Guidelines for determining polymer-water and polymer-polymer partition coefficients of organic compounds.

Abstract

Methods for the experimental determination of polymer-water partition coefficients (Kpw) and polymer-polymer partition coefficients (Kp1p2) are reviewed with the aim to improve the quality of passive sampling-based monitoring of organic compounds. Mechanistic models are used for optimizing the experimental design of Kpw measurements with respect to scaling (polymer mass, water volume, concentration levels) and equilibration times. It is shown that the polymer-water phase ratio has a profound effect on the rate of equilibrium attainment. Experimental artefacts are discussed and quality control measures for quantifying uncertainties in the reported Kpw values are suggested. Examples of experimental design modelling are provided. Experimental methods for determining Kp1p2 are not fully developed yet and several suggestions for the further development of Kp1p2 measurements are included. It is expected that this guideline will be useful for investigators who seek to improve their experimental procedures for determining polymer-water and polymer-polymer partition coefficients, or to assess the quality of literature values of these partition coefficients.