Correlation of the octanol/water partition coefficient with clearance halftimes of intratracheally instilled aromatic hydrocarbons in rats

International Nuclear Information System (INIS)

Bond, J.A.; Baker, S.M.; Bechtold, W.E.

1985-01-01

Studies on the lung retention of polycyclic aromatic hydrocarbons (PAH) after inhalation have indicated that, in general, the PAH are rapidly cleared from the respiratory tract. Clearance of the PAH from the lungs is best described as bi-phasic, with the long-term component of the clearance curve having a half-time of greater than 24 h. The purpose of this study was to determine whether a relationship exists between the lipophilicity (as measured by the octanol/water partition coefficient, P) of various PAH and the short-term and long-term clearance half-times of PAH in rat lungs. Female F344/Crl rats were administered intratracheally 1 nmol of 14 C-labelled anthracene (AN), benz (a) anthracene (BA), 1-nitropyrene (NP), 6-nitrobenzo (a) pyrene (6-NBP), or dibenzo (c, g) carbazole (DBC). At various times after instillation rats were sacrificed and the amount of 14 C from rat lungs following instillation of the different PAH was biphasic. In all cases, greater than 85% of the initial dose instilled was cleared with a half-time of less than 1 h. The half-times for clearance of the residual 14 C (1-15% of the dose) were 26, 30, 36, 53 and 63 h for AN, NP, 6-NBP, BA and DCB, respectively. The log of the octanol-water partition coefficients for the different PAH examined ranged from 4.1 (AN) to 6.05 (DBC). Plots of the octanol/water coefficients vs. the long-term clearance half-time for the PAH indicated a linear correlation (p 2 =0.96). The results from this study indicate that the greater the lipophilicity of the PAH, the slower the long-term clearance of a small fraction (1-15%) of PAH from rat lungs. These data suggest that predictions of long-term lung clearance can be made for PAH with log octanol-water partition coefficients between 4 and 6. (author)

Zone fluidics for measurement of octanol-water partition coefficient of drugs.

Science.gov (United States)

Wattanasin, Panwadee; Saetear, Phoonthawee; Wilairat, Prapin; Nacapricha, Duangjai; Teerasong, Saowapak

2015-02-20

A novel zone fluidics (ZF) system for the determination of the octanol-water partition coefficient (Pow) of drugs was developed. The ZF system consisted of a syringe pump with a selection valve, a holding column, a silica capillary flow-cell and an in-line spectrophotometer. Exact microliter volumes of solvents (octanol and phosphate buffer saline) and a solution of the drug, sandwiched between air segments, were sequentially loaded into the vertically aligned holding column. Distribution of the drug between the aqueous and octanol phases occurred by the oscillation movement of the syringe pump piston. Phase separation occurred due to the difference in densities. The liquid zones were then pushed into the detection flow cell. In this method, absorbance measurements in only one of the phase (octanol or aqueous) were employed, which together with the volumes of the solvents and pure drug sample, allowed the calculation of the Pow. The developed system was applied to the determination of the Pow of some common drugs. The log (Pow) values agreed well with a batch method (R(2)=0.999) and literature (R(2)=0.997). Standard deviations for intra- and inter-day analyses were both less than 0.1log unit. This ZF system provides a robust and automated method for screening of Pow values in the drug discovery process. Copyright © 2014 Elsevier B.V. All rights reserved.

Determining octanol-water partition coefficients for extremely hydrophobic chemicals by combining 'slow stirring' and solid phase micro extraction

NARCIS (Netherlands)

Jonker, Michiel T O

Octanol-water partition coefficients (Kow ) are widely used in fate and effects modelling of chemicals. Still, high quality experimental Kow data are scarce, in particular for very hydrophobic chemicals. This hampers reliable assessments of several fate and effect parameters and the development and

Estimation of octanol/water partition coefficient and aqueous solubility of environmental chemicals using molecular fingerprints and machine learning methods

Science.gov (United States)

Octanol/water partition coefficient (logP) and aqueous solubility (logS) are two important parameters in pharmacology and toxicology studies, and experimental measurements are usually time-consuming and expensive. In the present research, novel methods are presented for the estim...

QSPR modeling of octanol/water partition coefficient of antineoplastic agents by balance of correlations.

Science.gov (United States)

Toropov, Andrey A; Toropova, Alla P; Raska, Ivan; Benfenati, Emilio

2010-04-01

Three different splits into the subtraining set (n = 22), the set of calibration (n = 21), and the test set (n = 12) of 55 antineoplastic agents have been examined. By the correlation balance of SMILES-based optimal descriptors quite satisfactory models for the octanol/water partition coefficient have been obtained on all three splits. The correlation balance is the optimization of a one-variable model with a target function that provides both the maximal values of the correlation coefficient for the subtraining and calibration set and the minimum of the difference between the above-mentioned correlation coefficients. Thus, the calibration set is a preliminary test set. Copyright (c) 2009 Elsevier Masson SAS. All rights reserved.

Bioaccumulation Patterns Of PCBs In A Temperate, Freshwater Food Web And Their Relationshop To The Octanol-Water Partition Coefficient (Presentation)

Science.gov (United States)

We investigated polychlorinated biphenyl (PCB) bioaccumulation relative to octanol-water partition coefficient (KOW) and organism tropic position (TP) at the Lake Hartwell Superfund site (South Carolina, USA). We measured PCBs (127 congeners) and stable isotopes (δ

Using measured octanol-air partition coefficients to explain environmental partitioning of organochlorine pesticides.

Science.gov (United States)

Shoeib, Mahiba; Harner, Tom

2002-05-01

Octanol-air partition coefficients (Koa) were measured directly for 19 organochlorine (OC) pesticides over the temperature range of 5 to 35 degrees C. Values of log Koa at 25 degrees C ranged over three orders of magnitude, from 7.4 for hexachlorobenzene to 10.1 for 1,1-dichloro-2,2-bis(p-chlorophenyl) ethane. Measured values were compared to values calculated as KowRT/H (where R is the ideal gas constant [8.314 J mol(-1) K(-1)], T is absolute temperature, and H is Henry's law constant) were, in general, larger. Discrepancies of up to three orders of magnitude were observed, highlighting the need for direct measurements of Koa. Plots of Koa versus inverse absolute temperature exhibited a log-linear correlation. Enthalpies of phase transition between octanol and air (deltaHoa) were determined from the temperature slopes and were in the range of 56 to 105 kJ mol(-1) K(-1). Activity coefficients in octanol (gamma(o)) were determined from Koa and reported supercooled liquid vapor pressures (pL(o)), and these were in the range of 0.3 to 12, indicating near-ideal solution behavior. Differences in Koa values for structural isomers of hexachlorocyclohexane were also explored. A Koa-based model was described for predicting the partitioning of OC pesticides to aerosols and used to calculate particulate fractions at 25 and -10 degrees C. The model also agreed well with experimental results for several OC pesticides that were equilibrated with urban aerosols in the laboratory. A log-log regression of the particle-gas partition coefficient versus Koa had a slope near unity, indicating that octanol is a good surrogate for the aerosol organic matter.

Estimating the octanol/water partition coefficient for aliphatic organic compounds using semi-empirical electrotopological index.

Science.gov (United States)

Souza, Erica Silva; Zaramello, Laize; Kuhnen, Carlos Alberto; Junkes, Berenice da Silva; Yunes, Rosendo Augusto; Heinzen, Vilma Edite Fonseca

2011-01-01

A new possibility for estimating the octanol/water coefficient (log P) was investigated using only one descriptor, the semi-empirical electrotopological index (I(SET)). The predictability of four octanol/water partition coefficient (log P) calculation models was compared using a set of 131 aliphatic organic compounds from five different classes. Log P values were calculated employing atomic-contribution methods, as in the Ghose/Crippen approach and its later refinement, AlogP; using fragmental methods through the ClogP method; and employing an approach considering the whole molecule using topological indices with the MlogP method. The efficiency and the applicability of the I(SET) in terms of calculating log P were demonstrated through good statistical quality (r > 0.99; s < 0.18), high internal stability and good predictive ability for an external group of compounds in the same order as the widely used models based on the fragmental method, ClogP, and the atomic contribution method, AlogP, which are among the most used methods of predicting log P.

QSPR models for predicting generator-column-derived octanol/water and octanol/air partition coefficients of polychlorinated biphenyls.

Science.gov (United States)

Yuan, Jintao; Yu, Shuling; Zhang, Ting; Yuan, Xuejie; Cao, Yunyuan; Yu, Xingchen; Yang, Xuan; Yao, Wu

2016-06-01

Octanol/water (K(OW)) and octanol/air (K(OA)) partition coefficients are two important physicochemical properties of organic substances. In current practice, K(OW) and K(OA) values of some polychlorinated biphenyls (PCBs) are measured using generator column method. Quantitative structure-property relationship (QSPR) models can serve as a valuable alternative method of replacing or reducing experimental steps in the determination of K(OW) and K(OA). In this paper, two different methods, i.e., multiple linear regression based on dragon descriptors and hologram quantitative structure-activity relationship, were used to predict generator-column-derived log K(OW) and log K(OA) values of PCBs. The predictive ability of the developed models was validated using a test set, and the performances of all generated models were compared with those of three previously reported models. All results indicated that the proposed models were robust and satisfactory and can thus be used as alternative models for the rapid assessment of the K(OW) and K(OA) of PCBs. Copyright © 2016 Elsevier Inc. All rights reserved.

Octanol-air partition coefficients of polybrominated biphenyls.

Science.gov (United States)

Hongxia, Zhao; Jingwen, Chen; Xie, Quan; Baocheng, Qu; Xinmiao, Liang

2009-03-01

The octanol-air partition coefficients (K(OA)) for PBB15, PBB26, PBB31, PBB49, PBB103 and PBB153 were determined as a function of temperature using a gas chromatographic retention time technique with 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (p,p'-DDT) as a reference substance. The internal energies of phase change from octanol to air (Delta(OA)U) were calculated for the six compounds and were in the range from 74 to 116 kJ mol(-1). Simple regression equations of log K(OA) versus relative retention times (RRTs) on gas chromatography (GC), and log K(OA) versus molecular connectivity indexes (MCI) were obtained, for which the correlation coefficients (r(2)) were greater than 0.985 at 283.15K and 298.15K. Thus the K(OA) values of the remaining PBBs can be predicted by using their RRTs and MCI according to these relationships.

Determination of octanol-water partition coefficients of polar polycyclic aromatic compounds (N-PAC) by high performance liquid chromatography

DEFF Research Database (Denmark)

Helweg, C.; Nielsen, T.; Hansen, P.E.

1997-01-01

Prediction of 1-octanol water partition coefficients for a range of polar N-PAC from HPLC capacity coefficients has been investigated. Two commercially available columns, an ODS column and a Diol column were tested with water-methanol eluents. The best prediction of log K-ow for N-PAC was achieve...... with size and log K-ow for N-PAC was 1.1-1.3 lower than log K-ow for the equivalent PAH. Shielding of the nitrogen atom in the N-PAC compounds caused an increase in log K-ow. (C) 1997 Elsevier Science Ltd....

Alternative measures of lipophilicity: from octanol-water partitioning to IAM retention.

Science.gov (United States)

Giaginis, Costas; Tsantili-Kakoulidou, Anna

2008-08-01

This review describes lipophilicity parameters currently used in drug design and QSAR studies. After a short historical overview, the complex nature of lipophilicity as the outcome of polar/nonpolar inter- and intramolecular interactions is analysed and considered as the background for the discussion of the different lipophilicity descriptors. The first part focuses on octanol-water partitioning of neutral and ionisable compounds, evaluates the efficiency of predictions and provides a short description of the experimental methods for the determination of distribution coefficients. A next part is dedicated to reversed-phase chromatographic techniques, HPLC and TLC in lipophilicity assessment. The two methods are evaluated for their efficiency to simulate octanol-water and the progress achieved in the refinement of suitable chromatographic conditions, in particular in the field of HPLC, is outlined. Liposomes as direct models of biological membranes are examined and phospolipophilicity is compared to the traditional lipophilicity concept. Difficulties associated with liposome-water partitioning are discussed. The last part focuses on Immobilised Artificial Membrane (IAM) chromatography as an alternative which combines membrane simulation with rapid measurements. IAM chromatographic retention is compared to octanol-water and liposome-water partitioning as well as to reversed-phase retention and its potential to predict biopartitioning and biological activities is discussed.

Measurement of diffusion coefficients of parabens and steroids in water and 1-octanol.

Science.gov (United States)

Seki, Toshinobu; Mochida, Junko; Okamoto, Maiko; Hosoya, Osamu; Juni, Kazuhiko; Morimoto, Kazuhiro

2003-06-01

Diffusion coefficients (D) of parabens and steroids in water and 1-octanol were determined by using the chromatographic broadening method at 37 degrees C, and the relationships between the D values and the physicochemical properties of the drugs were discussed. The D values in 1-octanol were lower than those in water because of the higher viscosity of 1-octanol. The D values depend on not only the molecular weight (MW), but also the lipophilicity of the drugs in water and on the ability for hydrogen-bonding in 1-octanol. When the lipophilic index (LI), calculated from the retention time using in a reverse-phase column, was used as a parameter of drug lipophilicity, the following equation was obtained for D in water (D(w)); log D(w)=-0.215.log MW-0.077.log LI-4.367. When the hydrogen bond index (HI), the logarithm of the ratio of the partition coefficient of the drugs in 1-octanol and cyclohexane, was used as an index of hydrogen-bonding, the following equation was obtained for D in 1-octanol (D(o)); log D(o)=-0.690.log MW-0.074.log HI-4.085.

Salinity impacts on water solubility and n-octanol/water partition coefficients of selected pesticides and oil constituents.

Science.gov (United States)

Saranjampour, Parichehr; Vebrosky, Emily N; Armbrust, Kevin L

2017-09-01

Salinity has been reported to influence the water solubility of organic chemicals entering marine ecosystems. However, limited data are available on salinity impacts for chemicals potentially entering seawater. Impacts on water solubility would correspondingly impact chemical sorption as well as overall bioavailability and exposure estimates used in the regulatory assessment. The pesticides atrazine, fipronil, bifenthrin, and cypermethrin, as well as the crude oil constituent dibenzothiophene together with 3 of its alkyl derivatives, all have different polarities and were selected as model compounds to demonstrate the impact of salinity on their solubility and partitioning behavior. The n-octanol/water partition coefficient (K OW ) was measured in both distilled-deionized water and artificial seawater (3.2%). All compounds had diminished solubility and increased K OW values in artificial seawater compared with distilled-deionized water. A linear correlation curve estimated salinity may increase the log K OW value by 2.6%/1 log unit increase in distilled water (R 2  = 0.97). Salinity appears to generally decrease the water solubility and increase the partitioning potential. Environmental fate estimates based on these parameters indicate elevated chemical sorption to sediment, overall bioavailability, and toxicity in artificial seawater. These dramatic differences suggest that salinity should be taken into account when exposure estimates are made for marine organisms. Environ Toxicol Chem 2017;36:2274-2280. © 2017 SETAC. © 2017 SETAC.

n-Alcohol/Water Partition Coefficients for Decachlorobiphenyl (PCB 209)

Science.gov (United States)

Measurements of n-octanol/water partition coefficients (Kow) for highly hydrophobic chemicals are extremely difficult and are rarely made, in part due to the large volumes of water typically needed to quantify these compounds in the aqueous phase. An extrapolation approach using ...

Evaluation of the ability of arsenic species to traverse cell membranes by simple diffusion using octanol-water and liposome-water partition coefficients.

Science.gov (United States)

Chávez-Capilla, Teresa; Maher, William; Kelly, Tamsin; Foster, Simon

2016-11-01

Arsenic metabolism in living organisms is dependent on the ability of different arsenic species to traverse biological membranes. Simple diffusion provides an alternative influx and efflux route to mediated transport mechanisms that can increase the amount of arsenic available for metabolism in cells. Using octanol-water and liposome-water partition coefficients, the ability of arsenous acid, arsenate, methylarsonate, dimethylarsinate, thio-methylarsonate, thio-dimethylarsinic acid, arsenotriglutathione and monomethylarsonic diglutathione to diffuse through the lipid bilayer of cell membranes was investigated. Molecular modelling of arsenic species was used to explain the results. All arsenic species with the exception of arsenate, methylarsonate and thio-methylarsonate were able to diffuse through the lipid bilayer of liposomes, with liposome-water partition coefficients between 0.04 and 0.13. Trivalent arsenic species and thio-pentavalent arsenic species showed higher partition coefficients, suggesting that they can easily traverse cell membranes by passive simple diffusion. Given the higher toxicity of these species compared to oxo-pentavalent arsenic species, this study provides evidence supporting the risk associated with human exposure to trivalent and thio-arsenic species. Copyright © 2016. Published by Elsevier B.V.

Separation of very hydrophobic analytes by micellar electrokinetic chromatography IV. Modeling of the effective electrophoretic mobility from carbon number equivalents and octanol-water partition coefficients.

Science.gov (United States)

Huhn, Carolin; Pyell, Ute

2008-07-11

It is investigated whether those relationships derived within an optimization scheme developed previously to optimize separations in micellar electrokinetic chromatography can be used to model effective electrophoretic mobilities of analytes strongly differing in their properties (polarity and type of interaction with the pseudostationary phase). The modeling is based on two parameter sets: (i) carbon number equivalents or octanol-water partition coefficients as analyte descriptors and (ii) four coefficients describing properties of the separation electrolyte (based on retention data for a homologous series of alkyl phenyl ketones used as reference analytes). The applicability of the proposed model is validated comparing experimental and calculated effective electrophoretic mobilities. The results demonstrate that the model can effectively be used to predict effective electrophoretic mobilities of neutral analytes from the determined carbon number equivalents or from octanol-water partition coefficients provided that the solvation parameters of the analytes of interest are similar to those of the reference analytes.

QSAR models for predicting octanol/water and organic carbon/water partition coefficients of polychlorinated biphenyls.

Science.gov (United States)

Yu, S; Gao, S; Gan, Y; Zhang, Y; Ruan, X; Wang, Y; Yang, L; Shi, J

2016-04-01

Quantitative structure-property relationship modelling can be a valuable alternative method to replace or reduce experimental testing. In particular, some endpoints such as octanol-water (KOW) and organic carbon-water (KOC) partition coefficients of polychlorinated biphenyls (PCBs) are easier to predict and various models have been already developed. In this paper, two different methods, which are multiple linear regression based on the descriptors generated using Dragon software and hologram quantitative structure-activity relationships, were employed to predict suspended particulate matter (SPM) derived log KOC and generator column, shake flask and slow stirring method derived log KOW values of 209 PCBs. The predictive ability of the derived models was validated using a test set. The performances of all these models were compared with EPI Suite™ software. The results indicated that the proposed models were robust and satisfactory, and could provide feasible and promising tools for the rapid assessment of the SPM derived log KOC and generator column, shake flask and slow stirring method derived log KOW values of PCBs.

Confocal Raman Microscopy for in Situ Measurement of Octanol-Water Partitioning within the Pores of Individual C18-Functionalized Chromatographic Particles.

Science.gov (United States)

Kitt, Jay P; Harris, Joel M

2015-05-19

Octanol-water partitioning is one of the most widely used predictors of hydrophobicity and lipophilicity. Traditional methods for measuring octanol-water partition coefficients (K(ow)), including shake-flasks and generator columns, require hours for equilibration and milliliter quantities of sample solution. These challenges have led to development of smaller-scale methods for measuring K(ow). Recent advances in microfluidics have produced faster and smaller-volume approaches to measuring K(ow). As flowing volumes are reduced, however, separation of water and octanol prior to measurement and detection in small volumes of octanol phase are especially challenging. In this work, we reduce the receiver volume of octanol-water partitioning measurements from current practice by six-orders-of-magnitude, to the femtoliter scale, by using a single octanol-filled reversed-phase, octadecylsilane-modified (C18-silica) chromatographic particle as a collector. The fluid-handling challenges of working in such small volumes are circumvented by eliminating postequilibration phase separation. Partitioning is measured in situ within the pore-confined octanol phase using confocal Raman microscopy, which is capable of detecting and quantifying a wide variety of molecular structures. Equilibration times are fast (less than a minute) because molecular diffusion is efficient over distance scales of micrometers. The demonstrated amount of analyte needed to carry out a measurement is very small, less than 50 fmol, which would be a useful attribute for drug screening applications or testing of small quantities of environmentally sensitive compounds. The method is tested for measurements of pH-dependent octanol-water partitioning of naphthoic acid, and the results are compared to both traditional shake-flask measurements and sorption onto C18-modified silica without octanol present within the pores.

High-throughput determination of octanol/water partition coefficients using a shake-flask method and novel two-phase solvent system.

Science.gov (United States)

Morikawa, Go; Suzuka, Chihiro; Shoji, Atsushi; Shibusawa, Yoichi; Yanagida, Akio

2016-01-05

A high-throughput method for determining the octanol/water partition coefficient (P(o/w)) of a large variety of compounds exhibiting a wide range in hydrophobicity was established. The method combines a simple shake-flask method with a novel two-phase solvent system comprising an acetonitrile-phosphate buffer (0.1 M, pH 7.4)-1-octanol (25:25:4, v/v/v; AN system). The AN system partition coefficients (K(AN)) of 51 standard compounds for which log P(o/w) (at pH 7.4; log D) values had been reported were determined by single two-phase partitioning in test tubes, followed by measurement of the solute concentration in both phases using an automatic flow injection-ultraviolet detection system. The log K(AN) values were closely related to reported log D values, and the relationship could be expressed by the following linear regression equation: log D=2.8630 log K(AN) -0.1497(n=51). The relationship reveals that log D values (+8 to -8) for a large variety of highly hydrophobic and/or hydrophilic compounds can be estimated indirectly from the narrow range of log K(AN) values (+3 to -3) determined using the present method. Furthermore, log K(AN) values for highly polar compounds for which no log D values have been reported, such as amino acids, peptides, proteins, nucleosides, and nucleotides, can be estimated using the present method. The wide-ranging log D values (+5.9 to -7.5) of these molecules were estimated for the first time from their log K(AN) values and the above regression equation. Copyright © 2015 Elsevier B.V. All rights reserved.

Trophic Magnification of PCBs and Its Relationship to the Octanol−Water Partition Coefficient

Science.gov (United States)

We investigated polychlorinated biphenyl (PCB) bioaccumulation relative to octanol-water partition coefficient (KOW) and organism trophic position (TP) at the Lake Hartwell Superfund (South Carolina, USA). We measured PCBs (127 congeners) and stable isotopes (δ15...

Temperature dependencies of Henry's law constants and octanol/water partition coefficients for key plant volatile monoterpenoids.

Science.gov (United States)

Copolovici, Lucian O; Niinemets, Ulo

2005-12-01

To model the emission dynamics and changes in fractional composition of monoterpenoids from plant leaves, temperature dependencies of equilibrium coefficients must be known. Henry's law constants (H(pc), Pa m3 mol(-1) and octanol/water partition coefficients (K(OW), mol mol(-1)) were determined for 10 important plant monoterpenes at physiological temperature ranges (25-50 degrees C for H(pc) and 20-50 degrees C for K(OW)). A standard EPICS procedure was established to determine H(pc) and a shake flask method was used for the measurements of K(OW). The enthalpy of volatilization (deltaH(vol)) varied from 18.0 to 44.3 kJ mol(-1) among the monoterpenes, corresponding to a range of temperature-dependent increase in H(pc) between 1.3- and 1.8-fold per 10 degrees C rise in temperature. The enthalpy of water-octanol phase change varied from -11.0 to -23.8 kJ mol(-1), corresponding to a decrease of K(OW) between 1.15- and 1.32-fold per 10 degrees C increase in temperature. Correlations among physico-chemical characteristics of a wide range of monoterpenes were analyzed to seek the ways of derivation of H(pc) and K(OW) values from other monoterpene physico-chemical characteristics. H(pc) was strongly correlated with monoterpene saturated vapor pressure (P(v)), and for lipophilic monoterpenes, deltaH(vol) scaled positively with the enthalpy of vaporization that characterizes the temperature dependence of P(v) Thus, P(v) versus temperature relations may be employed to derive the temperature relations of H(pc) for these monoterpenes. These data collectively indicate that monoterpene differences in H(pc) and K(OW) temperature relations can importantly modify monoterpene emissions from and deposition on plant leaves.

Determining octanol-water partition coefficients for extremely hydrophobic chemicals by combining "slow stirring" and solid-phase microextraction.

Science.gov (United States)

Jonker, Michiel T O

2016-06-01

Octanol-water partition coefficients (KOW ) are widely used in fate and effects modeling of chemicals. Still, high-quality experimental KOW data are scarce, in particular for very hydrophobic chemicals. This hampers reliable assessments of several fate and effect parameters and the development and validation of new models. One reason for the limited availability of experimental values may relate to the challenging nature of KOW measurements. In the present study, KOW values for 13 polycyclic aromatic hydrocarbons were determined with the gold standard "slow-stirring" method (log KOW 4.6-7.2). These values were then used as reference data for the development of an alternative method for measuring KOW . This approach combined slow stirring and equilibrium sampling of the extremely low aqueous concentrations with polydimethylsiloxane-coated solid-phase microextraction fibers, applying experimentally determined fiber-water partition coefficients. It resulted in KOW values matching the slow-stirring data very well. Therefore, the method was subsequently applied to a series of 17 moderately to extremely hydrophobic petrochemical compounds. The obtained KOW values spanned almost 6 orders of magnitude, with the highest value measuring 10(10.6) . The present study demonstrates that the hydrophobicity domain within which experimental KOW measurements are possible can be extended with the help of solid-phase microextraction and that experimentally determined KOW values can exceed the proposed upper limit of 10(9) . Environ Toxicol Chem 2016;35:1371-1377. © 2015 SETAC. © 2015 SETAC.

Prediction of octanol-water partition coefficients of organic compounds by multiple linear regression, partial least squares, and artificial neural network.

Science.gov (United States)

Golmohammadi, Hassan

2009-11-30

A quantitative structure-property relationship (QSPR) study was performed to develop models those relate the structure of 141 organic compounds to their octanol-water partition coefficients (log P(o/w)). A genetic algorithm was applied as a variable selection tool. Modeling of log P(o/w) of these compounds as a function of theoretically derived descriptors was established by multiple linear regression (MLR), partial least squares (PLS), and artificial neural network (ANN). The best selected descriptors that appear in the models are: atomic charge weighted partial positively charged surface area (PPSA-3), fractional atomic charge weighted partial positive surface area (FPSA-3), minimum atomic partial charge (Qmin), molecular volume (MV), total dipole moment of molecule (mu), maximum antibonding contribution of a molecule orbital in the molecule (MAC), and maximum free valency of a C atom in the molecule (MFV). The result obtained showed the ability of developed artificial neural network to prediction of partition coefficients of organic compounds. Also, the results revealed the superiority of ANN over the MLR and PLS models. Copyright 2009 Wiley Periodicals, Inc.

Thermodynamic investigation of the water/n-octanol partition coefficient value of a 5-formyl-1,2-dithiole-3-thione

International Nuclear Information System (INIS)

Chollet-Krugler, Marylene; Legouin, Beatrice; Gargadennec, Sylvain; Burgot, Gwenola; Burgot, Jean-Louis

2004-01-01

Thermometric titrations performed in suitable conditions permit the determination of the enthalpic and entropic parts of the standard transfer-free enthalpy of a particular 5-formyl-1,2-dithiole-3-thione from water into n-octanol. It may be inferred from this determination that the far too high water/n-octanol log P values of 5-acyl-1,2-dithiole-3-thiones originate in an entropic effect which is in agreement with the hypothesis that these derivatives are more solvated in water than expected and hence with the hypothesis that during partitioning between the two phases, more molecules of water than expected are released from the solvated solute in the aqueous phase. The family of 1,2-dithiole-3-thiones is of growing importance in pharmacology

Thermodynamic investigation of the water/n-octanol partition coefficient value of a 5-formyl-1,2-dithiole-3-thione

Energy Technology Data Exchange (ETDEWEB)

Chollet-Krugler, Marylene; Legouin, Beatrice; Gargadennec, Sylvain; Burgot, Gwenola; Burgot, Jean-Louis

2004-12-15

Thermometric titrations performed in suitable conditions permit the determination of the enthalpic and entropic parts of the standard transfer-free enthalpy of a particular 5-formyl-1,2-dithiole-3-thione from water into n-octanol. It may be inferred from this determination that the far too high water/n-octanol log P values of 5-acyl-1,2-dithiole-3-thiones originate in an entropic effect which is in agreement with the hypothesis that these derivatives are more solvated in water than expected and hence with the hypothesis that during partitioning between the two phases, more molecules of water than expected are released from the solvated solute in the aqueous phase. The family of 1,2-dithiole-3-thiones is of growing importance in pharmacology.

COMPARISON OF THE OCTANOL-AIR PARTITION COEFFICIENT AND LIQUID-PHASE VAPOR PRESSURE AS DESCRIPTORS FOR PARTICLE/GAS PARTITIONING USING LABORATORY AND FIELD DATA FOR PCBS AND PCNS

Science.gov (United States)

The conventional Junge-Pankow adsorption model uses the sub-cooled liquid vapor pressure (pLo) as a correlation parameter for gas/particle interactions. An alternative is the octanol-air partition coefficient (Koa) absorption model. Log-log plots of the particle-gas partition c...

Determination of 1-octanol-air partition coefficient using gaseous diffusion in the air boundary layer.

Science.gov (United States)

Ha, Yeonjeong; Kwon, Jung-Hwan

2010-04-15

Exact determination of the partition coefficient between 1-octanol and air (K(OA)) is very important because it is a key descriptor for describing the thermodynamic partitioning between the air and organic phases. In spite of its importance, the number and quality of experimental K(OA) values for hydrophobic organic chemicals are limited because of experimental difficulties. Thus, to measure K(OA) values, a high-throughput method was developed that used liquid-phase extraction with 1-octanol drop at the tip of a microsyringe needle. The concentration in the headspace surrounding the 1 muL octanol drop was equilibrated with liquid octanol containing polycyclic aromatic hydrocarbons (PAHs). The change in concentrations of PAHs in the octanol drop was measured to obtain mass transfer rate constants, and these rate constants were then converted into K(OA) values using a film diffusion model. Thirteen polycyclic aromatic hydrocarbons with log K(OA) between 5 and 12 were chosen for the proof of the principle. Experimental determination of log K(OA) was accomplished in 30 h for PAHs with their log K(OA) less than 11. The measured log K(OA) values were very close to those obtained by various experimental and estimation methods in the literature, suggesting that this new method can provide a fast and easy determination of log K(OA) values for many chemicals of environmental interests. In addition, the applicability of the method can be extended to determine Henry's law constant for compounds with low vapor pressure and to estimate gaseous transfer rate of semivolatile compounds for environmental fate modeling.

[Application of reversed-phase ion-pair chromatography for universal estimation of octanol-water partition coefficients of acid, basic and amphoteric drugs].

Science.gov (United States)

Zhu, Hui; Yang, Ri-Fang; Yun, Liu-Hong; Jiang, Yu; Li, Jin

2009-09-01

This paper is to establish a reversed-phase ion-pair chromatography (RP-IPC) method for universal estimation of the octanol/water partition coefficients (logP) of a wide range of structurally diverse compounds including acidic, basic, neutral and amphoteric species. The retention factors corresponding to 100% water (logk(w)) were derived from the linear part of the logk'/phi relationship, using at least four isocratic logk' values containing different organic compositions. The logk(w) parameters obtained were close to the corresponding logP values obtained with the standard "shake flask" methods. The mean deviation for test drugs is 0.31. RP-IPC with trifluoroacetic acid as non classic ion-pair agents can be applicable to determine the logP values for a variety of drug-like molecules with increased accuracy.

Chromatographic retention prediction and octanol-water partition coefficient determination of monobasic weak acidic compounds in ion-suppression reversed-phase liquid chromatography using acids as ion-suppressors.

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Ming, Xin; Han, Shu-ying; Qi, Zheng-chun; Sheng, Dong; Lian, Hong-zhen

2009-08-15

Although simple acids, replacing buffers, have been widely applied to suppress the ionization of weakly ionizable acidic analytes in reversed-phase liquid chromatography (RPLC), none of the previously reported works focused on the systematic studies about the retention behavior of the acidic solutes in this ion-suppression RPLC mode. The subject of this paper was therefore to investigate the retention behavior of monobasic weak acidic compounds using acetic, perchloric and phosphoric acids as the ion-suppressors. The apparent octanol-water partition coefficient (K" ow) was proposed to calibrate the octanol-water partition coefficient (K(ow)) of these weak acidic compounds, which resulted in a better linear correlation with log k(w), the logarithm of the hypothetical retention factor corresponding to neat aqueous fraction of hydroorganic mobile phase. This log K" ow-log k w linear correlation was successfully validated by the results of monocarboxylic acids and monohydrating phenols, and moreover by the results under diverse experimental conditions for the same solutes. This straightforward relationship not only can be used to effectively predict the retention values of weak acidic solutes combined with Snyder-Soczewinski equation, but also can offer a promising medium for directly measuring K(ow) data of these compounds via Collander equation. In addition, the influence of the different ion-suppressors on the retention of weak acidic compounds was also compared in this RPLC mode.

Nanostructures in n-Octanol Equilibrated with Additives and/or Water.

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Cevc, Gregor; Berts, Ida; Fischer, Stefan F; Rädler, Joachim O; Nickel, Bert

2018-05-29

Fluid fatty alcohols are believed to be nanostructured but broadly amorphous (i.e., noncrystalline) fluids and solvents, including the most popular fatty tissue mimetic, hydrated n-octanol (i.e., hydro-octanol). To check this premise, we studied dry octanol and hydro-octanol as a model of relatively short fluid n-alkanols with small-angle X-ray scattering (SAXS). We also combined this alkanol with the matching alkane (i.e., octane) and with a common anti-inflammatory pain killer (ketoprofen). This revealed that (hydro-)octanol and arguably any other short fatty alcohol form a mesophase. Its basic structural motif are regularly packed polar nanoclusters, reflected in the inner peak in the SAXS diffractogram of (hydro-)octanol and other fluid n-alkanols. The nanoclusters arguably resemble tiny, (inverse) hydrated bilayer fragments, located on a thermally smeared para-crystalline lattice. Additives to hydro-octanol can change the nanoclusters only moderately, if at all. For example, octane and the drug ketoprofen added to hydro-octanol enlarge the nanoclusters only little because of the mixture's packing frustration. To associate with and to bring more water into hydro-octanol, an additive must hence transform the nanoclusters: it expands them into irregularly distributed aqueous lacunae that form a proto-microemulsion, reflected in the previously unknown Guinier's SAXS signal. A "weak" (i.e., a weakly polar or nonpolar) additive can moreover create only size-limited lacunae. Coexistence of nanoclusters and lacunae as well as size variability of the latter in hydro-octanol subvert the concept of octanol-water partition coefficient, which relies on the studied compartment homogeneity. In turn, it opens new possibilities for interfacial catalysis. Reinterpreting "octanol-water partition coefficient" data in terms of octanol-water association or binding constant(s) could furthermore diminish the variability of molecular lipophilicity description and pave the ground

CALCULATION OF COEFFICIENT OF SHARING OCTANOL-WATER OF ORGANIC COMPOUNDS USING MOLECULAR DESCRIPTORS

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B. Souyei

2010-12-01

Full Text Available A quantitative structure-property relationship (QSPR study is carried out to develop correlations that relate the molecular structures of organic compounds to their Octanol- Water partition coefficients, Kow , using molecular descriptors. The correlations are simple in application with good accuracy, which provide an easy, direct and relatively accurate way to calculate Kow. Such calculation gives us a model that gives results in remarkable correlation with the descriptors of blocks fragments of the atom-centered and functional groups (R2 = 0.949, δ = 0477 (R2 = 0.926,δ = 0,548 respectively.

Trophic magnification of PCBs and Its relationship to the octanol-water partition coefficient.

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Walters, David M; Mills, Marc A; Cade, Brian S; Burkard, Lawrence P

2011-05-01

We investigated polychlorinated biphenyl (PCB) bioaccumulation relative to octanol-water partition coefficient (K(OW)) and organism trophic position (TP) at the Lake Hartwell Superfund site (South Carolina). We measured PCBs (127 congeners) and stable isotopes (δ¹⁵N) in sediment, organic matter, phytoplankton, zooplankton, macroinvertebrates, and fish. TP, as calculated from δ¹⁵N, was significantly, positively related to PCB concentrations, and food web trophic magnification factors (TMFs) ranged from 1.5-6.6 among congeners. TMFs of individual congeners increased strongly with log K(OW), as did the predictive power (r²) of individual TP-PCB regression models used to calculate TMFs. We developed log K(OW)-TMF models for eight food webs with vastly different environments (freshwater, marine, arctic, temperate) and species composition (cold- vs warmblooded consumers). The effect of K(OW) on congener TMFs varied strongly across food webs (model slopes 0.0-15.0) because the range of TMFs among studies was also highly variable. We standardized TMFs within studies to mean = 0, standard deviation (SD) = 1 to normalize for scale differences and found a remarkably consistent K(OW) effect on TMFs (no difference in model slopes among food webs). Our findings underscore the importance of hydrophobicity (as characterized by K(OW)) in regulating bioaccumulation of recalcitrant compounds in aquatic systems, and demonstrate that relationships between chemical K(OW) and bioaccumulation from field studies are more generalized than previously recognized.

The influence of hydrogen bonding on partition coefficients

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Borges, Nádia Melo; Kenny, Peter W.; Montanari, Carlos A.; Prokopczyk, Igor M.; Ribeiro, Jean F. R.; Rocha, Josmar R.; Sartori, Geraldo Rodrigues

2017-02-01

This Perspective explores how consideration of hydrogen bonding can be used to both predict and better understand partition coefficients. It is shown how polarity of both compounds and substructures can be estimated from measured alkane/water partition coefficients. When polarity is defined in this manner, hydrogen bond donors are typically less polar than hydrogen bond acceptors. Analysis of alkane/water partition coefficients in conjunction with molecular electrostatic potential calculations suggests that aromatic chloro substituents may be less lipophilic than is generally believed and that some of the effect of chloro-substitution stems from making the aromatic π-cloud less available to hydrogen bond donors. Relationships between polarity and calculated hydrogen bond basicity are derived for aromatic nitrogen and carbonyl oxygen. Aligned hydrogen bond acceptors appear to present special challenges for prediction of alkane/water partition coefficients and this may reflect `frustration' of solvation resulting from overlapping hydration spheres. It is also shown how calculated hydrogen bond basicity can be used to model the effect of aromatic aza-substitution on octanol/water partition coefficients.

Quantitative structure-property relationships for octanol-water partition coefficients of polybrominated diphenyl ethers.

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Li, Linnan; Xie, Shaodong; Cai, Hao; Bai, Xuetao; Xue, Zhao

2008-08-01

Theoretical molecular descriptors were tested against logK(OW) values for polybrominated diphenyl ethers (PBDEs) using the Partial Least-Squares Regression method which can be used to analyze data with many variables and few observations. A quantitative structure-property relationship (QSPR) model was successfully developed with a high cross-validated value (Q(cum)(2)) of 0.961, indicating a good predictive ability and stability of the model. The predictive power of the QSPR model was further cross-validated. The values of logK(OW) for PBDEs are mainly governed by molecular surface area, energy of the lowest unoccupied molecular orbital and the net atomic charges on the oxygen atom. All these descriptors have been discussed to interpret the partitioning mechanism of PBDE chemicals. The bulk property of the molecules represented by molecular surface area is the leading factor, and K(OW) values increase with the increase of molecular surface area. Higher energy of the lowest unoccupied molecular orbital and higher net atomic charge on the oxygen atom of PBDEs result in smaller K(OW). The energy of the lowest unoccupied molecular orbital and the net atomic charge on PBDEs oxygen also play important roles in affecting the partition of PBDEs between octanol and water by influencing the interactions between PBDEs and solvent molecules.

Influence of bioassay volume, water column height, and octanol-water partition coefficient on the toxicity of pesticides to rainbow trout.

Science.gov (United States)

Altinok, Ilhan; Capkin, Erol; Boran, Halis

2011-06-01

Effects of water volume and water column height on toxicity of cypermethrin, carbaryl, dichlorvos, tetradifon, maneb, captan, carbosulfan endosulfan and HgCl₂ to juvenile rainbow trout (Oncorhynchus mykiss, 3.2 ± 0.7 g) were evaluated in different glass aquaria under static conditions. When fish were exposed to the chemical compounds in 23 cm water column height (25 L), their mortality ranged between 0% and 58%. At the same water volume, but lower water column height (9 cm), mortality of fish increased significantly and was in a range from 60% to 95%. At the same water column height, toxic effects of chemicals were significantly higher in 25 L water volume than that of 8.5 L, water except maneb which has lowest (-0.45) octanol-water partition coefficient value. Mortality rates ratio of 9 and 23 cm water column height ranged between 1.12 and 90 while mortality rates ratio of 9 and 25 L water volume ranged between 1.20 and 4.0. Because actual exposure concentrations were not affected by either water volume or water column height, we propose that increased pesticides' toxicity was related to an increase in bioassay volume, since more pesticide molecules were able to interact with or accumulate the fish. However, there seem to be no relationship between the effects of water volume, water column height and Kow value of chemicals with regard to toxicity in juvenile rainbow trout.

Effects of chain length, chlorination degree, and structure on the octanol-water partition coefficients of polychlorinated n-alkanes.

Science.gov (United States)

Hilger, Bettina; Fromme, Hermann; Völkel, Wolfgang; Coelhan, Mehmet

2011-04-01

Log octanol-water partition coefficients (log Kow) of 40 synthesized polychlorinated n-alkanes (PCAs) with different chlorination degrees were determined using reversed-phase high performance liquid chromatography (RP-HPLC). In addition, log Kow values of a technical mixture namely Cereclor 63L as well as 15 individual in house synthesized C10, C11, and C12 chloroalkanes with known chlorine positions were estimated. Based on these results, the effects of chain length, chlorination degree, and structure were explored. The estimated log Kow values ranged from 4.10 (polychlorinated n-decanes with 50.2% chlorine content) to 11.34 (polychlorinated n-octacosanes with 54.8% chlorine content) for PCAs and from 3.82 (1,2,5,6,9,10-hexachlorodecane) to 7.75 (1,1,1,3,9,11,11,11-octachlorododecane) for the individual chloroalkanes studied. The results showed that log Kow value was influenced linearly at a given chlorine content by chain length, while a polynominal effect was observed in dependence on the chlorination degree of an alkane chain. Chlorine substitution pattern influenced markedly the log Kow value of chloroalkanes.

Measurement of Diffusion Coefficients of Parabens and Steroids in Water and 1-Octanol

OpenAIRE

関, 俊暢; 持田, 純子; 岡本, 麻衣子; 細谷, 治; 從二, 和彦; Morimoto, Kazuhiro

2003-01-01

Diffusion coefficients (D) of parabens and steroids in water and 1-octanol were determined by using the chromatographic broadening method at 37 °C, and the relationships between the D values and the physicochemical properties of the drugs were discussed. The D values in 1-octanol were lower than those in water because of the higher viscosity of 1-octanol. The D values depend on not only the molecular weight (MW), but also the lipophilicity of the drugs in water and on the ability for hydrogen...

Polyacrylate–water partitioning of biocidal compounds: Enhancing the understanding of biocide partitioning between render and water

DEFF Research Database (Denmark)

Bollmann, Ulla E.; Ou, Yi; Mayer, Philipp

2014-01-01

-N-octylisothiazolinone). The correlation of the polyacrylate-water partition constants with the octanol-water partition constants is significant, but the polyacrylate-water partition constants were predominantly below octanol-water partition constants (Kow). The comparison with render-water distribution constants showed that estimating...

Effect of Atomic Charges on Octanol–Water Partition Coefficient Using Alchemical Free Energy Calculation

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Koji Ogata

2018-02-01

Full Text Available The octanol–water partition coefficient (logPow is an important index for measuring solubility, membrane permeability, and bioavailability in the drug discovery field. In this paper, the logPow values of 58 compounds were predicted by alchemical free energy calculation using molecular dynamics simulation. In free energy calculations, the atomic charges of the compounds are always fixed. However, they must be recalculated for each solvent. Therefore, three different sets of atomic charges were tested using quantum chemical calculations, taking into account vacuum, octanol, and water environments. The calculated atomic charges in the different environments do not necessarily influence the correlation between calculated and experimentally measured ∆Gwater values. The largest correlation coefficient values of the solvation free energy in water and octanol were 0.93 and 0.90, respectively. On the other hand, the correlation coefficient of logPow values calculated from free energies, the largest of which was 0.92, was sensitive to the combination of the solvation free energies calculated from the calculated atomic charges. These results reveal that the solvent assumed in the atomic charge calculation is an important factor determining the accuracy of predicted logPow values.

Absorption dynamics of organic chemical transport across trout gills as related to octanol-water partition coefficient

International Nuclear Information System (INIS)

McKim, J.; Schmieder, P.; Veith, G.

1985-01-01

An in vivo fish preparation was used that allowed a direct measure of the transport rates of 14 different organic chemicals across the gills of rainbow trout (Salmo gairdneri). The chemicals, all C14 labeled, were selected from five classes, encompassing a range of octanol-water partition coefficient (log P) values, from 0.23 (ethyl formate) to 7.5 (mirex). The uptake efficiency (extraction efficiency) of each chemical was determined by monitoring the inspired and expired water of trout exposed to each chemical over an exposure period of 1 to 6 hr. The mean gill extraction efficiency for all chemicals tested varied from a low of 7% to a high of 60%, extracted in a single pall of the chemical across the gills. The extraction efficiency of chemicals with log P or 1 or less were low and showed no relationship to log P. These low extraction efficiencies seen at log P of 1 and below with molecular weights below 100 were indicative of aqueous pore transport. The mean extraction efficiency for chemicals with log P values of 1 to 3 seemed to vary directly with log P, to a maximum of slightly greater than 60%, suggesting that uptake was controlled by the lipid membrane. The mean extraction efficiency for chemicals with log P of 3 to 6 was independent of log P and remained at 60%, which suggested that gill uptake was controlled by aqueous diffusion rates rather than gill membrane permeability. The mean extraction efficiency with mirex (log P . 7.5) decreased to 20%

Determination of reversed-phase high performance liquid chromatography based octanol-water partition coefficients for neutral and ionizable compounds: Methodology evaluation.

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Liang, Chao; Qiao, Jun-Qin; Lian, Hong-Zhen

2017-12-15

Reversed-phase liquid chromatography (RPLC) based octanol-water partition coefficient (logP) or distribution coefficient (logD) determination methods were revisited and assessed comprehensively. Classic isocratic and some gradient RPLC methods were conducted and evaluated for neutral, weak acid and basic compounds. Different lipophilicity indexes in logP or logD determination were discussed in detail, including the retention factor logk w corresponding to neat water as mobile phase extrapolated via linear solvent strength (LSS) model from isocratic runs and calculated with software from gradient runs, the chromatographic hydrophobicity index (CHI), apparent gradient capacity factor (k g ') and gradient retention time (t g ). Among the lipophilicity indexes discussed, logk w from whether isocratic or gradient elution methods best correlated with logP or logD. Therefore logk w is recommended as the preferred lipophilicity index for logP or logD determination. logk w easily calculated from methanol gradient runs might be the main candidate to replace logk w calculated from classic isocratic run as the ideal lipophilicity index. These revisited RPLC methods were not applicable for strongly ionized compounds that are hardly ion-suppressed. A previously reported imperfect ion-pair RPLC method was attempted and further explored for studying distribution coefficients (logD) of sulfonic acids that totally ionized in the mobile phase. Notably, experimental logD values of sulfonic acids were given for the first time. The IP-RPLC method provided a distinct way to explore logD values of ionized compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

QSPR models of n-octanol/water partition coefficients and aqueous solubility of halogenated methyl-phenyl ethers by DFT method.

Science.gov (United States)

Zeng, Xiao-Lan; Wang, Hong-Jun; Wang, Yan

2012-02-01

The possible molecular geometries of 134 halogenated methyl-phenyl ethers were optimized at B3LYP/6-31G(*) level with Gaussian 98 program. The calculated structural parameters were taken as theoretical descriptors to establish two new novel QSPR models for predicting aqueous solubility (-lgS(w,l)) and n-octanol/water partition coefficient (lgK(ow)) of halogenated methyl-phenyl ethers. The two models achieved in this work both contain three variables: energy of the lowest unoccupied molecular orbital (E(LUMO)), most positive atomic partial charge in molecule (q(+)), and quadrupole moment (Q(yy) or Q(zz)), of which R values are 0.992 and 0.970 respectively, their standard errors of estimate in modeling (SD) are 0.132 and 0.178, respectively. The results of leave-one-out (LOO) cross-validation for training set and validation with external test sets both show that the models obtained exhibited optimum stability and good predictive power. We suggests that two QSPR models derived here can be used to predict S(w,l) and K(ow) accurately for non-tested halogenated methyl-phenyl ethers congeners. Copyright © 2011 Elsevier Ltd. All rights reserved.

Ionization constants by curve fitting: determination of partition and distribution coefficients of acids and bases and their ions.

Science.gov (United States)

Clarke, F H; Cahoon, N M

1987-08-01

A convenient procedure has been developed for the determination of partition and distribution coefficients. The method involves the potentiometric titration of the compound, first in water and then in a rapidly stirred mixture of water and octanol. An automatic titrator is used, and the data is collected and analyzed by curve fitting on a microcomputer with 64 K of memory. The method is rapid and accurate for compounds with pKa values between 4 and 10. Partition coefficients can be measured for monoprotic and diprotic acids and bases. The partition coefficients of the neutral compound and its ion(s) can be determined by varying the ratio of octanol to water. Distribution coefficients calculated over a wide range of pH values are presented graphically as "distribution profiles". It is shown that subtraction of the titration curve of solvent alone from that of the compound in the solvent offers advantages for pKa determination by curve fitting for compounds of low aqueous solubility.

Removal of dissolved organic carbon by aquifer material: Correlations between column parameters, sorption isotherms and octanol-water partition coefficient.

Science.gov (United States)

Pradhan, Snigdhendubala; Boernick, Hilmar; Kumar, Pradeep; Mehrotra, Indu

2016-07-15

The correlation between octanol-water partition coefficient (KOW) and the transport of aqueous samples containing single organic compound is well documented. The concept of the KOW of river water containing the mixture of organics was evolved by Pradhan et al. (2015). The present study aims at determining the KOW and sorption parameters of synthetic aqueous samples and river water to finding out the correlation, if any. The laboratory scale columns packed with aquifer materials were fed with synthetic and river water samples. Under the operating conditions, the compounds in the samples did not separate, and all the samples that contain more than one organic compound yielded a single breakthrough curve. Breakthrough curves simulated from sorption isotherms were compared with those from the column runs. The sorption parameters such as retardation factor (Rf), height of mass transfer zone (HMTZ), rate of mass transfer zone (RMTZ), breakpoint column capacity (qb) and maximum column capacity (qx) estimated from column runs, sorption isotherms and models developed by Yoon-Nelson, Bohart-Adam and Thomas were in agreement. The empirical correlations were found between the KOW and sorption parameters. The transport of the organics measured as dissolved organic carbon (DOC) through the aquifer can be predicted from the KOW of the river water and other water samples. The novelty of the study is to measure KOW and to envisage the fate of the DOC of the river water, particularly during riverbank filtration. Statistical analysis of the results revealed a fair agreement between the observed and computed values. Copyright © 2016 Elsevier Ltd. All rights reserved.

Determination and prediction of octanol-air partition coefficients of hydroxylated and methoxylated polybrominated diphenyl ethers.

Science.gov (United States)

Zhao, Hongxia; Xie, Qing; Tan, Feng; Chen, Jingwen; Quan, Xie; Qu, Baocheng; Zhang, Xin; Li, Xiaona

2010-07-01

The octanol-air partition coefficient (K(OA)) of 19 hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and 10 methoxylated polybrominated diphenyl ethers (MeO-PBDEs) were measured as a function of temperature using a gas chromatographic retention time technique. At room temperature (298.15K), log K(OA) ranged from 8.30 for monobrominated OH/MeO-PBDEs to 13.29 for hexabrominated OH/MeO-PBDEs. The internal energies of phase change from octanol to air (Delta(OA)U) for 29 OH/MeO-PBDE congeners ranged from 72 to 126 kJ mol(-1). Using partial least-squares (PLS) analysis, a statistically quantitative structure-property relationship (QSPR) model for logK(OA) of OH/MeO-PBDE congeners was developed based on the 16 fundamental quantum chemical descriptors computed by PM3 Hamiltonian, for which the Q(cum)(2) was about 0.937. The molecular weight (Mw) and energy of the lowest unoccupied molecular orbital (E(LUMO)) were found to be main factors governing the log K(OA). 2010 Elsevier Ltd. All rights reserved.

Partitioning of polychlorinated biphenyls into human cells and adipose tissues: evaluation of octanol, triolein, and liposomes as surrogates.

Science.gov (United States)

Quinn, Cristina L; van der Heijden, Stephan A; Wania, Frank; Jonker, Michiel T O

2014-05-20

Whereas octanol, triacylglycerides, and liposomes have all been proposed as surrogates for measuring the affinity of hydrophobic organic contaminants to human lipids, no comparative evaluation of their suitability exists. Here we conducted batch sorption experiments with polyoxymethylene passive samplers to determine the partition coefficients at 37 °C of 18 polychlorinated biphenyls (PCBs) from water into (i) triolein (Ktriolein/water), (ii) eight types of liposomes (Kliposome/water), (iii) human abdominal fat tissues (KAFT/water) from seven individuals, and (iv) human MCF-7 cells cultured in vitro (Kcell/water). Differences between KAFT/water among individuals and between Kliposome/water among liposome types were very small and not correlated to structural attributes of the PCBs. Similarly, the length and degree of saturation of the phospholipid carbon chains, the headgroup, and the composition of the liposome did not affect the partitioning of PCBs into the studied liposomes. Whereas Kliposome/water values were similar to literature values of Koctanol/water adjusted to 37 °C, they both were lower than KAFT/water and Kcell/water by a factor of 3 on average. Partitioning of PCBs into triolein on the other hand closely mimicked that into human lipids, for which triolein is thus a better surrogate than either octanol or liposomes. Previously published polyparameter linear free energy relationships for partitioning from water into storage lipids and liposomes predicted the measured partition coefficients with a root-mean-square error of less than 0.15 log units, if the chosen equations and solute descriptors do not allow chlorine substitution in the ortho-position to influence the prediction. By guiding the selection of (i) a surrogate for the experimental determination and (ii) a method for the prediction of partitioning into human lipids, this study contributes to a better assessment of hydrophobic organic contaminant bioaccumulation in humans.

Estudio termodinámico de la transferencia de acetaminofén desde el agua hasta el octanol Thermodynamic study of acetaminophen's transfer from water to octanol

Directory of Open Access Journals (Sweden)

Yolima Baena

2004-09-01

Full Text Available Se determinó el coeficiente de reparto octanol/agua y la solubilidad de acetaminofén (paracetamol en octanol, agua y los solventes mutuamente saturados a 25.0, 30.0, 35.0 y 40.0 °C. Mediante el análisis termodinámico de Gibbs y van't Hoff se observa que el proceso de transferencia del fármaco desde el agua hasta el octanol es espontáneo y de conducción principalmente entálpica. Se encuentra que la saturación mutua de las fases juega un papel importante en el reparto y la solubilidad de este fármaco, lo cual se ha demostrado para otras sustancias semipolares tales como algunos derivados de la guanina y algunas sulfonamidas.The partition coefficients and solubilities in octanol, water and mutually saturated octanol-water phases were determined for acetaminophen at 25.0, 30.0, 35.0, and 40.0 °C. By means of Gibbs and van't Hoff thermodynamic analyses it may observe that the transfer of this drug from water to octanol is spontaneous and mainly driven enthalpically. As in other studies made with guanine derivatives and sulfonamides, it has been shown that the mutual saturation of the octanol and aqueous phases plays an important role in the partitioning and solubility of this drug.

Octanol-water distribution of engineered nanomaterials.

Science.gov (United States)

Hristovski, Kiril D; Westerhoff, Paul K; Posner, Jonathan D

2011-01-01

The goal of this study was to examine the effects of pH and ionic strength on octanol-water distribution of five model engineered nanomaterials. Distribution experiments resulted in a spectrum of three broadly classified scenarios: distribution in the aqueous phase, distribution in the octanol, and distribution into the octanol-water interface. Two distribution coefficients were derived to describe the distribution of nanoparticles among octanol, water and their interface. The results show that particle surface charge, surface functionalization, and composition, as well as the solvent ionic strength and presence of natural organic matter, dramatically impact this distribution. Distributions of nanoparticles into the interface were significant for nanomaterials that exhibit low surface charge in natural pH ranges. Increased ionic strengths also contributed to increased distributions of nanoparticle into the interface. Similarly to the octanol-water distribution coefficients, which represent a starting point in predicting the environmental fate, bioavailability and transport of organic pollutants, distribution coefficients such as the ones described in this study could help to easily predict the fate, bioavailability, and transport of engineered nanomaterials in the environment.

