A system coefficient approach for quantitative assessment of the solvent effects on membrane absorption from chemical mixtures

Abstract

A system coefficient approach is proposed for quantitative assessment of the solvent effects on membrane absorption from chemical mixtures. The complicated molecular interactions are dissected into basic molecular interaction forces via Abraham's linear solvation energy relationship (LSER). The molecular interaction strengths of a chemical are represented by a set of solute descriptors, while those of a membrane/chemical mixture system are represented by a set of system coefficients. The system coefficients can be determined by using a set of probe compounds with known solute descriptors. Polydimethylsiloxane (PDMS) membrane-coated fibres and 32 probe compounds were used to demonstrate the proposed approach. When a solvent was added into the chemical mixture, the system coefficients were altered and detected by the system coefficient approach. The system coefficients of the PDMS/water system were (0.09, 0.49, −1.11, −2.36, −3.78, 3.50). When 25% ethanol was added into the PDMS/water system, the system coefficients were altered significantly (0.38, 0.41, −1.18, −2.07, −3.40, 2.81); and the solvent effect was quantitatively described by the changes in the system coefficients (0.29, −0.08, −0.07, 0.29, 0.38, −0.69). The LSER model adequately described the experimental data with a correlation coefficient (r ²) of 0.995 and F-value of 1056 with p-value less than 0.0001.

Keywords:

• Membrane absorption
• Chemical mixtures
• Solvent effects
• System coefficient approach
• Solute descriptors

Acknowledgements

This work was supported by NIOSH, Grant R01-OH-07555 and US Air Force, Office of Scientific Research, Grants F49620-01-1-0080 and FA9550-04-1-0376.