number of calibration compounds. It is shown that the technique is capable of predicting the K(OA) of polychlorinated benzenes, biphenyls and naphthalenes as well as polybrominated diphenyl ethers within the environmentally relevant temperature range with an average deviation from directly measured values of <0.2 log units.