Automated high performance liquid chromatography and liquid scintillation counting determination of pesticide mixture octanol/water partition rates

International Nuclear Information System (INIS)

Moody, R.P.; Carroll, J.M.; Kresta, A.M.

1987-01-01

Two novel methods are reported for measuring octanol/water partition rates of pesticides. A liquid scintillation counting (LSC) method was developed for automated monitoring of 14 C-labeled pesticides partitioning in biphasic water/octanol cocktail systems with limited success. A high performance liquid chromatography (HPLC) method was developed for automated partition rate monitoring of several constituents in a pesticide mixture, simultaneously. The mean log Kow +/- SD determined from triplicate experimental runs were for: 2,4-D-DMA (2,4-dichlorophenoxyacetic acid dimethylamine), 0.65 +/- .17; Deet (N,N-diethyl-m-toluamide), 2.02 +/- .01; Guthion (O,O-dimethyl-S-(4-oxo-1,2,3-benzotriazin-3(4H)-ylmethyl) phosphorodithioate), 2.43 +/- .03; Methyl-Parathion (O,O-dimethyl-O-(p-nitrophenyl) phosphorothioate), 2.68 +/- .05; and Fenitrothion (O,O-dimethyl O-(4-nitro-m-tolyl) phosphorothioate), 3.16 +/- .03. A strong positive linear correlation (r = .9979) was obtained between log Kow and log k' (log Kow = 2.35 (log k') + 0.63). The advantages that this automated procedure has in comparison with the standard manual shake-flask procedure are discussed

Quantitative structure-property relationship study of n-octanol-water partition coefficients of some of diverse drugs using multiple linear regression

International Nuclear Information System (INIS)

Ghasemi, Jahanbakhsh; Saaidpour, Saadi

2007-01-01

A quantitative structure-property relationship (QSPR) study was performed to develop models those relate the structures of 150 drug organic compounds to their n-octanol-water partition coefficients (log P o/w ). Molecular descriptors derived solely from 3D structures of the molecular drugs. A genetic algorithm was also applied as a variable selection tool in QSPR analysis. The models were constructed using 110 molecules as training set, and predictive ability tested using 40 compounds. Modeling of log P o/w of these compounds as a function of the theoretically derived descriptors was established by multiple linear regression (MLR). Four descriptors for these compounds molecular volume (MV) (geometrical), hydrophilic-lipophilic balance (HLB) (constitutional), hydrogen bond forming ability (HB) (electronic) and polar surface area (PSA) (electrostatic) are taken as inputs for the model. The use of descriptors calculated only from molecular structure eliminates the need for experimental determination of properties for use in the correlation and allows for the estimation of log P o/w for molecules not yet synthesized. Application of the developed model to a testing set of 40 drug organic compounds demonstrates that the model is reliable with good predictive accuracy and simple formulation. The prediction results are in good agreement with the experimental value. The root mean square error of prediction (RMSEP) and square correlation coefficient (R 2 ) for MLR model were 0.22 and 0.99 for the prediction set log P o/w

Partitioning of fluorotelomer alcohols to octanol and different sources of dissolved organic carbon.

Science.gov (United States)

Carmosini, Nadia; Lee, Linda S

2008-09-01

Interest in the environmental fate of fluorotelomer alcohols (FTOHs) has spurred efforts to understand their equilibrium partitioning behavior. Experimentally determined partition coefficients for FTOHs between soil/water and air/water have been reported, but direct measurements of partition coefficients for dissolved organic carbon (DOC)/water (K(doc)) and octanol/ water(K(ow)) have been lacking. Here we measured the partitioning of 8:2 and 6:2 FTOH between one or more types of DOC and water using enhanced solubility or dialysis bag techniques, and also quantified K(ow) values for 4:2 to 8:2 FTOH using a batch equilibration method. The range in measured log K(doc) values for 8:2 FTOH using the enhanced solubility technique with DOC derived from two soils, two biosolids, and three reference humic acids is 2.00-3.97 with the lowest values obtained for the biosolids and an average across all other DOC sources (biosolid DOC excluded) of 3.54 +/- 0.29. For 6:2 FTOH and Aldrich humic acid, a log K(doc) value of 1.96 +/- 0.45 was measured using the dialysis technique. These average values are approximately 1 to 2 log units lower than previously indirectly estimated K(doc) values. Overall, the affinity for DOC tends to be slightly lower than that for particulate soil organic carbon. Measured log K(ow) values for 4:2 (3.30 +/- 0.04), 6:2 (4.54 +/- 0.01), and 8:2 FTOH (5.58 +/- 0.06) were in good agreement with previously reported estimates. Using relationships between experimentally measured partition coefficients and C-atom chain length, we estimated K(doc) and K(ow) values for shorter and longer chain FTOHs, respectively, that we were unable to measure experimentally.

Novel medium-throughput technique for investigating drug-cyclodextrin complexation by pH-metric titration using the partition coefficient method.

Science.gov (United States)

Dargó, Gergő; Boros, Krisztina; Péter, László; Malanga, Milo; Sohajda, Tamás; Szente, Lajos; Balogh, György T

2018-05-05

The present study was aimed to develop a medium-throughput screening technique for investigation of cyclodextrin (CD)-active pharmaceutical ingredient (API) complexes. Dual-phase potentiometric lipophilicity measurement, as gold standard technique, was combined with the partition coefficient method (plotting the reciprocal of partition coefficients of APIs as a function of CD concentration). A general equation was derived for determination of stability constants of 1:1 CD-API complexes (K 1:1,CD ) based on solely the changes of partition coefficients (logP o/w N -logP app N ), without measurement of the actual API concentrations. Experimentally determined logP value (-1.64) of 6-deoxy-6[(5/6)-fluoresceinylthioureido]-HPBCD (FITC-NH-HPBCD) was used to estimate the logP value (≈ -2.5 to -3) of (2-hydroxypropyl)-ß-cyclodextrin (HPBCD). The results suggested that the amount of HPBCD can be considered to be inconsequential in the octanol phase. The decrease of octanol volume due to the octanol-CD complexation was considered, thus a corrected octanol-water phase ratio was also introduced. The K 1:1,CD values obtained by this developed method showed a good accordance with the results from other orthogonal methods. Copyright © 2018 Elsevier B.V. All rights reserved.

Development of polyparameter linear free energy relationship models for octanol-air partition coefficients of diverse chemicals.

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Jin, Xiaochen; Fu, Zhiqiang; Li, Xuehua; Chen, Jingwen

2017-03-22

The octanol-air partition coefficient (K OA ) is a key parameter describing the partition behavior of organic chemicals between air and environmental organic phases. As the experimental determination of K OA is costly, time-consuming and sometimes limited by the availability of authentic chemical standards for the compounds to be determined, it becomes necessary to develop credible predictive models for K OA . In this study, a polyparameter linear free energy relationship (pp-LFER) model for predicting K OA at 298.15 K and a novel model incorporating pp-LFERs with temperature (pp-LFER-T model) were developed from 795 log K OA values for 367 chemicals at different temperatures (263.15-323.15 K), and were evaluated with the OECD guidelines on QSAR model validation and applicability domain description. Statistical results show that both models are well-fitted, robust and have good predictive capabilities. Particularly, the pp-LFER model shows a strong predictive ability for polyfluoroalkyl substances and organosilicon compounds, and the pp-LFER-T model maintains a high predictive accuracy within a wide temperature range (263.15-323.15 K).

Retention of bile salts in micellar electrokinetic chromatography: relation of capacity factor to octanol-water partition coefficient and critical micellar concentration.

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Lucangioli, S E; Carducci, C N; Tripodi, V P; Kenndler, E

2001-12-25

The capacity factors of 16 anionic cholates (from six bile salts, including their glyco- and tauro-conjugates) were determined in a micellar electrokinetic chromatography (MEKC) system consisting of buffer, pH 7.5 (phosphate-boric acid; 20 mmol/l) with 50 mmol/l sodium dodecyl sulfate (SDS) as micelle former and 10% acetonitrile as organic modifier. The capacity factors of the fully dissociated, negatively charged analytes (ranging between 0.2 and 60) were calculated from their mobilities, with a reference background electrolyte (BGE) without SDS representing "free" solution. For comparison, the capacity factors were derived for a second reference BGE where the SDS concentration (5 mmol/l) is close to the critical micellar concentration (CMC). The capacity factors are compared with the logarithm of the octanol-water partition coefficient, log Pow, as measure for lipophilicity. Clear disagreement between these two parameters is found especially for epimeric cholates with the hydroxy group in position 7. In contrast, fair relation between the capacity factor of the analytes and their CMC is observed both depending strongly on the orientation of the OH groups, and tauro-conjugation as well. In this respect the retention behaviour of the bile salts in MEKC seems to reflect their role as detergents in living systems, and might serve as model parameter beyond lipophilicity.

Potential of the octanol-water partition coefficient (logP) to predict the dermal penetration behaviour of amphiphilic compounds in aqueous solutions.

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Korinth, Gintautas; Wellner, Tanja; Schaller, Karl Heinz; Drexler, Hans

2012-11-23

Aqueous amphiphilic compounds may exhibit enhanced skin penetration compared with neat compounds. Conventional models do not predict this percutaneous penetration behaviour. We investigated the potential of the octanol-water partition coefficient (logP) to predict dermal fluxes for eight compounds applied neat and as 50% aqueous solutions in diffusion cell experiments using human skin. Data for seven other compounds were accessed from literature. In total, seven glycol ethers, three alcohols, two glycols, and three other chemicals were considered. Of these 15 compounds, 10 penetrated faster through the skin as aqueous solutions than as neat compounds. The other five compounds exhibited larger fluxes as neat applications. For 13 of the 15 compounds, a consistent relationship was identified between the percutaneous penetration behaviour and the logP. Compared with the neat applications, positive logP were associated with larger fluxes for eight of the diluted compounds, and negative logP were associated with smaller fluxes for five of the diluted compounds. Our study demonstrates that decreases or enhancements in dermal penetration upon aqueous dilution can be predicted for many compounds from the sign of logP (i.e., positive or negative). This approach may be suitable as a first approximation in risk assessments of dermal exposure. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

40 CFR 799.6756 - TSCA partition coefficient (n-octanol/water), generator column method.

Science.gov (United States)

2010-07-01

... using the CLogP3 computer program in paragraph (e)(9) of this section. 4 Hawker and Connell (1988... (B) Constant temperature bath with circulation pump-bath and capable of controlling temperature to 25...-partition coefficient correlation. Environmental Science and Technology 14:1227-1229 (1980). (2) Bruggemann...

Determination of n-octanol/water partition coefficient for DDT-related compounds by RP-HPLC with a novel dual-point retention time correction.

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Han, Shu-ying; Qiao, Jun-qin; Zhang, Yun-yang; Yang, Li-li; Lian, Hong-zhen; Ge, Xin; Chen, Hong-yuan

2011-03-01

n-Octanol/water partition coefficients (P) for DDTs and dicofol were determined by reversed-phase high performance liquid chromatography (RP-HPLC) on a C(18) column using methanol-water mixture as mobile phase. A dual-point retention time correction (DP-RTC) was proposed to rectify chromatographic retention time (t(R)) shift resulted from stationary phase aging. Based on this correction, the relationship between logP and logk(w), the logarithm of the retention factor extrapolated to pure water, was investigated for a set of 12 benzene homologues and DDT-related compounds with reliable experimental P as model compounds. A linear regression logP=(1.10±0.04) logk(w) - (0.60±0.17) was established with correlation coefficient R(2) of 0.988, cross-validated correlation coefficient R(cv)(2) of 0.983 and standard deviation (SD) of 0.156. This model was further validated using four verification compounds, naphthalene, biphenyl, 2,2-bis(4-chlorophenyl)-1,1-dichloroethane (p,p'-DDD) and 2,2-bis(4-chlorophenyl)-1,1-dichloroethene (p,p'-DDE) with similar structure to DDT. The RP-HPLC-determined P values showed good consistency with shake-flask (SFM) or slow-stirring (SSM) results, especially for highly hydrophobic compounds with logP in the range of 4-7. Then, the P values for five DDT-related compounds, 2-(2-chlorophenyl)-2-(4-chlorophenyl)-1,1,1-trichloroethane (o,p'-DDT), 2-(2-chlorophenyl)-2-(4-chlorophenyl)-1,1-dichloroethane (o,p'-DDD), 2-(2-chlorophenyl)-2-(4-chlorophenyl)-1,1-dichloroethene (o,p'-DDE), and 2,2,2-trichloro-1,1-bis(4-chlorophenyl)ethanol (dicofol) and its main degradation product 4,4'-dichlorobenzophenone (p,p'-DBP) were evaluated by the improved RP-HPLC method for the first time. The excellent precision with SD less than 0.03 proved that the novel DP-RTC protocol can significantly increases the determination accuracy and reliability of P by RP-HPLC. Copyright © 2011 Elsevier Ltd. All rights reserved.

Determination and prediction of octanol-air partition coefficients for organophosphate flame retardants.

Science.gov (United States)

Wang, Qingzhi; Zhao, Hongxia; Wang, Yan; Xie, Qing; Chen, Jingwen; Quan, Xie

2017-11-01

Organophosphate flame retardants (OPFRs) have attracted wide concerns due to their toxicities and ubiquitous occurrence in the environment. In this work, Octanol-air partition coefficient (K OA ) for 14 OPFRs including 4 halogenated alkyl-, 5 aryl- and 5 alkyl-OPFRs, were estimated as a function of temperature using a gas chromatographic retention time (GC-RT) method. Their log K OA-GC values and internal energies of phase transfer (Δ OA U/kJmol -1 ) ranged from 8.03 to 13.0 and from 69.7 to 149, respectively. Substitution pattern and molar volume (V M ) were found to be capable of influencing log K OA-GC values of OPFRs. The halogenated alkyl-OPFRs had higher log K OA-GC values than aryl- or alkyl-OPFRs. The bigger the molar volume was, the greater the log K OA-GC values increased. In addition, a predicted model of log K OA-GC versus different relative retention times (RRTs) was developed with a high cross-validated value (Q 2 (cum) ) of 0.951, indicating a good predictive ability and stability. Therefore, the log K OA-GC values of the remaining OPFRs can be predicted by using their RRTs on different GC columns. Copyright © 2017 Elsevier Inc. All rights reserved.

Solvation free energies and partition coefficients with the coarse-grained and hybrid all-atom/coarse-grained MARTINI models.

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Genheden, Samuel

2017-10-01

We present the estimation of solvation free energies of small solutes in water, n-octanol and hexane using molecular dynamics simulations with two MARTINI models at different resolutions, viz. the coarse-grained (CG) and the hybrid all-atom/coarse-grained (AA/CG) models. From these estimates, we also calculate the water/hexane and water/octanol partition coefficients. More than 150 small, organic molecules were selected from the Minnesota solvation database and parameterized in a semi-automatic fashion. Using either the CG or hybrid AA/CG models, we find considerable deviations between the estimated and experimental solvation free energies in all solvents with mean absolute deviations larger than 10 kJ/mol, although the correlation coefficient is between 0.55 and 0.75 and significant. There is also no difference between the results when using the non-polarizable and polarizable water model, although we identify some improvements when using the polarizable model with the AA/CG solutes. In contrast to the estimated solvation energies, the estimated partition coefficients are generally excellent with both the CG and hybrid AA/CG models, giving mean absolute deviations between 0.67 and 0.90 log units and correlation coefficients larger than 0.85. We analyze the error distribution further and suggest avenues for improvements.

Solvation free energies and partition coefficients with the coarse-grained and hybrid all-atom/coarse-grained MARTINI models

Science.gov (United States)

Genheden, Samuel

2017-10-01

We present the estimation of solvation free energies of small solutes in water, n-octanol and hexane using molecular dynamics simulations with two MARTINI models at different resolutions, viz. the coarse-grained (CG) and the hybrid all-atom/coarse-grained (AA/CG) models. From these estimates, we also calculate the water/hexane and water/octanol partition coefficients. More than 150 small, organic molecules were selected from the Minnesota solvation database and parameterized in a semi-automatic fashion. Using either the CG or hybrid AA/CG models, we find considerable deviations between the estimated and experimental solvation free energies in all solvents with mean absolute deviations larger than 10 kJ/mol, although the correlation coefficient is between 0.55 and 0.75 and significant. There is also no difference between the results when using the non-polarizable and polarizable water model, although we identify some improvements when using the polarizable model with the AA/CG solutes. In contrast to the estimated solvation energies, the estimated partition coefficients are generally excellent with both the CG and hybrid AA/CG models, giving mean absolute deviations between 0.67 and 0.90 log units and correlation coefficients larger than 0.85. We analyze the error distribution further and suggest avenues for improvements.

Variation in bioaccumulation of persistent organic pollutants based on octanol-air partitioning: Influence of respiratory elimination in marine species.

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Moses, Sara K; Harley, John R; Lieske, Camilla L; Muir, Derek C G; Whiting, Alex V; O'Hara, Todd M

2015-11-15

Risk assessments of persistent organic pollutants (POPs) are often based on octanol-water (KOW) partitioning dynamics and may not adequately reflect bioaccumulation in air-breathing organisms. It has been suggested that compounds with low KOW and high octanol-air partitioning (KOA) coefficients have the potential to bioaccumulate in air-breathing organisms, including marine mammals. Here we evaluate differences in concentrations of POPs for two trophically matched Arctic species, spotted seal (Phoca largha) and sheefish (Stenodus leucichthys). We compared concentrations of 108 POPs in matched tissues (liver and muscle) across three ranges of KOW. We found a significant positive correlation between POP concentration and log KOA in spotted seal tissues for low log KOW compounds (log KOW <5.5, p<0.05). This provides further evidence for empirical models and observed bioaccumulation patterns in air-breathing organisms, and highlights the potential for bioaccumulation of these compounds in Arctic marine mammals. Copyright © 2015 Elsevier Ltd. All rights reserved.

Correlation between octanol/water and liposome/water distribution coefficients and drug absorption of a set of pharmacologically active compounds.

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Esteves, Freddy; Moutinho, Carla; Matos, Carla

2013-06-01

Absorption and consequent therapeutic action are key issues in the development of new drugs by the pharmaceutical industry. In this sense, different models can be used to simulate biological membranes to predict the absorption of a drug. This work compared the octanol/water and the liposome/water models. The parameters used to relate the two models were the distribution coefficients between liposomes and water and octanol and water and the fraction of drug orally absorbed. For this study, 66 drugs were collected from literature sources and divided into four groups according to charge and ionization degree: neutral; positively charged; negatively charged; and partially ionized/zwitterionic. The results show a satisfactory linear correlation between the octanol and liposome systems for the neutral (R²= 0.9324) and partially ionized compounds (R²= 0.9367), contrary to the positive (R²= 0.4684) and negatively charged compounds (R²= 0.1487). In the case of neutral drugs, results were similar in both models because of the high fraction orally absorbed. However, for the charged drugs (positively, negatively, and partially ionized/zwitterionic), the liposomal model has a more-appropriate correlation with absorption than the octanol model. These results show that the neutral compounds only interact with membranes through hydrophobic bonds, whereas charged drugs favor electrostatic interactions established with the liposomes. With this work, we concluded that liposomes may be a more-appropriate biomembrane model than octanol for charged compounds.

Quantitative relationship between the octanol/water partition coefficient and the diffusion limitation of the exchange between adipose and blood.

Science.gov (United States)

Levitt, David G

2010-01-07

The goal of physiologically based pharmacokinetics (PBPK) is to predict drug kinetics from an understanding of the organ/blood exchange. The standard approach is to assume that the organ is "flow limited" which means that the venous blood leaving the organ equilibrates with the well-stirred tissue compartment. Although this assumption is valid for most solutes, it has been shown to be incorrect for several very highly fat soluble compounds which appear to be "diffusion limited". This paper describes the physical basis of this adipose diffusion limitation and its quantitative dependence on the blood/water (Kbld-wat) and octanol/water (Kow) partition coefficient. Experimental measurements of the time dependent rat blood and adipose concentration following either intravenous or oral input were used to estimate the "apparent" adipose perfusion rate (FA) assuming that the tissue is flow limited. It is shown that the ratio of FA to the anatomic perfusion rate (F) provides a measure of the diffusion limitation. A quantitative relationship between this diffusion limitation and Kbld-wat and Kow is derived. This analysis was applied to previously published data, including the Oberg et. al. measurements of the rat plasma and adipose tissue concentration following an oral dose of a mixture of 13 different polychlorinated biphenyls. Solutes become diffusion limited at values of log Kow greater than about 5.6, with the adipose-blood exchange rate reduced by a factor of about 30 for a solute with a log Kow of 7.36. Quantitatively, a plot of FA/F versus Kow is well described assuming an adipose permeability-surface area product (PS) of 750/min. This PS corresponds to a 0.14 micron aqueous layer separating the well-stirred blood from the adipose lipid. This is approximately equal to the thickness of the rat adipose capillary endothelium. These results can be used to quantitate the adipose-blood diffusion limitation as a function of Kow. This is especially important for the highly

Partition coefficients of some purine derivatives and its application to pharmacokinetics.

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Chrzanowska, M; Sobiak, J; Kuehn, M; Dorawa, E; Hermann, T

2009-12-01

Metazathioprine (MAZA), a methylated derivative of azathioprine (AZA), demonstrated the greatest values of apparent and specific partition coefficients in n-octanol/phosphate buffer at pH 5.7 and pH 7.4 among purine derivatives such as 6-mercaptopurine (6-MP), 6-thioguanine (6-TG) and AZA. Introduction of a methyl group into the imidazole ring of AZA increases lipophilic properties of MAZA compared to AZA. Mass balance of purine derivatives in n-octanol and in phosphate buffer indicated their chemical stability in those media.

Carrier Mediated Distribution System (CAMDIS): a new approach for the measurement of octanol/water distribution coefficients.

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Wagner, Bjoern; Fischer, Holger; Kansy, Manfred; Seelig, Anna; Assmus, Frauke

2015-02-20

Here we present a miniaturized assay, referred to as Carrier-Mediated Distribution System (CAMDIS) for fast and reliable measurement of octanol/water distribution coefficients, log D(oct). By introducing a filter support for octanol, phase separation from water is facilitated and the tendency of emulsion formation (emulsification) at the interface is reduced. A guideline for the best practice of CAMDIS is given, describing a strategy to manage drug adsorption at the filter-supported octanol/buffer interface. We validated the assay on a set of 52 structurally diverse drugs with known shake flask log D(oct) values. Excellent agreement with literature data (r(2) = 0.996, standard error of estimate, SEE = 0.111), high reproducibility (standard deviation, SD < 0.1 log D(oct) units), minimal sample consumption (10 μL of 100 μM DMSO stock solution) and a broad analytical range (log D(oct) range = -0.5 to 4.2) make CAMDIS a valuable tool for the high-throughput assessment of log D(oc)t. Copyright © 2014 Elsevier B.V. All rights reserved.

Determination of the n-octanol/water partition coefficients of weakly ionizable basic compounds by reversed-phase high-performance liquid chromatography with neutral model compounds.

Science.gov (United States)

Liang, Chao; Han, Shu-ying; Qiao, Jun-qin; Lian, Hong-zhen; Ge, Xin

2014-11-01

A strategy to utilize neutral model compounds for lipophilicity measurement of ionizable basic compounds by reversed-phase high-performance liquid chromatography is proposed in this paper. The applicability of the novel protocol was justified by theoretical derivation. Meanwhile, the linear relationships between logarithm of apparent n-octanol/water partition coefficients (logKow '') and logarithm of retention factors corresponding to the 100% aqueous fraction of mobile phase (logkw ) were established for a basic training set, a neutral training set and a mixed training set of these two. As proved in theory, the good linearity and external validation results indicated that the logKow ''-logkw relationships obtained from a neutral model training set were always reliable regardless of mobile phase pH. Afterwards, the above relationships were adopted to determine the logKow of harmaline, a weakly dissociable alkaloid. As far as we know, this is the first report on experimental logKow data for harmaline (logKow = 2.28 ± 0.08). Introducing neutral compounds into a basic model training set or using neutral model compounds alone is recommended to measure the lipophilicity of weakly ionizable basic compounds especially those with high hydrophobicity for the advantages of more suitable model compound choices and convenient mobile phase pH control. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Relevance of octanol-water distribution measurements to the potential ecological uptake of multi-walled carbon nanotubes.

Science.gov (United States)

Petersen, Elijah J; Huang, Qingguo; Weber, Walter J

2010-05-01

Many potential applications of carbon nanotubes (CNTs) require various physicochemical modifications prior to use, suggesting that nanotubes having varied properties may pose risks in ecosystems. A means for estimating bioaccumulation potentials of variously modified CNTs for incorporation in predictive fate models would be highly valuable. An approach commonly used for sparingly soluble organic contaminants, and previously suggested for use as well with carbonaceous nanomaterials, involves measurement of their octanol-water partitioning coefficient (KOW) values. To test the applicability of this approach, a methodology was developed to measure apparent octanol-water distribution behaviors for purified multi-walled carbon nanotubes and those acid treated. Substantial differences in apparent distribution coefficients between the two types of CNTs were observed, but these differences did not influence accumulation by either earthworms (Eisenia foetida) or oligochaetes (Lumbriculus variegatus), both of which showed minimal nanotube uptake for both types of nanotubes. The results suggest that traditional distribution behavior-based KOW approaches are likely not appropriate for predicting CNT bioaccumulation. Copyright (c) 2010 SETAC.

40 CFR 799.6755 - TSCA partition coefficient (n-octanol/water), shake flask method.

Science.gov (United States)

2010-07-01

... determined values of the P expressed as their common logarithms should fall within a range of ± 0.3 log units... substance. The test substance should be the purest available. For a material balance during the test a stock... following procedure to minimize the risk of including traces of the n-octanol: A glass syringe with a...

Optimised method to estimate octanol water distribution coefficient (logD) in a high throughput format.

Science.gov (United States)

Low, Ying Wei Ivan; Blasco, Francesca; Vachaspati, Prakash

2016-09-20

Lipophilicity is one of the molecular properties assessed in early drug discovery. Direct measurement of the octanol-water distribution coefficient (logD) requires an analytical method with a large dynamic range or multistep dilutions, as the analyte's concentrations span across several orders of magnitude. In addition, water/buffer and octanol phases which have very different polarity could lead to matrix effects and affect the LC-MS response, leading to erroneous logD values. Most compound libraries use DMSO stocks as it greatly reduces the sample requirement but the presence of DMSO has been shown to underestimate the lipophilicity of the analyte. The present work describes the development of an optimised shake flask logD method using deepwell 96 well plate that addresses the issues related to matrix effects, DMSO concentration and incubation conditions and is also amenable to high throughput. Our results indicate that the equilibrium can be achieved within 30min by flipping the plate on its side while even 0.5% of DMSO is not tolerated in the assay. This study uses the matched matrix concept to minimise the errors in analysing the two phases namely buffer and octanol in LC-MS. Copyright © 2016 Elsevier B.V. All rights reserved.

Automated Potentiometric Titrations in KCl/Water-Saturated Octanol: Method for Quantifying Factors Influencing Ion-Pair Partitioning

Science.gov (United States)

2009-01-01

The knowledge base of factors influencing ion pair partitioning is very sparse, primarily because of the difficulty in determining accurate log PI values of desirable low molecular weight (MW) reference compounds. We have developed a potentiometric titration procedure in KCl/water-saturated octanol that provides a link to log PI through the thermodynamic cycle of ionization and partitioning. These titrations have the advantage of being independent of the magnitude of log P, while maintaining a reproducibility of a few hundredths of a log P in the calculated difference between log P neutral and log P ion pair (diff (log PN − I)). Simple model compounds can be used. The titration procedure is described in detail, along with a program for calculating pKa′′ values incorporating the ionization of water in octanol. Hydrogen bonding and steric factors have a greater influence on ion pairs than they do on neutral species, yet these factors are missing from current programs used to calculate log PI and log D. In contrast to the common assumption that diff (log PN − I) is the same for all amines, they can actually vary more than 3 log units, as in our examples. A major factor affecting log PI is the ability of water and the counterion to approach the charge center. Bulky substituents near the charge center have a negative influence on log PI. On the other hand, hydrogen bonding groups near the charge center have the opposite effect by lowering the free energy of the ion pair. The use of this titration method to determine substituent ion pair stabilization values (IPS) should bring about more accurate log D calculations and encourage species-specific QSAR involving log DN and log DI. This work also brings attention to the fascinating world of nature’s highly stabilized ion pairs. PMID:19265385

Automated potentiometric titrations in KCl/water-saturated octanol: method for quantifying factors influencing ion-pair partitioning.

Science.gov (United States)

Scherrer, Robert A; Donovan, Stephen F

2009-04-01

The knowledge base of factors influencing ion pair partitioning is very sparse, primarily because of the difficulty in determining accurate log P(I) values of desirable low molecular weight (MW) reference compounds. We have developed a potentiometric titration procedure in KCl/water-saturated octanol that provides a link to log P(I) through the thermodynamic cycle of ionization and partitioning. These titrations have the advantage of being independent of the magnitude of log P, while maintaining a reproducibility of a few hundredths of a log P in the calculated difference between log P neutral and log P ion pair (diff (log P(N - I))). Simple model compounds can be used. The titration procedure is described in detail, along with a program for calculating pK(a)'' values incorporating the ionization of water in octanol. Hydrogen bonding and steric factors have a greater influence on ion pairs than they do on neutral species, yet these factors are missing from current programs used to calculate log P(I) and log D. In contrast to the common assumption that diff (log P(N - I)) is the same for all amines, they can actually vary more than 3 log units, as in our examples. A major factor affecting log P(I) is the ability of water and the counterion to approach the charge center. Bulky substituents near the charge center have a negative influence on log P(I). On the other hand, hydrogen bonding groups near the charge center have the opposite effect by lowering the free energy of the ion pair. The use of this titration method to determine substituent ion pair stabilization values (IPS) should bring about more accurate log D calculations and encourage species-specific QSAR involving log D(N) and log D(I). This work also brings attention to the fascinating world of nature's highly stabilized ion pairs.

The use of QSAR methods for determination of n-octanol/water partition coefficient using the example of hydroxyester HE-1

Science.gov (United States)

Guziałowska-Tic, Joanna

2017-10-01

According to the Directive of the European Parliament and of the Council concerning the protection of animals used for scientific purposes, the number of experiments involving the use of animals needs to be reduced. The methods which can replace animal testing include computational prediction methods, for instance, the quantitative structure-activity relationships (QSAR). These methods are designed to find a cohesive relationship between differences in the values of the properties of molecules and the biological activity of a series of test compounds. This paper compares the results of the author's own results of examination on the n-octanol/water coefficient for the hydroxyester HE-1 with those generated by means of three models: Kowwin, MlogP, AlogP. The test results indicate that, in the case of molecular similarity, the highest determination coefficient was obtained for the model MlogP and the lowest root-mean square error was obtained for the Kowwin method. When comparing the mean logP value obtained using the QSAR models with the value resulting from the author's own experiments, it was observed that the best conformity was that recorded for the model AlogP, where relative error was 15.2%.

The use of QSAR methods for determination of n-octanol/water partition coefficient using the example of hydroxyester HE-1

Directory of Open Access Journals (Sweden)

Guziałowska-Tic Joanna

2017-01-01

Full Text Available According to the Directive of the European Parliament and of the Council concerning the protection of animals used for scientific purposes, the number of experiments involving the use of animals needs to be reduced. The methods which can replace animal testing include computational prediction methods, for instance, the quantitative structure-activity relationships (QSAR. These methods are designed to find a cohesive relationship between differences in the values of the properties of molecules and the biological activity of a series of test compounds. This paper compares the results of the author's own results of examination on the n-octanol/water coefficient for the hydroxyester HE-1 with those generated by means of three models: Kowwin, MlogP, AlogP. The test results indicate that, in the case of molecular similarity, the highest determination coefficient was obtained for the model MlogP and the lowest root-mean square error was obtained for the Kowwin method. When comparing the mean logP value obtained using the QSAR models with the value resulting from the author's own experiments, it was observed that the best conformity was that recorded for the model AlogP, where relative error was 15.2%.

Influence of the structure of bile acids on their partition coefficient in dibutyl ether and chloroform

Directory of Open Access Journals (Sweden)

Sebenji Ana S.

2015-01-01

Full Text Available Bile acids are well known natural surfactants able to modify the per­meability of biological membranes. The logarithm of partition coefficient between, tradi­tionally used, n-octanol and water is a measure of lipophilicity as a predictor of solute membrane partitioning. The aim of this work was to determine partition coefficients of bile acids in a mixture of water and chloroform and dibutyl ether at different pH values and with addition of different concentrations of sodium ions, and to examine the influence of the structure of bile acid nucleus on measured partition coefficients. Partition coefficients of three bile acid salts were determined using shake-flask method and the concentration of bile acids was determined after twelve hours of shaking at the room temperature in aqueous and organic layer using reversed phase HPLC with DAD detector on 210 nm. For all three analysed bile acid salts values of logP are lower in dibutyl ether than in chloroform. At certain pH values, curves representing the dependence of partition coeffi­cient on pH value intersect, and these are the pH values for which partition coefficients are the same for both solvents. Increasing the solution ionic strength, this intersection is shifted toward lower pH values. It is found that, for both organic solvents, after the addition of hy­droxyl group in the steroid nucleus (i.e. if the bile acid is less hydrophobic the value of logP falls, especially if more hydroxyl groups are present. With chloroform as a solvent, system quickly comes to excess with electrolyte ions than with dibutyl ether. [Projekat Ministarstva nauke Republike Srbije, br. 172021

Determination of silicone rubber and low-density polyethylene diffusion and polymer/water partition coefficients for emerging contaminants.

Science.gov (United States)

Pintado-Herrera, Marina G; Lara-Martín, Pablo A; González-Mazo, Eduardo; Allan, Ian J

2016-09-01

There is a growing interest in assessing the concentration and distribution of new nonregulated organic compounds (emerging contaminants) in the environment. The measurement of freely dissolved concentrations using conventional approaches is challenging because of the low concentrations that may be encountered and their temporally variable emissions. Absorption-based passive sampling enables the estimation of freely dissolved concentrations of hydrophobic contaminants of emerging concern in water. In the present study, calibration was undertaken for 2 polymers, low-density polyethylene (LDPE) and silicone rubber for 11 fragrances, 5 endocrine-disrupting compounds, 7 ultraviolet (UV) filters, and 8 organophosphate flame retardant compounds. Batch experiments were performed to estimate contaminant diffusion coefficients in the polymers (Dp ), which in general decreased with increasing molecular weight. The values for fragrances, endocrine-disrupting compounds, and UV filters were in ranges similar to those previously reported for polycyclic aromatic hydrocarbons, but were 1 order of magnitude lower for organophosphate flame retardant compounds. Silicone rubber had higher Dp values than LDPE and was therefore selected for further experiments to calculate polymer/water partition coefficients (KPW ). The authors observed a positive correlation between log KPW and log octanol/water partition coefficient values. Field testing of silicone rubber passive samplers was undertaken though exposure in the River Alna (Norway) for an exposure time of 21 d to estimate freely dissolved concentration. Some fragrances and UV filters were predominant over other emerging and regulated contaminants, at levels up to 1600 ng L(-1) for galaxolide and 448 ng L(-1) for octocrylene. Environ Toxicol Chem 2016;35:2162-2172. © 2016 SETAC. © 2016 SETAC.

[Partitioning of taxifolin-iron ions complexes in octanol-water system].

Science.gov (United States)

Shatalin, Iu V; Shubina, V S

2014-01-01

The composition of taxifolin-iron ions complexes in an octanol-water biphasic system was studied using the method of absorption spectrophotometry. It was found that at pH 5.0 in an aqueous biphasic system the complex of [Tf2 x Fe x (OH)k(H2O)8-k] is present, but at pH 7.0 and 9.0 the complexes of [Tf2 x Fe x (OH)k(H2O)2-k] and [Tf x Fe x OH)k(H2O)4-k] are predominantly observed. The formation of a stable [Tf3 x Fe] complex occurred in octanol phase. The charged iron ion of this complex is surrounded by taxifolin molecules, which shield the iron ion from lipophilic solvent. During transition from water to octanol phase the changes of the composition of complexes are accompanied by reciprocal changes in portion of taxifolin and iron ions in these phases. It was shown that the portion of taxifolin in aqueous solution in the presence of iron ions is increased at high pH values, and the portion of iron ions is minimal at pH 7.0. In addition, the parameters of solubility limits of taxifolin-iron ions complexes in an aqueous solution were determined. The data obtained gain a better understanding of the role of complexation of polyphenol with metal of variable valency in passive transport of flavonoids and metal ions across lipid membranes.

Determination of partition coefficient and analysis of nitrophenols by three-phase liquid-phase microextraction coupled with capillary electrophoresis.

Science.gov (United States)

Sanagi, Mohd Marsin; Miskam, Mazidatulakmam; Wan Ibrahim, Wan Aini; Hermawan, Dadan; Aboul-Enein, Hassan Y

2010-07-01

A three-phase hollow fiber liquid-phase microextraction method coupled with CE was developed and used for the determination of partition coefficients and analysis of selected nitrophenols in water samples. The selected nitrophenols were extracted from 14 mL of aqueous solution (donor solution) with the pH adjusted to pH 3 into an organic phase (1-octanol) immobilized in the pores of the hollow fiber and finally backextracted into 40.0 microL of the acceptor phase (NaOH) at pH 12.0 located inside the lumen of the hollow fiber. The extractions were carried out under the following optimum conditions: donor solution, 0.05 M H(3)PO(4), pH 3.0; organic solvent, 1-octanol; acceptor solution, 40 microL of 0.1 M NaOH, pH 12.0; agitation rate, 1050 rpm; extraction time, 15 min. Under optimized conditions, the calibration curves for the analytes were linear in the range of 0.05-0.30 mg/L with r(2)>0.9900 and LODs were in the range of 0.01-0.04 mg/L with RSDs of 1.25-2.32%. Excellent enrichment factors of up to 398-folds were obtained. It was found that the partition coefficient (K(a/d)) values were high for 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol and 2,6-dinitrophenol and that the individual partition coefficients (K(org/d) and K(a/org)) promoted efficient simultaneous extraction from the donor through the organic phase and further into the acceptor phase. The developed method was successfully applied for the analysis of water samples.

Evaluating Force Fields for the Computational Prediction of Ionized Arginine and Lysine Side-Chains Partitioning into Lipid Bilayers and Octanol.

Science.gov (United States)

Sun, Delin; Forsman, Jan; Woodward, Clifford E

2015-04-14

Abundant peptides and proteins containing arginine (Arg) and lysine (Lys) amino acids can apparently permeate cell membranes with ease. However, the mechanisms by which these peptides and proteins succeed in traversing the free energy barrier imposed by cell membranes remain largely unestablished. Precise thermodynamic studies (both theoretical and experimental) on the interactions of Arg and Lys residues with model lipid bilayers can provide valuable clues to the efficacy of these cationic peptides and proteins. We have carried out molecular dynamics simulations to calculate the interactions of ionized Arg and Lys side-chains with the zwitterionic 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid bilayer for 10 widely used lipid/protein force fields: CHARMM36/CHARMM36, SLIPID/AMBER99SB-ILDN, OPLS-AA/OPLS-AA, Berger/OPLS-AA, Berger/GROMOS87, Berger/GROMOS53A6, GROMOS53A6/GROMOS53A6, nonpolarizable MARTINI, polarizable MARTINI, and BMW MARTINI. We performed umbrella sampling simulations to obtain the potential of mean force for Arg and Lys side-chains partitioning from water to the bilayer interior. We found significant differences between the force fields, both for the interactions between side-chains and bilayer surface, as well as the free energy cost for placing the side-chain at the center of the bilayer. These simulation results were compared with the Wimley-White interfacial scale. We also calculated the free energy cost for transferring ionized Arg and Lys side-chains from water to both dry and wet octanol. Our simulations reveal rapid diffusion of water molecules into octanol whereby the equilibrium mole fraction of water in the wet octanol phase was ∼25%. Surprisingly, our free energy calculations found that the high water content in wet octanol lowered the water-to-octanol partitioning free energies for cationic residues by only 0.6 to 0.7 kcal/mol.

A novel method for the investigation of liquid/liquid distribution coefficients and interface permeabilities applied to the water-octanol-drug system.

Science.gov (United States)

Stein, Paul C; di Cagno, Massimiliano; Bauer-Brandl, Annette

2011-09-01

In this work a new, accurate and convenient technique for the measurement of distribution coefficients and membrane permeabilities based on nuclear magnetic resonance (NMR) is described. This method is a novel implementation of localized NMR spectroscopy and enables the simultaneous analysis of the drug content in the octanol and in the water phase without separation. For validation of the method, the distribution coefficients at pH = 7.4 of four active pharmaceutical ingredients (APIs), namely ibuprofen, ketoprofen, nadolol, and paracetamol (acetaminophen), were determined using a classical approach. These results were compared to the NMR experiments which are described in this work. For all substances, the respective distribution coefficients found with the two techniques coincided very well. Furthermore, the NMR experiments make it possible to follow the distribution of the drug between the phases as a function of position and time. Our results show that the technique, which is available on any modern NMR spectrometer, is well suited to the measurement of distribution coefficients. The experiments present also new insight into the dynamics of the water-octanol interface itself and permit measurement of the interface permeability.

Determination of air-loop volume and radon partition coefficient for measuring radon in water sample.

Science.gov (United States)

Lee, Kil Yong; Burnett, William C

A simple method for the direct determination of the air-loop volume in a RAD7 system as well as the radon partition coefficient was developed allowing for an accurate measurement of the radon activity in any type of water. The air-loop volume may be measured directly using an external radon source and an empty bottle with a precisely measured volume. The partition coefficient and activity of radon in the water sample may then be determined via the RAD7 using the determined air-loop volume. Activity ratios instead of absolute activities were used to measure the air-loop volume and the radon partition coefficient. In order to verify this approach, we measured the radon partition coefficient in deionized water in the temperature range of 10-30 °C and compared the values to those calculated from the well-known Weigel equation. The results were within 5 % variance throughout the temperature range. We also applied the approach for measurement of the radon partition coefficient in synthetic saline water (0-75 ppt salinity) as well as tap water. The radon activity of the tap water sample was determined by this method as well as the standard RAD-H 2 O and BigBottle RAD-H 2 O. The results have shown good agreement between this method and the standard methods.

Determination of air-loop volume and radon partition coefficient for measuring radon in water sample

International Nuclear Information System (INIS)

Kil Yong Lee; Burnett, W.C.

2013-01-01

A simple method for the direct determination of the air-loop volume in a RAD7 system as well as the radon partition coefficient was developed allowing for an accurate measurement of the radon activity in any type of water. The air-loop volume may be measured directly using an external radon source and an empty bottle with a precisely measured volume. The partition coefficient and activity of radon in the water sample may then be determined via the RAD7 using the determined air-loop volume. Activity ratios instead of absolute activities were used to measure the air-loop volume and the radon partition coefficient. In order to verify this approach, we measured the radon partition coefficient in deionized water in the temperature range of 10-30 deg C and compared the values to those calculated from the well-known Weigel equation. The results were within 5 % variance throughout the temperature range. We also applied the approach for measurement of the radon partition coefficient in synthetic saline water (0-75 ppt salinity) as well as tap water. The radon activity of the tap water sample was determined by this method as well as the standard RAD-H 2 O and BigBottle RAD-H 2 O. The results have shown good agreement between this method and the standard methods. (author)

Determination of partition coefficients n-octanol/water for treosulfan and its epoxy-transformers: an example of a negative correlation between lipophilicity of unionized compounds and their retention in reversed-phase chromatography.

Science.gov (United States)

Główka, Franciszek K; Romański, Michał; Siemiątkowska, Anna

2013-04-01

For the last decade an alkylating agent treosulfan (TREO) has been successfully applied in clinical trials in conditioning prior to hematopoietic stem cell transplantation. Pharmacological activity of the pro-drug depends on its epoxy-transformers, monoepoxide (S,S-EBDM) and diepoxide (S,S-DEB), which are formed in a non-enzymatic consecutive reaction accompanied by a release of methanesulfonic acid. In the present study partition coefficient n-octanol/water (POW) of TREO as well as its biologically active epoxy-transformers was determined empirically (applying a classical shake-flask method) and in silico for the first time. In vitro the partition was investigated at 37°C in the system composed of the pre-saturated n-octanol and 0.05 M acetate buffer pH 4.4 adjusted with sodium and potassium chloride to ionic strength of 0.16 M. Concentration of the analytes was quantified by reversed-phase high performance liquid chromatography (RP-HPLC) method in which retention time increased from S,S-DEB to TREO. It was shown that neither association nor dissociation of the tested compounds in the applied phases occurred. Calculated logPOW (TREO: -1.58±0.04, S,S-EBDM: -1.18±0.02, S,S-DEB: -0.40±0.03) indicate the hydrophilic character of the all three entities, corresponding to its pharmacokinetic parameters described in the literature. Experimentally determined logPOW of the compounds were best comparable to the values predicted by algorithm ALOGPs. Interestingly, the POW values determined in vitro as well as in silico were inversely correlated with the retention times observed in the endcapped RP-HPLC column. It might be explained by the fact that a cleavage of methansulfonic acid from a small molecule of TREO generates significant changes in the molecular structure. Consequently, despite the common chemical origin, TREO, S,S-EBDM and S,S-DEB do not constitute a 'congeneric' series of compounds. We concluded that this might occur in other low-weight species, therefore

Parameterization of an empirical model for the prediction of n-octanol, alkane and cyclohexane/water as well as brain/blood partition coefficients.

Science.gov (United States)

Zerara, Mohamed; Brickmann, Jürgen; Kretschmer, Robert; Exner, Thomas E

2009-02-01

Quantitative information of solvation and transfer free energies is often needed for the understanding of many physicochemical processes, e.g the molecular recognition phenomena, the transport and diffusion processes through biological membranes and the tertiary structure of proteins. Recently, a concept for the localization and quantification of hydrophobicity has been introduced (Jäger et al. J Chem Inf Comput Sci 43:237-247, 2003). This model is based on the assumptions that the overall hydrophobicity can be obtained as a superposition of fragment contributions. To date, all predictive models for the logP have been parameterized for n-octanol/water (logP(oct)) solvent while very few models with poor predictive abilities are available for other solvents. In this work, we propose a parameterization of an empirical model for n-octanol/water, alkane/water (logP(alk)) and cyclohexane/water (logP(cyc)) systems. Comparison of both logP(alk) and logP(cyc) with the logarithms of brain/blood ratios (logBB) for a set of structurally diverse compounds revealed a high correlation showing their superiority over the logP(oct) measure in this context.

Lipid–water partition coefficients and correlations with uptakes by algae of organic compounds

International Nuclear Information System (INIS)

Hung, Wei-Nung; Chiou, Cary T.; Lin, Tsair-Fuh

2014-01-01

Graphical abstract: - Highlights: • Partition coefficients of contaminants with lipid triolein (K tw ) are measured. • Measured K tw values are nearly the same as the respective K ow . • Sorption of the contaminants to a dry algal powder is similarly measured. • Algal uptake of a compound occurs primarily by partition into the algal lipid. - Abstract: In view of the scarcity of the lipid–water partition coefficients (K tw ) for organic compounds, the log K tw values for many environmental contaminants were measured using ultra-pure triolein as the model lipid. Classes of compounds studied include alkyl benzenes, halogenated benzenes, short-chain chlorinated hydrocarbons, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organochlorine pesticides. In addition to log K tw determination, the uptakes of these compounds from water by a dry algal species were measured to evaluate the lipid effect on the algal uptake. The measured log K tw are closely related to their respective log K ow (octanol–water), with log K ow = 1.9 to 6.5. A significant difference is observed between the present and early measured log K tw for compounds with log K ow > ∼5, which is attributed to the presence and absence of a triolein microemulsion in water affecting the solute partitioning. The observed lipid-normalized algae–water distribution coefficients (log K aw/lipid ) are virtually identical to the respective log K tw values, which manifests the dominant lipid-partition effect of the compounds with algae

Prediction of octanol-air partition coefficients for polychlorinated biphenyls (PCBs) using 3D-QSAR models.

Science.gov (United States)

Chen, Ying; Cai, Xiaoyu; Jiang, Long; Li, Yu

2016-02-01

Based on the experimental data of octanol-air partition coefficients (KOA) for 19 polychlorinated biphenyl (PCB) congeners, two types of QSAR methods, comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA), are used to establish 3D-QSAR models using the structural parameters as independent variables and using logKOA values as the dependent variable with the Sybyl software to predict the KOA values of the remaining 190 PCB congeners. The whole data set (19 compounds) was divided into a training set (15 compounds) for model generation and a test set (4 compounds) for model validation. As a result, the cross-validation correlation coefficient (q(2)) obtained by the CoMFA and CoMSIA models (shuffled 12 times) was in the range of 0.825-0.969 (>0.5), the correlation coefficient (r(2)) obtained was in the range of 0.957-1.000 (>0.9), and the SEP (standard error of prediction) of test set was within the range of 0.070-0.617, indicating that the models were robust and predictive. Randomly selected from a set of models, CoMFA analysis revealed that the corresponding percentages of the variance explained by steric and electrostatic fields were 23.9% and 76.1%, respectively, while CoMSIA analysis by steric, electrostatic and hydrophobic fields were 0.6%, 92.6%, and 6.8%, respectively. The electrostatic field was determined as a primary factor governing the logKOA. The correlation analysis of the relationship between the number of Cl atoms and the average logKOA values of PCBs indicated that logKOA values gradually increased as the number of Cl atoms increased. Simultaneously, related studies on PCB detection in the Arctic and Antarctic areas revealed that higher logKOA values indicate a stronger PCB migration ability. From CoMFA and CoMSIA contour maps, logKOA decreased when substituents possessed electropositive groups at the 2-, 3-, 3'-, 5- and 6- positions, which could reduce the PCB migration ability. These results are

Lipid–water partition coefficients and correlations with uptakes by algae of organic compounds

Energy Technology Data Exchange (ETDEWEB)

Hung, Wei-Nung [Green Energy and Environment Research Laboratories, Industrial Technology Research Institute, Hsinchu 30011, Taiwan (China); Chiou, Cary T., E-mail: carychio@mail.ncku.edu.tw [Department of Environmental Engineering and Sustainable Environment Research Laboratory, National Cheng Kung University, Tainan 70101, Taiwan (China); U.S. Geological Survey, Denver Federal Center, Denver, CO 80225 (United States); Lin, Tsair-Fuh, E-mail: tflin@mail.ncku.edu.tw [Department of Environmental Engineering and Sustainable Environment Research Laboratory, National Cheng Kung University, Tainan 70101, Taiwan (China)

2014-08-30

Graphical abstract: - Highlights: • Partition coefficients of contaminants with lipid triolein (K{sub tw}) are measured. • Measured K{sub tw} values are nearly the same as the respective K{sub ow}. • Sorption of the contaminants to a dry algal powder is similarly measured. • Algal uptake of a compound occurs primarily by partition into the algal lipid. - Abstract: In view of the scarcity of the lipid–water partition coefficients (K{sub tw}) for organic compounds, the log K{sub tw} values for many environmental contaminants were measured using ultra-pure triolein as the model lipid. Classes of compounds studied include alkyl benzenes, halogenated benzenes, short-chain chlorinated hydrocarbons, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organochlorine pesticides. In addition to log K{sub tw} determination, the uptakes of these compounds from water by a dry algal species were measured to evaluate the lipid effect on the algal uptake. The measured log K{sub tw} are closely related to their respective log K{sub ow} (octanol–water), with log K{sub ow} = 1.9 to 6.5. A significant difference is observed between the present and early measured log K{sub tw} for compounds with log K{sub ow} > ∼5, which is attributed to the presence and absence of a triolein microemulsion in water affecting the solute partitioning. The observed lipid-normalized algae–water distribution coefficients (log K{sub aw/lipid}) are virtually identical to the respective log K{sub tw} values, which manifests the dominant lipid-partition effect of the compounds with algae.

Improving GC-PPC-SAFT equation of state for LLE of hydrocarbons and oxygenated compounds with water

DEFF Research Database (Denmark)

Nguyen, Thanh-Binh; Jean-Charles, De Hemptinne; Creton, Benoit

2014-01-01

, uαβ, and wαβ are fitted on mutual solubilities of water and organic compounds. The regressed values which are obtained for each chemical family, are subsequently used for predicting infinite dilution activity coefficient in water and n-octanol/water partition coefficient.In general, the results...... obtained are very much improved compared to the predictive approach discussed previously [Nguyen et al. Ind. Eng. Chem. Res. 52 (2013) 7014-7029]. The global deviation values on the decimal log scale for infinite dilution activity coefficient in water, water solubility and n-octanol/water partition...

In-coupled syringe assisted octanol-water partition microextraction coupled with high-performance liquid chromatography for simultaneous determination of neonicotinoid insecticide residues in honey.

Science.gov (United States)

Vichapong, Jitlada; Burakham, Rodjana; Srijaranai, Supalax

2015-07-01

A simple and fast method namely in-coupled syringe assisted octanol-water partition microextraction combined with high performance liquid chromatography (HPLC) has been developed for the extraction, preconcentration and determination of neonicotinoid insecticide residues (e.g. imidacloprid, acetamiprid, clothianidin, thiacloprid, thiamethoxam, dinotefuran, and nitenpyram) in honey. The experimental parameters affected the extraction efficiency, including kind and concentration of salt, kind of disperser solvent and its volume, kind of extraction solvent and its volume, shooting times and extraction time were investigated. The extraction process was carried out by rapid shooting of two syringes. Therefore, rapid dispersion and mass transfer processes was created between phases, and thus affects the extraction efficiency of the proposed method. The optimum extraction conditions were 10.00 mL of aqueous sample, 10% (w/v) Na2SO4, 1-octanol (100µL) as an extraction solvent, shooting 4 times and extraction time 2min. No disperser solvent and centrifugation step was necessary. Linearity was obtained within the range of 0.1-3000 ngmL(-1), with the correlation coefficients greater than 0.99. The high enrichment factor of the target analytes was 100 fold and low limit of detection (0.25-0.50 ngmL(-1)) could be obtained. This proposed method has been successfully applied in the analysis of neonicotinoid residues in honey, and good recoveries in the range of 96.93-107.70% were obtained. Copyright © 2015 Elsevier B.V. All rights reserved.

The search for reliable aqueous solubility (Sw) and octanol-water partition coefficient (Kow) data for hydrophobic organic compounds; DDT and DDE as a case study

Science.gov (United States)

Pontolillo, James; Eganhouse, R.P.

2001-01-01

The accurate determination of an organic contaminant?s physico-chemical properties is essential for predicting its environmental impact and fate. Approximately 700 publications (1944?2001) were reviewed and all known aqueous solubilities (Sw) and octanol-water partition coefficients (Kow) for the organochlorine pesticide, DDT, and its persistent metabolite, DDE were compiled and examined. Two problems are evident with the available database: 1) egregious errors in reporting data and references, and 2) poor data quality and/or inadequate documentation of procedures. The published literature (particularly the collative literature such as compilation articles and handbooks) is characterized by a preponderance of unnecessary data duplication. Numerous data and citation errors are also present in the literature. The percentage of original Sw and Kow data in compilations has decreased with time, and in the most recent publications (1994?97) it composes only 6?26 percent of the reported data. The variability of original DDT/DDE Sw and Kow data spans 2?4 orders of magnitude, and there is little indication that the uncertainty in these properties has declined over the last 5 decades. A criteria-based evaluation of DDT/DDE Sw and Kow data sources shows that 95?100 percent of the database literature is of poor or unevaluatable quality. The accuracy and reliability of the vast majority of the data are unknown due to inadequate documentation of the methods of determination used by the authors. [For example, estimates of precision have been reported for only 20 percent of experimental Sw data and 10 percent of experimental Kow data.] Computational methods for estimating these parameters have been increasingly substituted for direct or indirect experimental determination despite the fact that the data used for model development and validation may be of unknown reliability. Because of the prevalence of errors, the lack of methodological documentation, and unsatisfactory data

The antimalarial activity of Ru-chloroquine complexes against resistant Plasmodium falciparum is related to lipophilicity, basicity, and heme aggregation inhibition ability near water/n-octanol interfaces.

