Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1021/acs.est.2c06170
Title (Primary) Octanol/air partition coefficient - A general-purpose fragment model to predict log Koa from molecular structure
Author Ebert, R.-U.; Kühne, R. ORCID logo ; Schüürmann, G.
Source Titel Environmental Science & Technology
Year 2023
Department OEC
Volume 57
Issue 2
Page From 976
Page To 984
Language englisch
Topic T9 Healthy Planet
Keywords octanol/air partition coefficient; Koa; QSAR; fragment model; ChemProp
Abstract The octanol/air partition coefficient Koa is important for assessing the bioconcentration of airborne xenobiotics in foliage and in air-breathing organisms. Moreover, Koa informs about compound partitioning to aerosols and indoor dust, and complements the octanol/water partition coefficient Kow and the air/water partition coefficient Kaw for multimedia fate modeling. Experimental log Koa at 25 °C has been collected from literature for 2161 compounds with molecular weights from 16 to 959 Da. The curated data set covers 18.2 log units (from −1.0 to 17.2). A newly developed fragment model for predicting log Koa from molecular structure outperforms COSMOtherm, EPI-Suite KOAWIN, OPERA, and linear solvation energy relationships (LSERs) regarding the root-mean-squared error (rms) and the maximum negative and positive errors (mne and mpe) (rms: 0.57 vs 0.86 vs 1.09 vs 1.19 vs 1.05–1.53, mne: −2.55 vs −3.95 vs −7.51 vs −7.54 vs (−5.63) – (−7.34), mpe: 2.91 vs 5.97 vs 7.54 vs 4.24 vs 6.89–10.2 log units). The prediction capability, statistical robustness, and sound mechanistic basis are demonstrated through initial separation into a training and prediction set (80:20%), mutual leave-50%-out validation, and target value scrambling in terms of temporarily wrong compound-Koa allocations. The new general-purpose model is implemented in a fully automatized form in the ChemProp software available to the public. Regarding Koa indirectly determined through Kow and Kaw, a new approach is developed to convert from wet to dry octanol, enabling higher consistency in experimental (and thus also predicted) Koa.
Persistent UFZ Identifier
Ebert, R.-U., Kühne, R., Schüürmann, G. (2023):
Octanol/air partition coefficient - A general-purpose fragment model to predict log Koa from molecular structure
Environ. Sci. Technol. 57 (2), 976 - 984 10.1021/acs.est.2c06170