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Title: Characterizing PUF disk passive air samplers for alkyl-substituted PAHs: Measured and modelled PUF-AIR partition coefficients with COSMO-RS. Author: Parnis JM, Eng A, Mackay D, Harner T. Journal: Chemosphere; 2016 Feb; 145():360-4. PubMed ID: 26692513. Abstract: Isomers of alkyl-substituted polycyclic aromatic hydrocarbons (PAHs) and dibenzothiophenes are modelled with COSMO-RS theory to determine the effectiveness and accuracy of this approach for estimation of isomer-specific partition coefficients between air and polyurethane foam (PUF), i.e., KPUF-AIR. Isomer-specific equilibrium partitioning coefficients for a series of 23 unsubstituted and isomeric alkyl-substituted PAHs and dibenzothiophenes were measured at 22 °C. This data was used to determine the accuracy of estimated values using COSMO-RS, which is isomer specific, and the Global Atmospheric Passive Sampling (GAPS) template approach, which treats all alkyl-substitutions as a single species of a given side-chain carbon number. A recently developed oligomer-based model for PUF was employed, which consisted of a 1:1 condensed pair of 2,4-toluene-diisocyanide and glycerol. The COSMO-RS approach resulted in a significant reduction in the RMS error associated with simple PAHs and dibenzothiophene compared with the GAPS template approach. When used with alkylated PAHs and dibenzothiophenes grouped into carbon-number categories, the GAPS template approach gave lower RMS error (0.72) compared to the COSMO-RS result (0.87) when the latter estimates were averaged within the carbon-number-based categories. When the isomer-specific experimental results were used, the COSMO-RS approach resulted in a 21% reduction in RMS error with respect to the GAPS template approach, with a 0.57 RMS error for all alkylated PAHs and dibenzothiophenes studied. The results demonstrate that COSMO-RS theory is effective in generating isomer-specific PUF-air partition coefficients, supporting the application of PUF-based passive samplers for monitoring and research studies of polycyclic aromatic compounds (PACs) in air.[Abstract] [Full Text] [Related] [New Search]