Science.gov (United States)

Martínez, Alberto; Rajapakse, Chandima S K; Jalloh, Dalanda; Dautriche, Cula; Sánchez-Delgado, Roberto A

2009-08-01

We have measured water/n-octanol partition coefficients, pK(a) values, heme binding constants, and heme aggregation inhibition activity of a series of ruthenium-pi-arene-chloroquine (CQ) complexes recently reported to be active against CQ-resistant strains of Plasmodium falciparum. Measurements of heme aggregation inhibition activity of the metal complexes near water/n-octanol interfaces qualitatively predict their superior antiplasmodial action against resistant parasites, in relation to CQ; we conclude that this modified method may be a better predictor of antimalarial potency than standard tests in aqueous acidic buffer. Some interesting tendencies emerge from our data, indicating that the antiplasmodial activity is related to a balance of effects associated with the lipophilicity, basicity, and structural details of the compounds studied.

The antimalarial activity of Ru–chloroquine complexes against resistant Plasmodium falciparum is related to lipophilicity, basicity, and heme aggregation inhibition ability near water/n-octanol interfaces

Science.gov (United States)

Martínez, Alberto; Rajapakse, Chandima S. K.; Jalloh, Dalanda; Dautriche, Cula

2012-01-01

We have measured water/n-octanol partition coefficients, pKa values, heme binding constants, and heme aggregation inhibition activity of a series of ruthenium–πarene–chloroquine (CQ) complexes recently reported to be active against CQ-resistant strains of Plasmodium falciparum. Measurements of heme aggregation inhibition activity of the metal complexes near water/n-octanol interfaces qualitatively predict their superior antiplasmodial action against resistant parasites, in relation to CQ; we conclude that this modified method may be a better predictor of antimalarial potency than standard tests in aqueous acidic buffer. Some interesting tendencies emerge from our data, indicating that the antiplasmodial activity is related to a balance of effects associated with the lipophilicity, basicity, and structural details of the compounds studied. PMID:19343380

Octanol-solubility of dissolved and particulate trace metals in contaminated rivers: implications for metal reactivity and availability

Energy Technology Data Exchange (ETDEWEB)

Turner, Andrew [School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)]. E-mail: aturner@plymouth.ac.uk; Mawji, Edward [School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)

2005-05-01

The lipid-like, amphiphilic solvent, n-octanol, has been used to determine a hydrophobic fraction of dissolved and particulate trace metals (Al, Cd, Co, Cu, Mn, Ni, Pb, Zn) in contaminated rivers. In a sample from the River Clyde, southwest Scotland, octanol-solubility was detected for all dissolved metals except Co, with conditional octanol-water partition coefficients, D{sub ow}, ranging from about 0.2 (Al and Cu) to 1.25 (Pb). In a sample taken from the River Mersey, northwest England, octanol-solubility was detected for dissolved Al and Pb, but only after sample aliquots had been spiked with individual ionic metal standards and equilibrated. Spiking of the River Clyde sample revealed competition among different metals for hydrophobic ligands. Metal displacement from hydrophobic complexes was generally most significant following the addition of ionic Al or Pb, although the addition of either of these metals had little effect on the octanol-solubility of the other. In both river water samples hydrophobic metals were detected on the suspended particles retained by filtration following their extraction in n-octanol. In general, particulate Cu and Zn (up to 40%) were most available, and Al, Co and Pb most resistant (<1%) to octanol extraction. Distribution coefficients defining the concentration ratio of octanol-soluble particle-bound metal to octanol-soluble dissolved metal were in the range 10{sup 3.3}-10{sup 5.3} ml g{sup -1}. The presence of hydrophobic dissolved and particulate metal species has implications for our understanding of the biogeochemical behaviour of metals in aquatic environments. Specifically, such species are predicted to exhibit characteristics of non-polar organic contaminants, including the potential to penetrate the lipid bilayer. Current strategies for assessing the bioavailability and toxicity of dissolved and particulate trace metals in natural waters may, therefore, require revision. - New approaches are presented for fractionating

Determination of partition coefficients using 1 H NMR spectroscopy and time domain complete reduction to amplitude-frequency table (CRAFT) analysis.

Science.gov (United States)

Soulsby, David; Chica, Jeryl A M

2017-08-01

We have developed a simple, direct and novel method for the determination of partition coefficients and partitioning behavior using 1 H NMR spectroscopy combined with time domain complete reduction to amplitude-frequency tables (CRAFT). After partitioning into water and 1-octanol using standard methods, aliquots from each layer are directly analyzed using either proton or selective excitation NMR experiments. Signal amplitudes for each compound from each layer are then extracted directly from the time domain data in an automated fashion and analyzed using the CRAFT software. From these amplitudes, log P and log D 7.4 values can be calculated directly. Phase, baseline and internal standard issues, which can be problematic when Fourier transformed data are used, are unimportant when using time domain data. Furthermore, analytes can contain impurities because only a single resonance is examined and need not be UV active. Using this approach, we examined a variety of pharmaceutically relevant compounds and determined partition coefficients that are in excellent agreement with literature values. To demonstrate the utility of this approach, we also examined salicylic acid in more detail demonstrating an aggregation effect as a function of sample loading and partition coefficient behavior as a function of pH value. This method provides a valuable addition to the medicinal chemist toolbox for determining these important constants. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Octanol-solubility of dissolved and particulate trace metals in contaminated rivers: implications for metal reactivity and availability.

Science.gov (United States)

Turner, Andrew; Mawji, Edward

2005-05-01

The lipid-like, amphiphilic solvent, n-octanol, has been used to determine a hydrophobic fraction of dissolved and particulate trace metals (Al, Cd, Co, Cu, Mn, Ni, Pb, Zn) in contaminated rivers. In a sample from the River Clyde, southwest Scotland, octanol-solubility was detected for all dissolved metals except Co, with conditional octanol-water partition coefficients, D(ow), ranging from about 0.2 (Al and Cu) to 1.25 (Pb). In a sample taken from the River Mersey, northwest England, octanol-solubility was detected for dissolved Al and Pb, but only after sample aliquots had been spiked with individual ionic metal standards and equilibrated. Spiking of the River Clyde sample revealed competition among different metals for hydrophobic ligands. Metal displacement from hydrophobic complexes was generally most significant following the addition of ionic Al or Pb, although the addition of either of these metals had little effect on the octanol-solubility of the other. In both river water samples hydrophobic metals were detected on the suspended particles retained by filtration following their extraction in n-octanol. In general, particulate Cu and Zn (up to 40%) were most available, and Al, Co and Pb most resistant (octanol extraction. Distribution coefficients defining the concentration ratio of octanol-soluble particle-bound metal to octanol-soluble dissolved metal were in the range 10(3.3)-10(5.3)mlg(-1). The presence of hydrophobic dissolved and particulate metal species has implications for our understanding of the biogeochemical behaviour of metals in aquatic environments. Specifically, such species are predicted to exhibit characteristics of non-polar organic contaminants, including the potential to penetrate the lipid bilayer. Current strategies for assessing the bioavailability and toxicity of dissolved and particulate trace metals in natural waters may, therefore, require revision.

Computational estimation of logarithm of octanol/air partition coefficients and subcooled vapour pressures for each of 75 chloronaphtalene congeners

Energy Technology Data Exchange (ETDEWEB)

Puzyn, T.; Falandysz, J.; Rostkowski, P.; Piliszek, S.; Wilczyniska, A. [Univ. of Gdansk (Poland)

2004-09-15

Polychlorinated naphthalenes (PCNs, CNs) are known persistent organic pollutants, contaminating natural ecosystems in effect of technical human activity. Toxic effects induced by individual congers of PCNs are reported elsewhere. Great risk of these chemical compounds is additionally connected with theirs excellent ability to be transported via atmosphere from a source to the remote regions on the Glob. Chloronaphthalene congeners had been found in Arctic regions at significant level in spite of the fact, that they had never been synthesized there, and also thermal processes like municipal waste incineration or domestic heating (other possible sources of PCNs in the environment) were not so intensive there. In 1996 F. Wania and D. Mackay have formulated some empirical rules, which have been very useful in estimation and modeling of environmental transport processes of persistent organic pollutants like PCNs. Two very important physico-chemical parameters in the theory of global distillation and cold condensation are: logarithm of n-octanol/air partition coefficient (log K{sub OA}) and logarithm of subcooled vapour pressure (log P{sub L}). Values of log K{sub OA} and log P{sub L} in standard procedures are determined by means of chromatographic methods. In order to reduce costs and number of experiments, we have proposed simple computational method of estimation log K{sub OA} and log P{sub L}.

Accurate potentiometric determination of lipid membrane-water partition coefficients and apparent dissociation constants of ionizable drugs: electrostatic corrections.

Science.gov (United States)

Elsayed, Mustafa M A; Vierl, Ulrich; Cevc, Gregor

2009-06-01

Potentiometric lipid membrane-water partition coefficient studies neglect electrostatic interactions to date; this leads to incorrect results. We herein show how to account properly for such interactions in potentiometric data analysis. We conducted potentiometric titration experiments to determine lipid membrane-water partition coefficients of four illustrative drugs, bupivacaine, diclofenac, ketoprofen and terbinafine. We then analyzed the results conventionally and with an improved analytical approach that considers Coulombic electrostatic interactions. The new analytical approach delivers robust partition coefficient values. In contrast, the conventional data analysis yields apparent partition coefficients of the ionized drug forms that depend on experimental conditions (mainly the lipid-drug ratio and the bulk ionic strength). This is due to changing electrostatic effects originating either from bound drug and/or lipid charges. A membrane comprising 10 mol-% mono-charged molecules in a 150 mM (monovalent) electrolyte solution yields results that differ by a factor of 4 from uncharged membranes results. Allowance for the Coulombic electrostatic interactions is a prerequisite for accurate and reliable determination of lipid membrane-water partition coefficients of ionizable drugs from potentiometric titration data. The same conclusion applies to all analytical methods involving drug binding to a surface.

Evaluation of long-range transport potential of selected brominated flame retardants with measured 1-octanol-air partition coefficients

Energy Technology Data Exchange (ETDEWEB)

Lee, Hyun Jeong; Kwon, Jung Hwan [Div. of Environmental Science and Ecological Engineering, Korea University, Seoul (Korea, Republic of)

2016-10-15

Various alternative flame retardants are used in many countries since polybrominated diphenyl ethers (PBDEs) were classified as persistent organic pollutants (POPs). However, difficulties in the evaluation of the long-range transport potential (LRTP) of the alternatives are related to the lack of information on their physicochemical properties, which govern their environmental fates and transport. Based on the simulation of LRTP using OECD P{sub OV} and LRTP Screening Tool, five alternative brominated flame retardants (BFRs) (hexabromobenzene [HBB], 2,3,4,5,6-pentabromotoluene [PBT], 2,3,4,5,6-pentabromoethylbenzene [PBEB], 2-ethylhexyl 2,3,4,5-tetrabromobenzoate [TBB], and 1,2,4,5-tetrabromo-3,6-dimethylbenzene [TBX]), and 3 PBDEs (BDE-28, BDE-47, and BDE-99) were chosen to perform a refined assessment. This was done using an experimentally measured 1-octanol–air partition coefficient (K{sub OA}) for the calculation of the air–water partition coefficient (K{sub AW}) required for the model. The four selected alternative BFRs (HBB, PBT, PBEB, TBX) have K{sub OA} values close to the in silico estimation used in the screening evaluation. On the other hand, the measured K{sub OA} value for TBB was two orders of magnitude lower than the estimated value used in the screening simulation. The refined simulation showed that characteristic travel distance (CTD) and transfer efficiency (TE) for HBB, PBT, PBEB, and TBX were greater than those for BDE-28, whereas CTD and TE for TBB were lower than those for BDE-28. This suggested that TBB has a lower LRTP than BDE-28, considering the refined partition coefficients.

Simple Method to Determine the Partition Coefficient of Naphthenic Acid in Oil/Water

DEFF Research Database (Denmark)

Bitsch-Larsen, Anders; Andersen, Simon Ivar

2008-01-01

The partition coefficient for technical grade naphthenic acid in water/n-decane at 295 K has been determined (K-wo = 2.1 center dot 10(-4)) using a simple experimental technique with large extraction volumes (0.09 m(3) of water). Furthermore, nonequilibrium values at different pH values...

The development of a high-throughput measurement method of octanol/water distribution coefficient based on hollow fiber membrane solvent microextraction technique.

Science.gov (United States)

Bao, James J; Liu, Xiaojing; Zhang, Yong; Li, Youxin

2014-09-15

This paper describes the development of a novel high-throughput hollow fiber membrane solvent microextraction technique for the simultaneous measurement of the octanol/water distribution coefficient (logD) for organic compounds such as drugs. The method is based on a designed system, which consists of a 96-well plate modified with 96 hollow fiber membrane tubes and a matching lid with 96 center holes and 96 side holes distributing in 96 grids. Each center hole was glued with a sealed on one end hollow fiber membrane tube, which is used to separate the aqueous phase from the octanol phase. A needle, such as microsyringe or automatic sampler, can be directly inserted into the membrane tube to deposit octanol as the accepted phase or take out the mixture of the octanol and the drug. Each side hole is filled with aqueous phase and could freely take in/out solvent as the donor phase from the outside of the hollow fiber membranes. The logD can be calculated by measuring the drug concentration in each phase after extraction equilibrium. After a comprehensive comparison, the polytetrafluoroethylene hollow fiber with the thickness of 210 μm, an extraction time of 300 min, a temperature of 25 °C and atmospheric pressure without stirring are selected for the high throughput measurement. The correlation coefficient of the linear fit of the logD values of five drugs determined by our system to reference values is 0.9954, showed a nice accurate. The -8.9% intra-day and -4.4% inter-day precision of logD for metronidazole indicates a good precision. In addition, the logD values of eight drugs were simultaneously and successfully measured, which indicated that the 96 throughput measure method of logD value was accurate, precise, reliable and useful for high throughput screening. Copyright © 2014 Elsevier B.V. All rights reserved.

Partition Coefficients of Amino Acids, Peptides, and Enzymes in Dextran + Poly(Ethylene Glycol) + Water Aqueous Two-Phase Systems

Energy Technology Data Exchange (ETDEWEB)

Kakisaka, Keijiro.; Shindo, Takashi.; Iwai, Yoshio.; Arai, Yasuhiko. [Kyushu University, Fukuoka (Japan). Department of Chemical Systems and Engineering

1998-12-01

Partition coefficients are measured for five amino acids(aspartic acid, asparagine, methionine, cysteine and histidine) and tow peptides(glycyl-glycine and hexa-glycine) in dextran + poly(ethylene glycol) + water aqueous two-phase system. The partition coefficients of the amino acids and peptides are aorrelated using the osmotic virial equation. The interaction coefficients contained in the equation can be calculated by hydrophilic group parameters. The partition coefficients of {alpha}-amylase calculated by the osmotic virial equation with the hydrophilic group parameters are in fairly good agreement with the experimental data, though a relatively large discrepancy is shown for {beta}-amylase. (author)

Partition Coefficients of Amino Acids, Peptides, and Enzymes in Dextran + Poly(Ethylene Glycol) + Water Aqueous Two-Phase Systems

Energy Technology Data Exchange (ETDEWEB)

Kakisaka, Keijiro.; Shindo, Takashi.; Iwai, Yoshio.; Arai, Yasuhiko. (Kyushu University, Fukuoka (Japan). Department of Chemical Systems and Engineering)

1998-12-01

Partition coefficients are measured for five amino acids(aspartic acid, asparagine, methionine, cysteine and histidine) and tow peptides(glycyl-glycine and hexa-glycine) in dextran + poly(ethylene glycol) + water aqueous two-phase system. The partition coefficients of the amino acids and peptides are aorrelated using the osmotic virial equation. The interaction coefficients contained in the equation can be calculated by hydrophilic group parameters. The partition coefficients of [alpha]-amylase calculated by the osmotic virial equation with the hydrophilic group parameters are in fairly good agreement with the experimental data, though a relatively large discrepancy is shown for [beta]-amylase. (author)

Partitioning of organophosphorus pesticides into phosphatidylcholine small unilamellar vesicles studied by second-derivative spectrophotometry.

Science.gov (United States)

Takegami, Shigehiko; Kitamura, Keisuke; Ohsugi, Mayuko; Ito, Aya; Kitade, Tatsuya

2015-06-15

In order to quantitatively examine the lipophilicity of the widely used organophosphorus pesticides (OPs) chlorfenvinphos (CFVP), chlorpyrifos-methyl (CPFM), diazinon (DZN), fenitrothion (FNT), fenthion (FT), isofenphos (IFP), profenofos (PFF) and pyraclofos (PCF), their partition coefficient (Kp) values between phosphatidylcholine (PC) small unilamellar vesicles (SUVs) and water (liposome-water system) were determined by second-derivative spectrophotometry. The second-derivative spectra of these OPs in the presence of PC SUV showed a bathochromic shift according to the increase in PC concentration and distinct derivative isosbestic points, demonstrating the complete elimination of the residual background signal effects that were observed in the absorption spectra. The Kp values were calculated from the second-derivative intensity change induced by addition of PC SUV and obtained with a good precision of R.S.D. below 10%. The Kp values were in the order of CPFM>FT>PFF>PCF>IFP>CFVP>FNT⩾DZN and did not show a linear correlation relationship with the reported partition coefficients obtained using an n-octanol-water system (R(2)=0.530). Also, the results quantitatively clarified the effect of chemical-group substitution in OPs on their lipophilicity. Since the partition coefficient for the liposome-water system is more effective for modeling the quantitative structure-activity relationship than that for the n-octanol-water system, the obtained results are toxicologically important for estimating the accumulation of these OPs in human cell membranes. Copyright © 2015 Elsevier B.V. All rights reserved.

Determination of the air/water partition coefficient of groundwater radon using liquid scintillation counter

International Nuclear Information System (INIS)

Lee, K.Y.; Yoon, Y.Y.; Ko, K.S.

2010-01-01

A method was studied for measuring air/water partition coefficient (K air/water ) of groundwater radon by a simple procedure using liquid scintillation counter (LSC). In contrast conventional techniques such as equilibrium partitioning in a closed system or air striping methods, the described method allow for a simple and uncomplicated determination of the coefficient. The (K air/water ) of radon in pure water has been well known quantitatively over a wide range of temperatures. In this work, groundwater samples having high radon concentration instead of distilled water have been used to determine the (K air/water ) of radon in the temperature range of 0-25. Aqueous phase in a closed system was used in this study instead of gaseous phase in conventional methods. Three kinds of groundwater taken from different geologic environments were used to investigate the effect of groundwater properties. With the aim to evaluate the reproducibility of the data an appropriate number of laboratory experiments have been carried out. The results show that tie (K air/water ) of radon in the groundwater is smaller than that in the pure water. However, the temperature effect on the coefficient is similar in the groundwater and the pure water. The method using aqueous phase in a closed system by LSC can be used to determine the (K air/water ) of radon in various groundwaters with a simple procedure. The results will be presented at the NAC-IV conference

Performance of chromatographic systems to model soil-water sorption.

Science.gov (United States)

Hidalgo-Rodríguez, Marta; Fuguet, Elisabet; Ràfols, Clara; Rosés, Martí

2012-08-24

A systematic approach for evaluating the goodness of chromatographic systems to model the sorption of neutral organic compounds by soil from water is presented in this work. It is based on the examination of the three sources of error that determine the overall variance obtained when soil-water partition coefficients are correlated against chromatographic retention factors: the variance of the soil-water sorption data, the variance of the chromatographic data, and the variance attributed to the dissimilarity between the two systems. These contributions of variance are easily predicted through the characterization of the systems by the solvation parameter model. According to this method, several chromatographic systems besides the reference octanol-water partition system have been selected to test their performance in the emulation of soil-water sorption. The results from the experimental correlations agree with the predicted variances. The high-performance liquid chromatography system based on an immobilized artificial membrane and the micellar electrokinetic chromatography systems of sodium dodecylsulfate and sodium taurocholate provide the most precise correlation models. They have shown to predict well soil-water sorption coefficients of several tested herbicides. Octanol-water partitions and high-performance liquid chromatography measurements using C18 columns are less suited for the estimation of soil-water partition coefficients. Copyright © 2012 Elsevier B.V. All rights reserved.

Synergistic effect of dicarbollide anions in liquid-liquid extraction: a molecular dynamics study at the octanol-water interface.

Science.gov (United States)

Chevrot, G; Schurhammer, R; Wipff, G

2007-04-28

We report a molecular dynamics study of chlorinated cobalt bis(dicarbollide) anions [(B(9)C(2)H(8)Cl(3))(2)Co](-)"CCD(-)" in octanol and at the octanol-water interface, with the main aim to understand why these hydrophobic species act as strong synergists in assisted liquid-liquid cation extraction. Neat octanol is quite heterogeneous and is found to display dual solvation properties, allowing to well solubilize CCD(-), Cs(+) salts in the form of diluted pairs or oligomers, without displaying aggregation. At the aqueous interface, octanol behaves as an amphiphile, forming either monolayers or bilayers, depending on the initial state and confinement conditions. In biphasic octanol-water systems, CCD(-) anions are found to mainly partition to the organic phase, thus attracting Cs(+) or even more hydrophilic counterions like Eu(3+) into that phase. The remaining CCD(-) anions adsorb at the interface, but are less surface active than at the chloroform interface. Finally, we compare the interfacial behavior of the Eu(BTP)(3)(3+) complex in the absence and in the presence of CCD(-) anions and extractant molecules. It is found that when the CCD(-)'s are concentrated enough, the complex is extracted to the octanol phase. Otherwise, it is trapped at the interface, attracted by water. These results are compared to those obtained with chloroform as organic phase and discussed in the context of synergistic effect of CCD(-) in liquid-liquid extraction, pointing to the importance of dual solvation properties of octanol and of the hydrophobic character of CCD(-) for synergistic extraction of cations.

Partitioning of organochlorine pesticides from water to polyethylene passive samplers

International Nuclear Information System (INIS)

Hale, Sarah E.; Martin, Timothy J.; Goss, Kai-Uwe; Arp, Hans Peter H.; Werner, David

2010-01-01

The mass transfer rates and equilibrium partitioning behaviour of 14 diverse organochlorine pesticides (OCP) between water and polyethylene (PE) passive samplers, cut from custom made PE sheets and commercial polyethylene plastic bags, were quantified. Overall mass transfer coefficients, k O , estimated PE membrane diffusion coefficients, D PE , and PE-water partitioning coefficients, K PE-water, are reported. In addition, the partitioning of three polycyclic aromatic hydrocarbons (PAHs) from water to PE is quantified and compared with literature values. K PE-water values agreed mostly within a factor of two for both passive samplers and also with literature values for the reference PAHs. As PE is expected to exhibit similar sorption behaviour to long-chain alkanes, PE-water partitioning coefficients were compared to hexadecane-water partitioning coefficients estimated with the SPARC online calculator, COSMOtherm and a polyparameter linear free energy relationship based on the Abraham approach. The best correlation for all compounds tested was with COSMOtherm estimated hexadecane-water partitioning coefficients. - The partitioning of organochlorine pesticides between single phase polyethylene passive samplers and water is quantified.

Confocal Raman Microscopy for in Situ Measurement of Phospholipid-Water Partitioning into Model Phospholipid Bilayers within Individual Chromatographic Particles.

Science.gov (United States)

Kitt, Jay P; Bryce, David A; Minteer, Shelley D; Harris, Joel M

2018-06-05

The phospholipid-water partition coefficient is a commonly measured parameter that correlates with drug efficacy, small-molecule toxicity, and accumulation of molecules in biological systems in the environment. Despite the utility of this parameter, methods for measuring phospholipid-water partition coefficients are limited. This is due to the difficulty of making quantitative measurements in vesicle membranes or supported phospholipid bilayers, both of which are small-volume phases that challenge the sensitivity of many analytical techniques. In this work, we employ in situ confocal Raman microscopy to probe the partitioning of a model membrane-active compound, 2-(4-isobutylphenyl) propionic acid or ibuprofen, into both hybrid- and supported-phospholipid bilayers deposited on the pore walls of individual chromatographic particles. The large surface-area-to-volume ratio of chromatographic silica allows interrogation of a significant lipid bilayer area within a very small volume. The local phospholipid concentration within a confocal probe volume inside the particle can be as high as 0.5 M, which overcomes the sensitivity limitations of making measurements in the limited membrane areas of single vesicles or planar supported bilayers. Quantitative determination of ibuprofen partitioning is achieved by using the phospholipid acyl-chains of the within-particle bilayer as an internal standard. This approach is tested for measurements of pH-dependent partitioning of ibuprofen into both hybrid-lipid and supported-lipid bilayers within silica particles, and the results are compared with octanol-water partitioning and with partitioning into individual optically trapped phospholipid vesicle membranes. Additionally, the impact of ibuprofen partitioning on bilayer structure is evaluated for both within-particle model membranes and compared with the structural impacts of partitioning into vesicle lipid bilayers.

New sensitive micro-measurements of dynamic surface tension and diffusion coefficients: Validated and tested for the adsorption of 1-Octanol at a microscopic air-water interface and its dissolution into water.

Science.gov (United States)

Kinoshita, Koji; Parra, Elisa; Needham, David

2017-02-15

Currently available dynamic surface tension (DST) measurement methods, such as Wilhelmy plate, droplet- or bubble-based methods, still have various experimental limitations such as the large size of the interface, convection in the solution, or a certain "dead time" at initial measurement. These limitations create inconsistencies for the kinetic analysis of surfactant adsorption/desorption, especially significant for ionic surfactants. Here, the "micropipette interfacial area-expansion method" was introduced and validated as a new DST measurement having a high enough sensitivity to detect diffusion controlled molecular adsorption at the air-water interfaces. To validate the new technique, the diffusion coefficient of 1-Octanol in water was investigated with existing models: the Ward Tordai model for the long time adsorption regime (1-100s), and the Langmuir and Frumkin adsorption isotherm models for surface excess concentration. We found that the measured diffusion coefficient of 1-Octanol, 7.2±0.8×10 -6 cm 2 /s, showed excellent agreement with the result from an alternative method, "single microdroplet catching method", to measure the diffusion coefficient from diffusion-controlled microdroplet dissolution, 7.3±0.1×10 -6 cm 2 /s. These new techniques for determining adsorption and diffusion coefficients can apply for a range of surface active molecules, especially the less-characterized ionic surfactants, and biological compounds such as lipids, peptides, and proteins. Copyright © 2016 Elsevier Inc. All rights reserved.

Distribution coefficients for chemical components of a coal-oil/water system

Energy Technology Data Exchange (ETDEWEB)

Picel, K C; Stamoudis, V C; Simmons, M S

1988-09-01

Distribution coefficients (K/sub D/) were measured by equilibrating a coal oil comparative reference material (CRM-1) with water and then separating the oil and water phases. Aqueous phase concentrations were determined by direct analysis of this phase, while organic phase concentrations were determined from the original oil composition by difference. The log K/sub D/ values obtained for acidic and basic components were generally <3, while those for the neutral components ranged from 3 to 6. For aromatic hydrocarbons, strong correlations were observed between log K/sub D/ and log S/sub w/ (water solubility), and between log K/sub D/ and log K/sub o//sub w/ (octanol/water partition coefficient). Alkylated benzenes had significantly higher K/sub D/s than did unsubstituted aromatics of similar molecular weight. Examination of homologs revealed an increase of 0.307 log K/sub D/ units per additional carbon atom for polynuclear aromatic hydrocarbons having from 10 to 16 carbons. Alkyl substituent effects determined for various sets of homologs ranged from 0.391 to 0.466 log K/sub d/ units per -CH/sub 2/- group added. 38 refs., 5 figs., 7 tabs.

Octanol-solubility of dissolved and particulate trace metals in contaminated rivers: implications for metal reactivity and availability

International Nuclear Information System (INIS)

Turner, Andrew; Mawji, Edward

2005-01-01

The lipid-like, amphiphilic solvent, n-octanol, has been used to determine a hydrophobic fraction of dissolved and particulate trace metals (Al, Cd, Co, Cu, Mn, Ni, Pb, Zn) in contaminated rivers. In a sample from the River Clyde, southwest Scotland, octanol-solubility was detected for all dissolved metals except Co, with conditional octanol-water partition coefficients, D ow , ranging from about 0.2 (Al and Cu) to 1.25 (Pb). In a sample taken from the River Mersey, northwest England, octanol-solubility was detected for dissolved Al and Pb, but only after sample aliquots had been spiked with individual ionic metal standards and equilibrated. Spiking of the River Clyde sample revealed competition among different metals for hydrophobic ligands. Metal displacement from hydrophobic complexes was generally most significant following the addition of ionic Al or Pb, although the addition of either of these metals had little effect on the octanol-solubility of the other. In both river water samples hydrophobic metals were detected on the suspended particles retained by filtration following their extraction in n-octanol. In general, particulate Cu and Zn (up to 40%) were most available, and Al, Co and Pb most resistant ( 3.3 -10 5.3 ml g -1 . The presence of hydrophobic dissolved and particulate metal species has implications for our understanding of the biogeochemical behaviour of metals in aquatic environments. Specifically, such species are predicted to exhibit characteristics of non-polar organic contaminants, including the potential to penetrate the lipid bilayer. Current strategies for assessing the bioavailability and toxicity of dissolved and particulate trace metals in natural waters may, therefore, require revision. - New approaches are presented for fractionating trace metals in natural waters

A comparison of octanol-water partitioning between organic chemicals and their metabolites in mammals.

Science.gov (United States)

Pirovano, Alessandra; Borile, Nicolò; Jan Hendriks, A

2012-08-01

Bioaccumulation models take various elimination and uptake processes into account, estimating rates from chemical lipophilicity, expressed as the octanol-water partition ratio (K(ow)). Here, we focussed on metabolism, which transforms parent compounds into usually more polar metabolites, thus enhancing elimination. The aim of this study was to quantify the change in lipophilicity of relevant organic pollutants undergoing various biotransformation reactions in mammals. We considered oxidation reactions catalyzed by three enzyme groups: cytochrome P450 (CYP), alcohol dehydrogenase (ADH), and aldehyde dehydrogenase (ALDH). Estimated logK(ow) values of a selected dataset of parent compounds were compared with the logK(ow) of their first metabolites. The logK(ow) decreased by a factor that varies between 0 and -2, depending on the metabolic pathway. For reactions mediated by CYP, the decrease in K(ow) was one order of magnitude for hydroxylated and epoxidated compounds and two orders of magnitude for dihydroxylated and sulphoxidated xenobiotics. On the other hand, no significant change in lipophilicity was observed for compounds N-hydroxylated by CYP and for alcohols and aldehydes metabolized by ADH and ALDH. These trends could be anticipated by the calculus method of logK(ow). Yet, they were validated using experimental logK(ow) values, when available. These relationships estimate the extent to which the elimination of pollutants is increased by biotransformation. Thus, the quantification of the K(ow) reduction can be considered as a first necessary step in an alternative approach to anticipate biotransformation rates, which are hard to estimate with existing methods. Copyright © 2012 Elsevier Ltd. All rights reserved.

Partitioning of Nanoparticles into Organic Phases and Model Cells

Energy Technology Data Exchange (ETDEWEB)

Posner, J.D.; Westerhoff, P.; Hou, W-C.

2011-08-25

There is a recognized need to understand and predict the fate, transport and bioavailability of engineered nanoparticles (ENPs) in aquatic and soil ecosystems. Recent research focuses on either collection of empirical data (e.g., removal of a specific NP through water or soil matrices under variable experimental conditions) or precise NP characterization (e.g. size, degree of aggregation, morphology, zeta potential, purity, surface chemistry, and stability). However, it is almost impossible to transition from these precise measurements to models suitable to assess the NP behavior in the environment with complex and heterogeneous matrices. For decades, the USEPA has developed and applies basic partitioning parameters (e.g., octanol-water partition coefficients) and models (e.g., EPI Suite, ECOSAR) to predict the environmental fate, bioavailability, and toxicity of organic pollutants (e.g., pesticides, hydrocarbons, etc.). In this project we have investigated the hypothesis that NP partition coefficients between water and organic phases (octanol or lipid bilayer) is highly dependent on their physiochemical properties, aggregation, and presence of natural constituents in aquatic environments (salts, natural organic matter), which may impact their partitioning into biological matrices (bioaccumulation) and human exposure (bioavailability) as well as the eventual usage in modeling the fate and bioavailability of ENPs. In this report, we use the terminology "partitioning" to operationally define the fraction of ENPs distributed among different phases. The mechanisms leading to this partitioning probably involve both chemical force interactions (hydrophobic association, hydrogen bonding, ligand exchange, etc.) and physical forces that bring the ENPs in close contact with the phase interfaces (diffusion, electrostatic interactions, mixing turbulence, etc.). Our work focuses on partitioning, but also provides insight into the relative behavior of ENPs as either "more like

Xenon tissue/blood partition coefficient for pig urinary bladder

DEFF Research Database (Denmark)

Nielsen, K K; Bülow, J; Nielsen, S L

1990-01-01

In four landrace pigs the tissue/blood partition coefficient (lambda) for xenon (Xe) for the urinary bladder was calculated after chemical analysis for lipid, water and protein content and determination of the haematocrit. The coefficients varied from bladder to bladder owing to small differences...

Estimation of Bio-Accumulation by a Group Contribution Method

International Nuclear Information System (INIS)

Belhachem, B.; Canselier, J. P.

2009-01-01

The majority of organic pollutants, after their dispersion in water then their ingestion, have a strong tendency to accumulate in greases. That is due to the hydrophobic character of these molecules. To have an idea on the capacity of a substance to accumulate in the alive beings according to their lipidic mass, the modeling of the pollutant behaviour was made by considering its partition coefficient between n-octanol (representing the lipidic mass) and water. Its knowledge represents a very significant information for the petrochemical and the pharmaceutical industries. To dissipate any doubt about confidence concerning the obtained results, it is considered useful to check the effectiveness of UNIFAC method on the monomethylbenzoic acid such as, for example, the 3-methylbenzoic acid whose n-octanol-water partition coefficient is already listed in the literature.The small deviations observed between the n-octanol-water partition coefficients listed in the literature and the one calculated according UNIFAC method encouraged us to apply it in order to predict the n-octanol-water partition coefficient of the dimethylbenzoic acid. (author)

Study into the equilibrium mechanism between water and poly(dimethylsiloxane) for very apolar solutes : adsorption or sorption?

NARCIS (Netherlands)

Baltussen, H.A.; Sandra, P.J.F.; David, F.; Janssen, J.G.M.; Cramers, C.A.M.G.

1999-01-01

Recently several publications appeared correlating octanol-water partitioning coefficients (KO/W) with solid-phase microextraction (SPME) extraction coefficients on poly(dimethylsiloxane) (PDMS) fibers. This correlation seems very good for medium-polar to polar compounds but cannot explain the

Determination of descriptors for polycyclic aromatic hydrocarbons and related compounds by chromatographic methods and liquid-liquid partition in totally organic biphasic systems.

Science.gov (United States)

Ariyasena, Thiloka C; Poole, Colin F

2014-09-26

Retention factors on several columns and at various temperatures using gas chromatography and from reversed-phase liquid chromatography on a SunFire C18 column with various mobile phase compositions containing acetonitrile, methanol and tetrahydrofuran as strength adjusting solvents are combined with liquid-liquid partition coefficients in totally organic biphasic systems to calculate descriptors for 23 polycyclic aromatic hydrocarbons and eighteen related compounds of environmental interest. The use of a consistent protocol for the above measurements provides descriptors that are more self consistent for the estimation of physicochemical properties (octanol-water, air-octanol, air-water, aqueous solubility, and subcooled liquid vapor pressure). The descriptor in this report tend to have smaller values for the L and E descriptors and random differences in the B and S descriptors compared with literature sources. A simple atom fragment constant model is proposed for the estimation of descriptors from structure for polycyclic aromatic hydrocarbons. The new descriptors show no bias in the prediction of the air-water partition coefficient for polycyclic aromatic hydrocarbons unlike the literature values. Copyright © 2014 Elsevier B.V. All rights reserved.

Correlation of Benzene, 1,1,1-Trichloroethane, and Naphthalene Distribution Coefficients to the Characteristics of Aquifer Materials With Low Organic Carbon Content

DEFF Research Database (Denmark)

Larsen, Thomas; Kjeldsen, Peter; Christensen, Thomas Højlund

1992-01-01

area of the aquifer materials as a second regression parameter did not significantly improve the correlation. Estimated Koc values were up to 3 times higher than those predicted from regression equations based on the octanol-water partition coefficient. The reason for this is not known, but may...

Photoionization of environmentally polluting aromatic chlorides and nitrides on the water surface by laser and synchrotron radiations.

Science.gov (United States)

Sato, Miki; Maeda, Yuki; Ishioka, Toshio; Harata, Akira

2017-11-20

The detection limits and photoionization thresholds of polycyclic aromatic hydrocarbons and their chlorides and nitrides on the water surface are examined using laser two-photon ionization and single-photon ionization, respectively. The laser two-photon ionization methods are highly surface-selective, with a high sensitivity for aromatic hydrocarbons tending to accumulate on the water surface in the natural environment due to their highly hydrophobic nature. The dependence of the detection limits of target aromatic molecules on their physicochemical properties (photoionization thresholds relating to excess energy, molar absorptivity, and the octanol-water partition coefficient) is discussed. The detection limit clearly depends on the product of the octanol-water partition coefficient and molar absorptivity, and no clear dependence was found on excess energy. The detection limits of laser two-photon ionization for these types of molecules on the water surface are formulated.

Estudo QSPR sobre os coeficientes de partição: descritores mecânico-quânticos e análise multivariada QSPR study on partition coefficients: quantum-mechanical descriptors and multivariate analysis

Directory of Open Access Journals (Sweden)

Edilson Grünheidt Borges

2002-12-01

Full Text Available Quantum chemistry and multivariate analysis were used to estimate the partition coefficients between n-octanol and water for a serie of 188 compounds, with the values of the q 2 until 0.86 for crossvalidation test. The quantum-mechanical descriptors are obtained with ab initio calculation, using the solvation effects of the Polarizable Continuum Method. Two different Hartree-Fock bases were used, and two different ways for simulating solvent cavity formation. The results for each of the cases were analised, and each methodology proposed is indicated for particular case.

New Linear Partitioning Models Based on Experimental Water: Supercritical CO2 Partitioning Data of Selected Organic Compounds.

Science.gov (United States)

Burant, Aniela; Thompson, Christopher; Lowry, Gregory V; Karamalidis, Athanasios K

2016-05-17

Partitioning coefficients of organic compounds between water and supercritical CO2 (sc-CO2) are necessary to assess the risk of migration of these chemicals from subsurface CO2 storage sites. Despite the large number of potential organic contaminants, the current data set of published water-sc-CO2 partitioning coefficients is very limited. Here, the partitioning coefficients of thiophene, pyrrole, and anisole were measured in situ over a range of temperatures and pressures using a novel pressurized batch-reactor system with dual spectroscopic detectors: a near-infrared spectrometer for measuring the organic analyte in the CO2 phase and a UV detector for quantifying the analyte in the aqueous phase. Our measured partitioning coefficients followed expected trends based on volatility and aqueous solubility. The partitioning coefficients and literature data were then used to update a published poly parameter linear free-energy relationship and to develop five new linear free-energy relationships for predicting water-sc-CO2 partitioning coefficients. A total of four of the models targeted a single class of organic compounds. Unlike models that utilize Abraham solvation parameters, the new relationships use vapor pressure and aqueous solubility of the organic compound at 25 °C and CO2 density to predict partitioning coefficients over a range of temperature and pressure conditions. The compound class models provide better estimates of partitioning behavior for compounds in that class than does the model built for the entire data set.

Prediction of supercooled liquid vapor pressures and n-octanol/air partition coefficients for polybrominated diphenyl ethers by means of molecular descriptors from DFT method

International Nuclear Information System (INIS)

Wang Zunyao; Zeng Xiaolan; Zhai Zhicai

2008-01-01

The molecular geometries of 209 polybrominated diphenyl ethers (PBDEs) were optimized at the B3LYP/6-31G* level with Gaussian 98 program. The calculated structural parameters were taken as theoretical descriptors to establish two novel QSPR models for predicting supercooled liquid vapor pressures (P L ) and octanol/air partition coefficients (K OA ) of PBDEs based on the theoretical linear solvation energy relationship (TLSER) model, respectively. The two models achieved in this work both contain three variables: most negative atomic partial charge in molecule (q - ), dipole moment of the molecules (μ) and mean molecular polarizability (α), of which R 2 values are both as high as 0.997, their root-mean-square errors in modeling (RSMEE) are 0.069 and 0.062 respectively. In addition, the F-value of two models are both evidently larger than critical values F 0.05 and the variation inflation factors (VIF) of variables herein are all less than 5.0, suggesting obvious statistic significance of the P L and K OA predicting models. The results of Leave-One-Out (LOO) cross-validation for training set and validation with external test set both show that the two models obtained exhibited optimum stability and good predictive power. We suggest that the QSPRs derived here can be used to predict accurately P L and K OA for non-tested PBDE congeners from Mono-BDEs to Hepta-BDEs and from Mono-BDEs to Hexa-BDEs, respectively

Assessment of the arterial input curve for [99mTc]-d,l-HM-PAO by rapid octanol extraction

DEFF Research Database (Denmark)

Andersen, A R; Friberg, H; Lassen, N A

1988-01-01

The in vitro conversion of the lipophilic molecule [99mTc]-d,l-hexamethylpropyleneamine oxime [( 99mTc]-d,l-HM-PAO) to a hydrophilic form was studied in saline, plasma, and blood at 37 degrees C by paper chromatography and by octanol extraction. The octanol:saline ratio was 79.9. From this value...... and the corresponding octanol: plasma and octanol:blood partitioning values, an estimate of the transport of the lipophilic compound by various components of blood was made: 20% is carried in hemoglobin, 53% by the plasma proteins and 27% by the water phases of the red blood cell and plasma. Octanol extraction provided...

High-pressure (vapour + liquid) equilibria for ternary systems composed by {(E)-2-hexenal or hexanal + carbon dioxide + water}: Partition coefficient measurement

International Nuclear Information System (INIS)

Bejarano, Arturo; López, Pablo I.; Valle, José M. del; Fuente, Juan C. de la

2015-01-01

Highlights: • A new apparatus based on a static–analytic method was assembled in this work. • This work reports high-pressure VLE data of (E)-2-hexenal or hexanal + CO 2 + water. • Data includes (CO 2 + water) partition coefficients of (E)-2-hexenal and hexanal. • High separation factors from water (∼10 4 ) were found especially for (E)-2-hexenal. • The data were obtained at T = (313, 323, and 333) K and pressures from (8 to 19) MPa. - Abstract: A new apparatus based on a static–analytic method assembled in this work was utilised to perform high-pressure (vapour + liquid) equilibria measurements of aqueous ternary systems. This work includes values of isothermal partition coefficients between CO 2 and water of two apple aroma constituents, (E)-2-hexenal and hexanal. Additionally, this work reports new experimental (vapour + liquid) equilibria measurements for the ternary systems (CO 2 + (E)-2-hexenal + water) and (CO 2 + hexanal + water), at fixed liquid phase composition (600 mg · kg −1 ), at temperatures of (313, 323 and 333) K and at pressures from (8 to 19) MPa. Vapour liquid interphase was checked and monitored visually for all the systems studied in this work. No liquid immiscibility was observed at the composition, temperatures and pressures studied. In order to suggest reasonable operation conditions for fractionation of aromas with dense carbon dioxide, partition coefficients of the aroma compounds between CO 2 and water along with their separation factors from water were calculated. Partition coefficients of (E)-2-hexenal between CO 2 and water were in the range of (6 to 91) and where found to be near six times higher than those of hexanal (9 to 17). Very high separation factors from water were observed (∼10 4 ) especially for (E)-2-hexenal. The highest separation factor, for both compounds, was found at a temperature of 313 K and pressures from (12 to 14) MPa

Gas-particle partitioning of semi-volatile organics on organic aerosols using a predictive activity coefficient model: analysis of the effects of parameter choices on model performance

Science.gov (United States)

Chandramouli, Bharadwaj; Jang, Myoseon; Kamens, Richard M.

The partitioning of a diverse set of semivolatile organic compounds (SOCs) on a variety of organic aerosols was studied using smog chamber experimental data. Existing data on the partitioning of SOCs on aerosols from wood combustion, diesel combustion, and the α-pinene-O 3 reaction was augmented by carrying out smog chamber partitioning experiments on aerosols from meat cooking, and catalyzed and uncatalyzed gasoline engine exhaust. Model compositions for aerosols from meat cooking and gasoline combustion emissions were used to calculate activity coefficients for the SOCs in the organic aerosols and the Pankow absorptive gas/particle partitioning model was used to calculate the partitioning coefficient Kp and quantitate the predictive improvements of using the activity coefficient. The slope of the log K p vs. log p L0 correlation for partitioning on aerosols from meat cooking improved from -0.81 to -0.94 after incorporation of activity coefficients iγ om. A stepwise regression analysis of the partitioning model revealed that for the data set used in this study, partitioning predictions on α-pinene-O 3 secondary aerosol and wood combustion aerosol showed statistically significant improvement after incorporation of iγ om, which can be attributed to their overall polarity. The partitioning model was sensitive to changes in aerosol composition when updated compositions for α-pinene-O 3 aerosol and wood combustion aerosol were used. The octanol-air partitioning coefficient's ( KOA) effectiveness as a partitioning correlator over a variety of aerosol types was evaluated. The slope of the log K p- log K OA correlation was not constant over the aerosol types and SOCs used in the study and the use of KOA for partitioning correlations can potentially lead to significant deviations, especially for polar aerosols.

GC-PPC-SAFT equation of state for VLE and LLE of hydrocarbons and oxygenated compounds. Sensitivity analysis

DEFF Research Database (Denmark)

Nguyen, Thanh-Binh; De Hemptinne, Jean-Charles; Creton, Benoit

2013-01-01

-dilution activity coefficient in water; solubility in water; infinite-dilution n-octanol/water partition coefficient). In general, considering the predictive nature of the calculations, encouraging results were obtained. For pure-component vapor pressures and liquid molar volumes, the deviations are very small......, at 20% and 3%, respectively. The deviations in the prediction of the Henry's law constants are within a factor of 2, with the best results found for the methane and nitrogen solubilities. For solubilities in water and, consequently, for infinite-dilution n-octanol/water partition coefficients...

Prediction of Partition Coefficients of Organic Compounds for SPME/PDMS

Directory of Open Access Journals (Sweden)

Liao Hsuan-Yu

2016-01-01

Full Text Available The partition coefficients of 51 organic compounds between SPME/PDMS and gas were compiled from the literature sources in this study. The effect of physicochemical properties and descriptors on the partitioning process of partition coefficients was explicated by the correlation analysis. The PDMS-gas partition coefficients were well correlated to the molecular weight of organic compounds (r = 0.832, p < 0.05. An empirical model, consisting of the molecular weight and the polarizability, was developed to appropriately predict the partition coefficients of organic compounds. The empirical model for estimating the PDMS-gas partition coefficient will contribute to the practical applications of the SPME technique.

Prediction of Partition Coefficients of Organic Compounds for SPME/PDMS

OpenAIRE

Liao Hsuan-Yu; Huang Miao-Ling; Lu Yu-Ting; Chao Keh-Ping

2016-01-01

The partition coefficients of 51 organic compounds between SPME/PDMS and gas were compiled from the literature sources in this study. The effect of physicochemical properties and descriptors on the partitioning process of partition coefficients was explicated by the correlation analysis. The PDMS-gas partition coefficients were well correlated to the molecular weight of organic compounds (r = 0.832, p < 0.05). An empirical model, consisting of the molecular weight and the polarizability, was ...

Predicting solute partitioning in lipid bilayers: Free energies and partition coefficients from molecular dynamics simulations and COSMOmic

Science.gov (United States)

Jakobtorweihen, S.; Zuniga, A. Chaides; Ingram, T.; Gerlach, T.; Keil, F. J.; Smirnova, I.

2014-07-01

Quantitative predictions of biomembrane/water partition coefficients are important, as they are a key property in pharmaceutical applications and toxicological studies. Molecular dynamics (MD) simulations are used to calculate free energy profiles for different solutes in lipid bilayers. How to calculate partition coefficients from these profiles is discussed in detail and different definitions of partition coefficients are compared. Importantly, it is shown that the calculated coefficients are in quantitative agreement with experimental results. Furthermore, we compare free energy profiles from MD simulations to profiles obtained by the recent method COSMOmic, which is an extension of the conductor-like screening model for realistic solvation to micelles and biomembranes. The free energy profiles from these molecular methods are in good agreement. Additionally, solute orientations calculated with MD and COSMOmic are compared and again a good agreement is found. Four different solutes are investigated in detail: 4-ethylphenol, propanol, 5-phenylvaleric acid, and dibenz[a,h]anthracene, whereby the latter belongs to the class of polycyclic aromatic hydrocarbons. The convergence of the free energy profiles from biased MD simulations is discussed and the results are shown to be comparable to equilibrium MD simulations. For 5-phenylvaleric acid the influence of the carboxyl group dihedral angle on free energy profiles is analyzed with MD simulations.

Predicting solute partitioning in lipid bilayers: Free energies and partition coefficients from molecular dynamics simulations and COSMOmic

International Nuclear Information System (INIS)

Jakobtorweihen, S.; Ingram, T.; Gerlach, T.; Smirnova, I.; Zuniga, A. Chaides; Keil, F. J.

2014-01-01

Quantitative predictions of biomembrane/water partition coefficients are important, as they are a key property in pharmaceutical applications and toxicological studies. Molecular dynamics (MD) simulations are used to calculate free energy profiles for different solutes in lipid bilayers. How to calculate partition coefficients from these profiles is discussed in detail and different definitions of partition coefficients are compared. Importantly, it is shown that the calculated coefficients are in quantitative agreement with experimental results. Furthermore, we compare free energy profiles from MD simulations to profiles obtained by the recent method COSMOmic, which is an extension of the conductor-like screening model for realistic solvation to micelles and biomembranes. The free energy profiles from these molecular methods are in good agreement. Additionally, solute orientations calculated with MD and COSMOmic are compared and again a good agreement is found. Four different solutes are investigated in detail: 4-ethylphenol, propanol, 5-phenylvaleric acid, and dibenz[a,h]anthracene, whereby the latter belongs to the class of polycyclic aromatic hydrocarbons. The convergence of the free energy profiles from biased MD simulations is discussed and the results are shown to be comparable to equilibrium MD simulations. For 5-phenylvaleric acid the influence of the carboxyl group dihedral angle on free energy profiles is analyzed with MD simulations

SVOC partitioning between the gas phase and settled dust indoors

Science.gov (United States)

Weschler, Charles J.; Nazaroff, William W.

2010-09-01

Semivolatile organic compounds (SVOCs) are a major class of indoor pollutants. Understanding SVOC partitioning between the gas phase and settled dust is important for characterizing the fate of these species indoors and the pathways by which humans are exposed to them. Such knowledge also helps in crafting measurement programs for epidemiological studies designed to probe potential associations between exposure to these compounds and adverse health effects. In this paper, we analyze published data from nineteen studies that cumulatively report measurements of dustborne and airborne SVOCs in more than a thousand buildings, mostly residences, in seven countries. In aggregate, measured median data are reported in these studies for 66 different SVOCs whose octanol-air partition coefficients ( Koa) span more than five orders of magnitude. We use these data to test a simple equilibrium model for estimating the partitioning of an SVOC between the gas phase and settled dust indoors. The results demonstrate, in central tendency, that a compound's octanol-air partition coefficient is a strong predictor of its abundance in settled dust relative to its gas phase concentration. Using median measured results for each SVOC in each study, dustborne mass fractions predicted using Koa and gas-phase concentrations correlate reasonably well with measured dustborne mass fractions ( R2 = 0.76). Combined with theoretical understanding of SVOC partitioning kinetics, the empirical evidence also suggests that for SVOCs with high Koa values, the mass fraction in settled dust may not have sufficient time to equilibrate with the gas phase concentration.

Changes in lipid membrane mechanics induced by di- and tri-phenyltins

DEFF Research Database (Denmark)

Przybyło, Magda; Drabik, Dominik; Szostak, Kamila

2017-01-01

properties of biological membranes. It was found that the membrane/water partition coefficient equals 4, a value significantly higher than octanol/water partition coefficient. In addition, the effect of di- and tri-phenyltin chlorides on the mechanics of model lipid membranes was measured for the first time...

Estimation of Partition Coefficients of Benzene, Toluene, Ethylbenzene, and ρ-Xylene by Consecutive Extraction with Solid Phase Microextraction

International Nuclear Information System (INIS)

Eom, In Yong

2011-01-01

The results show that the partition coefficients of the BTEX compound can be estimated using the SPME method under the consecutive extraction mode. The proposed technique is much simpler than previously reported methods. Its novelty is that it eliminated the calibration step in the GC/FID, i. e., liquid injection method. The use of the autosampler for the SPME fiber can facilitate the adoption of consecutive extractions; thus, it allows estimation of the partition coefficients of various analytes. Recently, GC/MS has increasingly been used in analytical laboratories; this may facilitate the identification of an unknown analyte as well as the computation of the corresponding partition coefficients with the proposed method. It is very important to use partition coefficients of organic pollutants to predict their fate in the environment. A liquid-liquid extraction technique was used to determine the partition coefficients of organic compounds between water and organic solvent. The concentration of the target compounds must be determined after equilibrium is established between the two phases. The partition coefficients can be estimated using the capacity factors of HPLC and GC

Migration modeling to estimate exposure to chemicals in food packaging for application in highthroughput risk-based screening and Life Cycle Assessment

DEFF Research Database (Denmark)

Ernstoff, Alexi; Jolliet, O.; Huang, L.

2017-01-01

concentration in food for diverse scenarios. Therefore a partition coefficient model, as a function of a chemical’s octanol-water partition coefficient and a food’s ethanol-equivalency, was also developed. When using measured diffusion coefficients the model accurately predicted (R2 = 0.9, SE = 0.5) hundreds...

The distribution of branched octanols between dodecane and water

International Nuclear Information System (INIS)

Sagert, N.H.; Lau, D.W.P.

1985-01-01

The distribution of four branched chain octanols, 3-ethyl-3-hexanol, 4-ethyl-3-hexanol, 2-ethyl-4-methylpentanol, and 4-octanol, has been measured between dodecane and water. Measurements were made at alcohol concentrations in the dodecane of less than 0.1 mol/dmsup(3), and as a function of temperature from 10 degrees C to 35 degrees C. From these distribution data, standard thermodynamic functions for transfer were calculated. Standard Gibbs energies of transfer from water to dodecane at 25 degrees C were in the range -14.1 to -15.l kJ/mol, whereas the standard enthalpies of transfer at 25 degrees C varied from 29 to 39 kJ/mol. Thus, the change in the standard enthalpy tends to inhibit transfer, but a large standard entropy of transfer results in dodecane being the favoured phase

The octanol/water distribution of mercury compounds

International Nuclear Information System (INIS)

Halbach, S.

1985-01-01

Lipophilicity plays an important role in the biological action of mercurials. The distribution of one inorganic and five organic mercury compounds was determined in an n-octanol/water system. Lipophilicity decreased in the order CH 3 HgCl, bromomercurihydroxypropane HgCl 2 chlormerodrin, p-chloromercuribenzoic acid (PCMB), p-chloromercuriphenylsulfonic acid (PCMBS). The toxicity of mercurials, as reported in the literature, appears to parallel their lipophilicity. (orig.)

Analysis of liposomes using asymmetrical flow field-flow fractionation

DEFF Research Database (Denmark)

Kuntsche, Judith; Decker, Christiane; Fahr, Alfred

2012-01-01

completely (lipid recoveries were close to 100%) but there was a loss of incorporated drugs during separation with a strong dependence on the octanol-water partition coefficient of the drug. Whereas corticosterone (partition coefficient ~2) was washed out more or less completely (recovery about 2%), loss...

Soil-water partition coefficients for uranium and thorium: a systematic study of Tummalapalle mining site, India

International Nuclear Information System (INIS)

Dalvi, Aditi; Verma, Rakesh; Kumar, Sangita D.; Reddy, A.V.R.

