http://precedings.nature.com/tags/perfluoroalkyl%20carboxylates Recently posted documents tagged with 'perfluoroalkyl carboxylates' Nature Publishing Group en Nature Precedings http://precedings.nature.com/images/header_logo.gif http://precedings.nature.com http://dx.doi.org/10.1038/npre.2009.3282.2 New experimental data is available in the literature regarding the octanol-water distribution behavior of representative straight chain perfluoroalkyl carboxylate (PFCA) and sulfonate (PFSA) congeners. The current study provides the first investigation into the predictive ability of various software programs for estimating the corresponding octanol-water partitioning (log P) and distribution (log D) constants of PFCAs and PFSAs. Wide predictive variation was found within and between the various methods. Several programs were able to accurately estimate the log P/D fragmental contributions of a -CF2- group for PFCAs, as well as the associated Gibbs free energies for partitioning into octanol from water due to the hydrophobic character of the perfluoroalkyl chain (ΔhydrophobicGow). Only the SPARC log D method accurately predicted the electrostatic contributions of the carboxylate head group (ΔelectrostaticGow) towards octanol-water partitioning for PFCAs. Similar log D values and organic carbon normalized sediment-water partitioning coefficients (Koc) for PFCAs and PFSAs having equivalent perfluoroalkyl chain lengths suggests potentially equivalent ΔelectrostaticGow and ΔhydrophobicGow contributions towards lipophilic partitioning for these two contaminant classes at near neutral pH values, regardless of head group identity. In contrast, there are potentially different ΔelectrostaticGow and ΔhydrophobicGow contributions towards proteinophilic partitioning under biologically relevant conditions. http://dx.doi.org/10.1038/npre.2009.3282.2 Mon, 01 Jun 2009 10:51:14 UTC A comparative assessment of octanol-water partitioning and distribution constant estimation methods for perfluoroalkyl carboxylates and sulfonates doi:10.1038/npre.2009.3282.2 2009-06-01 Sierra Rayne Nature Precedings 2009-06-01T10:51:14Z Manuscript Chemistry Earth & Environment http://creativecommons.org/licenses/by/3.0/ http://precedings.nature.com/documents/3282/version/1 New experimental data is available in the literature regarding the octanol-water distribution behavior of representative straight chain perfluoroalkyl carboxylate (PFCA) and sulfonate (PFSA) congeners. The current study provides the first investigation into the predictive ability of various software programs for estimating the corresponding octanol-water partitioning (log P) and distribution (log D) constants of PFCAs and PFSAs. Wide predictive variation was found within and between the various methods. Several programs were able to accurately estimate the log P/D fragmental contributions of a -CF2- group for PFCAs, as well as the associated Gibbs free energies for partitioning into octanol from water due to the hydrophobic character of the perfluoroalkyl chain (ΔhydrophobicGow). Only the SPARC log D method accurately predicted the electrostatic contributions of the carboxylate head group (ΔelectrostaticGow) towards octanol-water partitioning for PFCAs. Similar log D values and organic carbon normalized sediment-water partitioning coefficients (Koc) for PFCAs and PFSAs having equivalent perfluoroalkyl chain lengths suggests potentially equivalent ΔelectrostaticGow and ΔhydrophobicGow contributions towards lipophilic partitioning for these two contaminant classes, regardless of head group identity. In contrast, there are potentially different ΔelectrostaticGow and ΔhydrophobicGow contributions towards proteinophilic partitioning. http://precedings.nature.com/documents/3282/version/1 Tue, 26 May 2009 10:22:59 UTC A comparative assessment of octanol-water partitioning and distribution constant estimation methods for perfluoroalkyl carboxylates and sulfonates hdl:10101/npre.2009.3282.1 2009-05-26 Sierra Rayne Nature Precedings 2009-05-26T10:22:59Z Manuscript Chemistry Earth & Environment http://creativecommons.org/licenses/by/3.0/ http://precedings.nature.com/documents/3256/version/1 SPARC, KOWWIN, and ALOGPS octanol-water partitioning (log Kow) and distribution (log D) constants were calculated for all C1 through C8 and the straight chain C9 through C15 perfluoroalkyl sulfonic acids (PFSAs) and carboxylic acids (PFCAs). Application of five established models for estimating bioconcentration factors (BCFs) were applied to the PFSA and PFCA log Kow and log D data and compared to available field and laboratory BCF data. Wide variability was observed between the methods for estimating log Kow and log D values, ranging up to several log units for particular congeners, and which was further compounded by additional variability introduced by the different BCF equations applied. With the exception of n-perfluorooctanecarboxylic acid (n-PFOA), whose experimental BCF was poorly modeled by all approaches, the experimental BCF values of the other PFSA and PFCA congeners were reasonably approximated by the ALOGPS log P values in combination with any of the five log Kow based BCF equations. The SPARC and KOWWIN log Kow and log D values provided generally less accurate BCF estimates regardless of the BCF equation applied. However, the SPARC Kow values did provide BCF estimates for PFSA congeners with errors http://precedings.nature.com/documents/3256/version/1 Mon, 18 May 2009 14:05:29 UTC An assessment of organic solvent based equilibrium partitioning methods for predicting the bioconcentration behavior of perfluorinated sulfonic acids, carboxylic acids, and sulfonamides hdl:10101/npre.2009.3256.1 2009-05-18 Sierra Rayne Nature Precedings 2009-05-18T14:05:29Z Manuscript Chemistry Earth & Environment http://creativecommons.org/licenses/by/3.0/ http://precedings.nature.com/documents/2936/version/1 Perfluoroalkyl carboxylates are contaminants whose environmental fate and toxicological effects are of broad interest within the academic, industrial, and governmental science and regulatory communities. In addition, coupled perfluoroalkyl and carboxylate moieties are often used in medicinal chemistry as part of the drug design process. However, to date there has been a notable absence of reliable acidity constant estimation programs for these compounds. Here we report that the ADME/Tox WEB method for in silico pKa value predictions is more accurate than the PM6, SPARC, and COSMOtherm methods for the longer chain perfluoroalkyl carboxylic acids, suggesting this may be a good general acidity constant estimation approach for these compounds. http://precedings.nature.com/documents/2936/version/1 Tue, 10 Mar 2009 14:27:55 UTC ADME/Tox WEB in silico predictions of longer chain perfluoroalkyl carboxylic acid pKa values are more accurate than other computational methods hdl:10101/npre.2009.2936.1 2009-03-10 Sierra Rayne Nature Precedings 2009-03-10T14:27:55Z Manuscript Chemistry Pharmacology Earth & Environment http://creativecommons.org/licenses/by/3.0/