Predicting low density polyethylene-air partition coefficients using theoretical linear solvation energy relationships

Passive air samplers have proven to be a widely used technique in measuring hydrophobic organic compounds (HOCs) in the atmosphere. Chemical partition coefficients between the sorbent material and air (K_PE-a) are significant for calculating chemical concentrations from passive sampling devices. We have established a theoretical linear solvation energy relationship (TLSER) model for predicting K_PE-a values by molecular descriptor. With the TLSER model, McGowan volume (V), chemical hardness (η) and dipole moment (DM) were screened as the most relevant variables. The model had a high correlation coefficient (R²), leave-one-out cross-validation coefficient (Q²_LOO) and bootstrapping coefficient (Q²_BOOT). To our knowledge, this is the first attempt to predict the LDPE-air partition coefficient using the TLSER model. Statistical parameters, determination coefficient (R²) and cross-validation coefficients (Q²) ranged from 0.896 to 0.931 and 0.883 to 0.909, respectively, which indicated that the TLSER model appropriately fitted the results, and also showed robustness and predictive capacity. Mechanism interpretation suggested that the factors governing the partition process for LDPE and air were the McGowan volume and molecular orbital energies. The results of this study provide a good tool for predicting log K_PE-a values of HOCs, within the applicability domains to reduce cost and time for innovation.