2012-01-01

The simplest and most common parameter for modeling radionuclide mobility in soils is the partition coefficient (K d ). The soil-water partition coefficient for radionuclide is affected by numerous geochemical parameters like pH, sorption to clays, presence of organic matter, iron oxides, other soil constituents and the chemical forms of the radionuclide as well as oxidation/reduction conditions and major ion chemistry. In these studies radionuclides uranium and thorium were systematically assessed for their behaviour in the soils from Tummalapalle mining site. Physico-chemical characteristics such as chemical composition, pH, CaCO 3 content and organic carbon were determined for soils and synthetic groundwater samples. Oven dried soil samples (1g) were taken in polycarbonate tube and washed with synthetic ground water till the pH of the supernatant solution remained unchanged. The soil sample was then equilibrated with 30 mL of synthetic ground water spiked with an element of interest. The pH was adjusted to its initial value by addition of small increments of dilute NaOH/HNO 3 . The tubes containing samples were gently shaken for 72 h at room temperature. On completion of the experiment, it was centrifuged using high-speed centrifugation for 30 min and the aqueous phase was separated and analysed. The blank was processed in the same manner without adding soil. Determination of U and Th in the supernatant was carried out using ICPMS. The K d of thorium was found to be two-three order of magnitude higher than that of uranium for both the soil samples assessed in this study. The presence of carbonates and organic carbon in the groundwater has a significant effect on the K d of uranium. The K d values for uranium were found to be hundred fold lower in the presence of carbonates. (author)

Evaluation of (vapor + liquid) equilibria for the binary systems (1-octanol + cyclohexane) and (1-octanol + n-hexane), at low alcohol compositions

International Nuclear Information System (INIS)

Ovejero, Gabriel; Dolores Romero, M.; Diez, Eduardo; Lopes, Tania; Diaz, Ismael

2008-01-01

Isobaric (vapor + liquid) equilibrium at p = 101.32 kPa of pressure has been determined for the systems (1-octanol + cyclohexane) and (1-octanol + n-hexane), at low alcohol mole fractions. These data were satisfactorily correlated, using ASPEN PLUS commercial software, with Wilson, NRTL, and UNIQUAC activity coefficient models to obtain the binary interaction parameters of both mixtures. Also, UNIFAC group contribution method was employed to predict the equilibrium of both mixtures. With regression values an accurate knowledge of (vapor + liquid) equilibrium for both mixtures can be reached in a range of 1-octanol mole fractions less than 0.1. UNIFAC method provides acceptable results for (1-octanol + n-hexane) system but not for (1-octanol + cyclohexane) system

Evaluation of (vapor + liquid) equilibria for the binary systems (1-octanol + cyclohexane) and (1-octanol + n-hexane), at low alcohol compositions

Energy Technology Data Exchange (ETDEWEB)

Ovejero, Gabriel [Grupo de Catalisis y Procesos de Separacion (CyPS), Departamento de Ingenieria Quimica, Facultad de C. Quimicas, Universidsad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain)], E-mail: govejero@quim.ucm.es; Dolores Romero, M.; Diez, Eduardo; Lopes, Tania; Diaz, Ismael [Grupo de Catalisis y Procesos de Separacion (CyPS), Departamento de Ingenieria Quimica, Facultad de C. Quimicas, Universidsad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain)

2008-11-15

Isobaric (vapor + liquid) equilibrium at p = 101.32 kPa of pressure has been determined for the systems (1-octanol + cyclohexane) and (1-octanol + n-hexane), at low alcohol mole fractions. These data were satisfactorily correlated, using ASPEN PLUS commercial software, with Wilson, NRTL, and UNIQUAC activity coefficient models to obtain the binary interaction parameters of both mixtures. Also, UNIFAC group contribution method was employed to predict the equilibrium of both mixtures. With regression values an accurate knowledge of (vapor + liquid) equilibrium for both mixtures can be reached in a range of 1-octanol mole fractions less than 0.1. UNIFAC method provides acceptable results for (1-octanol + n-hexane) system but not for (1-octanol + cyclohexane) system.

Partitioning of phthalates among the gas phase, airborne particles and settled dust in indoor environments

DEFF Research Database (Denmark)

Weschler, Charles J.; Salthammer, Tunga; Fromme, Hermann

2008-01-01

(s)) or the octanol/air partition coefficient (K-OA). For each phthalate in each apartment, the ratio of its particle concentration to its dust concentration (C-particle/C-Dust) was calculated, The median values of this ratio were within an order of magnitude of one another for five of the phthalate esters despite...

Atmospheric concentrations and phase partitioning of polycyclic aromatic hydrocarbons in Izmir, Turkey

Energy Technology Data Exchange (ETDEWEB)

Demircioglu, Eylem; Odabasi, Mustafa [Faculty of Engineering, Department of Environmental Engineering, Dokuz Eylul University, Izmir (Turkey); Sofuoglu, Aysun [Faculty of Engineering, Department of Chemical Engineering, Izmir Institute of Technology, Gulbahce-Urla (Turkey)

2011-04-15

Ambient air polycyclic aromatic hydrocarbon (PAH) samples were collected at a suburban (n = 63) and at an urban site (n = 14) in Izmir, Turkey. Average gas-phase total PAH (sum {sub 14}PAH) concentrations were 23.5 ng m{sup -3} for suburban and 109.7 ng m{sup -3} for urban sites while average particle-phase total PAH concentrations were 12.3 and 34.5 ng m{sup -3} for suburban and urban sites, respectively. Higher ambient PAH concentrations were measured in the gas-phase and sum {sub 14}PAH concentrations were dominated by lower molecular weight PAHs. Multiple linear regression analysis indicated that the meteorological parameters were effective on ambient PAH concentrations. Emission sources of particle-phase PAHs were investigated using a diagnostic plot of fluorene (FLN)/(fluorine + pyrene; PY) versus indeno[1,2,3-cd]PY/(indeno[1,2,3-cd]PY + benzo[g,h,i]perylene) and several diagnostic ratios. These approaches have indicated that traffic emissions (petroleum combustion) were the dominant PAH sources at both sites for summer and winter seasons. Experimental gas-particle partition coefficients (K{sub P}) were compared to the predictions of octanol-air (K{sub OA}) and soot-air (K{sub SA}) partition coefficient models. The correlations between experimental and modeled K{sub P} values were significant (r{sup 2} = 0.79 and 0.94 for suburban and urban sites, respectively, p < 0.01). Octanol-based absorptive partitioning model predicted lower partition coefficients especially for relatively volatile PAHs. However, overall there was a relatively good agreement between the measured K{sub P} and soot-based model predictions. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Native oxy-PAHs, N-PACs, and PAHs in historically contaminated soils from Sweden, Belgium, and France: their soil-porewater partitioning behavior, bioaccumulation in Enchytraeus crypticus, and bioavailability.

Science.gov (United States)

Arp, Hans Peter H; Lundstedt, Staffan; Josefsson, Sarah; Cornelissen, Gerard; Enell, Anja; Allard, Ann-Sofie; Kleja, Dan Berggren

2014-10-07

Soil quality standards are based on partitioning and toxicity data for laboratory-spiked reference soils, instead of real world, historically contaminated soils, which would be more representative. Here 21 diverse historically contaminated soils from Sweden, Belgium, and France were obtained, and the soil-porewater partitioning along with the bioaccumulation in exposed worms (Enchytraeus crypticus) of native polycyclic aromatic compounds (PACs) were quantified. The native PACs investigated were polycyclic aromatic hydrocarbons (PAHs) and, for the first time to be included in such a study, oxygenated-PAHs (oxy-PAHs) and nitrogen containing heterocyclic PACs (N-PACs). The passive sampler polyoxymethylene (POM) was used to measure the equilibrium freely dissolved porewater concentration, Cpw, of all PACs. The obtained organic carbon normalized partitioning coefficients, KTOC, show that sorption of these native PACs is much stronger than observed in laboratory-spiked soils (typically by factors 10 to 100), which has been reported previously for PAHs but here for the first time for oxy-PAHs and N-PACs. A recently developed KTOC model for historically contaminated sediments predicted the 597 unique, native KTOC values in this study within a factor 30 for 100% of the data and a factor 3 for 58% of the data, without calibration. This model assumes that TOC in pyrogenic-impacted areas sorbs similarly to coal tar, rather than octanol as typically assumed. Black carbon (BC) inclusive partitioning models exhibited substantially poorer performance. Regarding bioaccumulation, Cpw combined with liposome-water partition coefficients corresponded better with measured worm lipid concentrations, Clipid (within a factor 10 for 85% of all PACs and soils), than Cpw combined with octanol-water partition coefficients (within a factor 10 for 76% of all PACs and soils). E. crypticus mortality and reproducibility were also quantified. No enhanced mortality was observed in the 21 historically

Polymers as reference partitioning phase: polymer calibration for an analytically operational approach to quantify multimedia phase partitioning

DEFF Research Database (Denmark)

Gilbert, Dorothea; Witt, Gesine; Smedes, Foppe

2016-01-01

Polymers are increasingly applied for the enrichment of hydrophobic organic chemicals (HOCs) from various types of samples and media in many analytical partitioning-based measuring techniques. We propose using polymers as a reference partitioning phase and introduce polymer-polymer partitioning......-air) and multimedia partition coefficients (lipid-water, air-water) were calculated by applying the new concept of a polymer as reference partitioning phase and by using polymer-polymer partition coefficients as conversion factors. The present study encourages the use of polymer-polymer partition coefficients...

On the enrichment of hydrophobic organic compounds in fog droplets

Science.gov (United States)

Valsaraj, K. T.; Thoma, G. J.; Reible, D. D.; Thibodeaux, L. J.

The unusual degree of enrichment of hydrophobic organics in fogwater droplets reported by several investigators can be interpreted as a result of (a) the effects of temperature correction on the reported enrichment factors, (b) the effects of colloidal organic matter (both filterable and non-filterable) in fog water and (c) the effects of the large air-water interfacial adsorption of neutral hydrophobic organics on the tiny fog droplets. The enrichment factor was directly correlated to the hydrophobicity (or the activity coefficient in water) of the compounds, as indicated by their octanol-water partition constants. Compounds with large octanol-water partition coefficients (high activity coefficients in water) showed the largest enrichment. Available experimental data on the adsorption of hydrophobic compounds at the air-water interface and on colloidal organic carbon were used to show that the large specific air-water interfacial areas of fog droplets contribute significantly to the enrichment factor.

Dispersed three-pulse infrared photon echoes of nitrous oxide in water and octanol.

Science.gov (United States)

Shattuck, J T; Schneck, J R; Chieffo, L R; Erramilli, S; Ziegler, L D

2013-12-12

Dispersed IR three-pulse photon echoes due to the antisymmetric (ν3) stretch mode of N2O dissolved in H2O and 1-octanol at room temperature are reported and analyzed. The experimentally determined transition frequency-frequency correlation function (FFCF) in these two solvents is explained in terms of inertial solvent contributions, hydrogen bond network fluctuations, and, for octanol, the motions of the alkyl chains. The H2O hydrogen bond fluctuations result in 1.5 ps FFCF decay, in agreement with relaxation rates determined from photon echo based measurements of other aqueous solutions including salt solutions. In octanol, hydrogen bond fluctuations decay on a slower time scale of 3.3 ps and alkyl chain motions result in an inhomogeneous broadening contribution to the ν3 absorption spectrum that decays on a 35 ps time scale. Rotational reorientation of N2O is nearly 3 times faster in octanol as compared to water. Although the vibrational ν3 N2O absorption line shapes in water and octanol are similar, the line widths result from different coherence loss mechanisms. A hot band contribution in the N2O in octanol solution is found to have a significant effect on the echo spectrum due to its correspondingly stronger transition moment than that of the fundamental transition. The dephasing dynamics of the N2O ν3 stretch mode is of interest as a probe in ultrafast studies of complex or nanoconfined systems with both hydrophobic and hydrophilic regions such as phospholipids, nucleic acids, and proteins. These results demonstrate the value of the N2O molecule to act as a reporter of equilibrium fluctuations in such complex systems particularly due to its solubility characteristics and long vibrational lifetime.

Investigation of migrant-polymer interaction in pharmaceutical packaging material using the linear interaction energy algorithm.

Science.gov (United States)

Feenstra, Peter; Brunsteiner, Michael; Khinast, Johannes

2014-10-01

The interaction between drug products and polymeric packaging materials is an important topic in the pharmaceutical industry and often associated with high costs because of the required elaborative interaction studies. Therefore, a theoretical prediction of such interactions would be beneficial. Often, material parameters such as the octanol water partition coefficient are used to predict the partitioning of migrant molecules between a solvent and a polymeric packaging material. Here, we present the investigation of the partitioning of various migrant molecules between polymers and solvents using molecular dynamics simulations for the calculation of interaction energies. Our results show that the use of a model for the interaction between the migrant and the polymer at atomistic detail can yield significantly better results when predicting the polymer solvent partitioning than a model based on the octanol water partition coefficient. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

A linear solvation energy relationship model of organic chemical partitioning to dissolved organic carbon.

Science.gov (United States)

Kipka, Undine; Di Toro, Dominic M

2011-09-01

Predicting the association of contaminants with both particulate and dissolved organic matter is critical in determining the fate and bioavailability of chemicals in environmental risk assessment. To date, the association of a contaminant to particulate organic matter is considered in many multimedia transport models, but the effect of dissolved organic matter is typically ignored due to a lack of either reliable models or experimental data. The partition coefficient to dissolved organic carbon (K(DOC)) may be used to estimate the fraction of a contaminant that is associated with dissolved organic matter. Models relating K(DOC) to the octanol-water partition coefficient (K(OW)) have not been successful for many types of dissolved organic carbon in the environment. Instead, linear solvation energy relationships are proposed to model the association of chemicals with dissolved organic matter. However, more chemically diverse K(DOC) data are needed to produce a more robust model. For humic acid dissolved organic carbon, the linear solvation energy relationship predicts log K(DOC) with a root mean square error of 0.43. Copyright © 2011 SETAC.

Partitioning of naphthalene, methylnaphthalenes and biphenyl between wastewater treatment sludges and water

International Nuclear Information System (INIS)

Southworth, G.R.; Keller, J.L.

1984-01-01

Partition coefficients (K/sub p/) describing the partitioning of naphthalene, methylnaphthalenes and biphenyl between organic-rich wastes and water were determined using 14 C-tracer techniques as well as high performance liquid chromatographic analysis of the wastes and their aqueous extracts. Results of the two procedures were in good agreement. The concentrations of the specific organics in the wastes were not good predictors of concentrations in aqueous extracts, since K/sub p/ varied among the materials tested. Predictions of k/sub p/ based on organic carbon content of the sludges were well below observed values. Oil content of the wastes and oil-water partition coefficients appeared to be important factors in determining K/sub p/. 11 references, 5 tables

[The water content reference material of water saturated octanol].

Science.gov (United States)

Wang, Haifeng; Ma, Kang; Zhang, Wei; Li, Zhanyuan

2011-03-01

The national standards of biofuels specify the technique specification and analytical methods. A water content certified reference material based on the water saturated octanol was developed in order to satisfy the needs of the instrument calibration and the methods validation, assure the accuracy and consistency of results in water content measurements of biofuels. Three analytical methods based on different theories were employed to certify the water content of the reference material, including Karl Fischer coulometric titration, Karl Fischer volumetric titration and quantitative nuclear magnetic resonance. The consistency of coulometric and volumetric titration was achieved through the improvement of methods. The accuracy of the certified result was improved by the introduction of the new method of quantitative nuclear magnetic resonance. Finally, the certified value of reference material is 4.76% with an expanded uncertainty of 0.09%.

Influences of binding to dissolved organic matter on hydrophobic organic compounds in a multi-contaminant system: Coefficients, mechanisms and ecological risks.

Science.gov (United States)

Li, Yi-Long; He, Wei; Liu, Wen-Xiu; Kong, Xiang-Zhen; Yang, Bin; Yang, Chen; Xu, Fu-Liu

2015-11-01

The complexation flocculation (CF) method was successfully employed to identify binding coefficients (Kdoc) of specific organic contaminants to dissolved organic matter (DOM, often indicated by dissolved organic carbon, DOC) in a multi-contaminant hydrophobic organic contaminant (HOC) system. Kdoc values were obtained for most of the evaluated 33 HOCs, indicating the feasibility and applicability of the CF method in a multi-contaminant system. Significant positive correlations were observed between binding coefficients and octanol-water partition coefficients (Kow) for organic halogen compounds, such as polybrominated diphenyl ethers (PBDEs) (R(2) = 0.95, p mechanisms between PAHs and organic halogen compounds exist. These differences further result in discriminative competition partitions of HOCs between DOM and organisms. Assuming that only freely dissolved HOCs are bioconcentrative, the results of DOM-influenced bioconcentration factor (BCFDOM) and DOM-influenced lowest observed effect level (LOELDOM) indicate that the ecological risk of HOCs is decreased by DOM. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Tritiated Water Skin Barrier Integrity Test: Considerations for Acceptance Criteria with and Without 14C-Octanol.

Science.gov (United States)

Lehman, Paul A; Beatch, Kacie; Raney, Sam G; Franz, Thomas J

2017-01-01

A study was designed to assess barrier integrity simultaneously using separate compounds (probes) for polar and non-polar pathways through the skin, 3 H 2 O and 14 C-octanol, respectively; and to determine whether the two probe approach could better define barrier integrity. A 5-min dose of water containing 3 H 2 O and 14 C -octanol was applied to ex vivo human skin mounted in Franz diffusion cells. The receptor solution was sampled at 30 min, analyzed for 3 H and 14 C content, and the correlation between water and octanol absorption was determined by statistical tests suitable for non-normally distributed data. This study was conducted on skin from 37 donors with from 3 to 30 replicate skin sections per donor (a total of 426 sections). The correlation between 3 H 2 O and 14 C-octanol absorption was low (Pearson correlation coefficient = 0.3485). The 3 H 2 O absorption cutoff used in this study to select for a normal skin barrier rejected some sections in which 14 C-octanol absorption was within normal limits and accepted others in which 14 C-octanol absorption was abnormally high. The converse was true for 3 H 2 O absorption when the 14 C-octanol-based cutoff was used. The results of the 3 H 2 O test or of similar tests that primarily assess the permeability of polar pathways through the skin may not necessarily provide information relevant to the absorption of highly lipophilic compounds. Octanol, or another molecule that more closely matches the physicochemical attributes of the test compound, may characterize properties of the skin barrier that are more relevant to compounds of low water solubility.

Evaluation of Diclofenac Prodrugs for Enhancing Transdermal Delivery

OpenAIRE

Lobo, Shabbir; Li, Henan; Farhan, Nashid; Yan, Guang

2013-01-01

The purpose of this study was to evaluate the approach of using diclofenac acid (DA) prodrugs for enhancing transdermal delivery. Methanol diclofenac ester (MD), ethylene glycol diclofenac ester (ED), glycerol diclofenac ester (GD), and 1,3-propylene glycol diclofenac ester (PD) were synthesized and evaluated for their physicochemical properties such as solubilities, octanol/water partition coefficients, stratum corneum/water partition coefficients, hydrolysis rates, and bioconversion rates. ...

Determination of radon partition coefficients between water and different kinds of NAPLs for use in analysis of residual soil NAPLs

Energy Technology Data Exchange (ETDEWEB)

Bonfim, Sarah Andresa; Ferreira, Ângela Fortini Macedo, E-mail: sarah_andresa@hotmail.com [Universidade Federal de Migas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Franklin, Mariza Ramalho; Ferreira, Paulo Roberto Rocha [Instituto de Radioproteção e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Rocha, Zildete, E-mail: zildeter7@gmail.com [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2017-07-01

Different studies indicate the applicability of natural radon as a tracer in the determination of contaminated environments by Non-Aqueous Phase Liquids (NAPLs). Such use being due to the non-homogeneous distribution of this element between water, air and NAPL. Thus, it is known that the concentration of radon in a given soil / aquifer and in a given area may indicate that such site is contaminated by NAPL. However, the simple measurement of radon concentration activity allows only a qualitative evaluation of the area contaminated in study. For a quantitative estimate of the NAPL saturation in the pore space, it is necessary to know the radon partition coefficients between the coexisting phases, considering the kind of NAPL present. The present study, the radon partitioning coefficients between air, water and diverse types of NAPL mixtures, such as gasoline, diesel fuel, alcohol, kerosene and olive oil was measured. In a closed system, was applied an analytical method based on the distribution of the radon between the present phases with the use of a system of Flow Injection Analysis (FIA). The measurement of the specific activity of radon was performed by using an AlphaGUARD monitor. It is observed that, in the presence of NAPL, the concentration of radon in water and air is significantly lower than in its absence, indicating a negative correlation and allowing the evaluation of the contamination of the area by NAPL. (author)

Determination of radon partition coefficients between water and different kinds of NAPLs for use in analysis of residual soil NAPLs

International Nuclear Information System (INIS)

Bonfim, Sarah Andresa; Ferreira, Ângela Fortini Macedo; Rocha, Zildete

2017-01-01

Different studies indicate the applicability of natural radon as a tracer in the determination of contaminated environments by Non-Aqueous Phase Liquids (NAPLs). Such use being due to the non-homogeneous distribution of this element between water, air and NAPL. Thus, it is known that the concentration of radon in a given soil / aquifer and in a given area may indicate that such site is contaminated by NAPL. However, the simple measurement of radon concentration activity allows only a qualitative evaluation of the area contaminated in study. For a quantitative estimate of the NAPL saturation in the pore space, it is necessary to know the radon partition coefficients between the coexisting phases, considering the kind of NAPL present. The present study, the radon partitioning coefficients between air, water and diverse types of NAPL mixtures, such as gasoline, diesel fuel, alcohol, kerosene and olive oil was measured. In a closed system, was applied an analytical method based on the distribution of the radon between the present phases with the use of a system of Flow Injection Analysis (FIA). The measurement of the specific activity of radon was performed by using an AlphaGUARD monitor. It is observed that, in the presence of NAPL, the concentration of radon in water and air is significantly lower than in its absence, indicating a negative correlation and allowing the evaluation of the contamination of the area by NAPL. (author)

Partition of selected food preservatives in fish oil-water systems

DEFF Research Database (Denmark)

Cheng, Hongyuan; Friis, Alan; Leth, Torben

2010-01-01

The partition coefficients (Kow) of benzoic acid and sorbic acid in systems of fish oil (sand eel)–water, fish oil–buffer solution, rape oil–water and olive oil–water were experimentally determined in a temperature range from 5 to 43 °C and pH from 4.5 to 6.5 °C. The dimerization of benzoic acid...... in fish oil–water system was observed at 25 °C. Two modifications have been made to the Nordic Food Analysis Standard for the determination of sorbic acid by HPLC. The experimental results show that the Kow of benzoic acid and sorbic acid in fish oil–buffer system is ca. 100 times lower than that in fish...... oil–water system. The Kow values of benzoic acid and sorbic acid in fish oil and water system decrease with increasing system pH values. The partition coefficients of plant origin and fish origin oils are in the same order of magnitude even though their molecular structures are very different....

Seasonal and particle size-dependent variations in gas/particle partitioning of PCDD/Fs

International Nuclear Information System (INIS)

Lee, Se-Jin; Ale, Debaki; Chang, Yoon-Seok; Oh, Jeong-Eun; Shin, Sun Kyoung

2008-01-01

This study monitored particle size-dependent variations in atmospheric polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Two gas/particle partitioning models, the subcooled liquid vapor pressure (P L 0 ) and the octanol-air partition coefficient (K OA ) model, were applied to each particle sizes. The regression coefficients of each fraction against the gas/particle partition coefficient (K P ) were similar for separated particles within the same sample set but differed for particles collected during different periods. Gas/particle partitioning calculated from the integral of fractions was similar to that of size-segregated particles and previously measured bulk values. Despite the different behaviors and production mechanisms of atmospheric particles of different sizes, PCDD/F partitioning of each size range was controlled by meteorological conditions such as atmospheric temperature, O 3 and UV, which reflects no source related with certain particle size ranges but mixed urban sources within this city. Our observations emphasize that when assessing environmental and health effects, the movement of PCDD/Fs in air should be considered in conjunction with particle size in addition to the bulk aerosol. - Gas/particle partitioning of atmospheric PCDD/Fs for different particle sizes reflects the impacts of emitters of different size ranges

The partition coefficients of 133Xe between blood and bone

International Nuclear Information System (INIS)

Lahtinen, T.; Karjalainen, P.; Vaeaenaenen, A.; Lahtinen, R.; Alhava, E.M.

1981-01-01

The partition coefficients of 133 Xe between blood and haematopoietic bone marrow and homogenised bone have been determined in vitro. The partition coefficient lambda 1 corresponding to haematopoietic marrow was 0.95 ml g -1 while that corresponding to homogenised bone was a function of age, lambda 2 = 3.11 + 0.049(age)(ml g -1 ). These data can be used for calculating regional blood flow in healthy human femur by means of a simple 133 Xe radionuclide method. (author)

Spontaneous assembly of HSP90 inhibitors at water/octanol interface: A molecular dynamics simulation study

Science.gov (United States)

Zolghadr, Amin Reza; Boroomand, Samaneh

2017-02-01

Drug absorption at an acceptable dose depends on the pair of solubility and permeability. There are many potent therapeutics that are not active in vivo, presumably due to the lack of capability to cross the cell membrane. Molecular dynamics simulation of radicicol, diol-radicicol, cyclopropane-radicicol and 17-DMAG were performed at water/octanol interface to suggest interfacial activity as a physico-chemical characteristic of these heat shock protein 90 (HSP90) inhibitors. We have observed that orally active HSP90 inhibitors form aggregates at the water/octanol and DPPC-lipid/water interfaces by starting from an initial configuration with HSP90 inhibitors embedded in the water matrix.

Determination of partition coefficients of biomolecules in a microfluidic aqueous two phase system platform using fluorescence microscopy.

Science.gov (United States)

Silva, D F C; Azevedo, A M; Fernandes, P; Chu, V; Conde, J P; Aires-Barros, M R

2017-03-03

Aqueous two phase systems (ATPS) offer great potential for selective separation of a wide range of biomolecules by exploring differences in molecular solubility in each of the two immiscible phases. However, ATPS use has been limited due to the difficulty in predicting the behavior of a given biomolecule in the partition environment together with the empirical and time-consuming techniques that are used for the determination of partition and extraction parameters. In this work, a fast and novel technique based on a microfluidic platform and using fluorescence microscopy was developed to determine the partition coefficients of biomolecules in different ATPS. This method consists of using a microfluidic device with a single microchannel and three inlets. In two of the inlets, solutions containing the ATPS forming components were loaded while the third inlet was fed with the FITC tagged biomolecule of interest prepared in milli-Q water. Using fluorescence microscopy, it was possible to follow the location of the FITC-tagged biomolecule and, by simply varying the pumping rates of the solutions, to quickly test a wide variety of ATPS compositions. The ATPS system is allowed 4min for stabilization and fluorescence micrographs are used to determine the partition coefficient.The partition coefficients obtained were shown to be consistent with results from macroscale ATPS partition. This process allows for faster screening of partition coefficients using only a few microliters of material for each ATPS composition and is amenable to automation. The partitioning behavior of several biomolecules with molecular weights (MW) ranging from 5.8 to 150kDa, and isoelectric points (pI) ranging from 4.7 to 6.4 was investigated, as well as the effect of the molecular weight of the polymer ATPS component. Copyright © 2016 Elsevier B.V. All rights reserved.

Aspectos termodinámicos de la miscibilidad parcial entre el n-octanol y el agua Thermodynamic aspects of partial miscibility between n-octanol and water

Directory of Open Access Journals (Sweden)

Carolina P. Mora

2005-03-01

Full Text Available En este trabajo se realizó el tratamiento termodinámico de los datos en fracción molar del equilibrio líquido-líquido entre n-octanol y agua en función de la temperatura, utilizando el método de van't Hoff (ln S en función de T-1 y el planteado por Grant et al. (ln S en función de T-1 y ln T: para las dos escalas de concentración. Se encontró un comportamiento no lineal para las dos fases mutuamente saturadas en el tratamiento de van't Hoff, por lo que se utilizó un modelo de regresión parabólico, que fue derivado para resolver el cambio entálpico de solución, obteniendo procesos endotérmicos a todas las temperaturas estudiadas. En los dos sistemas los cambios de energía libre fueron positivos mientras que los cambios entrópicos fueron negativos indicando algún grado de organización en las soluciones saturadas, que en el caso del agua saturada de n-octanol podría explicarse por la hidratación hidrofóbica en torno a las cadenas octílicas y en el caso del n-octanol saturado de agua podría deberse como ha sido planteado en la literatura a la organización de las moléculas del n-octanol entorno a las moléculas de agua mediante la formación de enlaces de hidrógeno. Los valores termodinámicos calculados fueron comparados con los presentados por otros autores, obtenidos por calorimetría y también, mediante evaluación de constantes de equilibro en función de la temperatura.In the present work the thermodynamic analysis for those data presented by Dallos and Liszi on mole fraction n-octanol-water liquid-liquid equilibria was made. The values were analyzed using the van't Hoff method (ln S as a function of T-1 and those presented by Grant et al. (ln S as a function of T-1 and ln T. A non-lineal behavior was found in all cases studied by the van't Hoff method, which lead us to apply a parabolic regression model derived in order to calculate the enthalpic changes. Endothermic processes were obtained for all temperatures

Estudo do coeficiente de partição octanol-água de bifenilas policloradas (PCBs utilizando parâmetros topológicos

Directory of Open Access Journals (Sweden)

Silva Lucicleide Ribeiro da

2003-01-01

Full Text Available A model based on chemical structure was developed for the accurate prediction of octanol/water partition coefficient (K OW of polychlorinated biphenyls (PCBs, which are molecules of environmental interest. Partial least squares (PLS was used to build the regression model. Topological indices were used as molecular descriptors. Variable selection was performed by Hierarchical Cluster Analysis (HCA. In the modeling process, the experimental K OW measured for 30 PCBs by thin-layer chromatography - retention time (TLC-RT has been used. The developed model (Q² = 0,990 and r² = 0,994 was used to estimate the log K OW values for the 179 PCB congeners whose K OW data have not yet been measured by TLC-RT method. The results showed that topological indices can be very useful to predict the K OW.

Influences of the amount of ligand on the biochemical properties of 153Sm-HEDTMP

International Nuclear Information System (INIS)

Yang Yuqing; Luo Shunzhong; Wang Guanquan; He Jiaheng; Pu Manfei; Bing Wenzeng

2002-01-01

The Effect of the amount of ligand HEDTMP on biochemical properties of 153 Sm-HEDTMP is studied. The biochemical properties include partition coefficient of 153 Sm-HEDTMP in n-octanol-water which is measured by shake-flask method, combination characteristic with BSA (bovine serum albumin) which is measured through precipitation by TCA (trichloroacetic acid) and adsorption characteristic on HA (hydroxyapatite) which is measured with the same method used in 153 Sm-EDTMP. It is found that, with the increasing in the amount of ligand, partition coefficient of 153 Sm-HEDTMP. It is found that, with the increase in the amount of ligand, partition coefficient of 153 Sm-HEDTMP in n-octanol-water decreases, so does combination percentage with BSA, but the adsorption percentage on HA shows a little and unremarkable decrease. Considering the relationships between these three biochemical properties and in vivo metabolism of 153 Sm-HEDTMP this study supports the view that an appropriate high amount of ligand should be applied in practical use

Effects of solvation on partition and dimerization of benzoic acid in mixed solvent systems.

Science.gov (United States)

Yamada, H; Yajima, K; Wada, H; Nakagawa, G

1995-06-01

The partition of benzoic acid between 0.1M perchloric acid solution and two kinds of mixed solvents has been carried out at 25 degrees C. The partition and dimerization constants of benzoic acid have been determined in the 1-octanol-benzene and 2-octanone-benzene systems. In both the mixed solvent systems, with increasing content of 1-octanol and 2-octanone in each mixed solvent, the partition constant of benzoic acid has been found to increase, and the dimerization constant of benzoic acid in each organic phase to decrease. These phenomena are attributable to solvation of monomeric benzoic acid by 1-octanol and 2-octanone molecules in each mixed solvent.

Thermodynamic study of the transfer of acetanilide and phenacetin from water to different organic solvents.

Science.gov (United States)

Baena, Yolima; Pinzón, Jorge A; Barbosa, Helber J; Martínez, Fleming

2005-06-01

The molar (K(C)(o/w)) and rational (K(X)(o/w)) partition coefficients in the octanol/buffer, i-propyl myristate/buffer, chloroform/buffer, and cyclohexane/buffer systems were determined for acetanilide and phenacetin at 25.0, 30.0, 35.0, and 40.0 degrees C. In all cases except for cyclohexane, the K(C)(o/w) and K(X)(o/w) values were greater than unity. This demonstrates that these two drugs have predominantly lipophilic behavior. Gibbs and van't Hoff thermodynamic analyses have revealed that the transfer of these drugs from water to organic solvents is spontaneous and that it is mainly driven enthalpically for i-propyl myristate and chloroform, and entropy-driven for octanol and cyclohexane.

Impacts of environmental conditions on the sorption of volatile organic compounds onto tire powder

Energy Technology Data Exchange (ETDEWEB)

Oh, Dong I. [Division of R and D Planning and Management, Korea Institute of Environmental Science and Technology, Seoul (Korea, Republic of); Nam, Kyongphile [School of Civil, Urban and Geosystem Engineering, College of Engineering, Seoul National University, Gwanak-Ku, 151-742 Seoul (Korea, Republic of); Park, Jae W. [Department of Civil Engineering, Hanyang University, Seoul (Korea, Republic of); Khim, Jee H. [Department of Civil and Environmental Engineering, Korea University, Seoul (Korea, Republic of); Kim, Yong K. [School of Civil, Urban and Geosystem Engineering, College of Engineering, Seoul National University, Gwanak-Ku, 151-742 Seoul (Korea, Republic of); Kim, Jae Y. [School of Civil, Urban and Geosystem Engineering, College of Engineering, Seoul National University, Gwanak-Ku, 151-742 Seoul (Korea, Republic of)], E-mail: jaeykim@snu.ac.kr

2008-05-01

A series of batch tests were performed and the impacts of environmental conditions and phase change on the sorption of volatile organic compounds (VOCs) were investigated. Benzene, trichloroethylene, tetrachloroethylene, and ethylbenzene were selected as target VOCs. Sorption of VOCs onto tire powder was well demonstrated by a linear-partitioning model. Water-tire partition coefficients of VOCs (not tested in this study) could be estimated using a logarithmic relationship between observed water-tire partition coefficients and octanol-water partition coefficients of the VOCs tested. The target VOCs did not seem to compete with other VOCs significantly when sorbed onto the tire powder for the range of concentrations tested. The influence of environmental conditions, such as pH and ionic strength also did not seem to be significant. Water-tire partition coefficients of benzene, trichloroethylene, tetrachloroethylene, and ethylbenzene decreased as the sorbent dosage increased. However, they showed stable values when the sorbent dosage was greater than 10 g/L. Air-tire partition coefficient could be extrapolated from Henry's law constants and water-tire partition coefficient of VOCs.

Impacts of environmental conditions on the sorption of volatile organic compounds onto tire powder

International Nuclear Information System (INIS)

Oh, Dong I.; Nam, Kyongphile; Park, Jae W.; Khim, Jee H.; Kim, Yong K.; Kim, Jae Y.

2008-01-01

A series of batch tests were performed and the impacts of environmental conditions and phase change on the sorption of volatile organic compounds (VOCs) were investigated. Benzene, trichloroethylene, tetrachloroethylene, and ethylbenzene were selected as target VOCs. Sorption of VOCs onto tire powder was well demonstrated by a linear-partitioning model. Water-tire partition coefficients of VOCs (not tested in this study) could be estimated using a logarithmic relationship between observed water-tire partition coefficients and octanol-water partition coefficients of the VOCs tested. The target VOCs did not seem to compete with other VOCs significantly when sorbed onto the tire powder for the range of concentrations tested. The influence of environmental conditions, such as pH and ionic strength also did not seem to be significant. Water-tire partition coefficients of benzene, trichloroethylene, tetrachloroethylene, and ethylbenzene decreased as the sorbent dosage increased. However, they showed stable values when the sorbent dosage was greater than 10 g/L. Air-tire partition coefficient could be extrapolated from Henry's law constants and water-tire partition coefficient of VOCs

Assessment of PDMS-water partition coefficients: implications for passive environmental sampling of hydrophobic organic compounds

Science.gov (United States)

DiFilippo, Erica L.; Eganhouse, Robert P.

2010-01-01

Solid-phase microextraction (SPME) has shown potential as an in situ passive-sampling technique in aquatic environments. The reliability of this method depends upon accurate determination of the partition coefficient between the fiber coating and water (Kf). For some hydrophobic organic compounds (HOCs), Kf values spanning 4 orders of magnitude have been reported for polydimethylsiloxane (PDMS) and water. However, 24% of the published data examined in this review did not pass the criterion for negligible depletion, resulting in questionable Kf values. The range in reported Kf is reduced to just over 2 orders of magnitude for some polychlorinated biphenyls (PCBs) when these questionable values are removed. Other factors that could account for the range in reported Kf, such as fiber-coating thickness and fiber manufacturer, were evaluated and found to be insignificant. In addition to accurate measurement of Kf, an understanding of the impact of environmental variables, such as temperature and ionic strength, on partitioning is essential for application of laboratory-measured Kf values to field samples. To date, few studies have measured Kf for HOCs at conditions other than at 20 degrees or 25 degrees C in distilled water. The available data indicate measurable variations in Kf at different temperatures and different ionic strengths. Therefore, if the appropriate environmental variables are not taken into account, significant error will be introduced into calculated aqueous concentrations using this passive sampling technique. A multiparameter linear solvation energy relationship (LSER) was developed to estimate log Kf in distilled water at 25 degrees C based on published physicochemical parameters. This method provided a good correlation (R2 = 0.94) between measured and predicted log Kf values for several compound classes. Thus, an LSER approach may offer a reliable means of predicting log Kf for HOCs whose experimental log Kf values are presently unavailable. Future

Determination of solid-liquid partition coefficients (Kd) for the herbicides inspiration and trifluralin in five UK agricultural soils

International Nuclear Information System (INIS)

Cooke, Cindy M.; Shaw, George; Collins, Chris D.

2004-01-01

Isoproturon and trifluralin are herbicides of contrasting chemical characters and modes of action. Standard batch sorption procedures were carried out to investigate the individual sorption behaviour of 14 C-isoproturon and 14 C-trifluralin in five agricultural soils (1.8-4.2% OC), and the soil solid-liquid partition coefficients (K d values) were determined. Trifluralin exhibited strong partitioning to the soil solid phase (K d range 106-294) and low desorption potential, thus should not pose a threat to sensitive waters via leaching, although particle erosion and preferential flow pathways may facilitate transport. For isoproturon, soil adsorption was low (K d range 1.96-5.75) and desorption was high, suggesting a high leaching potential, consistent with isoproturon being the most frequently found pesticide in UK surface waters. Soil partitioning was directly related to soil organic carbon (OC) content. Accumulation isotherms were modelled using a dual-phase adsorption model to estimate adsorption and desorption rate coefficients. Associations between herbicides and soil humic substances were also shown using gel filtration chromatography. - Capsule: Herbicide soil sorption described by a dual-phase adsorption model reflected soil partitioning, as influenced by soil OC and humic substances

SAMPL5: 3D-RISM partition coefficient calculations with partial molar volume corrections and solute conformational sampling

Science.gov (United States)

Luchko, Tyler; Blinov, Nikolay; Limon, Garrett C.; Joyce, Kevin P.; Kovalenko, Andriy

2016-11-01

Implicit solvent methods for classical molecular modeling are frequently used to provide fast, physics-based hydration free energies of macromolecules. Less commonly considered is the transferability of these methods to other solvents. The Statistical Assessment of Modeling of Proteins and Ligands 5 (SAMPL5) distribution coefficient dataset and the accompanying explicit solvent partition coefficient reference calculations provide a direct test of solvent model transferability. Here we use the 3D reference interaction site model (3D-RISM) statistical-mechanical solvation theory, with a well tested water model and a new united atom cyclohexane model, to calculate partition coefficients for the SAMPL5 dataset. The cyclohexane model performed well in training and testing (R=0.98 for amino acid neutral side chain analogues) but only if a parameterized solvation free energy correction was used. In contrast, the same protocol, using single solute conformations, performed poorly on the SAMPL5 dataset, obtaining R=0.73 compared to the reference partition coefficients, likely due to the much larger solute sizes. Including solute conformational sampling through molecular dynamics coupled with 3D-RISM (MD/3D-RISM) improved agreement with the reference calculation to R=0.93. Since our initial calculations only considered partition coefficients and not distribution coefficients, solute sampling provided little benefit comparing against experiment, where ionized and tautomer states are more important. Applying a simple pK_{ {a}} correction improved agreement with experiment from R=0.54 to R=0.66, despite a small number of outliers. Better agreement is possible by accounting for tautomers and improving the ionization correction.

SAMPL5: 3D-RISM partition coefficient calculations with partial molar volume corrections and solute conformational sampling.

Science.gov (United States)

Luchko, Tyler; Blinov, Nikolay; Limon, Garrett C; Joyce, Kevin P; Kovalenko, Andriy

2016-11-01

Implicit solvent methods for classical molecular modeling are frequently used to provide fast, physics-based hydration free energies of macromolecules. Less commonly considered is the transferability of these methods to other solvents. The Statistical Assessment of Modeling of Proteins and Ligands 5 (SAMPL5) distribution coefficient dataset and the accompanying explicit solvent partition coefficient reference calculations provide a direct test of solvent model transferability. Here we use the 3D reference interaction site model (3D-RISM) statistical-mechanical solvation theory, with a well tested water model and a new united atom cyclohexane model, to calculate partition coefficients for the SAMPL5 dataset. The cyclohexane model performed well in training and testing ([Formula: see text] for amino acid neutral side chain analogues) but only if a parameterized solvation free energy correction was used. In contrast, the same protocol, using single solute conformations, performed poorly on the SAMPL5 dataset, obtaining [Formula: see text] compared to the reference partition coefficients, likely due to the much larger solute sizes. Including solute conformational sampling through molecular dynamics coupled with 3D-RISM (MD/3D-RISM) improved agreement with the reference calculation to [Formula: see text]. Since our initial calculations only considered partition coefficients and not distribution coefficients, solute sampling provided little benefit comparing against experiment, where ionized and tautomer states are more important. Applying a simple [Formula: see text] correction improved agreement with experiment from [Formula: see text] to [Formula: see text], despite a small number of outliers. Better agreement is possible by accounting for tautomers and improving the ionization correction.

Alkylarylnitrosoureas--stability in aqueous solution, partition coefficient, alkylating activity and its relationship to SCE induction in Chinese hamster V 79-E cells.

Science.gov (United States)

Mendel, J; Thust, R; Schwarz, H

1982-01-01

The alkylating activity, chemical stability in aqueous solution (pH 7.0; 37 degrees C), and partition coefficient (octanol/water) of the following compounds were determined: 1-methyl-3-phenyl-1-nitrosourea (MPNU), 1-ethyl-3-phenyl-1-nitrosourea (EPNU), 1-isopropyl-3-phenyl-1-nitrosourea (i-PrPNU), 1-methyl-3-(p-fluorophenyl)-1-nitrosourea (F-MPNU), 1-methyl-3-(p-chlorophenyl)-1-nitrosourea (Cl-MPNU), 1-methyl-3-(p-bromophenyl)-1-nitrosourea (Br-MPNU), 1,3-dimethyl-3-phenyl-1-nitrosourea (DMPNU), and 1-methyl-3-naphthyl-1-nitrosocarbamate (NCA). 1-Methyl-1-nitrosourea (MNU) and 1-ethyl-1-nitrosourea (ENU) were used for the comparison. THe rate of decomposition in aqueous solution is discussed concerning the influences of the substituents at the 1- and 3-N-atom. The mono- and disubstituted N-nitrosoureas showed a coarse correlation between alkylating activity and SCE induction in Chinese hamster V 79-E cells. On the other hand, this correlation is missing in the case of NCA, which is a potent SCE inducer despite relatively low alkylating activity. DMPNU is the strongest SCE inducer, but this compound shows a high stability in aqueous solution and, consequently, we were not able to detect an alkylating activity.

Experiments in water-macrophyte systems to uncover the dynamics of pesticide mitigation processes in vegetated surface waters/streams.

Science.gov (United States)

Stang, Christoph; Bakanov, Nikita; Schulz, Ralf

2016-01-01

Knowledge on the dynamics and the durability of the processes governing the mitigation of pesticide loads by aquatic vegetation in vegetated streams, which are characterized by dynamic discharge regimes and short chemical residence times, is scarce. In a static long-term experiment (48 h), the dissipation of five pesticides from the aqueous phase followed a biphasic pattern in the presence of aquatic macrophytes. A dynamic concentration decrease driven by sorption to the macrophytes ranged from 8.3 to 60.4% for isoproturon and bifenox, respectively, within the first 2 h of exposure. While the aqueous concentrations of imidacloprid, isoproturon, and tebufenozide remained constant thereafter, the continuous but decelerated concentration decrease of difenoconazole and bifenox in the water-macrophyte systems used here was assumed to be attributed to macrophyte-induced degradation processes. In addition, a semi-static short-term experiment was conducted, where macrophytes were transferred to uncontaminated medium after 2 h of exposure to simulate a transient pesticide peak. In the first part of the experiment, adsorption to macrophytes resulted in partitioning coefficients (logK D_Adsorp) ranging from 0.2 for imidacloprid to 2.2 for bifenox. One hour after the macrophytes were transferred to the uncontaminated medium, desorption of the compounds from the macrophytes resulted in a new phase equilibrium and K D_Desorp values of 1.46 for difenoconazole and 1.95 for bifenox were determined. A correlation analysis revealed the best match between the compound affinity to adsorb to macrophytes (expressed as K D_Adsorp) and their soil organic carbon-water partitioning coefficient (K OC) compared to their octanol-water partitioning coefficient (K OW) or a mathematically derived partitioning coefficient.

Sediment-to-Water Partition Coefficients: the Influence of Physicochemical and Seasonal Factors in Eastern Ontario

Energy Technology Data Exchange (ETDEWEB)

Yankovich, Tamara L. [International Atomic Energy Agency, P.O. Box 100, 1400 Vienna (Austria); Shultz, Carmen; Hartwig, Dale; Wills, C. Anne [Atomic Energy of Canada Limited, Chalk River Laboratories, Chalk River, Ontario, K0J 1J0 (Canada); Beresford, Nicholas A. [NERC Centre for Ecology and Hydrology, Lancaster Environment Center, Library Av., Bailrigg, Lancaster, LA1 4AP (United Kingdom); School of Environment and Life Sciences, University of Salford, Manchester, M4 4WT (United Kingdom); Wood, Michael D. [School of Environment and Life Sciences, University of Salford, Manchester, M4 4WT (United Kingdom)

2014-07-01

Sediments often represent an important reservoir for contaminants, such as radionuclides and metals, in aquatic ecosystems. Consequently, lake, stream, and river sediments can potentially act as significant contributors to the total contaminant exposure and radiological doses received by wildlife. Exposure to contaminated sediments is dependent upon several factors. These include net contaminant inputs to a system through time, the physicochemical attributes of the system, the tendency of each contaminant to partition into the sediments relative to water, the spatial distribution of contaminants in the sediments, and the behaviour or life-style of the biota inhabiting a water body. Increased understanding of such factors and their interactions will lead to improved predictions of the radionuclide exposure received by aquatic biota, particularly benthic organisms. Despite the complexity and the dynamic nature of sediments in general, for practical purposes, in environmental impact assessments (EIAs), it is often assumed that radionuclide activity concentrations in various compartments are at steady state with respect to one another. Therefore, ratios can be used to estimate concentrations in one compartment given a known concentration in another. In the case of sediments, sediment-to-water partition coefficients (K{sub d}) are often applied to estimate the contaminant concentration sorbed to particulate matter relative to the concentration measured in the surface water. However, K{sub d} values often range by several orders of magnitude between sampling locations due to site-specific differences in physicochemical conditions in surface waters, seasonal factors, as well as differences in sediment attributes that can affect contaminant partitioning between the dissolved and particulate phases. Consequently, in conducting EIAs, it becomes necessary to either apply generic K{sub d} values that ensure contaminant concentrations in sediments to which biota are exposed are

Determination of solid-liquid partition coefficients (Kd) for the herbicides isoproturon and trifluralin in five UK agricultural soils.

Science.gov (United States)

Cooke, Cindy M; Shaw, George; Collins, Chris D

2004-12-01

Isoproturon and trifluralin are herbicides of contrasting chemical characters and modes of action. Standard batch sorption procedures were carried out to investigate the individual sorption behaviour of 14C-isoproturon and 14C-trifluralin in five agricultural soils (1.8-4.2% OC), and the soil solid-liquid partition coefficients (Kd values) were determined. Trifluralin exhibited strong partitioning to the soil solid phase (Kd range 106-294) and low desorption potential, thus should not pose a threat to sensitive waters via leaching, although particle erosion and preferential flow pathways may facilitate transport. For isoproturon, soil adsorption was low (Kd range 1.96-5.75) and desorption was high, suggesting a high leaching potential, consistent with isoproturon being the most frequently found pesticide in UK surface waters. Soil partitioning was directly related to soil organic carbon (OC) content. Accumulation isotherms were modelled using a dual-phase adsorption model to estimate adsorption and desorption rate coefficients. Associations between herbicides and soil humic substances were also shown using gel filtration chromatography.

Effect of n-octanol on -uranyl extraction by tri-n-octylammonium sulfate

International Nuclear Information System (INIS)

Ochkin, A.V.; Kudrov, A.N.

1984-01-01

The effect of n-octanol on the extraction of uranyl sulfate by solutions of tri-n-octylamine sulfate in benzene has been studied. With the increase of alcohol concentration the coefficient of uranium distribution passes through the maximum. At low alcohol concentrations a decrease in water content in the organic phase is observed. It is shown that the increase in ammonium salt activity in replacement of part of hydrate At high alcohol concentration the decrease in uranium distribution coefficients is observed, which is related to TOA sulfate solvation by alcohol

A Systematic Methodology for Uncertainty Analysis of Group Contribution Based and Atom Connectivity Index Based Models for Estimation of Properties of Pure Components

DEFF Research Database (Denmark)

Hukkerikar, Amol; Sarup, Bent; Sin, Gürkan

, entropy of vaporization, surface tension, viscosity, flash point, auto ignition temperature, Hansen solubility parameters, Hildebrand solubility parameter, aqueous solubility, octanol/water partition coefficient, compressibility factor, molar volume, molar refraction, refractive index and lethal...

Ion-specific weak adsorption of salts and water/octanol transfer free energy of a model amphiphilic hexapeptide.

Science.gov (United States)

Déjugnat, Christophe; Dufrêche, Jean-François; Zemb, Thomas

2011-04-21

An amphiphilic hexapeptide has been used as a model to quantify how specific ion effects induced by addition of four salts tune the hydrophilic/hydrophobic balance and induce temperature-dependant coacervate formation from aqueous solution. The hexapeptide chosen is present as a dimer with low transfer energy from water to octanol. Taking sodium chloride as the reference state in the Hofmeister scale, we identify water activity effects and therefore measure the free energy of transfer from water to octanol and separately the free energy associated to the adsorption of chaotropic ions or the desorption of kosmotropic ions for the same amphiphilic peptide. These effects have the same order of magnitude: therefore, both energies of solvation as well as transfer into octanol strongly depend on the nature of the electrolytes used to formulate any buffer. Model peptides could be used on separation processes based on criteria linked to "Hofmeister" but different from volume and valency.

Octanol/water partitioning simulation by RP-HPLC for structurally diverse acidic drugs: comparison of three columns in the presence and absence of n-octanol as the mobile phase additive.

Science.gov (United States)

Giaginis, Costas; Theocharis, Stamatios; Tsantili-Kakoulidou, Anna

2013-12-01

The advantageous effect of n-octanol as a mobile phase additive for lipophilicity assessment of structurally diverse acidic drugs both in the neutral and ionized form was explored. Two RP C18 columns, ABZ+ and Aquasil, were used for the determination of logkw indices, and the results were compared with those previously reported on a base-deactivated silica column. At pH 2.5, the use of n-octanol-saturated buffer as the mobile phase aqueous component led to high-quality 1:1 correlation between logkw and logP for the ABZ+ column, while inferior statistics were obtained for Aquasil. At physiological pH, the correlations were significantly improved if strongly ionized acidic drugs were treated separately from weakly ionized ones. In the latter case, 1:1 correlations between logD7.4 and logkw(oct) indices were obtained in the presence of 0.25% n-octanol. Concerning strongly ionized compounds, adequate correlations were established under the same conditions; however, slopes were significantly lower than unity, while large negative intercepts were obtained. According to the absolute difference (diff = logD7.4 – logkw) pattern, base-deactivated silica showed a better performance than ABZ+, however, the latter seems more efficient for the lipophilicity assessment of highly lipophilic acidic compounds. Aquasil may be the column of choice if logD7.4<3 with the limitation, however, that very hydrophilic compounds cannot be measured.

Thermodynamic aspects of solubility and partitioning processes of some sulfonamides in the solvents modeling biological media

International Nuclear Information System (INIS)

Perlovich, German L.; Ryzhakov, Alex M.; Strakhova, Nadezda N.; Kazachenko, Vladimir P.; Schaper, Klaus-Jürgen; Raevsky, Oleg A.

2014-01-01

Highlights: • Solubility processes of some sulfonamide isomers in water and 1-octanol were investigated. • Transfer processes from water to 1-octanol were evaluated by analysis of enthalpic and entropic terms. • Impact of various substituents in phenyl rings on solubility and transfer processes was studied. -- Abstract: The thermodynamic aspects of solubility processes of sulfonamides (SAs) with the general structures 4-NH 2 –C 6 H 4 –SO 2 NH–C 6 H 2 (R 1 )(R 2 )-R 3 (R 1 = 2-CH 3 , 2-Cl; R 2 = 4-CH 3 , 4-Cl; R 3 =5-H, 5-Cl), 4-NH 2 -2-Cl–C 6 H 3 –SO 2 NH–C 6 H 3 (R 1 )-R 2 (R 1 = 2-H, 2-Cl; R 2 = 4-H, 4-Cl) and 4-NH 2 -2-CH 3 –C 6 H 3 –SO 2 NH–C 6 H 3 (R 1 )-R 2 (R 1 = 2-H, 2-Cl, 2-NO 2 ; R 2 = 4-H, 4-Cl) in water and 1-octanol (as phases modeling various drug delivery pathways) were studied using the isothermal saturation method. For the sulfonamides with various substituents in phenyl rings the processes of transfer from water to 1-octanol were studied by a diagram method combined with analysis of enthalpic and entropic terms. Distinguishing between enthalpy and entropy, as is possible through the present approach, leads to the insight that the contribution of these terms is different for different molecules (entropy- or enthalpy-determined). Thus, in contrast to the interpretation of only the Gibbs energy of transfer (extensively used for pharmaceuticals in the form of the partition coefficient, logP), the analysis of thermodynamic functions of the transfer process provides additional mechanistic information. This may be important for further evaluation of the physiological distribution of drug molecules and may provide a better understanding of biopharmaceutical properties of drugs

Heavy metal partitioning of suspended particulate matter-water and sediment-water in the Yangtze Estuary.

Science.gov (United States)

Feng, Chenghong; Guo, Xiaoyu; Yin, Su; Tian, Chenhao; Li, Yangyang; Shen, Zhenyao

2017-10-01

The partitioning of ten heavy metals (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, and Zn) between the water, suspended particulate matter (SPM), and sediments in seven channel sections during three hydrologic seasons in the Yangtze Estuary was comprehensively investigated. Special attention was paid to the role of tides, influential factors (concentrations of SPM and dissolved organic carbon, and particle size), and heavy metal speciation. The SPM-water and sediment-water partition coefficients (K p ) of the heavy metals exhibited similar changes along the channel sections, though the former were larger throughout the estuary. Because of the higher salinity, the K p values of most of the metals were higher in the north branch than in the south branch. The K p values of Cd, Co, and As generally decreased from the wet season to the dry season. Both the diagonal line method and paired samples t-test showed that no specific phase transfer of heavy metals existed during the flood and ebb tides, but the sediment-water K p was more concentrated for the diagonal line method, owing to the relatively smaller tidal influences on the sediment. The partition coefficients (especially the K p for SPM-water) had negative correlations with the dissolved organic carbon (DOC) but positive correlations were noted with the particle size for most of the heavy metals in sediment. Two types of significant correlations were observed between K p and metal speciation (i.e., exchangeable, carbonate, reducible, organic, and residual fractions), which can be used to identify the dominant phase-partition mechanisms (e.g., adsorption or desorption) of heavy metals. Copyright © 2017 Elsevier Ltd. All rights reserved.

Modulation of the partition coefficient between octanol and buffer at pH 7.4 and pKa to achieve the optimum balance of blood clearance and volume of distribution for a series of tetrahydropyran histamine type 3 receptor antagonists.

Science.gov (United States)

Hay, Tanya; Jones, Rhys; Beaumont, Kevin; Kemp, Mark

2009-09-01

The relationship between rat pharmacokinetics and physicochemical parameters [the partition coefficient between octanol and buffer at pH 7.4 (log D((7.4))) and pK(a)] was studied for a series of tetrahydropyran compounds. Sixteen compounds ranging in log D((7.4)) 0.1 to 1.8 were administered intravenously to rats, and the pharmacokinetic parameters were determined from blood concentration time curves. Across the series, a weak correlation was observed between log D((7.4)) and blood clearance, suggesting that log D((7.4)) values less than 0.5 were required to prevent clearance at hepatic blood flow. In terms of the volume of distribution (V(d)), the compounds fell into three distinct subseries characterized by the number of basic centers and differences in ionization of each basic center at physiological pH. These were referred to as the monobasic, weak second base, and strong second base subseries. All the compounds exhibited V(d) greater than body water, as would be expected from their lipophilic and basic nature. For a given clog P, the strong second base subseries showed higher V(d) than the weak second base subseries, which in turn exhibited higher values than the monobasic subseries. In addition, for the weak second base subseries, V(d) could be tuned by modulating the pK(a) of the second basic center. This relationship was rationalized in respect to the interactions of the ionizable centers with phospholipid heads in the cell membrane and/or lysosomal trapping. Compounds in the weak second base subseries showed optimal V(d), and when combined with a log D((7.4)) of 0.1, driving to moderate blood clearance, one compound showed the optimal pharmacokinetic profile.

Sediment pore water distribution coefficients of PCB congeners in enriched black carbon sediment

International Nuclear Information System (INIS)

Martinez, Andres; O'Sullivan, Colin; Reible, Danny; Hornbuckle, Keri C.

2013-01-01

More than 2300 sediment pore water distribution coefficients (K PCBids ) of 93 polychlorinated biphenyls (PCBs) were measured and modeled from sediments from Indiana Harbor and Ship Canal. K PCBids were calculated from previously reported bulk sediment values and newly analyzed pore water. PCBs in pore waters were measured using SPME PDMS-fiber and ∑PCB ranged from 41 to 1500 ng L −1 . The resulting K PCBids were ∼1 log unit lower in comparison to other reported values. A simple model for the K PCBid consisted of the product of the organic carbon fraction and the octanol–water partition coefficient and provided an excellent prediction for the measured values, with a mean square error of 0.09 ± 0.06. Although black carbon content is very high in these sediments and was expected to play an important role in the distribution of PCBs, no improvement was obtained when a two-carbon model was used. -- Highlights: •PCB sediment-pore water distribution coefficients were measured and modeled. •Distribution coefficients were lower in comparison to other reported values. •Organic carbon fraction times the K OW yielded the best prediction model. •The incorporation of black carbon into a model did not improve the results. -- The organic carbon fraction times the octanol–water partition coefficient yielded the best prediction model for the sediment pore water distribution coefficient of PCBs

Determination of solid-liquid partition coefficients (K{sub d}) for the herbicides inspiration and trifluralin in five UK agricultural soils

Energy Technology Data Exchange (ETDEWEB)

Cooke, Cindy M. [Department of Environmental Science and Technology, Faculty of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, Berkshire SL5 7PY (United Kingdom)]. E-mail: cindy.cooke@imperial.ac.uk; Shaw, George [Department of Environmental Science and Technology, Faculty of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, Berkshire SL5 7PY (United Kingdom); Collins, Chris D. [Department of Environmental Science and Technology, Faculty of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, Berkshire SL5 7PY (United Kingdom)

2004-12-01

Isoproturon and trifluralin are herbicides of contrasting chemical characters and modes of action. Standard batch sorption procedures were carried out to investigate the individual sorption behaviour of {sup 14}C-isoproturon and {sup 14}C-trifluralin in five agricultural soils (1.8-4.2% OC), and the soil solid-liquid partition coefficients (K{sub d} values) were determined. Trifluralin exhibited strong partitioning to the soil solid phase (K{sub d} range 106-294) and low desorption potential, thus should not pose a threat to sensitive waters via leaching, although particle erosion and preferential flow pathways may facilitate transport. For isoproturon, soil adsorption was low (K{sub d} range 1.96-5.75) and desorption was high, suggesting a high leaching potential, consistent with isoproturon being the most frequently found pesticide in UK surface waters. Soil partitioning was directly related to soil organic carbon (OC) content. Accumulation isotherms were modelled using a dual-phase adsorption model to estimate adsorption and desorption rate coefficients. Associations between herbicides and soil humic substances were also shown using gel filtration chromatography. - Capsule: Herbicide soil sorption described by a dual-phase adsorption model reflected soil partitioning, as influenced by soil OC and humic substances.

Ion-specific weak adsorption of salts and water/octanol transfer free energy of a model amphiphilic hexa-peptide

International Nuclear Information System (INIS)

Dejugnat, Ch.; Dufreche, J.F.; Zemb, Th.; Dejugnat, Ch.

2011-01-01

An amphiphilic hexa-peptide has been used as a model to quantify how specific ion effects induced by addition of four salts tune the hydrophilic/hydrophobic balance and induce temperature-dependant coacervate formation from aqueous solution. The hexa-peptide chosen is present as a dimer with low transfer energy from water to octanol. Taking sodium chloride as the reference state in the Hofmeister scale, we identify water activity effects and therefore measure the free energy of transfer from water to octanol and separately the free energy associated to the adsorption of chaotropic ions or the desorption of kosmotropic ions for the same amphiphilic peptide. These effects have the same order of magnitude: therefore, both energies of solvation as well as transfer into octanol strongly depend on the nature of the electrolytes used to formulate any buffer. Model peptides could be used on separation processes based on criteria linked to 'Hofmeister' but different from volume and valency. (authors)

Atmospheric concentration characteristics and gas-particle partitioning of PCBs in a rural area of eastern Germany

International Nuclear Information System (INIS)

Mandalakis, Manolis; Stephanou, Euripides G.

2007-01-01

Atmospheric concentrations of polychlorinated biphenyls (PCBs) were measured in 14 successive daytime and nighttime air samples collected from Melpitz, a rural site in eastern Germany. The average total concentration of PCBs was 110+/-80pgm -3 and they were predominately present in the gas phase (∼95%). Composition of individual congeners closely resembled those of Clophen A30 and Aroclor 1232. Partial vapor pressures of PCBs were well correlated with temperature and the steep slopes obtained from Clausius-Clapeyron plots (-4500 to -8000) indicated that evaporation from adjacent land surfaces still controls the atmospheric levels of these pollutants. Particle-gas partitioning coefficients (K P ) of PCBs were well correlated with the respective sub-cooled vapor pressures (P L o ), but the slopes obtained from logK P versus logP L o plots (-0.16 to -0.59) deviated significantly from the expected value of -1. Overall, gas-particle partitioning of PCBs was better simulated by Junge-Pankow than octanol/air partition coefficient-based model

Protometric thermometric titrations of sparingly soluble compounds in water in the presence of n-octanol.

Science.gov (United States)

Burgot, G; Burgot, J-L

2002-10-15

Thermometric titrimetry permits titration of acido-basic compounds in water in the presence of n-octanol. n-Octanol permits the solubilization of protolytes and moreover may also displace the equilibria of the titration reactions. Hydrochlorides of highly insoluble derivatives such as phenothiazine derivatives can be titrated with satisfactory accuracy and precision by sodium hydroxide despite their high pK(a) values. Likewise barbiturate salts can be titrated by hydrochloric acid. In the case of some salts, the methodology may permit the sequential titration of the ion and counter ion. Copyright 2002 Elsevier Science B.V.

The evaluation of the equilibrium partitioning method using sensitivity distributions of species in water and soil or sediment

NARCIS (Netherlands)

Beelen P van; Verbruggen EMJ; Peijnenburg WJGM; ECO

2002-01-01

The equilibrium partitioning method (EqP-method) can be used to derive environmental quality standards (like the Maximum Permissible Concentration or the intervention value) for soil or sediment, from aquatic toxicity data and a soil/water or sediment/water partitioning coefficient. The validity of

Soil microbial toxicity of eight polycyclic aromatic compounds: effects on nitrification, the genetic diversity of bacteria, and the total number of protozoans

DEFF Research Database (Denmark)

Sverdrup, Line Emilie; Ekelund, Flemming; Krogh, Paul Henning

2002-01-01

mg/kg. For effects on nitrification, toxicity (NOEC values) expressed as soil pore-water concentrations (log10(micromol/L)) showed a significant inverse relationship with lipophilicity (log octanol-water partition coefficient) of the substances (r2 = 0.69, p = 0.011, n = 8). This finding could...

Group-contribution⁺ (GC⁺) based estimation of properties of pure components: Improved property estimation and uncertainty analysis

DEFF Research Database (Denmark)

Hukkerikar, Amol; Sarup, Bent; Ten Kate, Antoon

2012-01-01

, Hansen solubility parameters, Hildebrand solubility parameter, octanol/water partition coefficient, acentric factor, and liquid molar volume at 298 K. Important issues related to property modeling such as reliability and predictive capability of the property prediction models, and thermodynamic...

Determination of the tissue-to-blood partition coefficient for 131iodo-antipyrine in human subcutaneous adipose tissue

DEFF Research Database (Denmark)

Jelnes, R; Astrup, A

1985-01-01

131Iodo-antipyrine (131I-AP) is commonly used for blood flow measurements in adipose tissue. These estimations have been based on the assumption of the tissue-to-blood partition coefficient being 1 ml g-1. No exact determination of the tissue-to-blood partition coefficient for 131I-AP in adipose...... tissue has been carried out. In the present study a partition coefficient of 1.12 +/- 0.06 (mean +/- S.D.) for 131I-AP in adipose tissue has been determined based on the partition coefficient for 131I-AP between lipid-saline (1.24 ml g-1), red blood cells-plasma (0.64 ml g-1), protein-saline (0.19 ml g-1...

Three-parameter modeling of the soil sorption of acetanilide and triazine herbicide derivatives.

Science.gov (United States)

Freitas, Mirlaine R; Matias, Stella V B G; Macedo, Renato L G; Freitas, Matheus P; Venturin, Nelson

2014-02-01

Herbicides have widely variable toxicity and many of them are persistent soil contaminants. Acetanilide and triazine family of herbicides have widespread use, but increasing interest for the development of new herbicides has been rising to increase their effectiveness and to diminish environmental hazard. The environmental risk of new herbicides can be accessed by estimating their soil sorption (logKoc), which is usually correlated to the octanol/water partition coefficient (logKow). However, earlier findings have shown that this correlation is not valid for some acetanilide and triazine herbicides. Thus, easily accessible quantitative structure-property relationship models are required to predict logKoc of analogues of the these compounds. Octanol/water partition coefficient, molecular weight and volume were calculated and then regressed against logKoc for two series of acetanilide and triazine herbicides using multiple linear regression, resulting in predictive and validated models.

Description, Properties, and Degradation of Selected Volatile Organic Compounds Detected in Ground Water--A Review of Selected Literature

Science.gov (United States)

Lawrence, Stephen J.

2006-01-01

This report provides abridged information describing the most salient properties and biodegradation of 27 chlorinated volatile organic compounds detected during ground-water studies in the United States. This information is condensed from an extensive list of reports, papers, and literature published by the U.S. Government, various State governments, and peer-reviewed journals. The list includes literature reviews, compilations, and summaries describing volatile organic compounds in ground water. This report cross-references common names and synonyms associated with volatile organic compounds with the naming conventions supported by the International Union of Pure and Applied Chemistry. In addition, the report describes basic physical characteristics of those compounds such as Henry's Law constant, water solubility, density, octanol-water partition (log Kow), and organic carbon partition (log Koc) coefficients. Descriptions and illustrations are provided for natural and laboratory biodegradation rates, chemical by-products, and degradation pathways.

Sediment-porewater partition of polycyclic aromatic hydrocarbons (PAHs) from Lanzhou Reach of Yellow River, China

Energy Technology Data Exchange (ETDEWEB)

Yu Yong [Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin 300071 (China); Xu Jian, E-mail: xujian@nankai.edu.cn [Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin 300071 (China); Wang Ping; Sun Hongwen; Dai Shugui [Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin 300071 (China)

2009-06-15

Pollution of polycyclic aromatic hydrocarbons (PAHs) in the aquatic environment has drawn much attention around the world. The occurrence of 16 priority PAHs in the sediments and corresponding porewaters in Lanzhou Reach of Yellow River, China, and their partitioning behavior between the two phases were investigated. The results demonstrated that the total PAH levels in the sediments were positively correlated with the sediment clay contents (R{sup 2} = 0.756). Concentrations of total PAHs in porewaters ranged from 48.2 to 206 {mu}g/L, and indeno[1,2,3-cd]pyrene (InP) was the most abundant compound measured in the porewater samples with a mean value of 42.9 {mu}g/L. The compositions of PAHs in porewaters were dominated by their compositions in the sediment samples. The in situ organic carbon normalized partition coefficients (logK{sub oc}{sup '}) of the PAHs between sediments and porewaters were significantly correlated with their octanol-water partition coefficients (log K{sub ow}) when log K{sub ow} values were less than 5.5 (naphthalene (Nap) excluded). logK{sub oc}{sup '} values of 14 PAHs were lower than those predicted by the Karickhoff relationship. This discrepancy was largest for InP, dibenzo[a,h]anthracene (DBA), and benzo[ghi]perylene (BgP). The results in present study showed the tendency of PAHs release from sediment to porewater, indicating that PAHs sequestered in the sediments may be a pollution source to aquatic ecosystem.

40 CFR 799.5085 - Chemical testing requirements for certain high production volume chemicals.

Science.gov (United States)

2010-07-01

... Ave., NW., Washington, DC or at the National Archives and Records Administration (NARA). For...) Method B: ASTM E 1147 (liquid chromatography) Method C: 40 CFR 799.6756 (generator column) 5. Water... (generator column) n-Octanol/water Partition Coefficient or log Kow:Which method is required, if any, is...

Strong binding of apolar hydrophobic organic contaminants by dissolved black carbon released from biochar: A mechanism of pseudomicelle partition and environmental implications.

Science.gov (United States)

Fu, Heyun; Wei, Chenhui; Qu, Xiaolei; Li, Hui; Zhu, Dongqiang

2018-01-01

Dissolved black carbon (DBC), the soluble fraction of black carbon (BC), is an important constituent of dissolved organic matter pool. However, little is known about the binding interactions between hydrophobic organic contaminants (HOCs) and DBC and their significance in the fate process. This study determined the binding ability of DBC released from rice-derived BC for a series of apolar HOCs, including four polycyclic aromatic hydrocarbons and four chlorinated benzenes, using batch sorption and solubility enhancement techniques. Bulk BC and a dissolved soil humic acid (DSHA) were included as benchmark sorbents. The organic carbon-normalized sorption coefficient of phenanthrene to DBC was slightly lower than bulk BC, but was over ten folds higher than DSHA. Consistently, DBC was more effective than DSHA in enhancing the apparent water solubility of the tested HOCs, and the enhancement positively correlated with solute n-octanol-water partition coefficient, indicating the predominance of hydrophobic partition. The much higher binding ability of DBC relative to DSHA was mainly attributed to its higher tendency to form pseudomicellar structures as supported by the fluorescence quenching and the pH-edge data. Our findings suggest that DBC might play a significant role in the environmental fate and transport of HOCs as both sorbent and carrier. Copyright © 2017 Elsevier Ltd. All rights reserved.

Stabilization of two-phase octanol/water flows inside poly(dimethylsiloxane) microchannels using polymer coatings

NARCIS (Netherlands)

van der Linden, H. J.; Jellema, L. C.; Holwerda, M.; Verpoorte, E.

In this paper we present our first results on the realization of stable water/octanol, two-phase flows inside poly(dimethylsiloxane) (PDMS) microchannels. Native PDMS microchannels were coated with high molecular weight polymers to change the surface properties of the microchannels and thus

Updated Abraham solvation parameters for polychlorinated biphenyls

NARCIS (Netherlands)

Noort, van P.C.M.; Haftka, J.J.H.; Parsons, J.R.

2010-01-01

This study shows that the recently published polychlorinated biphenyl (PCB) Abraham solvation parameters predict PCB air-n-hexadecane and n-octanol-water partition coefficients very poorly, especially for highly ortho-chlorinated congeners. Therefore, an updated set of PCB solvation parameters was

Measured and numerically partitioned phytoplankton spectral absorption coefficients in inland waters

NARCIS (Netherlands)

Zhang, Y.; Liu, M.; Van Dijk, M.A.; Zhu, G.; Gong, Z.; Li, Y.M.; Qin, B.

2009-01-01

Total particulate, tripton and phytoplankton absorption coefficients were measured for eutrophic (Lake Taihu), meso-eutrophic (Lake Tianmuhu) and mesotrophic waters (the Three Gorges Reservoir) in China using the quantitative filter technique. Meanwhile, tripton and phytoplankton absorption

Analysis of polyethoxylated surfactants in microemulsion-oil-water systems III. Fractionation and partitioning of polyethoxylated alcohol surfactants

International Nuclear Information System (INIS)

Marquez, N.; Bravo, B.; Ysambertt, F.; Chavez, G.; Subero, N.; Salager, J.L.

2002-01-01

Oligomer distribution of polyethoxylated alcohol and polyethoxylated nonylphenol surfactants is studied by normal and reverse-phase high performance liquid chromatography (HPLC). A RP8 column is able to efficiently separate these surfactants according to their alkyl chain (lipophilic) group, while silica and amino columns separate them according to their polyether chain length (hydrophilic group). Polyethoxylated alcohol and polyethoxylated nonylphenol oligomers selectively partition between the microemulsion-oil-water phases of a Winsor III system. Partitioning of these oligomers was analyzed by HPLC with RI detection. The logarithm of the partition coefficient between the water and oil linearly increases with the number of ethylene oxide groups per molecule of oligomer. For a same ethoxylation degree, the partition coefficient of a polyethoxylated tridecanol is found to be higher than the one of the corresponding nonylphenol specie. On the other hand, a polyethoxylated nonylphenol exhibits a higher solubilization than the matching polyethoxylated alcohol

Summer-winter concentrations and gas-particle partitioning of short chain chlorinated paraffins in the atmosphere of an urban setting.

Science.gov (United States)

Wang, Thanh; Han, Shanlong; Yuan, Bo; Zeng, Lixi; Li, Yingming; Wang, Yawei; Jiang, Guibin

2012-12-01

Short chain chlorinated paraffins (SCCPs) are semi-volatile chemicals that are considered persistent in the environment, potential toxic and subject to long-range transport. This study investigates the concentrations and gas-particle partitioning of SCCPs at an urban site in Beijing during summer and wintertime. The total atmospheric SCCP levels ranged 1.9-33.0 ng/m(3) during wintertime. Significantly higher levels were found during the summer (range 112-332 ng/m(3)). The average fraction of total SCCPs in the particle phase (ϕ) was 0.67 during wintertime but decreased significantly during the summer (ϕ = 0.06). The ten and eleven carbon chain homologues with five to eight chlorine atoms were the predominant SCCP formula groups in air. Significant linear correlations were found between the gas-particle partition coefficients and the predicted subcooled vapor pressures and octanol-air partition coefficients. The gas-particle partitioning of SCCPs was further investigated and compared with both the Junge-Pankow adsorption and K(oa)-based absorption models. Copyright © 2012 Elsevier Ltd. All rights reserved.

Research Article

African Journals Online (AJOL)

2018-01-01

Jan 1, 2018 ... ferrocene derivatives and potentially all analogous organometallic compounds. The results confirm the utility of use of square wave voltammetry techniques for measuring octanol-water partition coefficients of ferrocene derivatives. 5. ACKNOWLEDGEMENT. This research was financed by the laboratory of ...

Field determination and QSPR prediction of equilibrium-status soil/vegetation partition coefficient of PCDD/Fs.

Science.gov (United States)

Li, Li; Wang, Qiang; Qiu, Xinghua; Dong, Yian; Jia, Shenglan; Hu, Jianxin

2014-07-15

Characterizing pseudo equilibrium-status soil/vegetation partition coefficient KSV, the quotient of respective concentrations in soil and vegetation of a certain substance at remote background areas, is essential in ecological risk assessment, however few previous attempts have been made for field determination and developing validated and reproducible structure-based estimates. In this study, KSV was calculated based on measurements of seventeen 2,3,7,8-substituted PCDD/F congeners in soil and moss (Dicranum angustum), and rouzi grass (Thylacospermum caespitosum) of two background sites, Ny-Ålesund of the Arctic and Zhangmu-Nyalam region of the Tibet Plateau, respectively. By both fugacity modeling and stepwise regression of field data, the air-water partition coefficient (KAW) and aqueous solubility (SW) were identified as the influential physicochemical properties. Furthermore, validated quantitative structure-property relationship (QSPR) model was developed to extrapolate the KSV prediction to all 210 PCDD/F congeners. Molecular polarizability, molecular size and molecular energy demonstrated leading effects on KSV. Copyright © 2014 Elsevier B.V. All rights reserved.

Calculation of Physicochemical Properties for Short- and Medium-Chain Chlorinated Paraffins

Science.gov (United States)

Glüge, Juliane; Bogdal, Christian; Scheringer, Martin; Buser, Andreas M.; Hungerbühler, Konrad

2013-06-01

Short- and medium-chain chlorinated paraffins are potential PBT chemicals (persistent, bioaccumulative, toxic) and short-chain chlorinated paraffins are under review for inclusion in the UNEP Stockholm Convention on Persistent Organic Pollutants. Despite their high production volume of more than one million metric tonnes per year, only few data on their physicochemical properties are available. We calculated subcooled-liquid vapor pressure, subcooled-liquid solubility in water and octanol, Henry's law constant for water and octanol, as well as the octanol-water partition coefficient with the property calculation methods COSMOtherm, SPARC, and EPI Suite™, and compared the results to experimental data from the literature. For all properties, good or very good agreement between calculated and measured data was obtained for COSMOtherm; results from SPARC were in good agreement with the measured data except for subcooled-liquid water solubility, whereas EPI Suite™ showed the largest discrepancies for all properties. After critical evaluation of the three property calculation methods, a final set of recommended property data for short- and medium-chain chlorinated paraffins was derived. The calculated property data show interesting relationships with chlorine content and carbon chain length. Increasing chlorine content does not cause pronounced changes in water solubility and octanol-water partition coefficient (KOW) as long as it is below 55%. Increasing carbon chain length leads to strong increases in KOW and corresponding decreases in subcooled-liquid water solubility. The present data set can be used in further studies to assess the environmental fate and human exposure of this relevant compound class.

Estimation of the soil-water partition coefficient normalized to organic carbon for ionizable organic chemicals

DEFF Research Database (Denmark)

Franco, Antonio; Trapp, Stefan

2008-01-01

The sorption of organic electrolytes to soil was investigated. A dataset consisting of 164 electrolytes, composed of 93 acids, 65 bases, and six amphoters, was collected from literature and databases. The partition coefficient log KOW of the neutral molecule and the dissociation constant pKa were...... calculated by the software ACD/Labs®. The Henderson-Hasselbalch equation was applied to calculate dissociation. Regressions were developed to predict separately for the neutral and the ionic molecule species the distribution coefficient (Kd) normalized to organic carbon (KOC) from log KOW and pKa. The log...... KOC of strong acids (pKa correlated to these parameters. The regressions derived for weak acids and bases (undissociated at environmental pH) were similar. The highest sorption was found for strong bases (pKa > 7.5), probably due to electrical interactions. Nonetheless, their log KOC...

Quantitative structure-activity relationships for the toxicity and bioconcentration factor of nitrobenzene derivatives towards the guppy (Poecilia reticulata)

NARCIS (Netherlands)

Deneer, J.W.; Sinnige, T.L.; Seinen, W.; Hermens, J.L.M.

The acute toxicity and bioconcentration factor of a series of nitrobenzene derivatives was determined for the guppy. Toxicity is found to be determined by both hydrophobicity (expressed by the octanol/water partition coefficient) and rate of reduction of the nitro group (expressed by either

Rapid analysis of dissolved methane, ethylene, acetylene and ethane using partition coefficients and headspace-gas chromatography.

Science.gov (United States)

Lomond, Jasmine S; Tong, Anthony Z

2011-01-01

Analysis of dissolved methane, ethylene, acetylene, and ethane in water is crucial in evaluating anaerobic activity and investigating the sources of hydrocarbon contamination in aquatic environments. A rapid chromatographic method based on phase equilibrium between water and its headspace is developed for these analytes. The new method requires minimal sample preparation and no special apparatus except those associated with gas chromatography. Instead of Henry's Law used in similar previous studies, partition coefficients are used for the first time to calculate concentrations of dissolved hydrocarbon gases, which considerably simplifies the calculation involved. Partition coefficients are determined to be 128, 27.9, 1.28, and 96.3 at 30°C for methane, ethylene, acetylene, and ethane, respectively. It was discovered that the volume ratio of gas-to-liquid phase is critical to the accuracy of the measurements. The method performance can be readily improved by reducing the volume ratio of the two phases. Method validation shows less than 6% variation in accuracy and precision except at low levels of methane where interferences occur in ambient air. Method detection limits are determined to be in the low ng/L range for all analytes. The performance of the method is further tested using environmental samples collected from various sites in Nova Scotia.

Biocides from facade coatings in urban surface waters

DEFF Research Database (Denmark)

Bollmann, Ulla E; Styszko, Katarzyna; Ou, Yi

2015-01-01

catchment was performed in order to get knowledge about emission rates and processes. A first estimation of the leachability of a biocide is usually done using its octanol-water partition constant as well as water solubility. The present study introduces the possiblity of using the polyacrylate...

From emission to ecotoxicity: comparative assessment of fate and ecotoxicity in LCA using USEtox

DEFF Research Database (Denmark)

two orders of magnitude. However, for emission to air or soil, intermedia transfer and degradation may decrease the CF by up to 10 orders of magnitude. This result shows the importance of the Henry's law constant, the organic carbon and octanol-water partitioning coefficient, the degradation half...

Experimental determination of the partitioning coefficient of β-pinene oxidation products in SOAs.

Science.gov (United States)

Hohaus, Thorsten; Gensch, Iulia; Kimmel, Joel; Worsnop, Douglas R; Kiendler-Scharr, Astrid

2015-06-14

The composition of secondary organic aerosols (SOAs) formed by β-pinene ozonolysis was experimentally investigated in the Juelich aerosol chamber. Partitioning of oxidation products between gas and particles was measured through concurrent concentration measurements in both phases. Partitioning coefficients (Kp) of 2.23 × 10(-5) ± 3.20 × 10(-6) m(3) μg(-1) for nopinone, 4.86 × 10(-4) ± 1.80 × 10(-4) m(3) μg(-1) for apoverbenone, 6.84 × 10(-4) ± 1.52 × 10(-4) m(3) μg(-1) for oxonopinone and 2.00 × 10(-3) ± 1.13 × 10(-3) m(3) μg(-1) for hydroxynopinone were derived, showing higher values for more oxygenated species. The observed Kp values were compared with values predicted using two different semi-empirical approaches. Both methods led to an underestimation of the partitioning coefficients with systematic differences between the methods. Assuming that the deviation between the experiment and the model is due to non-ideality of the mixed solution in particles, activity coefficients of 4.82 × 10(-2) for nopinone, 2.17 × 10(-3) for apoverbenone, 3.09 × 10(-1) for oxonopinone and 7.74 × 10(-1) for hydroxynopinone would result using the vapour pressure estimation technique that leads to higher Kp. We discuss that such large non-ideality for nopinone could arise due to particle phase processes lowering the effective nopinone vapour pressure such as diol- or dimer formation. The observed high partitioning coefficients compared to modelled results imply an underestimation of SOA mass by applying equilibrium conditions.

Retention prediction and hydrophobicity estimation of weak acidic compounds by reversed-phase liquid chromatography using acetic and perchloric acids as ion suppressors.

Science.gov (United States)

Han, Shu-ying; Ming, Xin; Qi, Zheng-chun; Sheng, Dong; Lian, Hong-zhen

2010-11-01

Simple acids are usually applied to suppress the ionization of weakly ionizable acidic analytes in reversed-phase liquid chromatography. The purpose of this study is to investigate the retention behavior of various weak acidic compounds (monoprotic, diprotic, triprotic, and tetraprotic acids) using acetic or perchloric acid as ion suppressor in a binary hydroorganic mobile phase. The apparent n-octanol-water partition coefficient (K(ow)") was proposed to calibrate the n-octanol-water partition coefficient (K(ow)) of weak acidic compound. LogK(ow)" was found to have a better linear correlation with logk(w), the logarithm of the retention factor obtained by extrapolating to neat aqueous fraction of the mobile phase, for all weakly ionizable acidic compounds. This straightforward relationship offers a potential medium for direct measurement of K(ow) data of weak acidic analytes and can be used to predict retention behavior of these compounds in the ion suppression reversed-phase liquid chromatographic mode.

Partition coefficients of methylated DNA bases obtained from free energy calculations with molecular electron density derived atomic charges.

Science.gov (United States)

Lara, A; Riquelme, M; Vöhringer-Martinez, E

2018-05-11

Partition coefficients serve in various areas as pharmacology and environmental sciences to predict the hydrophobicity of different substances. Recently, they have also been used to address the accuracy of force fields for various organic compounds and specifically the methylated DNA bases. In this study, atomic charges were derived by different partitioning methods (Hirshfeld and Minimal Basis Iterative Stockholder) directly from the electron density obtained by electronic structure calculations in a vacuum, with an implicit solvation model or with explicit solvation taking the dynamics of the solute and the solvent into account. To test the ability of these charges to describe electrostatic interactions in force fields for condensed phases, the original atomic charges of the AMBER99 force field were replaced with the new atomic charges and combined with different solvent models to obtain the hydration and chloroform solvation free energies by molecular dynamics simulations. Chloroform-water partition coefficients derived from the obtained free energies were compared to experimental and previously reported values obtained with the GAFF or the AMBER-99 force field. The results show that good agreement with experimental data is obtained when the polarization of the electron density by the solvent has been taken into account, and when the energy needed to polarize the electron density of the solute has been considered in the transfer free energy. These results were further confirmed by hydration free energies of polar and aromatic amino acid side chain analogs. Comparison of the two partitioning methods, Hirshfeld-I and Minimal Basis Iterative Stockholder (MBIS), revealed some deficiencies in the Hirshfeld-I method related to the unstable isolated anionic nitrogen pro-atom used in the method. Hydration free energies and partitioning coefficients obtained with atomic charges from the MBIS partitioning method accounting for polarization by the implicit solvation model

Determination of Partition Coefficients of Selected Model Migrants between Polyethylene and Polypropylene and Nanocomposite Polypropylene

Directory of Open Access Journals (Sweden)

Pablo Otero-Pazos

2016-01-01

Full Text Available Studies on nanoparticles have focused the attention of the researchers because they can produce nanocomposites that exhibit unexpected hybrid properties. Polymeric materials are commonly used in food packaging, but from the standpoint of food safety, one of the main concerns on the use of these materials is the potential migration of low molecular substances from the packaging into the food. The key parameters of this phenomenon are the diffusion and partition coefficients. Studies on migration from food packaging with nanomaterials are very scarce. This study is focused on the determination of partition coefficients of different model migrants between the low-density polyethylene (LDPE and polypropylene (PP and between LDPE and nanocomposite polypropylene (naPP. The results show that the incorporation of nanoparticles in polypropylene increases the mass transport of model migrants from LDPE to naPP. This quantity of migrants absorbed into PP and naPP depends partially on the nature of the polymer and slightly on the chemical features of the migrant. Relation (RPP/naPP between partition coefficient KLDPE/PP and partition coefficient KLDPE/naPP at 60°C and 80°C shows that only BHT at 60°C has a RPP/naPP less than 1. On the other hand, bisphenol A has the highest RPP/naPP with approximately 50 times more.

Aquatic ecotoxicological indicators in life cycle assessment

DEFF Research Database (Denmark)

Pennington, David W.; Payet, Jerome; Hauschild, Michael Zwicky

2004-01-01

available methods, without the need to describe the entire SSDs and without the need for additional data. For example, the octanol-water partitioning coefficient provides a sufficient estimation basis for about 50% of existing chemicals that have a narcosis mode of action. This is also relevant in LCA...

Utilization of prodrugs to enhance the transdermal absorption of morphine

DEFF Research Database (Denmark)

Drustrup, J.; Fullerton, A.; Christrup, Lona Louring

1991-01-01

. The esters showed generally a higher water and lipid solubility than morphine and were also much more lipophilic than the parent drug in terms of octanol-buffer partition coefficients. Diffusion experiments in vitro using human skin samples showed that whereas morphine did not penetrate the skin to any...

JCSC_128_7_1163_1173_SI.docx

Indian Academy of Sciences (India)

head

a. Data set molecules and designed molecules. b. Predicted octanol/water partition coefficient log P. c. Predicted aqueous solubility's in mol/L. d. Predicted BBB permeability. e. Predicted Caco cell permeability in nm/s. f. Predicted apparent MDCK cell permeability in nm/s. g. Percentage of human oral absorption.

Determination of the pK values of 5-aminosalicylic acid and N-acetylaminosalicylic acid and comparison of the pH dependent lipid-water partition coefficients of sulphasalazine and its metabolites.

Science.gov (United States)

Allgayer, H; Sonnenbichler, J; Kruis, W; Paumgartner, G

1985-01-01

Sulphasalazine (SASP), used in the treatment of inflammatory bowel disease, is split into sulphapyridine (SP) and 5-aminosalicylic acid (5-ASA) in the colon. Lower plasma levels of SASP and 5-ASA as compared to those of SP may be due to different absorption rates from the colon because of different pK values and pH dependent lipid-water partition coefficients. In this study we determined the pK values of 5-ASA and its major metabolite, N-acetyl amino-salicylic acid (AcASA), by 13C-NMR spectroscopy and compared the pH dependent apparent benzene-water partition coefficients (Papp) of SASP, SP and 5-ASA with respect to their different plasma levels. The COOH group of 5-ASA had a pK value of 3.0, the -NH3+ group had 6.0, the -OH group 13.9; the -COOH group of AcASA had 2.7 and the -OH group 12.9; The Papp of SASP (0.042 +/- 0.004) and 5-ASA (0.059 +/- 0.01) were significantly lower than that of SP (0.092 +/- 0.03) (at pH 5.5).

Influence of microorganism content in suspended particles on the particle–water partitioning of mercury in semi-enclosed coastal waters

International Nuclear Information System (INIS)

Jang, Jiyi; Kim, Hyunji; Han, Seunghee

2014-01-01

It is known that particle scavenging of mercury (Hg) can be affected by the abundance of particulate organic matter in coastal waters. However, the role of living organic particles in Hg scavenging is not yet completely understood. In this study, we hypothesized that an abundance of living organic particles (i.e., phytoplankton and bacteria) would influence the particle–water partitioning of Hg in coastal waters. Surface seawater samples were collected from eight stations in Gwangyang Bay, Korea, in three seasons (November 2009, April 2010, and October 2010) for the determination of concentrations of suspended particulate matter (including chlorophyll-a and bacteria), and Hg in unfiltered and filtered waters. We found that more Hg partitioned toward particulate matter when phytoplankton biomass, indicated from the chlorophyll-a concentration in a particle, was higher. In the low algal season, when [chlorophyll-a] −1 , the bacterial number, instead of chlorophyll-a concentration in particle, showed a positive correlation with the particle–water partition coefficient of Hg. Overall, microbial abundance seems to play a critical role in particle scavenging of Hg in coastal water. Taking this result in light of Hg in pristine coastal zones, we predict that increases in algal biomass amplify the potential for algae to transfer Hg to marine food chains. - Highlights: • Abundance of phytoplankton and bacteria influenced particle–water partitioning of Hg. • More Hg partitioned toward particles when microorganism biomass in particle is large. • Increases of algal biomass may enhance Hg bioaccumulation in coastal ecosystem

Influence of microorganism content in suspended particles on the particle–water partitioning of mercury in semi-enclosed coastal waters

Energy Technology Data Exchange (ETDEWEB)

Jang, Jiyi [School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (Korea, Republic of); Global Bioresources Research Center, Korea Institute of Ocean Science and Technology (KIOST), Ansan 426-744 (Korea, Republic of); Kim, Hyunji [School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (Korea, Republic of); Han, Seunghee, E-mail: shan@gist.ac.kr [School of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (Korea, Republic of)

2014-02-01

It is known that particle scavenging of mercury (Hg) can be affected by the abundance of particulate organic matter in coastal waters. However, the role of living organic particles in Hg scavenging is not yet completely understood. In this study, we hypothesized that an abundance of living organic particles (i.e., phytoplankton and bacteria) would influence the particle–water partitioning of Hg in coastal waters. Surface seawater samples were collected from eight stations in Gwangyang Bay, Korea, in three seasons (November 2009, April 2010, and October 2010) for the determination of concentrations of suspended particulate matter (including chlorophyll-a and bacteria), and Hg in unfiltered and filtered waters. We found that more Hg partitioned toward particulate matter when phytoplankton biomass, indicated from the chlorophyll-a concentration in a particle, was higher. In the low algal season, when [chlorophyll-a] < 0.6 μg L{sup −1}, the bacterial number, instead of chlorophyll-a concentration in particle, showed a positive correlation with the particle–water partition coefficient of Hg. Overall, microbial abundance seems to play a critical role in particle scavenging of Hg in coastal water. Taking this result in light of Hg in pristine coastal zones, we predict that increases in algal biomass amplify the potential for algae to transfer Hg to marine food chains. - Highlights: • Abundance of phytoplankton and bacteria influenced particle–water partitioning of Hg. • More Hg partitioned toward particles when microorganism biomass in particle is large. • Increases of algal biomass may enhance Hg bioaccumulation in coastal ecosystem.

ESTIMATION OF OCTANOL/WATER PARTITION COEFFICIENTS USING LSER PARAMETERS. (R825370C064)

Science.gov (United States)

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

A study of the potential interaction of valsartan with some electrolytes

African Journals Online (AJOL)

The effect of electrolytes (salts) on the partition coefficient of valsartan was studied at room temperature. The investigation was done by partitioning valsartan between 1-octanol and electrolyte solutions of varying concentrations. It was found that all the electrolytes increased the partition coefficient of the drug except sodium ...

The complex formation-partition and partition-association models of solvent extraction of ions

International Nuclear Information System (INIS)

Siekierski, S.

1976-01-01

Two models of the extraction process have been proposed. In the first model it is assumed that the partitioning neutral species is at first formed in the aqueous phase and then transferred into the organic phase. The second model is based on the assumption that equivalent amounts of cations are at first transferred from the aqueous into the organic phase and then associated to form a neutral molecule. The role of the solubility parameter in extraction and the relation between the solubility of liquid organic substances in water and the partition of complexes have been discussed. The extraction of simple complexes and complexes with organic ligands has been discussed using the first model. Partition coefficients have been calculated theoretically and compared with experimental values in some very simple cases. The extraction of ion pairs has been discussed using the partition-association model and the concept of single-ion partition coefficients. (author)

Extraction of fluoride metal complexes by octanols

International Nuclear Information System (INIS)

Baklanova, I.V.; Nikolaev, A.I.; Il'in, E.G.; Majorov, V.G.

2005-01-01

The extraction of niobium(V) and tantalum(V) by octanols, including 1-octanol, 2-octanol, and iso-octanol (2-ethylhexanol), was studied. The composition of the octanols and their solubility in various aqueous solutions were evaluated. The capacity of the octanols for tantalum(V) and niobium(V), the extraction properties of the octanols, the viscosity of extracts under conditions of metal fluoride extraction, and the temperature dependence of the viscosity of the octanols were studied. The composition of the extracted complexes was studied by IR and NMR spectroscopy and chemical analysis, and the hydration-solvation mechanism of the extraction of tantalum(V) and niobium(V) was supported [ru

Distribution of polycyclic aromatic hydrocarbons in water and surface sediments from Daya Bay, China

International Nuclear Information System (INIS)

Zhou, J.L.; Maskaoui, K.

2003-01-01

Findings indicate an urgent need to establish a monitoring program for persistent organic pollutants in water and sediment. - Marine culture is thriving in China and represents a major component of the regional economy in coastal zones, yet the environmental quality of many of those areas has never been studied. This paper attempts to investigate the quality status of Daya Bay, a key aquaculture area in China. The levels of 16 polycyclic aromatic hydrocarbons (PAHs) were determined in water and sediment samples of the bay. The total concentrations of 16 PAHs varied from 4228 to 29325 ng l -1 in water, and from 115 to 1134 ng g -1 dry weight in sediments. In comparison to many other marine systems studied, the PAH levels in Daya Bay waters were relatively high, and at six sites they were sufficiently high (>10 μg l -1 ) to cause acute toxicity. The PAH composition pattern in sediments suggest dominance by medium to high molecular weight compounds, and the ratio of certain related PAHs indicate important pyrolytic and petrogenic sources. Further analysis showed that the distribution coefficient (K D ) increased with the particular organic carbon content of sediments, consistent with the PAH partition theory. The organic carbon normalised distribution coefficient (K oc ) also increased with the compounds' octanol/water partition coefficient (K ow ), confirming the potential applicability of the linear free energy relationships in the modelling and prediction of PAH behaviour in marine environments

A layer model of ethanol partitioning into lipid membranes.

Science.gov (United States)

Nizza, David T; Gawrisch, Klaus

2009-06-01

The effect of membrane composition on ethanol partitioning into lipid bilayers was assessed by headspace gas chromatography. A series of model membranes with different compositions have been investigated. Membranes were exposed to a physiological ethanol concentration of 20 mmol/l. The concentration of membranes was 20 wt% which roughly corresponds to values found in tissue. Partitioning depended on the chemical nature of polar groups at the lipid/water interface. Compared to phosphatidylcholine, lipids with headgroups containing phosphatidylglycerol, phosphatidylserine, and sphingomyelin showed enhanced partitioning while headgroups containing phosphatidylethanolamine resulted in a lower partition coefficient. The molar partition coefficient was independent of a membrane's hydrophobic volume. This observation is in agreement with our previously published NMR results which showed that ethanol resides almost exclusively within the membrane/water interface. At an ethanol concentration of 20 mmol/l in water, ethanol concentrations at the lipid/water interface are in the range from 30-15 mmol/l, corresponding to one ethanol molecule per 100-200 lipids.

Atmospheric occurrence, transport and gas-particle partitioning of polychlorinated biphenyls over the northwestern Pacific Ocean

Science.gov (United States)

Wu, Zilan; Lin, Tian; Li, Zhongxia; Li, Yuanyuan; Guo, Tianfeng; Guo, Zhigang

2017-10-01

Ship-board air samples were collected during March to May 2015 from the East China Sea (ECS) to the northwestern Pacific Ocean (NWP) to explore the atmospheric occurrence and gas-particle partitioning of polychlorinated biphenyls (PCBs) when the westerly East Asian Monsoon prevailed. Total PCB concentrations in the atmosphere ranged from 56.8 to 261 pg m-3. Higher PCB levels were observed off the coast and minor temperature-induced changes showed that continuous emissions from East Asia remain as an important source to the regional atmosphere. A significant relationship between Koa (octanol-air partition coefficient) and KP (gas-particle partition coefficient) for PCBs was observed under continental air masses, suggesting that land-derived organic aerosols affected the PCB gas-particle partitioning after long-range transport, while an absence of this correlation was identified in marine air masses. The PCB partitioning cannot be fully explained by the absorptive mechanism as the predicted KP were found to be 2-3 orders of magnitude lower than the measured Kp, while the prediction was closely matched when soot adsorption was considered. The results suggested the importance of soot carbon as a transport medium for PCBs during their long-range transport and considerable impacts of continental outflows on PCBs across the downwind area. The estimated transport mass of particulate PCBs into the ECS and NWP totals 2333 kg during the spring, constituting ca. 17% of annual emission inventories of unintentionally produced PCB in China.

Solubility of DCH18C6 and n-octanol in nitric acid system

International Nuclear Information System (INIS)

He Qiange; Wang Jianchen; Chen Jing

2011-01-01

Equilibrium solubility of DCH18C6 and n-octanol in aqueous solution were determined by GC. And effects of temperature, concentration of Sr 2+ or HNO 3 were studied. The results indicate that solubility of DCH18C6 is substantial and make the crown ether continually drain from organic phase which could be 3% at most. As diluent, n-octanol could dissolve in water with certain quantity. So n-octanol, and then kerosene should be used to extract DCH18C6 and n-octanol from aqueous phase. Or toluene is taken to recover DCH18C6 and n-octanol at the same time. Above extractants could recover more than 99% of solute from aqueous solution in the volume ratio 1:1. (author)

The prediction of blood-tissue partitions, water-skin partitions and skin permeation for agrochemicals.

Science.gov (United States)

Abraham, Michael H; Gola, Joelle M R; Ibrahim, Adam; Acree, William E; Liu, Xiangli

2014-07-01

There is considerable interest in the blood-tissue distribution of agrochemicals, and a number of researchers have developed experimental methods for in vitro distribution. These methods involve the determination of saline-blood and saline-tissue partitions; not only are they indirect, but they do not yield the required in vivo distribution. The authors set out equations for gas-tissue and blood-tissue distribution, for partition from water into skin and for permeation from water through human skin. Together with Abraham descriptors for the agrochemicals, these equations can be used to predict values for all of these processes. The present predictions compare favourably with experimental in vivo blood-tissue distribution where available. The predictions require no more than simple arithmetic. The present method represents a much easier and much more economic way of estimating blood-tissue partitions than the method that uses saline-blood and saline-tissue partitions. It has the added advantages of yielding the required in vivo partitions and being easily extended to the prediction of partition of agrochemicals from water into skin and permeation from water through skin. © 2013 Society of Chemical Industry.

Bioconcentration factors and plant-water partition coefficients of munitions compounds in barley.

Science.gov (United States)

Torralba-Sanchez, Tifany L; Kuo, Dave T F; Allen, Herbert E; Di Toro, Dominic M

2017-12-01

Plants growing in the soils at military ranges and surrounding locations are exposed, and potentially able to uptake, munitions compounds (MCs). The extent to which a compound is transferred from the environment into organisms such as plants, referred to as bioconcentration, is conventionally measured through uptake experiments with field/synthetic soils. Multiple components/phases that vary among different soil types and affect the bioavailability of the MC, however, hinder the ability to separate the effects of soil characteristics from the MC chemical properties on the resulting plant bioconcentration. To circumvent the problem, this work presents a protocol to measure steady state bioconcentration factors (BCFs) for MCs in barley (Hordeum vulgare L.) using inert laboratory sand rather than field/synthetic soils. Three MCs: 2,4,6-trinitrotoluene (TNT), 2,4-dinitrotoluene (2,4-DNT), and 2,4-dinitroanisole (2,4-DNAN), and two munition-like compounds (MLCs): 4-nitroanisole (4-NAN) and 2-methoxy-5-nitropyridine (2-M-5-NPYNE) were evaluated. Approximately constant plant biomass and exposure concentrations were achieved within a one-month period that produced steady state log BCF values: 0.62 ± 0.02, 0.70 ± 0.03, 1.30 ± 0.06, 0.52 ± 0.03, and 0.40 ± 0.05 L kg plant dwt -1 for TNT, 2,4-DNT, 2,4-DNAN, 4-NAN, and 2-M-5-NPYNE, respectively. Furthermore, results suggest that the upper-bounds of the BCFs can be estimated within an order of magnitude by measuring the partitioning of the compounds between barley biomass and water. This highlights the importance of partition equilibrium as a mechanism for the uptake of MCs and MLCs by barley from interstitial water. The results from this work provide chemically meaningful data for prediction models able to estimate the bioconcentration of these contaminants in plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

Octanol reduces end-plate channel lifetime

Science.gov (United States)

Gage, Peter W.; McBurney, Robert N.; Van Helden, Dirk

1978-01-01

1. Post-synaptic effects of n-octanol at concentrations of 0·1-1 mM were examined in toad sartorius muscles by use of extracellular and voltage-clamp techniques. 2. Octanol depressed the amplitude and duration of miniature end-plate currents and hence depressed neuromuscular transmission. 3. The decay of miniature end-plate currents remained exponential in octanol solutions even when the time constant of decay (τD) was decreased by 80-90%. 4. The lifetime of end-plate channels, obtained by analysis of acetylcholine noise, was also decreased by octanol. The average lifetime measured from noise spectra agreed reasonably well with the time constant of decay of miniature end-plate currents, both in control solution and in octanol solutions. 5. Octanol caused a reduction in the conductance of end-plate channels. Single channel conductance was on average about 25 pS in control solution and 20 pS in octanol. 6. In most cells the normal voltage sensitivity of the decay of miniature end-plate currents was retained in octanol solutions. The lifetime of end-plate channels measured from acetylcholine noise also remained voltage-sensitive in octanol solutions. In some experiments in which channel lifetime was exceptionally reduced the voltage sensitivity was less than normal. 7. In octanol solutions, τD was still very sensitive to temperature changes in most cells although in some the temperature sensitivity of τD was clearly reduced. Changes in τD with temperature could generally be fitted by the Arrhenius equation suggesting that a single step reaction controlled the decay of currents both in control and in octanol solutions. In some cells in which τD became less than 0·3 ms, the relationship between τD and temperature became inconsistent with the Arrhenius equation. 8. As the decay of end-plate currents in octanol solutions remains exponential, and the voltage and temperature sensitivity can be unchanged even when τD is significantly reduced, it seems likely that

Determination of polydimethylsiloxane–water partition coefficients for ten 1-chloro-4-[2,2,2-trichloro-1-(4-chlorophenyl)ethyl]benzene-related compounds and twelve polychlorinated biphenyls using gas chromatography/mass spectrometry

Science.gov (United States)

Eganhouse, Robert P.

2016-01-01

Polymer-water partition coefficients (Kpw) of ten DDT-related compounds were determined in pure water at 25 °C using commercial polydimethylsiloxane-coated optical fiber. Analyte concentrations were measured by thermal desorption-gas chromatography/full scan mass spectrometry (TD–GC/MSFS; fibers) and liquid injection-gas chromatography/selected ion monitoring mass spectrometry (LI–GC/MSSIM; water). Equilibrium was approached from two directions (fiber uptake and depletion) as a means of assessing data concordance. Measured compound-specific log Kpw values ranged from 4.8 to 6.1 with an average difference in log Kpw between the two approaches of 0.05 log units (∼12% of Kpw). Comparison of the experimentally-determined log Kpw values with previously published data confirmed the consistency of the results and the reliability of the method. A second experiment was conducted with the same ten DDT-related compounds and twelve selected PCB (polychlorinated biphenyl) congeners under conditions characteristic of a coastal marine field site (viz., seawater, 11 °C) that is currently under investigation for DDT and PCB contamination. Equilibration at lower temperature and higher ionic strength resulted in an increase in log Kpw for the DDT-related compounds of 0.28–0.49 log units (61–101% of Kpw), depending on the analyte. The increase in Kpw would have the effect of reducing by approximately half the calculated freely dissolved pore-water concentrations (Cfree). This demonstrates the importance of determining partition coefficients under conditions as they exist in the field.

Comparison of Aqueous and 1-Octanol Solubility as well as Liquid?Liquid Distribution of Acyclovir Derivatives and Their Complexes with Hydroxypropyl-?-Cyclodextrin

OpenAIRE

Ko?bia?, Ma?gorzata; Gierycz, Pawe?

2013-01-01

The aim of the presented work is the comparison of aqueous and 1-octanol solubilities of different acyclovir derivatives and their hydroxypropyl-?-cyclodextrin inclusion complexes. The solubility measurements were carried out at different temperatures over the range 25?45??C using water, 1-octanol, water saturated with 1-octanol, 1-octanol saturated with water, buffered aqueous solutions (pH?=?5.5 and 7.0) and buffered aqueous solutions containing cyclodextrin as solvents. The aqueous solubil...

REE Partition Coefficients from Synthetic Diogenite-Like Enstatite and the Implications of Petrogenetic Modeling

Science.gov (United States)

Schwandt, C. S.; McKay, G. A.

1996-01-01

Determining the petrogenesis of eucrites (basaltic achondrites) and diogenites (orthopyroxenites) and the possible links between the meteorite types was initiated 30 years ago by Mason. Since then, most investigators have worked on this question. A few contrasting theories have emerged, with the important distinction being whether or not there is a direct genetic link between eucrites and diogenites. One theory suggests that diogenites are cumulates resulting from the fractional crystallization of a parent magma with the eucrites crystallizing, from the residual magma after separation from the diogenite cumulates. Another model proposes that diogenites are cumulates formed from partial melts derived from a source region depleted by the prior generation of eucrite melts. It has also been proposed that the diogenites may not be directly linked to the eucrites and that they are cumulates derived from melts that are more orthopyroxene normative than the eucrites. This last theory has recently received more analytical and experimental support. One of the difficulties with petrogenetic modeling is that it requires appropriate partition coefficients for modeling because they are dependent on temperature, pressure, and composition. For this reason, we set out to determine minor- and trace-element partition coefficients for diogenite-like orthopyroxene. We have accomplished this task and now have enstatite/melt partition coefficients for Al, Cr, Ti, La, Ce, Nd, Sm, Eu, Dy, Er, Yb, and La.

Biotransformation model of neutral and weakly polar organic compounds in fish incorporating internal partitioning.

Science.gov (United States)

Kuo, Dave T F; Di Toro, Dominic M

2013-08-01

A model for whole-body in vivo biotransformation of neutral and weakly polar organic chemicals in fish is presented. It considers internal chemical partitioning and uses Abraham solvation parameters as reactivity descriptors. It assumes that only chemicals freely dissolved in the body fluid may bind with enzymes and subsequently undergo biotransformation reactions. Consequently, the whole-body biotransformation rate of a chemical is retarded by the extent of its distribution in different biological compartments. Using a randomly generated training set (n = 64), the biotransformation model is found to be: log (HLφfish ) = 2.2 (±0.3)B - 2.1 (±0.2)V - 0.6 (±0.3) (root mean square error of prediction [RMSE] = 0.71), where HL is the whole-body biotransformation half-life in days, φfish is the freely dissolved fraction in body fluid, and B and V are the chemical's H-bond acceptance capacity and molecular volume. Abraham-type linear free energy equations were also developed for lipid-water (Klipidw ) and protein-water (Kprotw ) partition coefficients needed for the computation of φfish from independent determinations. These were found to be 1) log Klipidw  = 0.77E - 1.10S - 0.47A - 3.52B + 3.37V + 0.84 (in Lwat /kglipid ; n = 248, RMSE = 0.57) and 2) log Kprotw  = 0.74E - 0.37S - 0.13A - 1.37B + 1.06V - 0.88 (in Lwat /kgprot ; n = 69, RMSE = 0.38), where E, S, and A quantify dispersive/polarization, dipolar, and H-bond-donating interactions, respectively. The biotransformation model performs well in the validation of HL (n = 424, RMSE = 0.71). The predicted rate constants do not exceed the transport limit due to circulatory flow. Furthermore, the model adequately captures variation in biotransformation rate between chemicals with varying log octanol-water partitioning coefficient, B, and V and exhibits high degree of independence from the choice of training chemicals. The

Treatment of Produced Waters Using a Surfactant Modified Zeolite/Vapor Phase Bioreactor System

Energy Technology Data Exchange (ETDEWEB)

Lynn E. Katz; Kerry A. Kinney; R. S. Bowman; E. J. Sullivan

2004-03-11

This report summarizes work of this project from October 2003 through March 2004. The major focus of the research was to further investigate BTEX removal from produced water, to quantify metal ion removal from produced water, and to evaluate a lab-scale vapor phase bioreactor (VPB) for BTEX destruction in off-gases produced during SMZ regeneration. Batch equilibrium sorption studies were conducted to evaluate the effect of semi-volatile organic compounds commonly found in produced water on the sorption of benzene, toluene, ethylbenzene, and xylene (BTEX) onto surfactant-modified zeolite (SMZ) and to examine selected metal ion sorption onto SMZ. The sorption of polar semi-volatile organic compounds and metals commonly found in produced water onto SMZ was also investigated. Batch experiments were performed in a synthetic saline solution that mimicked water from a produced water collection facility in Wyoming. Results indicated that increasing concentrations of semi-volatile organic compounds increased BTEX sorption. The sorption of phenol compounds could be described by linear isotherms, but the linear partitioning coefficients decreased with increasing pH, especially above the pKa's of the compounds. Linear correlations relating partitioning coefficients of phenol compounds with their respective solubilities and octanol-water partitioning coefficients were developed for data collected at pH 7.2. The sorption of chromate, selenate, and barium in synthetic produced water were also described by Langmuir isotherms. Experiments conducted with a lab-scale vapor phase bioreactor (VPB) packed with foam indicated that this system could achieve high BTEX removal efficiencies once the nutrient delivery system was optimized. The xylene isomers and benzene were found to require the greatest biofilter bed depth for removal. This result suggested that these VOCs would ultimately control the size of the biofilter required for the produced water application. The biofilter

Determination of Partition coefficients for a Mixture of Volatile Organic Compounds in Rats and Humans at Different Life Stages

National Research Council Canada - National Science Library

Mahle, Deidre A; Gearhart, Jeffrey M; Godfrey, Richard J; Mattie, David R; Cook, Robert S; Grisby, Claude C

2004-01-01

.... Partition coefficients (PCs) are an integral component of pharmacokinetic models and determining differences in tissue partitioning of volatile organic chemicals across life stages can help reduce the uncertainty in risk assessment...

The double isotope technique for in vivo determination of the tissue-to-blood partition coefficient for xenon in human subcutaneous adipose tissue--an evaluation

DEFF Research Database (Denmark)

Jelnes, Rolf; Astrup, A; Bülow, J

1985-01-01

the partition coefficient found by the double isotope technique, significantly lower values are obtained than if the in vitro determined coefficient is used. This difference is explained mainly by local dilution when injecting xenon subcutaneously. In short-term studies, utilization of the double isotope...... technique reduces the coefficient of variation on average flow determinations, thus an improvement in accuracy of local blood flow estimation can be obtained compared to the method in which an average partition coefficient is used. For long-term studies a partition coefficient of 7.5 ml g-1 seems valid.......Local subcutaneous 133xenon (133Xe) elimination was registered in the human forefoot in 34 patients. The tissue/blood partition coefficient for Xe was estimated individually by simultaneous registration of 133Xe and [131I]antipyrine ([131I]AP) washout from the same local depot. When measured...

Scanning tunnelling microscopy of a foldamer prototype at the liquid/solid interface : water/Au(111) versus 1-octanol/graphite

NARCIS (Netherlands)

Klymchenko, Andrey S.; Schuurmans, Norbert; van der Auweraer, Mark; Feringa, Ben L.; van Esch, Jan; De Feyter, Steven

2006-01-01

We report the design and synthesis of a catechol based foldamer containing amide functionalized alkyl chains, and its monolayer formation at the liquid/solid interface. By scanning tunnelling microscopy, both at the 1-octanol/graphite interface as well as at the water/Au( 111) interface, the

Contribution to the standardization of the chromatographic conditions for the lipophilicity assessment of neutral and basic drugs

Energy Technology Data Exchange (ETDEWEB)

Giaginis, Costas [Department of Pharmaceutical Chemistry, School of Pharmacy, University of Athens, Panepistimiopolis, Zografou, Athens 15771 (Greece); Department of Forensic Medicine and Toxicology, Medical School, University of Athens, 75 Mikras Asias Street, Athens 11527 (Greece); Theocharis, Stamatios [Department of Forensic Medicine and Toxicology, Medical School, University of Athens, 75 Mikras Asias Street, Athens 11527 (Greece); Tsantili-Kakoulidou, Anna [Department of Pharmaceutical Chemistry, School of Pharmacy, University of Athens, Panepistimiopolis, Zografou, Athens 15771 (Greece)]. E-mail: tsantili@pharm.uoa.gr

2006-07-28

The chromatographic conditions aiming to a better simulation of n-octanol-water partitioning using a base deactivated silica (BDS) column as stationary phase were investigated for structurally diverse basic and neutral drugs. Extrapolated retention factors log k{sub w}, determined using different methanol fractions as organic modifier, were considered as lipophilicity indices. The effect of n-decylamine and n-octanol as mobile phase additives was examined and the appropriateness of the final retention outcome to reproduce lipophilicity data was evaluated. Moreover, the influence of n-octanol on the linearity of the log k/methanol fraction relationship and on the uniformity of the retention mechanism was investigated. 1:1 correlation between log k{sub w} values and the logarithm of the distribution coefficient (log D) was established for basic drugs in presence of both n-decylamine and n-octanol as mobile phase additives. However, for neutral drugs n-decylamine proved to be a sufficient and more important factor than n-octanol.

Contribution to the standardization of the chromatographic conditions for the lipophilicity assessment of neutral and basic drugs

International Nuclear Information System (INIS)

Giaginis, Costas; Theocharis, Stamatios; Tsantili-Kakoulidou, Anna

2006-01-01

The chromatographic conditions aiming to a better simulation of n-octanol-water partitioning using a base deactivated silica (BDS) column as stationary phase were investigated for structurally diverse basic and neutral drugs. Extrapolated retention factors log k w , determined using different methanol fractions as organic modifier, were considered as lipophilicity indices. The effect of n-decylamine and n-octanol as mobile phase additives was examined and the appropriateness of the final retention outcome to reproduce lipophilicity data was evaluated. Moreover, the influence of n-octanol on the linearity of the log k/methanol fraction relationship and on the uniformity of the retention mechanism was investigated. 1:1 correlation between log k w values and the logarithm of the distribution coefficient (log D) was established for basic drugs in presence of both n-decylamine and n-octanol as mobile phase additives. However, for neutral drugs n-decylamine proved to be a sufficient and more important factor than n-octanol

Latex paint as a delivery vehicle for diethylphthalate and di-n-butylphthalate

DEFF Research Database (Denmark)

Schripp, Tobias; Salthammer, Tunga; Fauck, Christian

2014-01-01

gas-phase concentration at steady state(y). For both, DEP and DnBP, the y0 obtained was lower than the respective saturation vapor pressure (Ps). Furthermore, for both phthalates in latex paint, the material/air partition coefficient (C0/y0) was close in value to the octanol/air partition coefficient...

The influence of bile salts on the distribution of simvastatin in the octanol/buffer system.

Science.gov (United States)

Đanić, Maja; Pavlović, Nebojša; Stanimirov, Bojan; Vukmirović, Saša; Nikolić, Katarina; Agbaba, Danica; Mikov, Momir

2016-01-01

Distribution coefficient (D) is useful parameter for evaluating drugs permeability properties across biological membranes, which are of importance for drugs bioavailability. Given that bile acids are intensively studied as drug permeation-modifying and -solubilizing agents, the aim of this study was to estimate the influence of sodium salts of cholic (CA), deoxycholic (DCA) and 12-monoketocholic acids (MKC) on distribution coefficient of simvastatin (SV) (lactone [SVL] and acid form [SVA]) which is a highly lipophilic compound with extremely low water solubility and bioavailability. LogD values of SVA and SVL with or without bile salts were measured by liquid-liquid extraction in n-octanol/buffer systems at pH 5 and 7.4. SV concentrations in aqueous phase were determined by HPLC-DAD. Chem3D Ultra program was applied for computation of physico-chemical properties of analyzed compounds and their complexes. Statistically significant decrease in both SVA and SVL logD was observed for all three studied bile salts at both selected pH. MKC exerted the most pronounced effect in the case of SVA while there were no statistically significant differences between observed bile salts for SVL. The calculated physico-chemical properties of analyzed compounds and their complexes supported experimental results. Our data indicate that the addition of bile salts into the n-octanol/buffer system decreases the values of SV distribution coefficient at both studied pH values. This may be the result of the formation of hydrophilic complexes increasing the solubility of SV that could consequently impact the pharmacokinetic parameters of SV and the final drug response in patients.

Assessing the combined influence of TOC and black carbon in soil–air partitioning of PBDEs and DPs from the Indus River Basin, Pakistan

International Nuclear Information System (INIS)

Ali, Usman; Mahmood, Adeel; Syed, Jabir Hussain; Li, Jun; Zhang, Gan; Katsoyiannis, Athanasios; Jones, Kevin C.; Malik, Riffat Naseem

2015-01-01

Levels of polybrominated diphenyl ethers (PBDEs) and dechlorane plus (DPs) were investigated in the Indus River Basin from Pakistan. Concentrations of ∑PBDEs and ∑DPs were ranged between 0.05 and 2.38 and 0.002–0.53 ng g −1 in the surface soils while 1.43–22.1 and 0.19–7.59 pg m −3 in the passive air samples, respectively. Black carbon (f BC ) and total organic carbon (f TOC ) fractions were also measured and ranged between 0.73 and 1.75 and 0.04–0.2%, respectively. The statistical analysis revealed strong influence of f BC than f TOC on the distribution of PBDEs and DPs in the Indus River Basin soils. BDE's congener profile suggested the input of penta–bromodiphenylether (DE-71) commercial formulation in the study area. Soil–air partitioning of PBDEs were investigated by employing octanol-air partition coefficients (K OA ) and black carbon-air partition coefficients (K BC−A ). The results of both models suggested the combined influence of total organic carbon (absorption) and black carbon (adsorption) in the studied area. - Highlights: • Model based calculations of black carbon-air partition coefficients for PBDEs. • Soil and air levels of PBDEs and DPs reported first time for ecologically important sites of the Indus River Basin, Pakistan. • Both, f BC and f TOC showed combined influence on soil–air partitioning of PBDEs in the Indus River Basin, Pakistan. - BC and TOC showed combined influence on soil–air partitioning of POPs i-e., PBDEs in the Indus River Basin, Pakistan

Temperature dependence of the particle/gas partition coefficient: An application to predict indoor gas-phase concentrations of semi-volatile organic compounds

Energy Technology Data Exchange (ETDEWEB)

Wei, Wenjuan, E-mail: Wenjuan.Wei@cstb.fr [University of Paris-Est, Scientific and Technical Center for Building (CSTB), Health and Comfort Department, French Indoor Air Quality Observatory (OQAI), 84 Avenue Jean Jaurès, Champs sur Marne, 77447 Marne la Vallée Cedex 2 (France); Mandin, Corinne [University of Paris-Est, Scientific and Technical Center for Building (CSTB), Health and Comfort Department, French Indoor Air Quality Observatory (OQAI), 84 Avenue Jean Jaurès, Champs sur Marne, 77447 Marne la Vallée Cedex 2 (France); INSERM-U1085, Irset-Research Institute for Environmental and Occupational Health, Rennes (France); LERES-Environment and Health Research Laboratory (Irset and EHESP Technologic Platform), Rennes (France); Blanchard, Olivier [EHESP-School of Public Health, Sorbonne Paris Cité, Rennes (France); INSERM-U1085, Irset-Research Institute for Environmental and Occupational Health, Rennes (France); Mercier, Fabien [EHESP-School of Public Health, Sorbonne Paris Cité, Rennes (France); LERES-Environment and Health Research Laboratory (Irset and EHESP Technologic Platform), Rennes (France); INSERM-U1085, Irset-Research Institute for Environmental and Occupational Health, Rennes (France); Pelletier, Maud [EHESP-School of Public Health, Sorbonne Paris Cité, Rennes (France); INSERM-U1085, Irset-Research Institute for Environmental and Occupational Health, Rennes (France); Le Bot, Barbara [EHESP-School of Public Health, Sorbonne Paris Cité, Rennes (France); LERES-Environment and Health Research Laboratory (Irset and EHESP Technologic Platform), Rennes (France); INSERM-U1085, Irset-Research Institute for Environmental and Occupational Health, Rennes (France); and others

2016-09-01

The indoor gas-phase concentrations of semi-volatile organic compounds (SVOCs) can be predicted from their respective concentrations in airborne particles by applying the particle/gas partitioning equilibrium. The temperature used for partitioning is often set to 25 °C. However, indoor temperatures frequently differ from this reference value. This assumption may result in errors in the predicted equilibrium gas-phase SVOC concentrations. To improve the prediction model, the temperature dependence of the particle/gas partition coefficient must be addressed. In this paper, a theoretical relationship between the particle/gas partition coefficient and temperature was developed based on the SVOC absorptive mechanism. The SVOC particle/gas partition coefficients predicted by employing the derived theoretical relationship agree well with the experimental data retrieved from the literature (R > 0.93). The influence of temperature on the equilibrium gas-phase SVOC concentration was quantified by a dimensionless analysis of the derived relationship between the SVOC particle/gas partition coefficient and temperature. The predicted equilibrium gas-phase SVOC concentration decreased by between 31% and 53% when the temperature was lowered by 6 °C, while it increased by up to 750% when the indoor temperature increased from 15 °C to 30 °C. - Highlights: • A theoretical relationship between K{sub p} and temperature was developed. • The relationship was based on the SVOC absorptive mechanism. • The temperature impact was quantified by a dimensionless analysis.

Entry of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine into the rat brain

International Nuclear Information System (INIS)

Riachi, N.J.; LaManna, J.C.; Harik, S.I.

1989-01-01

We studied blood-to-brain entry of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), 1-methyl-4-phenylpyridinium (MPP+) and butanol in anesthetized rats using the indicator-fractionation method with right atrial bolus injection. Minimal amounts of MPP+, which has low octanol/water partition coefficient, crossed the blood-brain barrier. MPTP and butanol, both of which have high octanol/water partition coefficients, were almost completely extracted by all regions of the brain on the first pass. The main difference between the MPTP and butanol tracers is that butanol rapidly left the brain with an exponential rate constant of 1.24 min-1, whereas MPTP was avidly retained by the brain with a washout rate constant of 0.10 min-1 (mean values for the four brain regions that we studied). Early retention of MPTP by the brain was not due to its rapid metabolism by monoamine oxidase because pargyline pretreatment did not affect this rate constant. However, 30 min after [ 3 H]MPTP injection, brain retention of the 3H tracer was reduced significantly by pargyline treatment, and the ratio of brain MPTP/MPP+ was increased markedly

Correlations between chromatographic parameters and bioactivity predictors of potential herbicides.

Science.gov (United States)

Janicka, Małgorzata

2014-08-01

Different liquid chromatography techniques, including reversed-phase liquid chromatography on Purosphere RP-18e, IAM.PC.DD2 and Cosmosil Cholester columns and micellar liqud chromatography with a Purosphere RP-8e column and using buffered sodium dodecyl sulfate-acetonitrile as the mobile phase, were applied to study the lipophilic properties of 15 newly synthesized phenoxyacetic and carbamic acid derivatives, which are potential herbicides. Chromatographic lipophilicity descriptors were used to extrapolate log k parameters (log kw and log km) and log k values. Partitioning lipophilicity descriptors, i.e., log P coefficients in an n-octanol-water system, were computed from the molecular structures of the tested compounds. Bioactivity descriptors, including partition coefficients in a water-plant cuticle system and water-human serum albumin and coefficients for human skin partition and permeation were calculated in silico by ACD/ADME software using the linear solvation energy relationship of Abraham. Principal component analysis was applied to describe similarities between various chromatographic and partitioning lipophilicities. Highly significant, predictive linear relationships were found between chromatographic parameters and bioactivity descriptors. © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A biomimetic absorbent for removal of trace level persistent organic pollutants from water

International Nuclear Information System (INIS)

Liu Huijuan; Qu Jiuhui; Dai Ruihua; Ru Jia; Wang Zijian

2007-01-01

A novel biomimetic absorbent containing the lipid triolein was developed for removing persistent organic pollutants (POPs) from water. The structural characteristics of the absorbent were obtained by SEM and a photoluminescence method. Under optimum preparation conditions, triolein was perfectly embedded in the cellulose acetate (CA) spheres, the absorbent was stable and no triolein leaked into the water. Dieldrin, endrin, aldrin and heptachlor epoxide were effectively removed by the CA-triolein absorbent in laboratory batch experiments. This suggests that CA-triolein absorbent may serve as a good absorbent for those selected POPs. Triolein in the absorbent significantly increased the absorption capacity, and lower residual concentrations of POPs were achieved when compared to the use of cellulose acetate absorbent. The absorption rate for lipophilic pollutants was very fast and exhibited some relationship with the octanol-water partition coefficient of the analyte. The absorption mechanism is discussed in detail. - Triolein-embedded absorbent was developed and it could remove lipophilic pollutants from water effectively

Determination of the partition coefficient between dissolved organic carbon and seawater using differential equilibrium kinetics.

Science.gov (United States)

Kim, Du Yung; Kwon, Jung-Hwan

2018-05-04

Because the freely dissolved fraction of highly hydrophobic organic chemicals is bioavailable, knowing the partition coefficient between dissolved organic carbon and water (K DOCw ) is crucial to estimate the freely dissolved fraction from the total concentration. A kinetic method was developed to obtain K DOCw that required a shorter experimental time than equilibrium methods. The equilibrium partition coefficients of four polychlorinated biphenyls (PCBs) (2,4,4'-trichlorobiphenyl (PCB 28), 2,2',3,5'-tetrachlorobiphenyl (PCB 44), 2,2',4,5,5'-pentachlorobiphenyl (PCB 101), and 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153)) between dissolved organic carbon and seawater (K DOCsw ) were determined using seawater samples from the Korean coast. The log K DOCsw values of PCB 28 were measured by equilibrating PCB 28, the least hydrophobic congener, with seawater samples, and the values ranged from 6.60 to 7.20. For the more hydrophobic PCBs (PCB 44, PCB 101, and PCB 153), kinetic experiments were conducted to determine the sorption rate constants (k 2 ) and their log K DOCsw values were obtained by comparing their k 2 with that of PCB 28. The calculated log K DOCsw values were 6.57-7.35 for PCB 44, 6.23-7.44 for PCB 101, and 6.35-7.73 for PCB 153. The validity of the proposed method was further confirmed using three less hydrophobic polycyclic aromatic hydrocarbons. This kinetic method shortened the experimental time to obtain the K DOCsw values of the more hydrophobic PCBs, which did not reach phase equilibrium. Copyright © 2018 Elsevier Ltd. All rights reserved.

Extraction of lanthanide(III) nitrates from water-salt solutions with n.-octanol

International Nuclear Information System (INIS)

Keskinov, V.A.; Kudrova, A.V.; Valueva, O.V.; Pyartman, A.K.

2004-01-01

Extraction of lanthanide(III) nitrates (Ln=La-Nd, Sm-Gd) from aqueous-salt solutions at 298.15 K was studied using solution of n.-octanol, its concentration 6.31 mol/l. It was ascertained that at Ln(NO 3 ) 3 concentration in aqueous phase below 0.6 mol/l, there is actually no extraction. At higher concentrations of nitrates in aqueous phase the content of lanthanides(III) in organic phase increases in the series La-Gd. Isotherms of extraction were ascertained, its phase equilibria being described mathematically. It is shown that extraction of lanthanide(III) nitrates with n.-octanol should be realized from concentrated aqueous solutions [ru

Tissue/blood partition coefficients for xenon in various adipose tissue depots in man

DEFF Research Database (Denmark)

Bülow, J; Jelnes, Rolf; Astrup, A

1987-01-01

Tissue/blood partition coefficients (lambda) for xenon were calculated for subcutaneous adipose tissue from the abdominal wall and the thigh, and for the perirenal adipose tissue after chemical analysis of the tissues for lipid, water and protein content. The lambda in the perirenal tissue...... was found to correlate linearly to the relative body weight (RBW) in per cent with the regression equation lambda = 0.045 . RBW + 0.99. The subcutaneous lambda on the abdomen correlated linearly to the local skinfold thickness (SFT) with the equation lambda = 0.22 SFT + 2.99. Similarly lambda on the thigh...... correlated to SFT with the equation lambda = 0.20 . SFT + 4.63. It is concluded that the previously accepted lambda value of 10 is generally too high in perirenal as well as in subcutaneous tissue. Thus, by application of the present regression equations, it is possible to obtain more exact estimates...

Temporal–spatial variation and partitioning prediction of antibiotics in surface water and sediments from the intertidal zones of the Yellow River Delta, China

International Nuclear Information System (INIS)

Zhao, Shengnan; Liu, Xinhui; Cheng, Dengmiao; Liu, Guannan; Liang, Baocui; Cui, Baoshan; Bai, Junhong

2016-01-01

As special zones, the intertidal zones of the Yellow River Delta (YRD) are highly variable along with time and space. Fluvial–marine and land–ocean interactions which frequently occur in these areas have a great impact on the fate of pollutants. Antibiotics, which contribute to antibiotic-resistant genes (ARGs), are widely detected in wastewater, natural water, soil, sediments, and even drinking water. Therefore, it is meaningful to investigate the occurrence and fate of antibiotics in these special zones. In this study, eight antibiotics belonging to tetracyclines (TCs), fluoroquinolones (FQs), and macrolides (MLs) were detected in the surface water and sediments from the intertidal zones of YRD during two seasons. Two models were established to predict the partitioning coefficients of norfloxacin (NOR) and erythromycin (ETM) using physicochemical properties of sediments, respectively. The total concentrations of these antibiotics were 82.94–230.96 ng·L"− "1 and 40.97–207.44 ng·g"− "1, respectively, in the surface water and sediments. Seasonal variation was mainly influenced by the frequency of antibiotics use and environment factors. The regions with river supply exhibited the highest concentrations of antibiotics in surface water and sediments. Meanwhile, particle-size fractions, cation exchange capability (CEC), and metal ions content played dominant roles in the partitioning behaviors of NOR and ETM between the surface water and sediments. Both models established in this study featured accuracy and feasibility, which provided the methods for predicting the partitioning coefficients of emerging contaminants similar in structures to NOR and ETM in the intertidal zones. - Highlights: • The intertidal zones of YRD were polluted by antibiotics to some extent. • The river supply was a major pathway for the antibiotic pollution of the intertidal zones of YRD. • The partitioning coefficients of NOR and ETM can be predicted using the physicochemical

Oil-soluble and water-soluble BTPhens and their europium complexes in octanol/water solutions: interface crossing studied by MD and PMF simulations.

Science.gov (United States)

Benay, G; Wipff, G

2013-01-31

Bistriazinyl-phenantroline "BTPhen" ligands L display the remarkable feature to complex trivalent lanthanide and actinide ions, with a marked selectivity for the latter. We report on molecular dynamics studies of tetrasubstituted X(4)BTPhens: L(4+) (X = (+)Et(3)NCH(2)-), L(4-) (X = (-)SO(3)Ph-), and L(0) (X = CyMe(4)) and their complexes with Eu(III) in binary octanol/water solutions. Changes in free energies upon interface crossing are also calculated for typical solutes by potential of mean force PMF simulations. The ligands and their complexes partition, as expected, to either the aqueous or the oil phase, depending on the "solubilizing" group X. Furthermore, most of them are found to be surface active. The water-soluble L(4+) and L(4-) ligands and their (L)Eu(NO(3))(3) complexes adsorb at the aqueous side of the interface, more with L(4-) than with L(4+). The oil soluble ligand L(0) is not surface active in its endo-endo form but adsorbs on the oil side of the interface in its most polar endo-exo form, as well as in its protonated L(0)H(+) and complexed (L(0))Eu(NO(3))(3) states. Furthermore, comparing PMFs of the Eu(III) complexes with and without nitric acid shows that acidifying the aqueous phase has different effects, depending on the ligand charge. In particular, acid promotes the Eu(III) extraction by L(0) via the (L(0))(2)Eu(NO(3))(2+) complex, as observed experimentally. Overall, the results point to the importance of interfacial adsorption for the liquid-liquid extraction of trivalent lanthanide and actinide cations by BTPhens and analogues.

Thermodynamic aspects of solubility, solvation and partitioning processes of some sulfonamides

Energy Technology Data Exchange (ETDEWEB)

Perlovich, German L., E-mail: glp@isc-ras.r [Department of Computer-Aided Molecular Design, Institute of Physiologically Active Compounds, Russian Academy of Sciences, 142432 Chernogolovka (Russian Federation); Institute of Solution Chemistry, Russian Academy of Sciences, 153045 Ivanovo (Russian Federation); Ryzhakov, Alex M. [Institute of Solution Chemistry, Russian Academy of Sciences, 153045 Ivanovo (Russian Federation); Strakhova, Nadezda N.; Kazachenko, Vladimir P. [Department of Computer-Aided Molecular Design, Institute of Physiologically Active Compounds, Russian Academy of Sciences, 142432 Chernogolovka (Russian Federation); Schaper, Klaus-Juergen [Research Center Borstel, Leibniz Center for Medicine and Biosciences, D-23845 Borstel (Germany); Raevsky, Oleg A. [Department of Computer-Aided Molecular Design, Institute of Physiologically Active Compounds, Russian Academy of Sciences, 142432 Chernogolovka (Russian Federation)

2011-05-15

Research highlights: {yields} The thermodynamic aspects of sublimation processes of some sulfonamides were studied by investigating the temperature dependence of vapor pressure using the transpiration method. {yields} Solubility processes of the compounds in water, phosphate buffer with pH 7.4 and n-octanol were investigated and corresponding thermodynamic functions were calculated as well. {yields} Thermodynamic characteristics of the sulfonamides solvation were evaluated. - Abstract: The thermodynamic aspects of sublimation processes of three sulfonamides with the general structures C{sub 6}H{sub 5}-SO{sub 2}NH-C{sub 6}H{sub 4}-R (R = 4-NO{sub 2}) and 4-NH{sub 2}-C{sub 6}H{sub 4}-SO{sub 2}NH-C{sub 6}H{sub 4}-R (R = 4-NO{sub 2}; 4-CN) were studied by investigating the temperature dependence of vapor pressure using the transpiration method. These data together with those obtained earlier for C{sub 6}H{sub 5}-SO{sub 2}NH-C{sub 6}H{sub 4}-R (R = 4-Cl) and 4-NH{sub 2}-C{sub 6}H{sub 4}-SO{sub 2}NH-C{sub 6}H{sub 4}-R (R = 4-Cl; 4-OMe; 4-C{sub 2}H{sub 5}) were analyzed and compared. A correlation was derived between sublimation Gibbs free energies and the sum of H-bond acceptor factors of the molecules. Solubility processes of the compounds in water, phosphate buffer with pH 7.4 and n-octanol (as phases modeling various drug delivery pathways) were investigated and corresponding thermodynamic functions were calculated as well. Thermodynamic characteristics of the sulfonamides solvation were evaluated. Also in this case a correlation between solubility/solvation Gibbs free energy values and the sum of H-bond acceptor factors was observed. For the sulfonamides with various substituents at para-position the processes of transfer from one solvent (water or buffer) to n-octanol were studied by a diagram method combined with analysis of enthalpic and entropic terms. Distinguishing between enthalpy and entropy, as is possible through the present approach, leads to the insight

Effect of Strain, Region, and Tissue Composition on Glucose Partitioning in Meniscus Fibrocartilage.

Science.gov (United States)

Kleinhans, Kelsey L; Jackson, Alicia R

2017-03-01

A nearly avascular tissue, the knee meniscus relies on diffusive transport for nutritional supply to cells. Nutrient transport depends on solute partitioning in the tissue, which governs the amount of nutrients that can enter a tissue. The purpose of the present study was to investigate the effects of mechanical strain, tissue region, and tissue composition on the partition coefficient of glucose in meniscus fibrocartilage. A simple partitioning experiment was employed to measure glucose partitioning in porcine meniscus tissues from two regions (horn and central), from both meniscal components (medial and lateral), and at three levels of compression (0%, 10%, and 20%). Partition coefficient values were correlated to strain level, water volume fraction, and glycosaminoglycan (GAG) content of tissue specimens. Partition coefficient values ranged from 0.47 to 0.91 (n = 48). Results show that glucose partition coefficient is significantly (p < 0.001) affected by compression, decreasing with increasing strain. Furthermore, we did not find a statistically significant effect of tissue when comparing medial versus lateral (p = 0.181) or when comparing central and horn regions (p = 0.837). There were significant positive correlations between tissue water volume fraction and glucose partitioning for all groups. However, the correlation between GAG content and partitioning was only significant in the lateral horn group. Determining how glucose partitioning is affected by tissue composition and loading is necessary for understanding nutrient availability and related tissue health and/or degeneration. Therefore, this study is important for better understanding the transport and nutrition-related mechanisms of meniscal degeneration.

Accumulation of contaminants of emerging concern in food crops-part 2: Plant distribution.

Science.gov (United States)

Hyland, Katherine C; Blaine, Andrea C; Higgins, Christopher P

2015-10-01

Arid agricultural regions often turn to using treated wastewater (reclaimed water) to irrigate food crops. Concerns arise, however, when considering the potential for persistent contaminants of emerging concern to accumulate into plants intended for human consumption. The present study examined the accumulation of a suite of 9 contaminants of emerging concern into 2 representative food crops, lettuce and strawberry, following uptake via the roots and subsequent distribution to other plant tissues. Calculating accumulation metrics (concentration factors) allowed for comparison of the compartmental affinity of each chemical for each plant tissue compartment. The root concentration factor was found to exhibit a positive linear correlation with the pH-adjusted octanol-water partition coefficient (DOW ) for the target contaminants of emerging concern. Coupled with the concentration-dependent accumulation observed in the roots, this result implies that accumulation of these contaminants of emerging concern into plant roots is driven by passive partitioning. Of the contaminants of emerging concern examined, nonionizable contaminants, such as triclocarban, carbamazepine, and organophosphate flame retardants displayed the greatest potential for translocation from the roots to above-ground plant compartments. In particular, the organophosphate flame retardants displayed increasing affinity for shoots and fruits with decreasing size/octanol-water partition coefficient (KOW ). Cationic diphenhydramine and anionic sulfamethoxazole, once transported to the shoots of the strawberry plant, demonstrated the greatest potential of the contaminants examined to be then carried to the edible fruit portion. © 2015 SETAC.

Environmental Containment Property Estimation Using QSARs in an Expert System

Science.gov (United States)

1993-01-15

Soil Adsorption , Octanol- Water Partition Coefficients, Water Solubilities, Bioconcentration Factors and the Parachor. J. Agric. Food Chý’m., 1981. 29...CCOO CH3CO CH3SH CH3SH CH2COO CH2SH HCOO HCOO Furfural Furfural CH20 CH30 DOH (CH2OH)2 CH20 I I CH-O Br Br FCH20 C=C CH=C CNH2 CJ’-NH2 C=C Ci,2NH2 DMSO

Determination of drug lipophilicity by phosphatidylcholine-modified microemulsion high-performance liquid chromatography.

Science.gov (United States)

Xuan, Xueyi; Xu, Liyuan; Li, Liangxing; Gao, Chongkai; Li, Ning

2015-07-25

A new biomembrane-mimetic liquid chromatographic method using a C8 stationary phase and phosphatidylcholine-modified (PC-modified) microemulsion mobile phase was used to estimate unionized and ionized drugs lipophilicity expressed as an n-octanol/water partition coefficient (logP and logD). The introduction of PC into sodium dodecyl sulfate (SDS) microemulsion yielded a good correlation between logk and logD (R(2)=0.8). The optimal composition of the PC-modified microemulsion liquid chromatography (PC-modified MELC) mobile phase was 0.2% PC-3.0% SDS-6.0% n-butanol-0.8% ethyl acetate-90.0% water (pH 7.0) for neutral and ionized molecules. The interactions between the analytes and system described by this chromatographic method is more similar to biological membrane than the n-octanol/water partition system. The result in this paper suggests that PC-modified MELC can serve as a possible alternative to the shake-flask method for high-throughput unionized and ionized drugs lipophilicity determination and simulation of biological processes. Copyright © 2015 Elsevier B.V. All rights reserved.

Partitioning of polychlorinated biphenyls into human cells and adipose tissues: evaluation of octanol, triolein, and liposomes as surrogates

NARCIS (Netherlands)

Quinn, Cristina L.; Van Der Heijden, Stephan A.; Wania, Frank; Jonker, Michiel T O

2014-01-01

Whereas octanol, triacylglycerides, and liposomes have all been proposed as surrogates for measuring the affinity of hydrophobic organic contaminants to human lipids, no comparative evaluation of their suitability exists. Here we conducted batch sorption experiments with polyoxymethylene passive

Myocardial T1 mapping and determination of partition coefficients at 3 tesla: comparison between gadobenate dimeglumine and gadofosveset trisodium

Directory of Open Access Journals (Sweden)

Marcelo Souto Nacif

2018-01-01

Full Text Available Abstract Objective: To compare an albumin-bound gadolinium chelate (gadofosveset trisodium and an extracellular contrast agent (gadobenate dimeglumine, in terms of their effects on myocardial longitudinal (T1 relaxation time and partition coefficient. Materials and Methods: Study subjects underwent two imaging sessions for T1 mapping at 3 tesla with a modified look-locker inversion recovery (MOLLI pulse sequence to obtain one pre-contrast T1 map and two post-contrast T1 maps (mean 15 and 21 min, respectively. The partition coefficient was calculated as ΔR1myocardium /ΔR1blood , where R1 is 1/T1. Results: A total of 252 myocardial and blood pool T1 values were obtained in 21 healthy subjects. After gadolinium administration, the myocardial T1 was longer for gadofosveset than for gadobenate, the mean difference between the two contrast agents being −7.6 ± 60 ms (p = 0.41. The inverse was true for the blood pool T1, which was longer for gadobenate than for gadofosveset, the mean difference being 56.5 ± 67 ms (p < 0.001. The partition coefficient (λ was higher for gadobenate than gadofosveset (0.41 vs. 0.33, indicating slower blood pool washout for gadofosveset than for gadobenate. Conclusion: Myocardial T1 times did not differ significantly between gadobenate and gadofosveset. At typical clinical doses of the contrast agents, partition coefficients were significantly lower for the intravascular contrast agent than for the extravascular agent.

A Quantitative Property-Property Relationship for Estimating Packaging-Food Partition Coefficients of Organic Compounds

DEFF Research Database (Denmark)

Huang, L.; Ernstoff, Alexi; Xu, H.

2017-01-01

Organic chemicals encapsulated in beverage and food packaging can migrate to the food and lead to human exposures via ingestion. The packaging-food (Kpf) partition coefficient is a key parameter to estimate the chemical migration from packaging materials. Previous studies have simply set Kpf to 1...... or 1000, or provided separate linear correlations for several discrete values of ethanol equivalencies of food simulants (EtOH-eq). The aim of the present study is to develop a single quantitative property-property relationship (QPPR) valid for different chemical-packaging combinations and for water...... because only two packaging types are included. This preliminary QPPR demonstrates that the Kpf for various chemicalpackaging-food combinations can be estimated by a single linear correlation. Based on more than 1000 collected Kpf in 15 materials, we will present extensive results for other packaging types...

Preliminary studies on the extraction of 95Zr(IV) with alizarin into n-octanol (Paper No. AL-5 6)

International Nuclear Information System (INIS)

Bhatia, D.S.; Turel, Z.R.

1990-02-01

A rapid and selective method is described for the extraction of Zr(IV) with alizarin into n-octanol. The extraction coefficient value(E) of Zr(IV) between n-octanol and aqueous phase shows a maximum value of (E=118) at pH of 0.4. The percentage of extraction was found to be better than 99% over pH range of 3.5 to 4.5 at an equilibrium time of 3 min. (author)

Phase diagram of tetradecyltrimethylammonium bromide (TTAB) + water + octanol system with application of mechanical deformation

Science.gov (United States)

Yavuz, Aykut Evren; Masalci, Özgür; Kazanci, Nadide

2014-11-01

Morphological properties of tetradecyltrimethylammonium bromide (TTAB) + water + octanol system in different concentrations have been studied. In the process, isotropic phase (L1) and nematic calamitic (NC), nematic discotic (ND), hexagonal E and lamellar D anizotropic mesophases have been determined by polarizing microscopy method and partial ternary phase diagram of the system set up. Textural properties of the anisotropic mesophases of the system have been discussed and their birefringence values measured. Mechanical deformation has been applied to the mesophases. The textural properties and the birefringence values have been observed to be changed by the deformation, after and before which changes have been compared.

Determination of polyparameter linear free energy relationship (pp-LFER) substance descriptors for established and alternative flame retardants.

Science.gov (United States)

Stenzel, Angelika; Goss, Kai-Uwe; Endo, Satoshi

2013-02-05

Polyparameter linear free energy relationships (pp-LFERs) can predict partition coefficients for a multitude of environmental and biological phases with high accuracy. In this work, the pp-LFER substance descriptors of 40 established and alternative flame retardants (e.g., polybrominated diphenyl ethers, hexabromocyclododecane, bromobenzenes, trialkyl phosphates) were determined experimentally. In total, 251 data for gas-chromatographic (GC) retention times and liquid/liquid partition coefficients (K) were measured and used to calibrate the pp-LFER substance descriptors. Substance descriptors were validated through a comparison between predicted and experimental log K for the systems octanol/water (K(ow)), water/air (K(wa)), organic carbon/water (K(oc)) and liposome/water (K(lipw)), revealing a high reliability of pp-LFER predictions based on our descriptors. For instance, the difference between predicted and experimental log K(ow) was <0.3 log units for 17 out of 21 compounds for which experimental values were available. Moreover, we found an indication that the H-bond acceptor value (B) depends on the solvent for some compounds. Thus, for predicting environmentally relevant partition coefficients it is important to determine B values using measurements in aqueous systems. The pp-LFER descriptors calibrated in this study can be used to predict partition coefficients for which experimental data are unavailable, and the predicted values can serve as references for further experimental measurements.

A critical compilation and review of default soil solid/liquid partition coefficients, Kd, for use in environmental assessments

International Nuclear Information System (INIS)

Thibault, D.H.; Sheppard, M.I.; Smith, P.A.

1990-03-01

Environmental assessments of the Canadian concept for disposal of nuclear fuel waste in plutonic rock formations require analyses of the migration of nuclides from the disposal vault to the biosphere. Analyses of nuclide migration via groundwater through the geosphere, unconsolidated overburden and soil use models requiring solid/liquid partition coefficients (K d ) to describe the interaction of the nuclides with the solid materials. This report presents element-specific soil solid/liquid partition coefficients based on a detailed survey of the literature. Values for clays, silt, sand and organic soils are summarized. Partition coefficients for the following elements are presented: americium, antimony, arsenic, barium, boron, cadmium, calcium, carbon, cerium, cesium, chromium, cobalt, copper, curium, europium, iodine, iron, lead, lithium, manganese, molybdenum, neptunium, nickel, niobium, palladium, phosphorus, plutonium, polonium, radium, ruthenium, samarium, selenium, silver, strontium, technetium, tellurium, terbium, thorium, tin, tritium, uranium, zinc, and zirconium. The values compiled in this study are compared with earlier K d value compendiums and are the values recommended for the use in the soil, deep sediment and overburden models for the Environmental Impact Statement on the concept for disposal of Canada's nuclear fuel waste

Prediction of passive blood-brain partitioning: straightforward and effective classification models based on in silico derived physicochemical descriptors.

Science.gov (United States)

Vilar, Santiago; Chakrabarti, Mayukh; Costanzi, Stefano

2010-06-01

The distribution of compounds between blood and brain is a very important consideration for new candidate drug molecules. In this paper, we describe the derivation of two linear discriminant analysis (LDA) models for the prediction of passive blood-brain partitioning, expressed in terms of logBB values. The models are based on computationally derived physicochemical descriptors, namely the octanol/water partition coefficient (logP), the topological polar surface area (TPSA) and the total number of acidic and basic atoms, and were obtained using a homogeneous training set of 307 compounds, for all of which the published experimental logBB data had been determined in vivo. In particular, since molecules with logBB>0.3 cross the blood-brain barrier (BBB) readily while molecules with logBB<-1 are poorly distributed to the brain, on the basis of these thresholds we derived two distinct models, both of which show a percentage of good classification of about 80%. Notably, the predictive power of our models was confirmed by the analysis of a large external dataset of compounds with reported activity on the central nervous system (CNS) or lack thereof. The calculation of straightforward physicochemical descriptors is the only requirement for the prediction of the logBB of novel compounds through our models, which can be conveniently applied in conjunction with drug design and virtual screenings. Published by Elsevier Inc.

Application of Multi-Analyte Methods for Pesticide Formulations

Energy Technology Data Exchange (ETDEWEB)

Lantos, J.; Virtics, I. [Plant Protection & Soil Conservation Service of Szabolcs-Szatmár-Bereg County, Nyíregyháza (Hungary)

2009-07-15

The application of multi-analyte methods for pesticide formulations by GC analysis is discussed. HPLC was used to determine active ingredients. HPLC elution sequences were related to individual n-octanol/water partition coefficients. Real laboratory data are presented and evaluated with regard to validation requirements. The retention time data of pesticides on different HPLC columns under gradient and isocratic conditions are compared to illustrate the applicability of the methodologies. (author)

Partition coefficients of organics between water and carbon dioxide revisited: Correlation with solute molecular descriptors and solvent cohesive properties

Czech Academy of Sciences Publication Activity Database

Roth, Michal

2016-01-01

Roč. 50, č. 23 (2016), s. 12857-12863 ISSN 0013-936X R&D Projects: GA ČR(CZ) GA16-03749S Institutional support: RVO:68081715 Keywords : partitioning between water and supercritical CO2 * organic solutes * K-factor modeling * linear solvation energy relationship Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 6.198, year: 2016

Partitioning behaviour of perfluorinated alkyl contaminants between water, sediment and fish in the Orge River (nearby Paris, France)

International Nuclear Information System (INIS)

Labadie, Pierre; Chevreuil, Marc

2011-01-01

This paper reports on the partitioning behaviour of 15 perfluorinated compounds (PFCs), including C 4 -C 10 sulfonates and C 5 -C 14 carboxylic acids, between water, sediment and fish (European chub, Leuciscus cephalus) in the Orge River (nearby Paris). Total PFC levels were 73.0 ± 3.0 ng L -1 in water and 8.4 ± 0.5 ng g -1 in sediment. They were in the range 43.1-4997.2 ng g -1 in fish, in which PFC tissue distribution followed the order plasma > liver > gills > gonads > muscle. Sediment-water distribution coefficients (log K d ) and bioaccumulation factors (log BAF) were in the range 0.8-4.3 and 0.9-6.7, respectively. Both distribution coefficients positively correlated with perfluoroalkyl chain length. Field-based biota-sediment accumulation factors (BSAFs) are also reported, for the first time for PFCs other than perfluorooctane sulfonate. log BSAF ranged between -1.3 and 1.5 and was negatively correlated with the perfluoroalkyl chain length in the case of carboxylic acids. - Research highlights: → PFC tissue distribution in European chub followed the order plasma > liver > gills > gonads > muscle. → K d and BAF correlated with PFC alkyl chain length. → BSAF negatively correlated with the perfluoroalkyl chain length in the case of carboxylic acids. → BSAF did not correlate with alkyl chain length of sulfonates. - Sediment-water, biota-water and biota-sediment partitioning coefficients were determined for perfluorinated acids and sulfonates and were generally correlated with alkyl chain length.

Water concentration controlled hydrolysis and crystallization in n-octanol to TiO{sub 2} nanocrystals with size below 10 nm

Energy Technology Data Exchange (ETDEWEB)

Wang Meilan [School of Chemical and Biological Science and Engineering, Yantai University, Yantai 264005 (China); He Tao, E-mail: htzy79@yahoo.com.cn [School of Chemical and Biological Science and Engineering, Yantai University, Yantai 264005 (China); Pan Yanfei; Liao Weiping [School of Chemical and Biological Science and Engineering, Yantai University, Yantai 264005 (China); Zhang Shangzhou; Du Wei [School of Environment and Materials Engineering, Yantai University, Yantai 264005 (China)

2011-11-01

Highlights: {yields} Controlled hydrolysis of alkoxide was realized by adjusting water concentration. {yields} Carrying out hydrolysis under different water concentration gave hydrolyzed intermediate with different composition. {yields} A precise size control below 10 nm for anatase TiO{sub 2} nanocrystals was realized. - Abstract: Hydrolysis of tetrabutyl titanate (TBT) and crystallization from hydrolyzed intermediates were carried out in a simple ternary system including n-octanol, TBT and water. Anatase TiO{sub 2} nanocrystals (NCS) were prepared with precise size control below 10 nm. The hydrolysis rate at different water concentration (C{sub water}) was evaluated by measuring the induction time before turbidity changing of the synthetic solution. Fourier transform infrared spectrum (FT-IR) and thermogravimetric/differential thermal analysis (TG/DTA) techniques were applied to make clear the composition of hydrolyzed intermediates obtained at different C{sub water}. Powder X-ray diffraction (XRD) technique was used to track the crystallization process of TiO{sub 2} NCS. Transmission electron microscopy (TEM), XRD, FT-IR and TG/DTA techniques were used to characterize the particular properties of NCS. The C{sub water} controlled mechanism responsible for the slow hydrolysis and crystallization were discussed. Since no other organic capping ligands or rapid injecting techniques were used to limit NCS' growth and the solvent n-octanol can be easily separated and reused, this simple synthetic process is of green chemistry and has application potential in large-scale preparation of inorganic NCS.

A technique for a rapid imaging of regional CBF and partition coefficient using dynamic SPECT and N-isopropyl-p-[123I]iodoamphetamine (123I-IMP)

International Nuclear Information System (INIS)

Itoh, Hiroshi; Iida, Hidehiro; Murakami, Matsutaro

1993-01-01

IMP (iodoamphetamine) is a flow tracer due to a large first pass extraction fraction and high affinity in the brain, but significant clearance from the brain causes change of distribution when the beginning time of scan is delayed. The purpose of the present study was to develop a new method to rapidly calculate a quantitative cerebral blood flow (CBF) image by taking clearance effects into account. A dynamic SPECT scan was performed on 5 subjects (4 patients with cerebral infarction and one normal volunteer) following slow intravenous infusion of 123 I-IMP. The arterial input function was obtained by frequent blood sampling and by measuring an octanol extraction ratio for each sample. Firstly, non-linear least square fitting (NLS) was performed to investigate the tracer kinetics of 123 I-IMP. The 3 compartment model analysis yielded negligibly small k 3 (retaining rate constant) (0.0056±0.0128 (ml/ml/min)), and consistent k 1 (transport rate constant) with those determined by 2 compartment model (2CM) analysis (r=0.96, p 1 was consistent with CBF measured by 15 O water PET technique. These observations suggested the validity of using 2CM for describing the IMP tracer kinetics. Secondly, a weighted integration (WI) technique has been implemented to calculate rapidly images of CBF and partition coefficient (V d ). The WI technique yielded values of CBF (k 1 ) and V d (k 1 /k 2 ). They were confirmed to be consistent with those determined by NLS technique (CBF; r=0.99, p d ; r=0.99, p 1 agreed well with PET CBF (r=0.91, p d in infarcted patients. This supports an importance for calculating V d image. V d image will provide additional clinical information because 123 I-IMP binding mechanism may be related to cell viability. (author)

Enhanced delivery of ketobemidone through porcine buccal mucosa in vitro via more lipophilic ester prodrugs

DEFF Research Database (Denmark)

Hansen, L.B.; Christrup, Lona Louring; Bundgaard, H.

1992-01-01

of permeation relative to ketobemidone, the permeability coefficients being 3-30-times higher than that of ketobemidone. The permeability coefficients increased with increasing lipophilicity, expressed in terms of octanol-buffer (pH 7.4) partition coefficients (P), up to log P values of about 1.5 whereupon...

Vasoconstriction Potency Induced by Aminoamide Local Anesthetics Correlates with Lipid Solubility

Directory of Open Access Journals (Sweden)

Hui-Jin Sung

2012-01-01

Full Text Available Aminoamide local anesthetics induce vasoconstriction in vivo and in vitro. The goals of this in vitro study were to investigate the potency of local anesthetic-induced vasoconstriction and to identify the physicochemical property (octanol/buffer partition coefficient, pKa, molecular weight, or potency of local anesthetics that determines their potency in inducing isolated rat aortic ring contraction. Cumulative concentration-response curves to local anesthetics (levobupivacaine, ropivacaine, lidocaine, and mepivacaine were obtained from isolated rat aorta. Regression analyses were performed to determine the relationship between the reported physicochemical properties of local anesthetics and the local anesthetic concentration that produced 50% (ED50 of the local anesthetic-induced maximum vasoconstriction. We determined the order of potency (ED50 of vasoconstriction among local anesthetics to be levobupivacaine > ropivacaine > lidocaine > mepivacaine. The relative importance of the independent variables that affect the vasoconstriction potency is octanol/buffer partition coefficient > potency > pKa > molecular weight. The ED50 in endothelium-denuded aorta negatively correlated with the octanol/buffer partition coefficient of local anesthetics (r2=0.9563; P<0.001. The potency of the vasoconstriction in the endothelium-denuded aorta induced by local anesthetics is determined primarily by lipid solubility and, in part, by other physicochemical properties including potency and pKa.

Temporal–spatial variation and partitioning prediction of antibiotics in surface water and sediments from the intertidal zones of the Yellow River Delta, China

Energy Technology Data Exchange (ETDEWEB)

Zhao, Shengnan [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875 (China); Liu, Xinhui, E-mail: xhliu@bnu.edu.cn [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875 (China); Cheng, Dengmiao [Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Key Laboratory of Plant Nutrition and Fertilizer, Ministry of Agriculture, Beijing 100081 (China); Liu, Guannan [MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, CAGS, Beijing 100037 (China); Liang, Baocui; Cui, Baoshan; Bai, Junhong [State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875 (China)

2016-11-01

As special zones, the intertidal zones of the Yellow River Delta (YRD) are highly variable along with time and space. Fluvial–marine and land–ocean interactions which frequently occur in these areas have a great impact on the fate of pollutants. Antibiotics, which contribute to antibiotic-resistant genes (ARGs), are widely detected in wastewater, natural water, soil, sediments, and even drinking water. Therefore, it is meaningful to investigate the occurrence and fate of antibiotics in these special zones. In this study, eight antibiotics belonging to tetracyclines (TCs), fluoroquinolones (FQs), and macrolides (MLs) were detected in the surface water and sediments from the intertidal zones of YRD during two seasons. Two models were established to predict the partitioning coefficients of norfloxacin (NOR) and erythromycin (ETM) using physicochemical properties of sediments, respectively. The total concentrations of these antibiotics were 82.94–230.96 ng·L{sup −} {sup 1} and 40.97–207.44 ng·g{sup −} {sup 1}, respectively, in the surface water and sediments. Seasonal variation was mainly influenced by the frequency of antibiotics use and environment factors. The regions with river supply exhibited the highest concentrations of antibiotics in surface water and sediments. Meanwhile, particle-size fractions, cation exchange capability (CEC), and metal ions content played dominant roles in the partitioning behaviors of NOR and ETM between the surface water and sediments. Both models established in this study featured accuracy and feasibility, which provided the methods for predicting the partitioning coefficients of emerging contaminants similar in structures to NOR and ETM in the intertidal zones. - Highlights: • The intertidal zones of YRD were polluted by antibiotics to some extent. • The river supply was a major pathway for the antibiotic pollution of the intertidal zones of YRD. • The partitioning coefficients of NOR and ETM can be predicted using

The 'Salting Out' Effect: Investigating the Influence of Both the Nature and Concentration of Salt on the Partition Coefficient of Butan-1,4-Dioic Acid

Science.gov (United States)

McCullagh, John

2018-01-01

This sixth-form chemistry activity describes how students can use acid-base titrimetry to investigate how adding salt to the aqueous phase may change the value of the partition coefficient of an organic acid between water and 2-methylpropan-1-ol. While the presence of lithium chloride and sodium chloride increases the value of the partition…

Modeling water and hydrogen networks with partitioning regeneration units

Directory of Open Access Journals (Sweden)

W.M. Shehata

2015-03-01

Full Text Available Strict environment regulations in chemical and refinery industries lead to minimize resource consumption by designing utility networks within industrial process plants. The present study proposed a superstructure based optimization model for the synthesis of water and hydrogen networks with partitioning regenerators without mixing the regenerated sources. This method determines the number of partitioning regenerators needed for the regeneration of the sources. The number of the regenerators is based on the number of sources required to be treated for recovery. Each source is regenerated in an individual partitioning regenerator. Multiple regeneration systems can be employed to achieve minimum flowrate and costs. The formulation is linear in the regenerator balance equations. The optimized model is applied for two systems, partitioning regeneration systems of the fixed outlet impurity concentration and partitioning regeneration systems of the fixed impurity load removal ratio (RR for water and hydrogen networks. Several case studies from the literature are solved to illustrate the ease and applicability of the proposed method.

Predictive performance of the human Cell Line Activation Test (h-CLAT) for lipophilic chemicals with high octanol-water partition coefficients.

Science.gov (United States)

Takenouchi, Osamu; Miyazawa, Masaaki; Saito, Kazutoshi; Ashikaga, Takao; Sakaguchi, Hitoshi

2013-01-01

To meet the urgent need for a reliable alternative test for predicting skin sensitizing potential of many chemicals, we have developed a cell-based in vitro test, human Cell Line Activation Test (h-CLAT). However, the predictive performance for lipophilic chemicals in the h-CLAT still remains relatively unknown. Moreover, it's suggested that low water solubility of chemicals might induce false negative outcomes. Thus, in this study, we tested relatively low water soluble 37 chemicals with log Kow values above and below 3.5 in the h-CLAT. The small-scale assessment resulted in nine false negative outcomes for chemicals with log Kow values greater than 3.5. We then created a dataset of 143 chemicals by combining the existing dataset of 106 chemicals and examined the predictive performance of the h-CLAT for chemicals with a log Kow of less than 3.5; a total of 112 chemicals from the 143 chemicals in the dataset. The sensitivity and overall accuracy for the 143 chemicals were 83% and 80%, respectively. In contrast, sensitivity and overall accuracy for the 112 chemicals with log Kow values below 3.5 improved to 94% and 88%, respectively. These data suggested that the h-CLAT could successfully detect sensitizers with log Kow values up to 3.5. When chemicals with log Kow values greater than 3.5 that were deemed positive by h-CLAT were included with the 112 chemicals, the sensitivity and accuracy in terms of the resulting applicable 128 chemicals out of the 143 chemicals became 95% and 88%, respectively. The use of log Kow values gave the h-CLAT a higher predictive performance. Our results demonstrated that the h-CLAT could predict sensitizing potential of various chemicals, which contain lipophilic chemicals using a large-scale chemical dataset.

Determination and importance of temperature dependence of retention coefficient (RPHPLC) in QSAR model of nitrazepams' partition coefficient in bile acid micelles.

Science.gov (United States)

Posa, Mihalj; Pilipović, Ana; Lalić, Mladena; Popović, Jovan

2011-02-15

Linear dependence between temperature (t) and retention coefficient (k, reversed phase HPLC) of bile acids is obtained. Parameters (a, intercept and b, slope) of the linear function k=f(t) highly correlate with bile acids' structures. Investigated bile acids form linear congeneric groups on a principal component (calculated from k=f(t)) score plot that are in accordance with conformations of the hydroxyl and oxo groups in a bile acid steroid skeleton. Partition coefficient (K(p)) of nitrazepam in bile acids' micelles is investigated. Nitrazepam molecules incorporated in micelles show modified bioavailability (depo effect, higher permeability, etc.). Using multiple linear regression method QSAR models of nitrazepams' partition coefficient, K(p) are derived on the temperatures of 25°C and 37°C. For deriving linear regression models on both temperatures experimentally obtained lipophilicity parameters are included (PC1 from data k=f(t)) and in silico descriptors of the shape of a molecule while on the higher temperature molecular polarisation is introduced. This indicates the fact that the incorporation mechanism of nitrazepam in BA micelles changes on the higher temperatures. QSAR models are derived using partial least squares method as well. Experimental parameters k=f(t) are shown to be significant predictive variables. Both QSAR models are validated using cross validation and internal validation method. PLS models have slightly higher predictive capability than MLR models. Copyright © 2010 Elsevier B.V. All rights reserved.

Water Partitioning in Planetary Embryos and Protoplanets with Magma Oceans

Science.gov (United States)

Ikoma, M.; Elkins-Tanton, L.; Hamano, K.; Suckale, J.

2018-06-01

The water content of magma oceans is widely accepted as a key factor that determines whether a terrestrial planet is habitable. Water ocean mass is determined as a result not only of water delivery and loss, but also of water partitioning among several reservoirs. Here we review our current understanding of water partitioning among the atmosphere, magma ocean, and solid mantle of accreting planetary embryos and protoplanets just after giant collisions. Magma oceans are readily formed in planetary embryos and protoplanets in their accretion phase. Significant amounts of water are partitioned into magma oceans, provided the planetary building blocks are water-rich enough. Particularly important but still quite uncertain issues are how much water the planetary building blocks contain initially and how water goes out of the solidifying mantle and is finally degassed to the atmosphere. Constraints from both solar-system explorations and exoplanet observations and also from laboratory experiments are needed to resolve these issues.

Externally predictive single-descriptor based QSPRs for physico-chemical properties of polychlorinated-naphthalenes: Exploring relationships of log SW, log KOA, and log KOW with electron-correlation

International Nuclear Information System (INIS)

Chayawan; Vikas

2015-01-01

Highlights: • Aqueous solubility and partition coefficient are modelled using single-parameter. • Electron-correlation observed as a vital predictorof physico-chemical properties. • For octanol-air partition coefficient, energy and polarizability yield best models. • Dipole-moment is found to be worst single-descriptor for the properties analysed. - Abstract: Quantitative structure–property relationships (QSPRs), based only on a single-parameter, are proposed for the prediction of physico-chemical properties, namely, aqueous solubility (log S W ), octanol–water partition coefficient (log K OW ) and octanol–air partition coefficient (log K OA ) of polychloronaphthalenes (PCNs) including all the 75 chloronaphthalene congeners. The QSPR models are developed using molecular descriptors computed through quantum mechanical methods including ab-initio as well as advanced semi-empirical methods. The predictivity of the developed models is tested through state-of-the-art external validation procedures employing an external prediction set of compounds. To analyse the role of instantaneous interactions between electrons (the electron-correlation), the models are also compared with those developed using only the electron-correlation contribution of the quantum chemical descriptor. The electron-correlation contribution towards the chemical hardness and the LUMO energy are observed to be the best predictors for octanol–water partition coefficient, whereas for the octanol–air partition coefficient, the total electronic energy and electron-correlation energy are found to be reliable descriptors, in fact, even better than the polarisability. For aqueous solubility of PCNs, the absolute electronegativity is observed to be the best predictor. This work suggests that the electron-correlation contribution of a quantum-chemical descriptor can be used as a reliable indicator for physico-chemical properties, particularly the partition coefficients

Externally predictive single-descriptor based QSPRs for physico-chemical properties of polychlorinated-naphthalenes: Exploring relationships of log S{sub W}, log K{sub OA}, and log K{sub OW} with electron-correlation

Energy Technology Data Exchange (ETDEWEB)

Chayawan; Vikas, E-mail: qlabspu@pu.ac.in

2015-10-15

Highlights: • Aqueous solubility and partition coefficient are modelled using single-parameter. • Electron-correlation observed as a vital predictorof physico-chemical properties. • For octanol-air partition coefficient, energy and polarizability yield best models. • Dipole-moment is found to be worst single-descriptor for the properties analysed. - Abstract: Quantitative structure–property relationships (QSPRs), based only on a single-parameter, are proposed for the prediction of physico-chemical properties, namely, aqueous solubility (log S{sub W}), octanol–water partition coefficient (log K{sub OW}) and octanol–air partition coefficient (log K{sub OA}) of polychloronaphthalenes (PCNs) including all the 75 chloronaphthalene congeners. The QSPR models are developed using molecular descriptors computed through quantum mechanical methods including ab-initio as well as advanced semi-empirical methods. The predictivity of the developed models is tested through state-of-the-art external validation procedures employing an external prediction set of compounds. To analyse the role of instantaneous interactions between electrons (the electron-correlation), the models are also compared with those developed using only the electron-correlation contribution of the quantum chemical descriptor. The electron-correlation contribution towards the chemical hardness and the LUMO energy are observed to be the best predictors for octanol–water partition coefficient, whereas for the octanol–air partition coefficient, the total electronic energy and electron-correlation energy are found to be reliable descriptors, in fact, even better than the polarisability. For aqueous solubility of PCNs, the absolute electronegativity is observed to be the best predictor. This work suggests that the electron-correlation contribution of a quantum-chemical descriptor can be used as a reliable indicator for physico-chemical properties, particularly the partition coefficients.

Rules for distinguishing toxicants that cause type I and type II narcosis syndromes.

OpenAIRE

Veith, G D; Broderius, S J

1990-01-01

Narcosis is a nonspecific reversible state of arrested activity of protoplasmic structures caused by a wide variety of organic chemicals. The vast majority of industrial organic chemicals can be characterized by a baseline structure-toxicity relationship as developed for diverse aquatic organisms, using only the n-octanol/water partition coefficient as a descriptor. There are, however, many apparent narcotic chemicals that are more toxic than baseline narcosis predicts. Some of these chemical...

Factors determining the passage of drugs from blood into saliva.

OpenAIRE

Stephen, K W; McCrossan, J; Mackenzie, D; Macfarlane, C B; Speirs, C F

1980-01-01

1. Following single oral dosing of ampicillin, cephalexin, tetracycline, erythromycin estolate, clindamycin and rifampicin to six normal volunteers, antibacterial activity was measured at 1, 3 and 6 h in serum, gingival fluid and minor gland saliva from all subjects and in parotid and submandiabular saliva from three. 2. pH values of all gingival fluid and saliva specimens were noted. 3. Partition coefficients between n-octanol and water were measured for erythromycin, clindamycin and rifampi...

Bioaccumulation Potential Of Air Contaminants: Combining Biological Allometry, Chemical Equilibrium And Mass-Balances To Predict Accumulation Of Air Pollutants In Various Mammals

Energy Technology Data Exchange (ETDEWEB)

Veltman, Karin; McKone, Thomas E.; Huijbregts, Mark A.J.; Hendriks, A. Jan

2009-03-01

In the present study we develop and test a uniform model intended for single compartment analysis in the context of human and environmental risk assessment of airborne contaminants. The new aspects of the model are the integration of biological allometry with fugacity-based mass-balance theory to describe exchange of contaminants with air. The developed model is applicable to various mammalian species and a range of chemicals, while requiring few and typically well-known input parameters, such as the adult mass and composition of the species, and the octanol-water and air-water partition coefficient of the chemical. Accumulation of organic chemicals is typically considered to be a function of the chemical affinity forlipid components in tissues. Here, we use a generic description of chemical affinity for neutral and polar lipids and proteins to estimate blood-air partition coefficients (Kba) and tissue-air partition coefficients (Kta) for various mammals. This provides a more accurate prediction of blood-air partition coefficients, as proteins make up a large fraction of total blood components. The results show that 75percent of the modeled inhalation and exhalation rate constants are within a factor of 2 from independent empirical values for humans, rats and mice, and 87percent of the predicted blood-air partition coefficients are within a factor of 5 from empirical data. At steady-state, the bioaccumulation potential of air pollutants is shown to be mainly a function of the tissue-air partition coefficient and the biotransformation capacity of the species and depends weakly on the ventilation rate and the cardiac output of mammals.

Distribuição ambiental de poluentes orgânicos encontrados em lodos de esgoto Environmental distribution of the organic contaminants found in sewage sludge

Directory of Open Access Journals (Sweden)

Lourival Costa Paraíba

2005-09-01

, water solubility, Henry's constant, octanol-water partition coefficient and soil half-life of each contaminant were used by the model. The bioconcentration factors in aquatic biota, roots, xylem sap, soil sorption coefficient were estimated by expressions that correlate each one of these bioconcentration factors with the octanol-water partition coefficient of the contaminants. The partition coefficients air-water and leaf-air, and the GUS index were calculated and used in this study. The modeling and simulations presented in this work reveal the preferential compartments of the contaminants.

Determination of partition and diffusion coefficient of formaldehyde in selected building materials and impact of relative humidity

Science.gov (United States)

The partition and effective diffusion coefficients of formaldehyde were measured for three materials (conventional gypsum wallboard, "green" gypsum wallboard, and "green" carpet) under three relative humidity (RH) conditions (20%, 50% and 70% RH). A dynamic dual-chamber test meth...

Physico-chemical characterization antituberculosis thioacetazone: Vapor pressure, solubility and lipophilicity

International Nuclear Information System (INIS)

Sharapova, Angelica; Ol'khovich, Marina; Blokhina, Svetlana; Perlovich, German

2017-01-01

Highlights: • Vapor pressures of antituberculosis thioacetazone were determined by transpiration method. • Solubilities of the TAZ in four modeling solvents were measured at different temperatures. • Temperature dependence of octanol/buffer pH 7.4 partition coefficients was obtained. • Thermodynamics parameters of solubility, sublimation, solvation and transfer were calculated. - Abstract: Vapor pressure of thioacetazone (TAZ) has been determined in the temperature range of 404.15–429.15 K by the transpiration method. The obtained data were used to calculate the standard molar enthalpy of sublimation that was found to be 164.1 kJ/mol at T = 298.15 K. The drug solubility was measured at seven temperatures from 288.15 to 318.15 K in modeling solvents: octanol, hexane and aqueous buffers pH 2.0 and 7.4 by the saturation shake-flask method by using spectrophotometric analysis. It has been found that TAZ has poor solubility in hexane and buffer solutions and limited solubility in octanol. The experimental data were well correlated by van’t Hoff and modified Apelblat equations. A temperature dependence of TAZ partition coefficient in the octanol/buffer pH 7.4 system has been derived. The partition coefficient value in this system (logP = 1.82) refers to the optimal interval for oral absorption drugs. The thermodynamic parameters of sublimation, solubility, solvation and transfer have been determined based on experimental data. The dominant effect of enthalpy and entropy contributions to the Gibbs energy of the investigated processes has been revealed.

Extractions of isoquinoline alkaloids with butanol and octanol.

Science.gov (United States)

Gregorová, Jana; Babica, Jan; Marek, Radek; Paulová, Hana; Táborská, Eva; Dostál, Jirí

2010-09-01

Six different isoquinoline alkaloids (sanguinarine, chelerythrine, berberine, coptisine, allocryptopine, and protopine) were extracted by butanol and octanol from aqueous solution, pH 4.5. The samples were analyzed by HPLC. Butanol extraction was non-selective, alkaloids passed into organic phase in 83-98%. Octanol extraction provided more selective yields: sanguinarine 99%, chelerythrine 94%, berberine 18%, coptisine 16%, allocryptopine 7.5%, protopine 7%. Further, we tested octanol treatment of extract from Dicranostigma lactucoides. The octanol extraction yields were also selective: sanguinarine 98%, chelerythrine 92%, chelirubine 92.5%, protopine 6% and allocryptopine 3.5%. 6-Butoxy-5,6-dihydrosanguinarine and 6-butoxy-5,6-dihydrochelerythrine were prepared and their NMR and MS data are reported and discussed. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Comparison of hydrogen bonding in 1-octanol and 2-octanol as probed by spectroscopic techniques.

Science.gov (United States)

Palombo, Francesca; Sassi, Paola; Paolantoni, Marco; Morresi, Assunta; Cataliotti, Rosario Sergio

2006-09-14

Liquid 1-octanol and 2-octanol have been investigated by infrared (IR), Raman, and Brillouin experiments in the 10-90 degrees C temperature range. Self-association properties of the neat liquids are described in terms of a three-state model in which OH oscillators differently implicated in the formation of H-bonds are considered. The results are in quantitative agreement with recent computational studies for 1-octanol. The H-bond probability is obtained by Raman data, and a stochastic model of H-bonded chains gives a consistent picture of the self-association characteristics. Average values of hydrogen bond enthalpy and entropy are evaluated. The H-bond formation enthalpy is ca. -22 kJ/mol and is slightly dependent on the structural isomerism. The different degree of self-association for the two octanols is attributed to entropic factors. The more shielded 2-isomer forms larger fractions of smaller, less cooperative, and more ordered clusters, likely corresponding to cyclic structures. Signatures of a different cluster organization are also evidenced by comparing the H-bond energy dispersion (HBED) of OH stretching IR bands. A limiting cooperative H-bond enthalpy value of 27 kJ/mol is found. It is also proposed that the different H-bonding capabilities may modulate the extent of interaggregate hydrocarbon interactions, which is important in explaining the differences in molar volume, compressibility, and vaporization enthalpy for the two isomers.

Binding affinity and decontamination of dermal decontamination gel to model chemical warfare agent simulants.

Science.gov (United States)

Cao, Yachao; Elmahdy, Akram; Zhu, Hanjiang; Hui, Xiaoying; Maibach, Howard

2018-05-01

Six chemical warfare agent simulants (trimethyl phosphate, dimethyl adipate, 2-chloroethyl methyl sulfide, diethyl adipate, chloroethyl phenyl sulfide and diethyl sebacate) were studied in in vitro human skin to explore relationship between dermal penetration/absorption and the mechanisms of simulant partitioning between stratum corneum (SC) and water as well as between dermal decontamination gel (DDGel) and water. Both binding affinity to and decontamination of simulants using DDGel were studied. Partition coefficients of six simulants between SC and water (Log P SC/w ) and between DDGel and water (Log P DDGel/w ) were determined. Results showed that DDGel has a similar or higher binding affinity to each simulant compared to SC. The relationship between Log P octanol/water and Log P SC/w as well as between Log P octanol/water and Log P DDGel/w demonstrated that partition coefficient of simulants correlated to their lipophilicity or hydrophilicity. Decontamination efficiency results with DDGel for these simulants were consistent with binding affinity results. Amounts of percentage dose of chemicals in DDGel of trimethyl phosphate, dimethyl adipate, 2-chloroethyl methyl sulfide, diethyl adipate, chloroethyl phenyl sulfide and diethyl sebacate were determined to be 61.15, 85.67, 75.91, 53.53, 89.89 and 76.58, with corresponding amounts absorbed in skin of 0.96, 0.65, 1.68, 0.72, 0.57 and 1.38, respectively. In vitro skin decontamination experiments coupled with a dermal absorption study demonstrated that DDGel can efficiently remove chemicals from skin surface, back-extract from the SC, and significantly reduced chemical penetration into skin or systemic absorption for all six simulants tested. Therefore, DDGel offers a great potential as a NextGen skin Decon platform technology for both military and civilian use. Copyright © 2018 John Wiley & Sons, Ltd.

Environmental concentration and atmospheric deposition of halogenated flame retardants in soil from Nepal: Source apportionment and soil-air partitioning.

Science.gov (United States)

Yadav, Ishwar Chandra; Devi, Ningombam Linthoingambi; Li, Jun; Zhang, Gan

2018-02-01

While various investigations have been driven on polybrominated diphenyl ethers (PBDEs) and other flame retardants (FRs) in different framework around the world, information about contamination and fate of PBDEs and other FRs in developing countries especially in the Indian subcontinent is uncommon. Nepal being located in the Indian subcontinent, very little is known about contamination level of semi-volatile organic pollutants discharged into the environment. This motivated us to investigate the environmental fate of halogenated flame retardant (HFRs) in Nepalese condition. In this study, we investigated the concentration, fate, and sources of 9 PBDEs, 2 dechlorane plus isomers (DPs), and 6 novel brominated flame retardants (NBFRs). Moreover, air-soil exchange and soil-air partitioning were also evaluated to characterize the pattern of air-soil exchange and environmental fate. In general, the concentrations of NBFRs in soil were more prevalent than PBDEs and DPs, and accounted 95% of ∑HFRs. By and large, the concentrations of NBFRs and DPs were measured high in Kathmandu, while PBDEs level exceeded in Pokhara. Principal component analysis (PCA) study suggested contributions from commercial penta-, octa-, and deca-BDEs products and de-bromination of highly brominated PBDEs as the significant source of PBDEs. Likewise, low f anti ratio suggested DPs in soil might have originated from long-range atmospheric transport from remote areas, while high levels of decabromodiphenyl ethane (DBDPE) in soil were linked with the use of wide varieties of consumer products. The estimated fugacity fraction (ff) for individual HFR was quite lower (soil is overwhelming. Soil-air partitioning study revealed neither octanol-air partition coefficient (K OA ) nor black carbon partition coefficient (K BC-A ) is an appropriate surrogate for soil organic matter (SOM), subsequently, absorption by SOM has no or little role in the partitioning of HFRs. Copyright © 2017 Elsevier Ltd. All

Determination of uptake kinetics (sampling rates) by lipid-containing semipermeable membrane devices (SPMDs) for polycyclic aromatic hydrocarbons (PAHs) in water

Science.gov (United States)

Huckins, J.N.; Petty, J.D.; Orazio, C.E.; Lebo, J.A.; Clark, R.C.; Gibson, V.L.; Gala, W.R.; Echols, K.R.

1999-01-01

The use of lipid-containing semipermeable membrane devices (SPMDs) is becoming commonplace, but very little sampling rate data are available for the estimation of ambient contaminant concentrations from analyte levels in exposed SPMDs. We determined the aqueous sampling rates (R(s)s; expressed as effective volumes of water extracted daily) of the standard (commercially available design) 1-g triolein SPMD for 15 of the priority pollutant (PP) polycyclic aromatic hydrocarbons (PAHs) at multiple temperatures and concentrations. Under the experimental conditions of this study, recovery- corrected R(s) values for PP PAHs ranged from ???1.0 to 8.0 L/d. These values would be expected to be influenced by significant changes (relative to this study) in water temperature, degree of biofouling, and current velocity- turbulence. Included in this paper is a discussion of the effects of temperature and octanol-water partition coefficient (K(ow)); the impacts of biofouling and hydrodynamics are reported separately. Overall, SPMDs responded proportionally to aqueous PAH concentrations; i.e., SPMD R(s) values and SPMD-water concentration factors were independent of aqueous concentrations. Temperature effects (10, 18, and 26 ??C) on Rs values appeared to be complex but were relatively small.The use of lipid-containing semipermeable membrane devices (SPMDs) is becoming commonplace, but very little sampling rate data are available for the estimation of ambient contaminant concentrations from analyte levels in exposed SPMDs. We determined the aqueous sampling rates (Rss; expressed as effective volumes of water extracted daily) of the standard (commercially available design) 1-g triolein SPMD for 15 of the priority pollutant (PP) polycyclic aromatic hydrocarbons (PAHs) at multiple temperatures and concentrations. Under the experimental conditions of this study, recovery-corrected Rs values for PP PAHs ranged from ???1.0 to 8.0 L/d. These values would be expected to be influenced by

Evaluation of diclofenac prodrugs for enhancing transdermal delivery.

Science.gov (United States)

Lobo, Shabbir; Li, Henan; Farhan, Nashid; Yan, Guang

2014-03-01

Abstract Objective: The purpose of this study was to evaluate the approach of using diclofenac acid (DA) prodrugs for enhancing transdermal delivery. Methanol diclofenac ester (MD), ethylene glycol diclofenac ester (ED), glycerol diclofenac ester (GD) and 1,3-propylene glycol diclofenac ester (PD) were synthesized and evaluated for their physicochemical properties such as solubilities, octanol/water partition coefficients, stratum corneum/water partition coefficients, hydrolysis rates and bioconversion rates. In vitro fluxes across human epidermal membrane (HEM) in the Franz diffusion cell were determined on DA-, MD-, ED-, GD- and PD-saturated aqueous solutions. The formation of GD and ED led to the prodrugs with higher aqueous solubilities and lower partition coefficients than those of the parent drug. Prodrugs with improved aqueous solubility showed better fluxes across HEM in aqueous solution than that of the parent drug, with GD showing the highest aqueous solubility and also the highest flux. There is a linear relationship between the aqueous solubility and flux for DA, ED and PD, but GD and MD deviated from the linear line. Diclofenac prodrugs with improved hydrophilicity than the parent drug could be utilized for enhancing transdermal diclofenac delivery.

Evaluation of Diclofenac Prodrugs for Enhancing Transdermal Delivery

Science.gov (United States)

Lobo, Shabbir; Li, Henan; Farhan, Nashid; Yan, Guang

2016-01-01

The purpose of this study was to evaluate the approach of using diclofenac acid (DA) prodrugs for enhancing transdermal delivery. Methanol diclofenac ester (MD), ethylene glycol diclofenac ester (ED), glycerol diclofenac ester (GD), and 1,3-propylene glycol diclofenac ester (PD) were synthesized and evaluated for their physicochemical properties such as solubilities, octanol/water partition coefficients, stratum corneum/water partition coefficients, hydrolysis rates, and bioconversion rates. In vitro fluxes across human epidermal membrane (HEM) in Franz diffusion cell were determined on DA, MD, ED, GD, and PD saturated aqueous solutions. The formation of GD and ED led to the prodrugs with higher aqueous solubilities and lower partition coefficients than those of the parent drug. Prodrugs with improved aqueous solubility showed better fluxes across HEM in aqueous solution than that of the parent drug, with GD showing the highest aqueous solubility and also the highest flux. There is a linear relationship between the aqueous solubility and flux for DA, ED and PD, but GD and MD deviated from the linear line. Overall, diclofenac prodrugs with improved hydrophilicity than the parent drug could be utilized for enhancing transdermal diclofenac delivery. PMID:24517636

Determination of partition and diffusion coefficients of formaldehyde in selected building materials and impact of relative humidity (journal)

Science.gov (United States)

The partition and effective diffusion coefficients of formaldehyde were measured for three materials (conventional gypsum wallboard, "green" gypsum wallboard, and "green" carpet) under three relative humidity (RH) conditions (20%, 50% and 70% RH). A dynamic dual-chamber test meth...

Equilibrium partitioning of drug molecules between aqueous and amino acid ester-based ionic liquids

International Nuclear Information System (INIS)

Jing, Jun; Li, Zhiyong; Pei, Yuanchao; Wang, Huiyong; Wang, Jianji

2013-01-01

Highlights: ► Partition coefficients of twelve drug molecules in ILs have been determined. ► The possible mechanism has been investigated from 13 C NMR measurements. ► Hydrophobic π–π interaction is the main driving force for the partitioning of drug molecules. -- Abstract: In this work, a series of novel room temperature ionic liquids (ILs) have been synthesized with cheap, naturally α-amino acid ester as cations and bis(trifluoromethylsulfonyl)imide as anion. The glass transition temperature and thermal decomposition temperature of these ILs, partition coefficients of some coumarins and purine alkaloids between water and the amino acid ester-based ILs at T = 298.15 K, and Gibbs energy, enthalpy and entropy changes for the transfer of caffeine and 6,7-dihydroxycoumarin from water to [LeuC 2 ][Tf 2 N] have been determined. It is shown that these ILs are highly effective materials for the extraction of drug compounds like coumarin, 4-hydroxycoumarin, 7-hydroxycoumarin, 3-aminocoumarin, coumarin-3-carboxylic acid, 6,7-dihydroxycoumarin, 6,7-dihydroxy-4-methylcoumarin, caffeine, theobromine, theophylline, inosine, and 2,6-diaminopurine. The partition process is driven by enthalpy term, and partition coefficients of the drug molecules increase with the increase of hydrophobicity of both the drug molecules and the ILs. Furthermore, the possible partition mechanism has been investigated from 13 C NMR measurements

Partitioning of monomethylmercury between freshwater algae and water.

Science.gov (United States)

Miles, C J; Moye, H A; Phlips, E J; Sargent, B

2001-11-01

Phytoplankton-water monomethylmercury (MeHg) partition constants (KpI) have been determined in the laboratory for two green algae Selenastrum capricornutum and Cosmarium botrytis, the blue-green algae Schizothrix calcicola, and the diatom Thallasiosira spp., algal species that are commonly found in natural surface waters. Two methods were used to determine KpI, the Freundlich isotherm method and the flow-through/dialysis bag method. Both methods yielded KpI values of about 10(6.6) for S. capricornutum and were not significantly different. The KpI for the four algae studied were similar except for Schizothrix, which was significantly lower than S. capricornutum. The KpI for MeHg and S. capricornutum (exponential growth) was not significantly different in systems with predominantly MeHgOH or MeHgCl species. This is consistent with other studies that show metal speciation controls uptake kinetics, but the reactivity with intracellular components controls steady-state concentrations. Partitioning constants determined with exponential and stationary phase S. capricornutum cells at the same conditions were not significantly different, while the partitioning constant for exponential phase, phosphorus-limited cells was significantly lower, suggesting that P-limitation alters the ecophysiology of S. capricornutum sufficiently to impact partitioning, which may then ultimately affect mercury levels in higher trophic species.

Predicting cyclohexane/water distribution coefficients for the SAMPL5 challenge using MOSCED and the SMD solvation model

Science.gov (United States)

Diaz-Rodriguez, Sebastian; Bozada, Samantha M.; Phifer, Jeremy R.; Paluch, Andrew S.

2016-11-01

We present blind predictions using the solubility parameter based method MOSCED submitted for the SAMPL5 challenge on calculating cyclohexane/water distribution coefficients at 298 K. Reference data to parameterize MOSCED was generated with knowledge only of chemical structure by performing solvation free energy calculations using electronic structure calculations in the SMD continuum solvent. To maintain simplicity and use only a single method, we approximate the distribution coefficient with the partition coefficient of the neutral species. Over the final SAMPL5 set of 53 compounds, we achieved an average unsigned error of 2.2± 0.2 log units (ranking 15 out of 62 entries), the correlation coefficient ( R) was 0.6± 0.1 (ranking 35), and 72± 6 % of the predictions had the correct sign (ranking 30). While used here to predict cyclohexane/water distribution coefficients at 298 K, MOSCED is broadly applicable, allowing one to predict temperature dependent infinite dilution activity coefficients in any solvent for which parameters exist, and provides a means by which an excess Gibbs free energy model may be parameterized to predict composition dependent phase-equilibrium.

Biphasic whole-cell synthesis of R-2-octanol with recycling of the ionic liquid

OpenAIRE

Dennewald, Danielle

2011-01-01

Whole-cell biocatalysis in biphasic systems permits the synthesis of inhibiting chiral alcohols if appropriate non-water miscible ionic liquids are used. Taking the asymmetric reduction of 2-octanone to R-2-octanol by a recombinant Escherichia coli as a model reaction, a detailed characterisation of the biocatalytic reaction was performed with [HMPL][NTF] as ionic liquid. This made the asymmetric synthesis of R-2-octanol in a simple batch at a conversion > 99 % and at an enantiomeric excess >...

Studies on the lipophilicity of vehicles (or co-vehicles) and botanical oils used in cosmetic products.

Science.gov (United States)

Mbah, C J

2007-05-01

The lipophilic character of five vehicles (or co-vehicles): diethylhexylmaleate, dimethicone, light mineral oil, octyldodecanol and oleyl alcohol and eight botanical oils: Aloe vera oil, coconut oil, extra virgin olive oil, grape leaf oil, grape seed oil, hazelnut oil, jojoba oil and safflower oil was determined by partitioning esters of p-hydroxybenzoic acid (parabens) between them and phosphate buffer (pH 7.4). The results were compared to those obtained with 1-octanol. The most lipophilic effects were observed with octyldodecanol and oleyl alcohol for the vehicles (or co-vehicles), coconut oil, jojoba oil and safflower oil for botanical oils. Light mineral oil showed the least lipophilic effect. With butylparaben, it was observed that oleyl alcohol, octyldodecanol, coconut oil and jojoba oil were 0.94, 0.91, 0.74 and 0.68 times as lipophilic as 1-octanol respectively. The study indicates that octyldodecanol and oleyl alcohol could be good substitutes for 1-octanol in partition coefficient determination. The estimated permeability coefficients of the parabens suggest that octyldodecanol, oleyl alcohol, coconut oil and jojoba oil could be potential dermal permeation enhancers.

Visualising the equilibrium distribution and mobility of organic contaminants in soil using the chemical partitioning space.

Science.gov (United States)

Wong, Fiona; Wania, Frank

2011-06-01

Assessing the behaviour of organic chemicals in soil is a complex task as it is governed by the physical chemical properties of the chemicals, the characteristics of the soil as well as the ambient conditions of the environment. The chemical partitioning space, defined by the air-water partition coefficient (K(AW)) and the soil organic carbon-water partition coefficient (K(OC)), was employed to visualize the equilibrium distribution of organic contaminants between the air-filled pores, the pore water and the solid phases of the bulk soil and the relative importance of the three transport processes removing contaminants from soil (evaporation, leaching and particle erosion). The partitioning properties of twenty neutral organic chemicals (i.e. herbicides, pharmaceuticals, polychlorinated biphenyls and volatile chemicals) were estimated using poly-parameter linear free energy relationships and superimposed onto these maps. This allows instantaneous estimation of the equilibrium phase distribution and mobility of neutral organic chemicals in soil. Although there is a link between the major phase and the dominant transport process, such that chemicals found in air-filled pore space are subject to evaporation, those in water-filled pore space undergo leaching and those in the sorbed phase are associated with particle erosion, the partitioning coefficient thresholds for distribution and mobility can often deviate by many orders of magnitude. In particular, even a small fraction of chemical in pore water or pore air allows for evaporation and leaching to dominate over solid phase transport. Multiple maps that represent soils that differ in the amount and type of soil organic matter, water saturation, temperature, depth of surface soil horizon, and mineral matters were evaluated.

Modeling of the solution interaction properties of plastic materials used in pharmaceutical product container systems.

Science.gov (United States)

Jenke, Dennis; Couch, Tom; Gillum, Amy; Sadain, Salma

2009-01-01

Material/water equilibrium binding constants (Eb) were determined for 14 organic solutes and 17 plastic raw materials that could be used in pharmaceutical product container systems. Correlations between the measured binding constants and the organic solute's octanol/water and hexane/water partition coefficients were obtained. In general, while the materials examined exhibited a wide range of binding characteristics, the tested materials by and large fell within two broad classes: (1) those that were octanol-like in their binding characteristics, and (2) those that were hexane-like. Materials of the same class (e.g., polypropylenes) generally had binding models that were very similar. Rank ordering of the materials in terms of their magnitude of drug binding (least binding to most binding) was as follows: polypropylene < polyethylene < polyamide < styrene-ethylene-butylene-styrene < copolyester ether elastomer approximately equal to amine-terminated poly fatty acid amide polymer. The utilization of the developed models to estimate drug loss via sorption by the container is discussed.

Neurobehavioral effects during experimental exposure to 1-octanol and isopropanol.

Science.gov (United States)

van Thriel, Christoph; Kiesswetter, Erns; Blaszkewicz, Meinolf; Golka, Klaus; Seeber, Andreas

2003-04-01

The study examined acute neurobehavioral effects provoked by controlled exposure to 1-octanol and isopropanol among male volunteers. In a 29-m3 exposure laboratory, 24 male students (mean age 25.8 years) were exposed to 1-octanol and isopropanol. Each substance was used in two concentrations (0.1 and 6.4 ppm for 1-octanol; 34.9 and 189.9 ppm for isopropanol:). In a crossover design, each subject was exposed for 4 hours to the conditions. Twelve subjects reported enhanced chemical sensitivity; the other 12 were age-matched controls. At the onset and end of the exposures neurobehavioral tests were administered and symptoms were rated. At the end of the high and low isopropanol exposures the tiredness ratings were elevated, but no dose-dependence could be confirmed. For both substances and concentrations, the annoyance ratings increased during the exposure, but only for isopropanol did the increase show a dose-response relation. The subjects reported olfactory symptoms during the exposure to the high isopropanol and both 1-octanol concentrations. Isopropanol provoked no sensory irritation, whereas high 1-octanol exposure slightly enhanced it. Only among the subjects with enhanced chemical sensitivity were both 1-octanol concentrations associated with a stronger increase in annoyance, and lower detection rates were observed in a divided attention task. Previous studies reporting no neurobehavioral effects for isopropanol (up to 400 ppm) were confirmed. The results obtained for 1-octanol lacked dose-dependency, and their evaluation, is difficult. The annoying odor of 1-octanol may mask sensory irritation and prevent subjects with enhanced chemical sensitivity from concentrating on performance in a demanding task.

Octanol-assisted liposome assembly on chip

Science.gov (United States)

Deshpande, Siddharth; Caspi, Yaron; Meijering, Anna E. C.; Dekker, Cees

2016-01-01

Liposomes are versatile supramolecular assemblies widely used in basic and applied sciences. Here we present a novel microfluidics-based method, octanol-assisted liposome assembly (OLA), to form monodisperse, cell-sized (5-20 μm), unilamellar liposomes with excellent encapsulation efficiency. Akin to bubble blowing, an inner aqueous phase and a surrounding lipid-carrying 1-octanol phase is pinched off by outer fluid streams. Such hydrodynamic flow focusing results in double-emulsion droplets that spontaneously develop a side-connected 1-octanol pocket. Owing to interfacial energy minimization, the pocket splits off to yield fully assembled solvent-free liposomes within minutes. This solves the long-standing fundamental problem of prolonged presence of residual oil in the liposome bilayer. We demonstrate the unilamellarity of liposomes with functional α-haemolysin protein pores in the membrane and validate the biocompatibility by inner leaflet localization of bacterial divisome proteins (FtsZ and ZipA). OLA offers a versatile platform for future analytical tools, delivery systems, nanoreactors and synthetic cells.

Illustrating sensitivity in environmental fate models using partitioning maps - application to selected contaminants

Energy Technology Data Exchange (ETDEWEB)

Meyer, T.; Wania, F. [Univ. of Toronto at Scarborough - DPES, Toronto (Canada)

2004-09-15

Generic environmental multimedia fate models are important tools in the assessment of the impact of organic pollutants. Because of limited possibilities to evaluate generic models by comparison with measured data and the increasing regulatory use of such models, uncertainties of model input and output are of considerable concern. This led to a demand for sensitivity and uncertainty analyses for the outputs of environmental fate models. Usually, variations of model predictions of the environmental fate of organic contaminants are analyzed for only one or at most a few selected chemicals, even though parameter sensitivity and contribution to uncertainty are widely different for different chemicals. We recently presented a graphical method that allows for the comprehensive investigation of model sensitivity and uncertainty for all neutral organic chemicals simultaneously. This is achieved by defining a two-dimensional hypothetical ''chemical space'' as a function of the equilibrium partition coefficients between air, water, and octanol (K{sub OW}, K{sub AW}, K{sub OA}), and plotting sensitivity and/or uncertainty of a specific model result to each input parameter as function of this chemical space. Here we show how such sensitivity maps can be used to quickly identify the variables with the highest influence on the environmental fate of selected, chlorobenzenes, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), hexachlorocyclohexanes (HCHs) and brominated flame retardents (BFRs).

Determination of the Partition Coefficients of Organophosphorus Compounds Using High-Performance Liquid Chromatography.

Science.gov (United States)

1987-12-01

have claimed an advantage to deter- mining values of k’ in 100% aqueous mobile phases by extrapolation of linear plots of log k’ vs. percent organic...im parti- cle size chemically bonded octadecylsilane (ODS) packing ( Alltech Econo- sphere). As required, this column was saturated with I-octanol by in

Prediction of air-to-blood partition coefficients of volatile organic compounds using genetic algorithm and artificial neural network

International Nuclear Information System (INIS)

Konoz, Elahe; Golmohammadi, Hassan

2008-01-01

An artificial neural network (ANN) was constructed and trained for the prediction of air-to-blood partition coefficients of volatile organic compounds. The inputs of this neural network are theoretically derived descriptors that were chosen by genetic algorithm (GA) and multiple linear regression (MLR) features selection techniques. These descriptors are: R maximal autocorrelation of lag 1 weighted by atomic Sanderson electronegativities (R1E+), electron density on the most negative atom in molecule (EDNA), maximum partial charge for C atom (MXPCC), surface weighted charge partial surface area (WNSA1), fractional charge partial surface area (FNSA2) and atomic charge weighted partial positive surface area (PPSA3). The standard errors of training, test and validation sets for the ANN model are 0.095, 0.148 and 0.120, respectively. Result obtained showed that nonlinear model can simulate the relationship between structural descriptors and the partition coefficients of the molecules in data set accurately

Desorption modeling of hydrophobic organic chemicals from plastic sheets using experimentally determined diffusion coefficients in plastics.

Science.gov (United States)

Lee, Hwang; Byun, Da-Eun; Kim, Ju Min; Kwon, Jung-Hwan

2018-01-01

To evaluate rate of migration from plastic debris, desorption of model hydrophobic organic chemicals (HOCs) from polyethylene (PE)/polypropylene (PP) films to water was measured using PE/PP films homogeneously loaded with the HOCs. The HOCs fractions remaining in the PE/PP films were compared with those predicted using a model characterized by the mass transfer Biot number. The experimental data agreed with the model simulation, indicating that HOCs desorption from plastic particles can generally be described by the model. For hexachlorocyclohexanes with lower plastic-water partition coefficients, desorption was dominated by diffusion in the plastic film, whereas desorption of chlorinated benzenes with higher partition coefficients was determined by diffusion in the aqueous boundary layer. Evaluation of the fraction of HOCs remaining in plastic films with respect to film thickness and desorption time showed that the partition coefficient between plastic and water is the most important parameter influencing the desorption half-life. Copyright © 2017 Elsevier Ltd. All rights reserved.

Application of radial basis function neural network to predict soil sorption partition coefficient using topological descriptors.

Science.gov (United States)

Sabour, Mohammad Reza; Moftakhari Anasori Movahed, Saman

2017-02-01

The soil sorption partition coefficient logK oc is an indispensable parameter that can be used in assessing the environmental risk of organic chemicals. In order to predict soil sorption partition coefficient for different and even unknown compounds in a fast and accurate manner, a radial basis function neural network (RBFNN) model was developed. Eight topological descriptors of 800 organic compounds were used as inputs of the model. These 800 organic compounds were chosen from a large and very diverse data set. Generalized Regression Neural Network (GRNN) was utilized as the function in this neural network model due to its capability to adapt very quickly. Hence, it can be used to predict logK oc for new chemicals, as well. Out of total data set, 560 organic compounds were used for training and 240 to test efficiency of the model. The obtained results indicate that the model performance is very well. The correlation coefficients (R2) for training and test sets were 0.995 and 0.933, respectively. The root-mean square errors (RMSE) were 0.2321 for training set and 0.413 for test set. As the results for both training and test set are extremely satisfactory, the proposed neural network model can be employed not only to predict logK oc of known compounds, but also to be adaptive for prediction of this value precisely for new products that enter the market each year. Copyright © 2016 Elsevier Ltd. All rights reserved.

Prediction of gas/particle partitioning of polybrominated diphenyl ethers (PBDEs) in global air: A theoretical study

Science.gov (United States)

Li, Y.-F.; Ma, W.-L.; Yang, M.

2015-02-01

Gas/particle (G/P) partitioning of semi-volatile organic compounds (SVOCs) is an important process that primarily governs their atmospheric fate, long-range atmospheric transport, and their routes of entering the human body. All previous studies on this issue are hypothetically based on equilibrium conditions, the results of which do not predict results from monitoring studies well in most cases. In this study, a steady-state model instead of an equilibrium-state model for the investigation of the G/P partitioning behavior of polybrominated diphenyl ethers (PBDEs) was established, and an equation for calculating the partition coefficients under steady state (KPS) of PBDEs (log KPS = log KPE + logα) was developed in which an equilibrium term (log KPE = log KOA + logfOM -11.91 where fOM is organic matter content of the particles) and a non-equilibrium term (log α, caused by dry and wet depositions of particles), both being functions of log KOA (octanol-air partition coefficient), are included. It was found that the equilibrium is a special case of steady state when the non-equilibrium term equals zero. A criterion to classify the equilibrium and non-equilibrium status of PBDEs was also established using two threshold values of log KOA, log KOA1, and log KOA2, which divide the range of log KOA into three domains: equilibrium, non-equilibrium, and maximum partition domain. Accordingly, two threshold values of temperature t, tTH1 when log KOA = log KOA1 and tTH2 when log KOA = log KOA2, were identified, which divide the range of temperature also into the same three domains for each PBDE congener. We predicted the existence of the maximum partition domain (the values of log KPS reach a maximum constant of -1.53) that every PBDE congener can reach when log KOA ≥ log KOA2, or t ≤ tTH2. The novel equation developed in this study was applied to predict the G/P partition coefficients of PBDEs for our Chinese persistent organic pollutants (POPs) Soil and Air Monitoring

Partition Coefficients of Organic Molecules in Squalane and Water/Ethanol Mixtures by Molecular Dynamics Simulations

DEFF Research Database (Denmark)

Lundsgaard, Rasmus; Kontogeorgis, Georgios; Economou, Ioannis G.

2011-01-01

coefficient can be estimated for both a small hydrophilic and a hydrophobic organic molecules between squalane (used here to mimic low density poly ethylene) and water/ethanol solutes using thermodynamic integration to calculate the free energy of solvation. Molecular dynamics simulations are performed, using...... the GROMACS software, by slowly decoupling of firstly the electrostatic and then the Lennard–Jones interactions between molecules in the simulation box. These calculations depend very much on the choice of force field. Two force fields have been tested in this work, the TraPPE-UA (united-atom) and the OPLS...

[Determination by thermometric titrimetry of the thermodynamic parameters of water/n-octanol transfer of several non-steroidal anti-inflammatory drugs].

Science.gov (United States)

Burgot, G; Burgot, J L

1995-01-01

The calorimetric determination by thermometric titrimetry of the water/n-octanol transfer enthalpies of some non steroidic anti-inflammatory compounds is described. By combining the values obtained with that of the free enthalpies of transfer issuing from the values of corresponding log P, it is possible to determinate the transfer entropies of the solutes. The whole results of the show that almost the transfers are both enthalpy and entropy driven. They demonstrate the occurrence of three different mechanisms of transfer.

Influence of soil pH on the sorption of ionizable chemicals: modeling advances.

Science.gov (United States)

Franco, Antonio; Fu, Wenjing; Trapp, Stefan

2009-03-01

The soil-water distribution coefficient of ionizable chemicals (K(d)) depends on the soil acidity, mainly because the pH governs speciation. Using pH-specific K(d) values normalized to organic carbon (K(OC)) from the literature, a method was developed to estimate the K(OC) of monovalent organic acids and bases. The regression considers pH-dependent speciation and species-specific partition coefficients, calculated from the dissociation constant (pK(a)) and the octanol-water partition coefficient of the neutral molecule (log P(n)). Probably because of the lower pH near the organic colloid-water interface, the optimal pH to model dissociation was lower than the bulk soil pH. The knowledge of the soil pH allows calculation of the fractions of neutral and ionic molecules in the system, thus improving the existing regression for acids. The same approach was not successful with bases, for which the impact of pH on the total sorption is contrasting. In fact, the shortcomings of the model assumptions affect the predictive power for acids and for bases differently. We evaluated accuracy and limitations of the regressions for their use in the environmental fate assessment of ionizable chemicals.

Electrochemical Sensing and Assessment of Parabens in Hydro- Alcoholic Solutions and Water Using a Boron-Doped Diamond Electrode

Directory of Open Access Journals (Sweden)

Vasile Ostafe

2008-07-01

Full Text Available In this paper, the electrochemical behaviour of several parabens preservatives, i.e. esters of p-hydroxybenzoic acid, methyl-, ethyl- and propyl-4-hydroxybenzoates as methyl-, ethyl- and propyl-parabens (MB, EB, and PB, has been investigated at a commercial boron-doped diamond electrode (BDDE, especially in the anodic potential range, in both hydro-alcoholic and aqueous media. The cyclic voltammetric and chronoamperometric measurements yielded calibration plots with very good linearity (R2 between 0.990 and 0.998 and high sensitivity, useful for detection and analytical applications. The determination of the characteristics of individual compounds, of an “overall paraben index”, the assessment of the stability and the saturation solubility in water, and the amperometric sensing and determination in double distilled, tap and river water matrix of the relatively slightly soluble investigated parabens have been carried out using electrochemical alternative. Estimated water solubility was correlated with the octanol-water partition coefficient. Several ideas regarding stability and persistence of the presumptive eco-toxic investigated preservatives in the environment or water systems have been adjacently discussed.

Comparison of 2-Octanol and Tributyl Phosphate in Recovery of Tungsten from Sulfuric-Phosphoric Acid Leach Solution of Scheelite

Science.gov (United States)

Liao, Yulong; Zhao, Zhongwei

2018-04-01

Tungsten was recovered from sulfuric-phosphoric acid leach solution of scheelite using 2-octanol and tributyl phosphate (TBP). Approximately 76% of the tungsten and less than 6.2% of the iron were extracted when using 70% 2-octanol, showing good selectivity for tungsten over iron; the tungsten extraction could not be significantly enhanced using a three-stage countercurrent simulation test. Moreover, more than 99.2% of the W and 91.0% of the Fe were extracted when using 70% TBP, showing poor selectivity, but after pretreating the leach solution with iron powder, less than 5.5% of the Fe was extracted. The loaded phases were stripped using deionized water and ammonia solution. The maximum stripping rate of tungsten from loaded 2-octanol was 45.6% when using water, compared with only 13.1% from loaded TBP. Tungsten was efficiently stripped from loaded phases using ammonia solution without formation of Fe(OH)3 precipitate. Finally, a flow sheet for recovery of tungsten with TBP is proposed.

Regional water coefficients for U.S. industrial sectors

Directory of Open Access Journals (Sweden)

Riccardo Boero

2017-12-01

Full Text Available Designing policies for water systems management requires the capability to assess the economic impacts of water availability and to effectively couple water withdrawals by human activities with natural hydrologic dynamics. At the core of any scientific approach to these issues there is the estimation of water withdrawals by industrial sectors in the form of water coefficients, which are measurements of the quantity of water withdrawn per dollar of GDP or output. In this work we focus on the contiguous United States and on the estimation of water coefficients for regional scale analyses. We first compare an established methodology for the estimation of national water coefficients with a parametric one we propose. Second, we introduce a method to estimate water coefficients at the level of ecological regions and we discuss how they reduce possible biases in regional analyses of water systems. We conclude discussing advantages and limits of regional water coefficients.

Partition coefficients for Ni, Cu, Pd, Pt, Rh, and Ir between monosulfide solid solution and sulfide liquid and the formation of compositionally zoned Ni-Cu sulfide bodies by fractional crystallization of sulfide liquid

DEFF Research Database (Denmark)

Barnes, S.J.; Makovicky, E.; Makovicky, M.

1996-01-01

of the system. There is a positive correlation between the partition coefficients and sulfur content of the monosulfide solid solution and between the partition coefficients and the sulfur content of the liquid. In sulfur-saturated and sulfur-over-saturated experimental systems, the metals behave in a manner...... (Alexo, Abitibi Greenstone Belt) and a zoned tholeiite-related ore (Oktyabr'sky, Noril'sk region, Siberia). In both cases, the experimental partition coefficients numerically model the composition zones of the actual ores. This supports the model of fractional crystallization of a monosulfide solid...

Thermodynamic and structural description of europium complexation in 1-octanol - H2O solutions

International Nuclear Information System (INIS)

Vu, T.H.; Charbonnel, M.C.; Boubals, N.; Couston, L.; Arnaud, F.

2008-01-01

Polydentate N-bearing ligands such as bis-triazinyl-pyridines (BTPs) are interesting extractants for actinide(III)/lanthanide(III) separation. A description of europium complexation in 1-octanol solutions was undertaken to enhance the knowledge of the extraction mechanisms. The first solvation shell for europium(III) nitrate, chloride, and perchlorate with different amounts of water was determined by Time-Resolved Laser-Induced Fluorescence (TRLIF) spectroscopy. Europium nitrate complexation by iPr-BTP was then studied by TRLIF and micro-calorimetry; similar stability constants related to the formation of Eu(BTP) 2 3+ and Eu(BTP) 3 3+ were obtained by both techniques (log(β 2 ) = 9.0 ± 0.3 and log(β 3 ) = 13.8 ± 0.2). The presence of water in the octanol diluent has an influence on solvation of europium and also on the [Eu(BTP) 2 3+ ] / [Eu(BTP) 3 3+ ] ratio. (authors)

The use of phospholipid modified column for the determination of lipophilic properties in high performance liquid chromatography.

Science.gov (United States)

Godard, Tal; Grushka, Eli

2011-03-04

A new chromatographic stationary phase obtained by coating a reversed phase amide column with phosphatidylcholine based liposomes solution to yield a phospholipid modified column (PLM). The modification is achieved by the dynamic coating method which recycles the coating solution through the column in a closed loop for a period of 24 h. The chromatographic properties of the new column have changed significantly as compared to the original amide column due to the phospholipid coating. A good correlation was observed between n-octanol/water logP values and the logarithm of the retention factor obtained on the PLM column for a large number of solutes. In addition the PLM column was characterized using the linear solvation energy relationship (LSER). The values of the LSER system constants for the PLM column were calculated and were found to be very close to those of the n-octanol/water extraction system thus suggesting that the PLM column can be used for the estimation of n-octanol/water partition coefficient and serve as a possible alternative to the shake-flask method for lipophilicity determination. In addition, the results suggest that the PLM column can provide an alternative to other phospholipid-based column such as the IAM and the DPC columns. Copyright © 2011 Elsevier B.V. All rights reserved.

Measurement and prediction of aromatic solute distribution coefficients for aqueous-organic solvent systems. Final report

Energy Technology Data Exchange (ETDEWEB)

Campbell, J.R.; Luthy, R.G.

1984-06-01

Experimental and modeling activities were performed to assess techniques for measurement and prediction of distribution coefficients for aromatic solutes between water and immiscible organic solvents. Experiments were performed to measure distribution coefficients in both clean water and wastewater systems, and to assess treatment of a wastewater by solvent extraction. The theoretical portions of this investigation were directed towards development of techniques for prediction of solute-solvent/water distribution coefficients. Experiments were performed to assess treatment of a phenolic-laden coal conversion wastewater by solvent extraction. The results showed that solvent extraction for recovery of phenolic material offered several wastewater processing advantages. Distribution coefficients were measured in clean water and wastewater systems for aromatic solutes of varying functionality with different solvent types. It was found that distribution coefficients for these compounds in clean water systems were not statistically different from distribution coefficients determined in a complex coal conversion process wastewater. These and other aromatic solute distribution coefficient data were employed for evaluation of modeling techniques for prediction of solute-solvent/water distribution coefficients. Eight solvents were selected in order to represent various chemical classes: toluene and benzene (aromatics), hexane and heptane (alkanes), n-octanol (alcohols), n-butyl acetate (esters), diisopropyl ether (ethers), and methylisobutyl ketone (ketones). The aromatic solutes included: nonpolar compounds such as benzene, toluene and naphthalene, phenolic compounds such as phenol, cresol and catechol, nitrogenous aromatics such as aniline, pyridine and aminonaphthalene, and other aromatic solutes such as naphthol, quinolinol and halogenated compounds. 100 references, 20 figures, 34 tables.

Evaluating use stage exposure to food contact materials in a LCA framework

DEFF Research Database (Denmark)

Ernstoff, Alexi; Jolliet, Olivier; Fantke, Peter

2015-01-01

We present novel methods to incorporate exposure to chemicals within food contact materials (FCM) (e.g. packaging) into life cycle impact assessment (LCIA). Chemical migration into food is modeled as a function of contact temperature, time, and various chemical, FCM, and food properties. In order...... in a way compatible with intake fraction, iF, a metric traditionally used in LCIA. The model predicts PiF increases with temperature and for compounds with lower octanol-water partition coefficients within more permeable materials which are in contact with foods with high ethanol equivalencies (fatty foods)....

Salt partitioning between water and high-pressure ices. Implication for the dynamics and habitability of icy moons and water-rich planetary bodies

Science.gov (United States)

Journaux, Baptiste; Daniel, Isabelle; Petitgirard, Sylvain; Cardon, Hervé; Perrillat, Jean-Philippe; Caracas, Razvan; Mezouar, Mohamed

2017-04-01

Water-rich planetary bodies including large icy moons and ocean exoplanets may host a deep liquid water ocean underlying a high-pressure icy mantle. The latter is often considered as a limitation to the habitability of the uppermost ocean because it would limit the availability of nutrients resulting from the hydrothermal alteration of the silicate mantle located beneath the deep ice layer. To assess the effects of salts on the physical properties of high-pressure ices and therefore the possible chemical exchanges and habitability inside H2O-rich planetary bodies, we measured partitioning coefficients and densities in the H2O-RbI system up to 450 K and 4 GPa; RbI standing as an experimentally amenable analog of NaCl in the H2O-salt solutions. We measured the partitioning coefficient of RbI between the aqueous fluid and ices VI and VII, using in-situ Synchrotron X-ray Fluorescence (XRF). With in-situ X-ray diffraction, we measured the unit-cell parameters and the densities of the high-pressure ice phases in equilibrium with the aqueous fluid, at pressures and temperatures relevant to the interior of planetary bodies. We conclude that RbI is strongly incompatible towards ice VI with a partitioning coefficient Kd(VI-L) = 5.0 (± 2.1) ṡ10-3 and moderately incompatible towards ice VII, Kd(VII-L) = 0.12 (± 0.05). RbI significantly increases the unit-cell volume of ice VI and VII by ca. 1%. This implies that RbI-poor ice VI is buoyant compared to H2O ice VI while RbI-enriched ice VII is denser than H2O ice VII. These new experimental results might profoundly impact the internal dynamics of water-rich planetary bodies. For instance, an icy mantle at moderate conditions of pressure and temperature will consist of buoyant ice VI with low concentration of salt, and would likely induce an upwelling current of solutes towards the above liquid ocean. In contrast, a deep and/or thick icy mantle of ice VII will be enriched in salt and hence would form a stable chemical boundary

Funciones termodinámicas relativas a la transferencia del ketoprófen desde el agua hasta algunos sistemas orgánicos Thermodynamic functions relative to the transfer of ketoprofen from water to some organic systems

Directory of Open Access Journals (Sweden)

Hernán R. Lozano

2006-07-01

Full Text Available The thermodynamics of molal partitioning of ketoprofen (KTP was studied in cyclohexane/buffer (CH/W, octanol/buffer (ROH/W, and dimyristoyl phosphatidylcholine (DMPC, dipalmitoyl phosphatidylcholine (DPPC, and egg lecithin (EGG/W liposome systems. In all cases the partition coefficients (Kmo/wwere greater than unity; therefore the standard free energies of transfer were negative indicating affinity of KTP for organic media. The Kmo/w values were approximately seventy-fold higher in the ROH/W system compared with the CH/W system. On the other hand, the Kmo/w values were approximately ten or fifty-fold higher in the liposomes compared with the ROH/W system. In all cases, the standard enthalpies and entropies of transfer of KTP were positive indicating some degree of participation of the hydrophobic hydration on partitioning processes.

Mapping Pesticide Partition Coefficients By Electromagnetic Induction

Science.gov (United States)

A potential method for reducing pesticide leaching is to base application rates on the leaching potential of a specific chemical and soil combination. However, leaching is determined in part by the partitioning of the chemical between the soil and soil solution, which varies across a field. Standard...

Metal partitioning and uptake in central Ontario forests

International Nuclear Information System (INIS)

Watmough, Shaun A.; Dillon, Peter J.; Epova, Ekaterina N.

2005-01-01

Evaluation of the potential environmental risk posed by metals depends to a great extent on modeling the fate and mobility of metals with soil-solution partitioning coefficients (K d ). However, the effect of biological cycling on metal partitioning is rarely considered in standard risk assessments. We determined soil-solution partitioning coefficients for 5 metals (Cd, Zn, Pb, Co and Ni) at 46 forested sites that border the Precambrian Shield in central Ontario, where soil pH aq varied from 3.9 to 8.1. Foliage from the dominant tree species and forest floor samples were also collected from each site to compare their metal levels with K d predictions. Analogous to other studies, log K d values for all metals were predicted by empirical linear regression with soil pH (r 2 = 0.66-0.72), demonstrating that metal partitioning between soil and soil solution can be reliably predicted for relatively unpolluted forest mineral soils by soil pH. In contrast, whereas the so-called bioavailable water-soluble metal fraction could be predicted from soil pH, metal concentrations in foliage and the forest floor at each site were not consistently related to pH. Risk assessment of metals should take into account the role of biota in metal cycling and partitioning in forests, particularly if metal bio-accumulation and chronic toxicity in the food chain, rather than metal mobility in soils, are of primary concern. - Metal cycling by plants should be considered in risk assessment studies

Biodegradação de alcoóis, ftalatos e adipatos em um solo tropical contaminado Biodegradation of alcohol, phthalates and adipates in a tropical soil

Directory of Open Access Journals (Sweden)

Ieda Domingues Ferreira

2010-01-01

Full Text Available The adipic and phthalic acid esters are plasticizers, have low water solubility, high partition octanol/water coefficients (Kow and accumulate in soil and sediments. These compounds are considered teratogenic, carcinogenic and endocrine disruptors chemicals. This study evaluated the bioremediation of tropical soil contaminated with plasticizers process wastes, in aerobic conditions, with and without introduction of acclimated bacteria. It was selected 200 kg of contaminated tropical soil for the biodegradation study. The plasticizers concentrations in soil ranged between 153 mgDOA/kg up to 15552 mgDIDP/kg and after 90 days of biodegradation, the lower removal efficiencies were 72% with a 1-2 log simultaneous bacterial growth.

A rapid-mix study on the effect of lipophilicity of nitroimidazoles on the radiosensitization of mammalian cells in vitro

International Nuclear Information System (INIS)

Watts, M.E.; Hodgkiss, R.J.; Jones, N.R.; Sehmi, D.S.; Woodcock, M.

1983-01-01

A liquid flow rapid-mixing apparatus has been used to study the role of lipophilicity (octanol: water partition coefficient, P) in the sensitization of hypoxic V79 cells by nitroimidazoles. Sensitization by seven neutral 2-nitroimidazoles of similar reduction potential but widely differing partition (0.11-77) and one basic 2-nitroimidazole (pKsub(a) = 8.9; p = 8.5 (of free base)) was studied as a function of pre-irradiated contact time ca. 3-40 ms. With increasing P, sensitization occurs at increasingly shorter pre-irradiated contact times. The results suggest that even though factors other than passive diffusion control the sensitization observed with the base Ro 03-8799 it is able to diffuse to the target site faster than misonidazole. (author)

Polychlorinated biphenyls and their interaction with the environment

Energy Technology Data Exchange (ETDEWEB)

Dickerson, K.S.; Korte, N.E.

1994-05-01

This document is a review of the existing technical literature regarding the physical and biological properties of polychlorinated biphenyls (PCBs) and their interaction with the environment. It is intended to be used when evaluating PCB-contaminated soil and the effects of specific environmental conditions on PCB degradation. PCBs are a class of chlorinated aromatic compounds with 209 possible structural arrangements. The composition of PCBs in the environment changes over time due to various physiochemical and biological properties and processes: vapor pressure, solubility, octanol-water partitioning, adsorption, and biodegradation. As the number of chlorine atoms increases, both vapor pressure and water solubility decrease, while adsorption and the octanol-water partitioning coefficient increase. Dechlorination of PCBs occurs primarily through aerobic and anaerobic microbial degradation. Aerobic bacteria preferentially dechlorinate less-chlorinated PCBs, while anaerobic bacteria preferentially dechlorinate more highly chlorinated PCBs. The less-chlorinated PCB congeners are less persistent in the environment due to volatilization, solubility, and aerobic biodegradation, while the more-chlorinated PCBs are more persistent in the environment due to adsorption. The composition of an original PCB mixture in the environment can be expected to change due to a combination of processes described above. Any attempt to determine the source of PCBs or Aroclors identified in an environment sample must be approached with caution to avoid inaccurate conclusions.

Trauma-induced reactive gliosis is reduced after treatment with octanol and carbenoxolone.

Science.gov (United States)

Andersson, Heléne C; Anderson, Michelle F; Porritt, Michelle J; Nodin, Christina; Blomstrand, Fredrik; Nilsson, Michael

2011-07-01

Reactive gliosis and scar formation after brain injury can inhibit the recovery process. As many glial cells utilize gap junctions for intercellular signaling, this study investigated whether two commonly used gap junction blockers, octanol and carbenoxolone, could attenuate reactive gliosis following a minor traumatic brain injury. Octanol (710 mg/kg) or carbenoxolone (90 mg/kg) was administered 30 minutes before or after a needle track injury in adult male Sprague-Dawley rats. To mark dividing cells, animals were injected with bromodeoxyuridine (BrdU; 150 mg/kg) intraperitoneally two times per day, 8 hours apart and killed 2 days later. Immunohistochemistry for BrdU and markers for reactive glial cells [glial fibrillary acidic protein (GFAP), ED1, and NG2] were investigated using immunohistochemistry and western blot techniques. Two days after injury, increased cellular proliferation, activated astrocytes and microglia, and upregulation of NG2 expression were observed surrounding the injury site. Octanol and carbenoxolone administrated prior to injury significantly decreased cell proliferation by 60 and 70% respectively. The distance of GFAP immunoreactive astrocytes from the wound margin was decreased by 32 and 18% when octanol was administrated prior to or post injury respectively. Treatment with octanol also decreased the number of reactive microglia by 55% and, when administrated prior to injury, octanol reduced the distance of NG2 expression from the wound by 48%. The present study demonstrates that two important components of reactive gliosis, cellular activation and proliferation, can be attenuated by octanol and carbenoxolone.

A novel method for the determination of adsorption partition coefficients of minor gases in a shale sample by headspace gas chromatography.

Science.gov (United States)

Zhang, Chun-Yun; Hu, Hui-Chao; Chai, Xin-Sheng; Pan, Lei; Xiao, Xian-Ming

2013-10-04

A novel method has been developed for the determination of adsorption partition coefficient (Kd) of minor gases in shale. The method uses samples of two different sizes (masses) of the same material, from which the partition coefficient of the gas can be determined from two independent headspace gas chromatographic (HS-GC) measurements. The equilibrium for the model gas (ethane) was achieved in 5h at 120°C. The method also involves establishing an equation based on the Kd at higher equilibrium temperature, from which the Kd at lower temperature can be calculated. Although the HS-GC method requires some time and effort, it is simpler and quicker than the isothermal adsorption method that is in widespread use today. As a result, the method is simple and practical and can be a valuable tool for shale gas-related research and applications. Copyright © 2013 Elsevier B.V. All rights reserved.

Influence of monitoring data selection for optimization of a steady state multimedia model on the magnitude and nature of the model prediction bias.

Science.gov (United States)

Kim, Hee Seok; Lee, Dong Soo

2017-11-01

SimpleBox is an important multimedia model used to estimate the predicted environmental concentration for screening-level exposure assessment. The main objectives were (i) to quantitatively assess how the magnitude and nature of prediction bias of SimpleBox vary with the selection of observed concentration data set for optimization and (ii) to present the prediction performance of the optimized SimpleBox. The optimization was conducted using a total of 9604 observed multimedia data for 42 chemicals of four groups (i.e., polychlorinated dibenzo-p-dioxins/furans (PCDDs/Fs), polybrominated diphenyl ethers (PBDEs), phthalates, and polycyclic aromatic hydrocarbons (PAHs)). The model performance was assessed based on the magnitude and skewness of prediction bias. Monitoring data selection in terms of number of data and kind of chemicals plays a significant role in optimization of the model. The coverage of the physicochemical properties was found to be very important to reduce the prediction bias. This suggests that selection of observed data should be made such that the physicochemical property (such as vapor pressure, octanol-water partition coefficient, octanol-air partition coefficient, and Henry's law constant) range of the selected chemical groups be as wide as possible. With optimization, about 55%, 90%, and 98% of the total number of the observed concentration ratios were predicted within factors of three, 10, and 30, respectively, with negligible skewness. Copyright © 2017 Elsevier Ltd. All rights reserved.

The role of octanol in the extraction of hydrochloric acid by trilaurylamine dissolved in benzene

International Nuclear Information System (INIS)

Muhammed, M.A.

1976-01-01

The extraction of hydrochloric acid by trilaurylamine (TLA) dissolved in benzene was studied in the presence and in absence of n-octanol. The extraction of HCl was found to be enhanced by the addition of octanol to the organic phase. In order to explain this effect by means of the law of mass action, the systems TLA-HCl-benzene and n-octanol-HCl-benzene as well as TLA-octanol-benzene were also studied. It was found that TLA reacts with octanol to form a complex TLAROH, while the octanol itself associates in benzene to form dimers and tetramers, although it does not extract HCl alone from the dilute solutions used in the present study. The enhancement of the extraction of HCl by TLA upon the addition of n-octanol could be described by the formation of the species TLA.ROH.HCl and its stability constant was determined. (author)

Sorption of radon-222 to natural sediments

International Nuclear Information System (INIS)

Wong, C.S.; Chin, Y.P.; Gschwend, P.M.

1992-01-01

The sorption of radon to sediments was investigated, since this may affect the use of porewater radon profiles for estimating bed irrigation rates. Batch experiments showed that radon has an organic-carbon-normalized sediment-water partition coefficient (K oc , L kg oc -1 ) of 21.1 ± 2.9 for a Boston Harbor sediment, 25.3 ± 2.1 for a Charles River sediment, and 22.4 ± 2.6 for a Buzzards Bay sediment. These values are in close agreement with predictions using radon's octanol-water partition coefficient (K ow ), which was measured to be 32.4 ± 1.5. Temperature and ionic strength effects on K oc were estimated to be small. Given rapid sorption kinetics, the authors suggest that slurry stripping techniques used by many investigators to measure 222 Rn in sediment samples collect both sorbed and dissolved radon. Sorption effects were included in a transport model to obtain revised estimates of irrigation rates from existing literature profiles. Irrigation rates had to be increased over previously reported values in proportion to the sediment organic matter content

Influence of biochar on isoproturon partitioning and bioaccessibility in soil.

Science.gov (United States)

Reid, B J; Pickering, F L; Freddo, A; Whelan, M J; Coulon, F

2013-10-01

The influence of biochar (5%) on the loss, partitioning and bioaccessibility of (14)C-isoproturon ((14)C-IPU) was evaluated. Results indicated that biochar had a dramatic effect upon (14)C-IPU partitioning: (14)C-IPU extractability (0.01 M CaCl2) in biochar-amended treatments was reduced to <2% while, (14)C-IPU extractability in biochar free treatments decreased with ageing from 90% to 40%. A partitioning model was constructed to derive an effective partition coefficient for biochar:water (KBW of 7.82 × 10(4) L kg(-1)). This was two orders of magnitude greater than the apparent Kfoc value of the soil organic carbon:water (631 L kg(-1)). (14)C-radiorespirometry assays indicated high competence of microorganisms to mineralise (14)C-IPU in the absence of biochar (40.3 ± 0.9%). Where biochar was present (14)C-IPU mineralisation never exceeded 2%. These results indicate reduced herbicide bioaccessibility. Increasing IPU application to ×10 its recommended dose was ineffective at redressing IPU sequestration and its low bioaccessibility. Copyright © 2013 Elsevier Ltd. All rights reserved.

Preparation of (S)-1-Halo-2-octanols Using Ionic Liquids and Biocatalysts.

Science.gov (United States)

Oromí-Farrús, Mireia; Eras, Jordi; Sala, Núria; Torres, Mercè; Canela, Ramon

2009-10-23

Preparation of (S)-1-chloro-2-octanol and (S)-1-bromo-2-octanol was carried out by the enzymatic hydrolysis of halohydrin palmitates using biocatalysts. Halohydrin palmitates were prepared by various methods from palmitic acid and 1,2-octanediol. A tandem hydrolysis was carried out using lipases from Candida antarctica (Novozym 435), Rhizomucor miehei (Lipozyme IM), and "resting cells" from a Rhizopus oryzae strain that was not mycotoxigenic. The influence of the enzyme and the reaction medium on the selective hydrolysis of isomeric mixtures of halohydrin esters is described. Novozym 435 allowed preparation of (S)-1-chloro-2-octanol and (S)-1-bromo-2-octanol after 1-3 h of reaction at 40 degrees C in [BMIM][PF(6)].

Solution thermodynamics of pyrazinamide, isoniazid, and p-aminobenzoic acid in buffers and octanol

International Nuclear Information System (INIS)

Blokhina, Svetlana V.; Ol’khovich, Marina V.; Sharapova, Angelica V.; Volkova, Tatyana V.; Perlovich, German L.

2015-01-01

Highlights: • Solubility of pyrazinamide, isoniazid, p-aminobenzoic acid were measured. • The activity coefficients of the compounds at infinite dilution were determined. • Thermodynamic functions of dissolution and solvation were calculated. - Abstract: The solubility values of pyrazinamide, isoniazid, and p-aminobenzoic acid in buffers (pH 2.0 and 7.4) and octanol were measured in the temperature range of 293.15 to 313.15 K. The dissolution Gibbs energy, enthalpy, and entropy were calculated. The dissolving process was endothermic and enthalpy-determined. The activity coefficients of the compounds at infinite dilution were determined based on the solubility data and thermophysical parameters. A positive deviation from the ideality was observed in all the solutions. A common tendency of the solubility increase with a decrease in the activity coefficients at T = 298.15 K was revealed for the investigated solute-solvent systems. The excess thermodynamic solubility functions were calculated from the temperature dependences of the activity coefficients. The solvation processes were found to have a considerable influence on the solubility of the substances in solutions studied.

Lipid solubility of the platinum group metals Pt, Pd and Rh in dependence on the presence of complexing agents

International Nuclear Information System (INIS)

Zimmermann, Sonja; Menzel, Christoph M.; Stueben, Doris; Taraschewski, Horst; Sures, Bernd

2003-01-01

All complexing agents had a significant influence on octanol solubility of PGM. - Investigations on the bioaccumulation of the platinum group metals (PGM) Pt, Pd and Rh in aquatic organisms are of growing interest in environmental research due to the increasing emission of these metals by motor vehicles with catalytic converters. Until now, nothing is known about the possible influence of complexing agents on the bioaccumulation capacity of these precious metals. According to the partition coefficient between 1-octanol and water (P OW ) as a measure of bioaccumulation, in this study a simple shaking method was performed in order to investigate the effects of different complexing agents (L-methionine, thio urea, EDTA, humic substances, bile compounds) on the octanol solubility of the PGM. The results demonstrated a significant influence of all agents used. L-Methionine and thio urea decreased the lipid solubility. In contrast, the presence of EDTA, humic substances and especially bile caused a higher transfer of metals in the octanol phase. For most complexing agents tested, the transfer of Pd to the lipid phase was significantly higher compared with Rh and Pt, except for bile acid where the highest octanol solubility was found for Pt. Recent experimental results on PGM accumulation in zebra mussels confirm a high bioaccumulation of Pd which could be predicted from the lipid solubility

Lipid solubility of the platinum group metals Pt, Pd and Rh in dependence on the presence of complexing agents

Energy Technology Data Exchange (ETDEWEB)

Zimmermann, Sonja; Menzel, Christoph M.; Stueben, Doris; Taraschewski, Horst; Sures, Bernd

2003-07-01

All complexing agents had a significant influence on octanol solubility of PGM. - Investigations on the bioaccumulation of the platinum group metals (PGM) Pt, Pd and Rh in aquatic organisms are of growing interest in environmental research due to the increasing emission of these metals by motor vehicles with catalytic converters. Until now, nothing is known about the possible influence of complexing agents on the bioaccumulation capacity of these precious metals. According to the partition coefficient between 1-octanol and water (P{sub OW}) as a measure of bioaccumulation, in this study a simple shaking method was performed in order to investigate the effects of different complexing agents (L-methionine, thio urea, EDTA, humic substances, bile compounds) on the octanol solubility of the PGM. The results demonstrated a significant influence of all agents used. L-Methionine and thio urea decreased the lipid solubility. In contrast, the presence of EDTA, humic substances and especially bile caused a higher transfer of metals in the octanol phase. For most complexing agents tested, the transfer of Pd to the lipid phase was significantly higher compared with Rh and Pt, except for bile acid where the highest octanol solubility was found for Pt. Recent experimental results on PGM accumulation in zebra mussels confirm a high bioaccumulation of Pd which could be predicted from the lipid solubility.

Calculating the Solubilities of Drugs and Drug-Like Compounds in Octanol.

Science.gov (United States)

Alantary, Doaa; Yalkowsky, Samuel

2016-09-01

A modification of the Van't Hoff equation is used to predict the solubility of organic compounds in dry octanol. The new equation describes a linear relationship between the logarithm of the solubility of a solute in octanol to its melting temperature. More than 620 experimentally measured octanol solubilities, collected from the literature, are used to validate the equation without using any regression or fitting. The average absolute error of the prediction is 0.66 log units. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Partition thermodynamics of ionic surfactants between phosphatidylcholine vesicle and water phases

Science.gov (United States)

Chu, Shin-Chi; Hung, Chia-Hui; Wang, Shun-Cheng; Tsao, Heng-Kwong

2003-08-01

The partition of ionic surfactants (sodium alkyl sulfate and alkyl trimethyl ammonium bromide) between phosphatidylcholine vesicles and aqueous phase is investigated by simple conductometry under different temperatures. The experimental results can be well represented by the proposed regular solution theory and the thermodynamic parameters satisfy the thermodynamic consistency. The deviation from ideal partition is manifested through the effective interaction energy between lipid and surfactant wb, which is O(kT) large. It is found that wb rises as the alkyl chain is decreased for a specified head group. This is attributed to significant mismatch of chain lengths between surfactant and lipid molecules. The partition coefficient K declines with increasing temperature. The energy barrier from bilayer to aqueous phase, Δμ/kT∝ln K, is in the range of 16-26 kJ/mol. As the alkyl chain length is decreased for a given head group, Δμ is lowered by 1.3-1.5 kJ/mol per methylene group. Two independent analyses are employed to confirm this result. Using the thermodynamic parameters determined from experiments, the internal energy, entropy, and free energy of the partition process can be derived. Partition is essentially driven by the internal energy gain. The solubilizing ability, which is represented by the maximum surfactant-lipid ratio in the bilayer, Reb also decreases in accord with the K parameter. It is because the change in temperature influences the surfactant incorporation into the bilayer more than the formation of micelles.

Partitioning of etofenprox under simulated California rice-growing conditions.

Science.gov (United States)

Vasquez, Martice E; Gunasekara, Amrith S; Cahill, Thomas M; Tjeerdema, Ronald S

2010-01-01

The pyrethroid insecticide etofenprox is of current interest to rice farmers in the Sacramento Valley owing to its effectiveness against the rice water weevil, Lissorhoptrus oryzophilus Kuschel. This study aimed to describe the partitioning of etofenprox under simulated rice field conditions by determining its Henry's law constant (H) (an estimate of volatilization) and organic carbon-normalized soil-water distribution coefficient (K(oc)) at representative field temperatures. A comparison of etofenprox and lambda-cyhalothrin is presented using a level-1 fugacity model. Experimental determination of H revealed that etofenprox partitioned onto the apparatus walls and did not significantly volatilize; the maximum value of H was estimated to be 6.81 x 10(-1) Pa m(3) mol(-1) at 25 degrees C, based on its air and water method detection limits. Calculated values for H ranged from 5.6 x 10(-3) Pa m(3) mol(-1) at 5 degrees C to 2.9 x 10(-1) Pa m(3) mol(-1) at 40 degrees C, based on estimated solubility and vapor pressure values at various temperatures. Log K(oc) values (at 25 degrees C) were experimentally determined to be 6.0 and 6.4 for Princeton and Richvale rice field soils, respectively, and were very similar to the values for other pyrethroids. Finally, temperature appears to have little influence on etofenprox sorption, as the log K(oc) for the Princeton soil at 35 degrees C was 6.1. High sorption coefficients and relatively insignificant desorption and volatilization of etofenprox suggest that its insolubility drives it to partition from water by sorbing to soils with high affinity. Offsite movement is unlikely unless transported in a bound state on suspended sediments.

Study on superhydrophobic surfaces of octanol grafted electrospun silica nanofibers

International Nuclear Information System (INIS)

Meng, Long-Yue; Han, Shunyu; Jiang, Nanzhe; Meng, Wan

2014-01-01

In this work, superhydrophobic surfaces were successfully prepared by grafting of octanol on the surface of electrospun silica nanofibers (SNFs). The chemical compositions and microstructures of the prepared SNFs surfaces were investigated by using N 2 full isotherms, Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and contact angle measurements. The results indicate that the surface of SNFs changed from being superhydrophilic to superhydrophobic by octanol surface grafting. The contact angle of the octanol-grafted SNFs was close to 150.2° because their surface was modified by –(CH 2 ) 6 –CH 3 groups. The 3D network of SNFs networks and the low surface energy of the alkyl side chains played important roles in creating the superhydrophobic surface of the SNFs. - Highlights: • Superhydrophobic surface was prepared from electrospinning SNFs and by grafting octanol on their surface. • The surface of SNFs changed from superhydrophilic to superhydrophobic. • The CA of MSNFs became 150.2° because of interactions between grafted octyl groups

Study on superhydrophobic surfaces of octanol grafted electrospun silica nanofibers

Energy Technology Data Exchange (ETDEWEB)

Meng, Long-Yue [Key Laboratory of Natural Resources of Changbai Mountain and Functional Molecules, Yanbian University, Yanji 133002 (China); Department of Chemical Engineering, College of Engineering, Yanbian University, 977 Gongyuan Road, Yanji 133002 (China); Han, Shunyu; Jiang, Nanzhe [Department of Chemical Engineering, College of Engineering, Yanbian University, 977 Gongyuan Road, Yanji 133002 (China); Meng, Wan, E-mail: mengw@ybu.edu.cn [Department of Chemical Engineering, College of Engineering, Yanbian University, 977 Gongyuan Road, Yanji 133002 (China)

2014-12-15

In this work, superhydrophobic surfaces were successfully prepared by grafting of octanol on the surface of electrospun silica nanofibers (SNFs). The chemical compositions and microstructures of the prepared SNFs surfaces were investigated by using N{sub 2} full isotherms, Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and contact angle measurements. The results indicate that the surface of SNFs changed from being superhydrophilic to superhydrophobic by octanol surface grafting. The contact angle of the octanol-grafted SNFs was close to 150.2° because their surface was modified by –(CH{sub 2}){sub 6}–CH{sub 3} groups. The 3D network of SNFs networks and the low surface energy of the alkyl side chains played important roles in creating the superhydrophobic surface of the SNFs. - Highlights: • Superhydrophobic surface was prepared from electrospinning SNFs and by grafting octanol on their surface. • The surface of SNFs changed from superhydrophilic to superhydrophobic. • The CA of MSNFs became 150.2° because of interactions between grafted octyl groups.

Thermodynamic and structural description of europium complexation in 1-octanol - H{sub 2}O solutions

Energy Technology Data Exchange (ETDEWEB)

Vu, T.H.; Charbonnel, M.C.; Boubals, N.; Couston, L. [CEA Marcoule, DEN/DRCP/SCPS/LCAM, BP 17171, 30207 Bagnols-sur-Ceze (France); Arnaud, F. [Laboratoire de Chimie Physique, IPHC, 25 rue Becquerel, 67087 Strasbourg (France)

2008-07-01

Polydentate N-bearing ligands such as bis-triazinyl-pyridines (BTPs) are interesting extractants for actinide(III)/lanthanide(III) separation. A description of europium complexation in 1-octanol solutions was undertaken to enhance the knowledge of the extraction mechanisms. The first solvation shell for europium(III) nitrate, chloride, and perchlorate with different amounts of water was determined by Time-Resolved Laser-Induced Fluorescence (TRLIF) spectroscopy. Europium nitrate complexation by iPr-BTP was then studied by TRLIF and micro-calorimetry; similar stability constants related to the formation of Eu(BTP){sub 2}{sup 3+} and Eu(BTP){sub 3}{sup 3+} were obtained by both techniques (log({beta}{sub 2}) = 9.0 {+-} 0.3 and log({beta}{sub 3}) = 13.8 {+-} 0.2). The presence of water in the octanol diluent has an influence on solvation of europium and also on the [Eu(BTP){sub 2}{sup 3+}] / [Eu(BTP){sub 3}{sup 3+}] ratio. (authors)

Occurrence and partitioning of antibiotic compounds found in the water column and bottom sediments from a stream receiving two wastewater treatment plant effluents in Northern New Jersey, 2008

Energy Technology Data Exchange (ETDEWEB)

Gibs, Jacob, E-mail: jgibs@usgs.gov [U.S. Geological Survey, 810 Bear Tavern Road, West Trenton, NJ 08628 (United States); Heckathorn, Heather A. [U.S. Geological Survey, 810 Bear Tavern Road, West Trenton, NJ 08628 (United States); Meyer, Michael T. [U.S. Geological Survey, 4821 Quail Crest Place, Lawrence, KS 66049 (United States); Klapinski, Frank R.; Alebus, Marzooq; Lippincott, Robert L. [New Jersey Department of Environmental Protection, PO Box 413, Trenton, NJ 08625 (United States)

2013-08-01

An urban watershed in northern New Jersey was studied to determine the presence of four classes of antibiotic compounds (macrolides, fluoroquinolones, sulfonamides, and tetracyclines) and six degradates in the water column and bottom sediments upstream and downstream from the discharges of two wastewater treatment plants (WWTPs) and a drinking-water intake (DWI). Many antibiotic compounds in the four classes not removed by conventional WWTPs enter receiving waters and partition to stream sediments. Samples were collected at nine sampling locations on 2 days in September 2008. Two of the nine sampling locations were background sites upstream from two WWTP discharges on Hohokus Brook. Another background site was located upstream from a DWI on the Saddle River above the confluence with Hohokus Brook. Because there is a weir downstream of the confluence of Hohokus Brook and Saddle River, the DWI receives water from Hohokus Brook at low stream flows. Eight antibiotic compounds (azithromycin (maximum concentration 0.24 μg/L), ciprofloxacin (0.08 μg/L), enrofloxacin (0.015 μg/L), erythromycin (0.024 μg/L), ofloxacin (0.92 μg/L), sulfamethazine (0.018 μg/L), sulfamethoxazole (0.25 μg/L), and trimethoprim (0.14 μg/L)) and a degradate (erythromycin–H{sub 2}O (0.84 μg/L)) were detected in the water samples from the sites downstream from the WWTP discharges. The concentrations of six of the eight detected compounds and the detected degradate compound decreased with increasing distance downstream from the WWTP discharges. Azithromycin, ciprofloxacin, ofloxacin, and trimethoprim were detected in stream-bottom sediments. The concentrations of three of the four compounds detected in sediments were highest at a sampling site located downstream from the WWTP discharges. Trimethoprim was detected in the sediments from a background site. Pseudo-partition coefficients normalized for streambed sediment organic carbon concentration were calculated for azithromycin

Occurrence and partitioning of antibiotic compounds found in the water column and bottom sediments from a stream receiving two wastewater treatment plant effluents in Northern New Jersey, 2008

International Nuclear Information System (INIS)

Gibs, Jacob; Heckathorn, Heather A.; Meyer, Michael T.; Klapinski, Frank R.; Alebus, Marzooq; Lippincott, Robert L.

2013-01-01

An urban watershed in northern New Jersey was studied to determine the presence of four classes of antibiotic compounds (macrolides, fluoroquinolones, sulfonamides, and tetracyclines) and six degradates in the water column and bottom sediments upstream and downstream from the discharges of two wastewater treatment plants (WWTPs) and a drinking-water intake (DWI). Many antibiotic compounds in the four classes not removed by conventional WWTPs enter receiving waters and partition to stream sediments. Samples were collected at nine sampling locations on 2 days in September 2008. Two of the nine sampling locations were background sites upstream from two WWTP discharges on Hohokus Brook. Another background site was located upstream from a DWI on the Saddle River above the confluence with Hohokus Brook. Because there is a weir downstream of the confluence of Hohokus Brook and Saddle River, the DWI receives water from Hohokus Brook at low stream flows. Eight antibiotic compounds (azithromycin (maximum concentration 0.24 μg/L), ciprofloxacin (0.08 μg/L), enrofloxacin (0.015 μg/L), erythromycin (0.024 μg/L), ofloxacin (0.92 μg/L), sulfamethazine (0.018 μg/L), sulfamethoxazole (0.25 μg/L), and trimethoprim (0.14 μg/L)) and a degradate (erythromycin–H 2 O (0.84 μg/L)) were detected in the water samples from the sites downstream from the WWTP discharges. The concentrations of six of the eight detected compounds and the detected degradate compound decreased with increasing distance downstream from the WWTP discharges. Azithromycin, ciprofloxacin, ofloxacin, and trimethoprim were detected in stream-bottom sediments. The concentrations of three of the four compounds detected in sediments were highest at a sampling site located downstream from the WWTP discharges. Trimethoprim was detected in the sediments from a background site. Pseudo-partition coefficients normalized for streambed sediment organic carbon concentration were calculated for azithromycin, ciprofloxacin

Bayesian approach to estimate AUC, partition coefficient and drug targeting index for studies with serial sacrifice design.

Science.gov (United States)

Wang, Tianli; Baron, Kyle; Zhong, Wei; Brundage, Richard; Elmquist, William

2014-03-01

The current study presents a Bayesian approach to non-compartmental analysis (NCA), which provides the accurate and precise estimate of AUC 0 (∞) and any AUC 0 (∞) -based NCA parameter or derivation. In order to assess the performance of the proposed method, 1,000 simulated datasets were generated in different scenarios. A Bayesian method was used to estimate the tissue and plasma AUC 0 (∞) s and the tissue-to-plasma AUC 0 (∞) ratio. The posterior medians and the coverage of 95% credible intervals for the true parameter values were examined. The method was applied to laboratory data from a mice brain distribution study with serial sacrifice design for illustration. Bayesian NCA approach is accurate and precise in point estimation of the AUC 0 (∞) and the partition coefficient under a serial sacrifice design. It also provides a consistently good variance estimate, even considering the variability of the data and the physiological structure of the pharmacokinetic model. The application in the case study obtained a physiologically reasonable posterior distribution of AUC, with a posterior median close to the value estimated by classic Bailer-type methods. This Bayesian NCA approach for sparse data analysis provides statistical inference on the variability of AUC 0 (∞) -based parameters such as partition coefficient and drug targeting index, so that the comparison of these parameters following destructive sampling becomes statistically feasible.

Performance, combustion and emission analysis of mustard oil biodiesel and octanol blends in diesel engine

Science.gov (United States)

Devarajan, Yuvarajan; Munuswamy, Dinesh Babu; Nagappan, Beemkumar; Pandian, Amith Kishore

2018-01-01

Biodiesels from the mustard oil promise to be an alternative to the conventional diesel fuel due to their similarity in properties. Higher alcohols are added to neat Mustard oil biodiesel (M100) to vary the properties of biodiesel for improving its combustion, emission and performance characteristics. N-Octanol has the ability to act as an oxygen buffer during combustion which contributes to the catalytic effect and accelerates the combustion process. N-Octanol is dispersed to neat Mustard oil biodiesel in the form of emulsions at different dosage levels of 10, 20 and 30% by volume. Three emulsion fuels prepared for engine testing constitutes of 90% of biodiesel and 10% of n-Octanol (M90O10), 80% of biodiesel and 20% of n-Octanol (M80O20) and 70% of biodiesel and 30% of n-Octanol (M70O30) by volume respectively. AVL 5402 diesel engine is made to run on these fuels to study the effect of n-Octanol on combustion, emission and performance characteristics of the mustard oil biodiesel. Experimental results show that addition of n-octanol has a positive effect on performance, combustion and emission characteristics owing to its inbuilt oxygen content. N-octanol was found to be the better oxidizing catalyst as it was more effective in reducing HC and CO emissions. A significant reduction in NOx emission was found when fuelled with emulsion techniques. The blending of n-octanol to neat Mustard oil biodiesel reduces the energy and fuel consumption and a marginal increase in brake thermal efficiency. Further, n-octanol also reduces the ignition delay and aids the combustion.

Performance, combustion and emission analysis of mustard oil biodiesel and octanol blends in diesel engine

Science.gov (United States)

Devarajan, Yuvarajan; Munuswamy, Dinesh Babu; Nagappan, Beemkumar; Pandian, Amith Kishore

2018-06-01

Biodiesels from the mustard oil promise to be an alternative to the conventional diesel fuel due to their similarity in properties. Higher alcohols are added to neat Mustard oil biodiesel (M100) to vary the properties of biodiesel for improving its combustion, emission and performance characteristics. N-Octanol has the ability to act as an oxygen buffer during combustion which contributes to the catalytic effect and accelerates the combustion process. N-Octanol is dispersed to neat Mustard oil biodiesel in the form of emulsions at different dosage levels of 10, 20 and 30% by volume. Three emulsion fuels prepared for engine testing constitutes of 90% of biodiesel and 10% of n-Octanol (M90O10), 80% of biodiesel and 20% of n-Octanol (M80O20) and 70% of biodiesel and 30% of n-Octanol (M70O30) by volume respectively. AVL 5402 diesel engine is made to run on these fuels to study the effect of n-Octanol on combustion, emission and performance characteristics of the mustard oil biodiesel. Experimental results show that addition of n-octanol has a positive effect on performance, combustion and emission characteristics owing to its inbuilt oxygen content. N-octanol was found to be the better oxidizing catalyst as it was more effective in reducing HC and CO emissions. A significant reduction in NOx emission was found when fuelled with emulsion techniques. The blending of n-octanol to neat Mustard oil biodiesel reduces the energy and fuel consumption and a marginal increase in brake thermal efficiency. Further, n-octanol also reduces the ignition delay and aids the combustion.

The distribution and partitioning of common antibiotics in water and sediment of the Pearl River Estuary, South China.

Science.gov (United States)

Liang, Ximei; Chen, Baowei; Nie, Xiangping; Shi, Zhen; Huang, Xiaoping; Li, Xiangdong

2013-09-01

Antibiotics released into the aquatic environment play an important role in the spread of antibiotic resistance. In the Pearl River Estuary (PRE) and the coastal zone, the concentrations of antibiotics decreased from the Pearl River to the estuary, suggesting that antibiotics primarily originated from river tributaries and terrigenous sources. Within the PRE area, the concentrations of antibiotics in water were higher in the west coast than the east side, reflecting the high density of anthropogenic activities and hydraulic conditions along the west riverbank. Seasonal variations were also observed for most of detected antibiotics in water. The pseudo-partitioning coefficient of norfloxacin had a good correlation with the TOC content of sediments, as did erythromycin-H2O with the pH of water. The results suggest that environmental conditions can significantly affect the distribution of antibiotics between water and sediment. Copyright © 2013 Elsevier Ltd. All rights reserved.

Application of the Monte Carlo method for building up models for octanol-water partition coefficient of platinum complexes

Science.gov (United States)

Toropov, Andrey A.; Toropova, Alla P.

2018-06-01

Predictive model of logP for Pt(II) and Pt(IV) complexes built up with the Monte Carlo method using the CORAL software has been validated with six different splits into the training and validation sets. The improving of the predictive potential of models for six different splits has been obtained using so-called index of ideality of correlation. The suggested models give possibility to extract molecular features, which cause the increase or vice versa decrease of the logP.

Evaluation of the phase ratio for three C18 high performance liquid chromatographic columns.

Science.gov (United States)

Caiali, Edvin; David, Victor; Aboul-Enein, Hassan Y; Moldoveanu, Serban C

2016-02-26

For a chromatographic column, phase ratio Φ is defined as the ratio between the volume of the stationary phase Vst and the void volume of the column V0, and it is an important parameter characterizing the HPLC process. Although apparently simple, the evaluation of Φ presents difficulties because there is no sharp boundary between the mobile phase and the stationary phase. In addition, the boundary depends not only on the nature of the stationary phase, but also on the composition of the mobile phase. In spite of its importance, phase ratio is seldom reported for commercially available HPLC columns and the data typically provided by the vendors about the columns do not provide key information that would allow the calculation of Φ based on Vst and V0 values. A different procedure for the evaluation of Φ is based on the following formula: log k'j=a log Kow,j+log Φ, where k'j is the retention factor for a compound j that must be a hydrocarbon, Kow,j is the octanol/water partition coefficient, and a is a proportionality constant. Present study describes the experimental evaluation of Φ based on the measurement of k'j for the compounds in the homologous series between benzene and butylbenzene for three C18 columns: Gemini C18, Luna C18 both with 5 μm particles, and a Chromolith Performance RP-18. The evaluation was performed for two mobile phase systems at different proportions of methanol/water and acetonitrile/water. The octanol/water partition coefficients were obtained from the literature. The results obtained in the study provide further support for the new procedure for the evaluation of phase ratio. Copyright © 2016 Elsevier B.V. All rights reserved.

Pharmaceuticals in the Environment, Information for Assessing Risk (PEiAR)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The database provides information on prescribed amounts, levels detected in aquatic environments, chemical structure, molecular weight, octanol-water partition...

Positronium quenching in liquid and solid octanol and benzene

DEFF Research Database (Denmark)

Shantarovich, V.P.; Mogensen, O.E.; Goldanskii, V.I.

1970-01-01

The lifetimes of orthopositronium in several solutions in liquid and solid octanol and benzene have been measured. The Ps-quenching constant was found to be two to thirty times higher in the solid than in the liquid phase.......The lifetimes of orthopositronium in several solutions in liquid and solid octanol and benzene have been measured. The Ps-quenching constant was found to be two to thirty times higher in the solid than in the liquid phase....

Physical and chemical properties of pyrethroids.

Science.gov (United States)

Laskowski, Dennis A

2002-01-01

The physical and chemical properties of the pyrethroids bifenthrin, cyfluthrin, cypermethrin (also zetacypermethrin), deltamethrin, esfenvalerate (also fenvalerate), fenpropathrin, lambda-cyhalothrin (also cyhalothrin), permethrin, and tralomethrin have been reviewed and summarized in this paper. Physical properties included molecular weight, octanol-water partition coefficient, vapor pressure, water solubility, Henry's law constant, fish biocencentration factor, and soil sorption, desorption, and Freundlich coefficients. Chemical properties included rates of degradation in water as a result of hydrolysis, photodecomposition, aerobic or anaerobic degradation by microorganisms in the absence of light, and also rates of degradation in soil incubated under aerobic or anaerobic conditions. Collectively, the pyrethroids display a highly nonpolar nature of low water solubility, low volatility, high octanol-water partition coefficients, and have high affinity for soil and sediment particulate matter. Pyrethroids have low mobility in soil and are sorbed strongly to the sediments of natural water systems. Although attracted to living organisms because of their nonpolar nature, their capability to bioconcentrate is mitigated by their metabolism and subsequent elimination by the organisms. In fish, bioconcentration factors (BCF) ranged from 360 and 6000. Pyrethroids in water solution tend to be stable at acid and neutral pH but [table: see text] become increasingly susceptible to hydrolysis at pH values beyond neutral. Exceptions at higher pH are bifenthrin (stable), esfenvalerate (stable), and permethrin (half-life, 240 d). Pyrethroids vary in susceptibility to sunlight. Cyfluthrin and tralomethrin in water had half-lives of 0.67 and 2.5 d; lambda-cyhalothrin, esfenvalerate, deltamethrin, permethrin, and cypermethrin were intermediate with a range of 17-110 d; and bifenthrin and fenpropathrin showed the least susceptibility with half-lives of 400 and 600 d, respectively

Molecular Interaction Study of some ortho and para Substituted Anilines with 1-Octanol

OpenAIRE

Manjunatha, M. S.; Sannappa, J.

2010-01-01

Interactions between ortho and para substituents of anilines such as chloroaniline, methylaniline and methoxyaniline with 1-octanol have been studied in carbon tetrachloride. The most likely association of complex between 1-octanol and substituents of anilines is 1:1 stoichiometric complex, through hydroxyl group of 1-octanol and amine group of ortho and para substituents of anilines. Interactions are studied on the bases of formation constant and free energy changes. Formation constant of...

The persistence of polynuclear aromatic hydrocarbons in sewage sludge-amended agricultural soils

International Nuclear Information System (INIS)

Wild, S.R.; Jones, K.C.; Berrow, M.L.

1992-01-01

In 1968 five metal enriched sewage sludges containing different concentrations of polynuclear aromatic hydrocarbons (PAHs) were applied to different plots on field soils at two experimental sites, Luddington and Lee Valley in the UK. This resulted in substantial increases in soil ΣPAH concentrations in all plots. Since application compound specific losses have occurred, with the high molecular weight PAHs being more persistent. Calculated half-lives range from under 2 years for naphthalene to over 9 years for benzo[ghi]perylene and coronene. The loss of PAH compounds in these field experiments can be related, in part, to certain physico-chemical properties, namely water solubility and the octanol:water partition coefficients. 20 refs., 3 figs., 1 tab

Fast gradient HPLC method to determine compounds binding to human serum albumin. Relationships with octanol/water and immobilized artificial membrane lipophilicity.

Science.gov (United States)

Valko, Klara; Nunhuck, Shenaz; Bevan, Chris; Abraham, Michael H; Reynolds, Derek P

2003-11-01

A fast gradient HPLC method (cycle time 15 min) has been developed to determine Human Serum Albumin (HSA) binding of discovery compounds using chemically bonded protein stationary phases. The HSA binding values were derived from the gradient retention times that were converted to the logarithm of the equilibrium constants (logK HSA) using data from a calibration set of molecules. The method has been validated using literature plasma protein binding data of 68 known drug molecules. The method is fully automated, and has been used for lead optimization in more than 20 company projects. The HSA binding data obtained for more than 4000 compounds were suitable to set up global and project specific quantitative structure binding relationships that helped compound design in early drug discovery. The obtained HSA binding of known drug molecules were compared to the Immobilized Artificial Membrane binding data (CHI IAM) obtained by our previously described HPLC-based method. The solvation equation approach has been used to characterize the normal binding ability of HSA, and this relationship shows that compound lipophilicity is a significant factor. It was found that the selectivity of the "baseline" lipophilicity governing HSA binding, membrane interaction, and octanol/water partition are very similar. However, the effect of the presence of positive or negative charges have very different effects. It was found that negatively charged compounds bind more strongly to HSA than it would be expected from the lipophilicity of the ionized species at pH 7.4. Several compounds showed stronger HSA binding than can be expected from their lipophilicity alone, and comparison between predicted and experimental binding affinity allows the identification of compounds that have good complementarities with any of the known binding sites. Copyright 2003 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 92:2236-2248, 2003

Review of the partitioning of chemicals into different plastics: Consequences for the risk assessment of marine plastic debris

International Nuclear Information System (INIS)

O'Connor, Isabel A.; Golsteijn, Laura; Hendriks, A. Jan

2016-01-01

Marine plastic debris are found worldwide in oceans and coastal areas. They degrade only slowly and contain chemicals added during manufacture or absorbed from the seawater. Therefore, they can pose a long-lasting contaminant source and potentially transfer chemicals to marine organisms when ingested. In order to assess their risk, the contaminant concentration in the plastics needs to be estimated and differences understood. We collected from literature plastic water partition coefficients of various organic chemicals for seven plastic types: polydimethylsiloxane (PDMS), high-density, low-density and ultra-high molecular weight polyethylene (LDPE, HDPE, UHMWPE), polystyrene (PS), polypropylene (PP), and polyvinyl chloride (PVC). Most data was available for PDMS (1060) and LDPE (220), but much less for the remaining plastics (73). Where possible, regression models were developed and the partitioning was compared between the different plastic types. The partitioning of chemicals follows the order of LDPE ≈ HDPE ≥ PP > PVC ≈ PS. Data describing the impact of weathering are urgently needed. - Highlights: • Comparison of organic chemicals partitioning into seven plastic types • Linear correlation between plastic-water partition coefficient K pw and K ow • More data is needed for polypropylene, polystyrene and polyvinyl chloride. • In all plastic types, most K pw were similar to/smaller than the corresponding K ow .

Partitioning of polar and non-polar neutral organic chemicals into human and cow milk.

Science.gov (United States)

Geisler, Anett; Endo, Satoshi; Goss, Kai-Uwe

2011-10-01

The aim of this work was to develop a predictive model for milk/water partition coefficients of neutral organic compounds. Batch experiments were performed for 119 diverse organic chemicals in human milk and raw and processed cow milk at 37°C. No differences (milk were observed. The polyparameter linear free energy relationship model fit the calibration data well (SD=0.22 log units). An experimental validation data set including hormones and hormone active compounds was predicted satisfactorily by the model. An alternative modelling approach based on log K(ow) revealed a poorer performance. The model presented here provides a significant improvement in predicting enrichment of potentially hazardous chemicals in milk. In combination with physiologically based pharmacokinetic modelling this improvement in the estimation of milk/water partitioning coefficients may allow a better risk assessment for a wide range of neutral organic chemicals. Copyright © 2011 Elsevier Ltd. All rights reserved.

The influence of the surface composition of mixed monolayer films on the evaporation coefficient of water.

Science.gov (United States)

Miles, Rachael E H; Davies, James F; Reid, Jonathan P

2016-07-20

We explore the dependence of the evaporation coefficient of water from aqueous droplets on the composition of a surface film, considering in particular the influence of monolayer mixed component films on the evaporative mass flux. Measurements with binary component films formed from long chain alcohols, specifically tridecanol (C13H27OH) and pentadecanol (C15H31OH), and tetradecanol (C14H29OH) and hexadecanol (C16H33OH), show that the evaporation coefficient is dependent on the mole fractions of the two components forming the monolayer film. Immediately at the point of film formation and commensurate reduction in droplet evaporation rate, the evaporation coefficient is equal to a mole fraction weighted average of the evaporation coefficients through the equivalent single component films. As a droplet continues to diminish in surface area with continued loss of water, the more-soluble, shorter alkyl chain component preferentially partitions into the droplet bulk with the evaporation coefficient tending towards that through a single component film formed simply from the less-soluble, longer chain alcohol. We also show that the addition of a long chain alcohol to an aqueous-sucrose droplet can facilitate control over the degree of dehydration achieved during evaporation. After undergoing rapid gas-phase diffusion limited water evaporation, binary aqueous-sucrose droplets show a continued slow evaporative flux that is limited by slow diffusional mass transport within the particle bulk due to the rapidly increasing particle viscosity and strong concentration gradients that are established. The addition of a long chain alcohol to the droplet is shown to slow the initial rate of water loss, leading to a droplet composition that remains more homogeneous for a longer period of time. When the sucrose concentration has achieved a sufficiently high value, and the diffusion constant of water has decreased accordingly so that bulk phase diffusion arrest occurs in the monolayer

Anion and cation partitioning between olivine, plagioclase phenocrysts and the host magma

International Nuclear Information System (INIS)

Yurimoto, Hisayoshi; Sueno, Shigeho

1984-01-01

Partition coefficients for -1, -2, -3, +1, +2, +3, +4 and +5 valent ions between the groundmass of tholeiite basalt and coexisting olivine and plagioclase phenocrysts from the Mid-Atlantic Ridge have been determined by secondary ion mass spectrometry. The present cation partitioning strongly supports the 'crystal structure control' mechanism. The partition coefficient for an anion is also under control of the crystal structure, so that each of the cation and anion positions in the crystal structure gives rise to a parabola-shaped peak on the partition coefficient vs. ionic radius diagram. (author)

Solvation and complexation study by fluorescence spectroscopy of Eu(III) and Cm(III) ions in octanol solution and at the interface with water

International Nuclear Information System (INIS)

Vu, T.H.

2008-01-01

Polydentate N-donors ligands like bis-triazine-pyridine (BTP) and bis-triazine-bis-pyridine (BTBP) can selectively extract minor actinides (III) from lanthanides (III) ions and therefore have been studied in the field of nuclear waste reprocessing. The aim of the researches carried out during this thesis is a better description of this family in biphasic systems: speciation in the organic phase and around the interfacial area. After an exhaustive description of the solvation of europium(III) cation in mixed solutions n-octanol water with TRLIF spectrometry, the complexation with nitrogen ligands iPr-BTP, C5-BTBP and CyMe4-BTBP has been studied by TRLIF and ESI-MS techniques. For each compound, the inner sphere of europium has been described and the conditional stability constants determined. The composition of the organic medium, and particularly the hydration degree of n-octanol, has an impact on the nature and the ratio of species 'cation - counter ion - ligand - water'. With high water content (representative of extraction systems), the complexes observed with Cm(III) and Eu(III) have the same stoichiometry but the affinity towards the curium cation is higher and consistent to separation factors measured with biphasic systems. The method TIRF (total internal reflection fluorescence) was retained to study the behaviour of europium(III) inside the interfacial area. Fluorescence spectra of europium have been obtained but side signals and the high depth resolution of detection lead to difficulty in obtaining the signal of interfacial europium alone. The selected technique remains promising but some improvements need to be implemented for forthcoming measurement at liquid/liquid interface. (author) [fr

Measurements of activity coefficients at infinite dilution for organic solutes and water in the ionic liquid 1-butyl-1-methylpyrrolidinium tricyanomethanide

International Nuclear Information System (INIS)

Domańska, Urszula; Lukoshko, Elena Vadimovna

2013-01-01

Highlights: • Measurements of activity coefficients at infinite dilution using GLC. • 62 organic solvents and water in the ionic liquid 1-butyl-1-methylpyrrolidinium tricyanomethanide. • High capacity for thiophene, 1.37 at T = 328.15 K. • Possible entrainer for extraction of sulfur, or nitrogen compounds from fuels. • The excess thermodynamic functions and the gas–liquid partition coefficients were calculated. -- Abstract: The activity coefficients at infinite dilution, γ 13 ∞ , for 62 solutes, including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, thiophene, ethers, ketones, acetonitrile, pyridine and 1-nitropropane in the ionic liquid 1-butyl-1-methylpyrrolidinium tricyanomethanide, [BMPYR][TCM] were determined by gas–liquid chromatography at six temperatures over the range of (318.15 to 368.15) K. The partial molar excess Gibbs free energy, ΔG 1 E ∞, enthalpy ΔH 1 E ∞, and entropy term T ref ΔS 1 E ,∞ at infinite dilution were calculated from the experimental γ 13 ∞ values obtained over the temperature range. The densities of [BMPYR][TCM] were measured within temperature range from 318.15 K to 368.15 K. The gas–liquid partition coefficients, K L were calculated for all solutes. The values of selectivity for few separation problems as hexane/benzene, cyclohexane/benzene, heptane/thiophene were calculated from γ 13 ∞ and compared to literature values for N-methyl-2-pyrrolidinone (NMP), sulfolane, and other ionic liquids based on [BMPYR] + cation. In comparison with the former measured ILs, [BMPYR][TCM] present quite high selectivity for the separation of aromatic hydrocarbons and aliphatics hydrocarbons, an average capacity for benzene. The data presented here shows that [BMPYR][TCM] ionic liquid can be used as an alternative solvent for the separation of thiophene from the aliphatic hydrocarbons

Partitioning Water Vapor and Carbon Dioxide Fluxes using Correlation Analysis

Science.gov (United States)

Scanlon, T. M.

2008-12-01

A variety of methods are currently available to partition water vapor fluxes (into components of transpiration and direct evaporation) and carbon dioxide fluxes (into components of photosynthesis and respiration), using chambers, isotopes, and regression modeling approaches. Here, a methodology is presented that accounts for correlations between high-frequency measurements of water vapor (q) and carbon dioxide (c) concentrations being influenced by their non-identical source-sink distributions and the relative magnitude of their constituent fluxes. Flux-variance similarity assumptions are applied separately to the stomatal and the non-stomatal exchange, and the flux components are identified by considering the q-c correlation. Water use efficiency for the vegetation, and how it varies with respect to vapor pressure deficit, is the only input needed for this approach that uses standard eddy covariance measurements. The method is demonstrated using data collected over a corn field throughout a growing season. In particular, the research focuses on the partitioning of the water flux with the aim of improving how direct evaporation is handled in soil-vegetation- atmosphere transfer models over the course of wetting and dry-down cycles.

Octanol-assisted liposome assembly on chip

NARCIS (Netherlands)

Deshpande, S.R.; Caspi, Y.; Meijering, A.E.C.; Dekker, C.

2016-01-01

Liposomes are versatile supramolecular assemblies widely used in basic and applied sciences. Here we present a novel microfluidics-based method, octanol-assisted liposome assembly (OLA), to form monodisperse, cell-sized (5–20 μm), unilamellar liposomes with excellent encapsulation efficiency. Akin

Immobilization of Pseudomonas fluorescens lipase onto magnetic nanoparticles for resolution of 2-octanol.

Science.gov (United States)

Xun, Er-na; Lv, Xiao-li; Kang, Wei; Wang, Jia-xin; Zhang, Hong; Wang, Lei; Wang, Zhi

2012-10-01

The lipase from Pseudomonas fluorescens (Lipase AK, AKL) was immobilized onto the magnetic Fe(3)O(4) nanoparticles via hydrophobic interaction. Enzyme loading and immobilization yield were determined as 21.4±0.5 mg/g and 49.2±1.8 %, respectively. The immobilized AKL was successfully used for resolution of 2-octanol with vinyl acetate used as acyl donor. Effects of organic solvent, water activity, substrate ratio, and temperature were investigated. Under the optimum conditions, the preferred isomer for AKL is the (R)-2-octanol and the highest enantioselectivity (E=71.5±2.2) was obtained with a higher enzyme activity (0.197±0.01 μmol/mg/min). The results also showed that the immobilized lipase could be easily separated from reaction media by the magnetic steel and remained 89 % of its initial activity as well as the nearly unchanged enantioselectivity after five consecutive cycles, indicating a high stability in practical operation.

Limiting partition coefficients of solutes in biphasic trihexyltetradecylphosphonium chloride ionic liquid-supercritical CO2 system: measurement and LSER-based correlation

Czech Academy of Sciences Publication Activity Database

Planeta, Josef; Karásek, Pavel; Roth, Michal

2007-01-01

Roč. 111, č. 26 (2007), s. 7620-7625 ISSN 1520-6106 R&D Projects: GA AV ČR KJB400310504; GA ČR GA203/05/2106; GA ČR GA203/07/0886 Institutional research plan: CEZ:AV0Z40310501 Keywords : phosphonium ionic liquid * supercritical carbon dioxide * solute partition coefficient Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.086, year: 2007

Microbial production of 1-octanol: A naturally excreted biofuel with diesel-like properties

Directory of Open Access Journals (Sweden)

M. Kalim Akhtar

2015-12-01

Full Text Available The development of sustainable, bio-based technologies to convert solar energy and carbon dioxide into fuels is a grand challenge. A core part of this challenge is to produce a fuel that is compatible with the existing transportation infrastructure. This task is further compounded by the commercial desire to separate the fuel from the biotechnological host. Based on its fuel characteristics, 1-octanol was identified as an attractive metabolic target with diesel-like properties. We therefore engineered a synthetic pathway specifically for the biosynthesis of 1-octanol in Escherichia coli BL21(DE3 by over-expression of three enzymes (thioesterase, carboxylic acid reductase and aldehyde reductase and one maturation factor (phosphopantetheinyl transferase. Induction of this pathway in a shake flask resulted in 4.4 mg 1-octanol L−1 h−1 which exceeded the productivity of previously engineered strains. Furthermore, the majority (73% of the fatty alcohol was localised within the media without the addition of detergent or solvent overlay. The deletion of acrA reduced the production and excretion of 1-octanol by 3-fold relative to the wild-type, suggesting that the AcrAB–TolC complex may be responsible for the majority of product efflux. This study presents 1-octanol as a potential fuel target that can be synthesised and naturally accumulated within the media using engineered microbes. Keywords: 1-Octanol, Fatty alcohol, Diesel, Biofuel, Excretion

Membrane Biotreatment of VOC-Laden Air

National Research Council Canada - National Science Library

Peretti, Stephen

2000-01-01

...%, depending primarily on air contact time. Octanol was used as the stripping fluid because of its low vapor pressure and water solubility, its high partitioning of VOCs from air, and its compatibility...

Molecular Interaction Study of some ortho and para Substituted Anilines with 1-Octanol

Directory of Open Access Journals (Sweden)

M. S. Manjunatha

2010-01-01

Full Text Available Interactions between ortho and para substituents of anilines such as chloroaniline, methylaniline and methoxyaniline with 1-octanol have been studied in carbon tetrachloride. The most likely association of complex between 1-octanol and substituents of anilines is 1:1 stoichiometric complex, through hydroxyl group of 1-octanol and amine group of ortho and para substituents of anilines. Interactions are studied on the bases of formation constant and free energy changes. Formation constant of the complex has been calculated using Nash method. The result shows that molecular interaction of 1-octanol as proton donor with methyl and chloride substitution of anilines in ortho position is smaller than the para position substitution of anilines. The results shows, the ability of acceptors is in the order p-methoxyaniline < o-chloroaniline

Deactivation of Ni-MoS2 by bio-oil impurities during hydrodeoxygenation of phenol and octanol

DEFF Research Database (Denmark)

Mortensen, Peter Mølgaard; Gardini, Diego; Damsgaard, Christian Danvad

2016-01-01

The stability of Ni-MoS2/ZrO2 toward water, potassium, and chlorine containing compounds during hydrodeoxygenation (HDO) of a mixture of phenol and 1-octanol was investigated in a high pressure gas and liquid continuous flow fixed bed setup at 280 °C and 100 bar. To maintain the stability...

Quasi-equilibrium analysis of the ion-pair mediated membrane transport of low-permeability drugs.

Science.gov (United States)

Miller, Jonathan M; Dahan, Arik; Gupta, Deepak; Varghese, Sheeba; Amidon, Gordon L

2009-07-01

The aim of this research was to gain a mechanistic understanding of ion-pair mediated membrane transport of low-permeability drugs. Quasi-equilibrium mass transport analyses were developed to describe the ion-pair mediated octanol-buffer partitioning and hydrophobic membrane permeation of the model basic drug phenformin. Three lipophilic counterions were employed: p-toluenesulfonic acid, 2-naphthalenesulfonic acid, and 1-hydroxy-2-naphthoic acid (HNAP). Association constants and intrinsic octanol-buffer partition coefficients (Log P(AB)) of the ion-pairs were obtained by fitting a transport model to double reciprocal plots of apparent octanol-buffer distribution coefficients versus counterion concentration. All three counterions enhanced the lipophilicity of phenformin, with HNAP providing the greatest increase in Log P(AB), 3.7 units over phenformin alone. HNAP also enhanced the apparent membrane permeability of phenformin, 27-fold in the PAMPA model, and 4.9-fold across Caco-2 cell monolayers. As predicted from a quasi-equilibrium analysis of ion-pair mediated membrane transport, an order of magnitude increase in phenformin flux was observed per log increase in counterion concentration, such that log-log plots of phenformin flux versus HNAP concentration gave linear relationships. These results provide increased understanding of the underlying mechanisms of ion-pair mediated membrane transport, emphasizing the potential of this approach to enable oral delivery of low-permeability drugs.

Effect of vehicles and sodium lauryl sulphate on xenobiotic permeability and stratum corneum partitioning in porcine skin

International Nuclear Information System (INIS)

Merwe, Deon van der; Riviere, Jim E.

2005-01-01

Dermal contact with potentially toxic agricultural and industrial chemicals is a common hazard encountered in occupational, accidental spill and environmental contamination scenarios. Different solvents and chemical mixtures may influence dermal absorption. The effects of sodium lauryl sulphate (SLS) on the stratum corneum partitioning and permeability in porcine skin of 10 agricultural and industrial chemicals in water, ethanol and propylene glycol were investigated. The chemicals were phenol, p-nitrophenol, pentachlorophenol, methyl parathion, ethyl parathion, chlorpyrifos, fenthion, simazine, atrazine and propazine. SLS decreased partitioning into stratum corneum from water for lipophilic compounds, decreased partitioning from propylene glycol and did not alter partitioning from ethanol. SLS effects on permeability were less consistent, but generally decreased permeability from water, increased permeability from ethanol and had an inconsistent effect on permeability from propylene glycol. It was concluded that, for the compounds tested, partitioning into the stratum corneum was determined by the relative solubility of the solute in the donor solvent and the stratum corneum lipids. Permeability, however, reflected the result of successive, complex processes and was not predictable from stratum corneum partitioning alone. Addition of SLS to solvents altered partitioning and absorption characteristics across a range of compounds, which indicates that partition coefficients or skin permeability from neat chemical exposure should be used with caution in risk assessment procedures for chemical mixtures

The impact of aerosol composition on the particle to gas partitioning of reactive mercury.

Science.gov (United States)

Rutter, Andrew P; Schauer, James J

2007-06-01

A laboratory system was developed to study the gas-particle partitioning of reactive mercury (RM) as a function of aerosol composition in synthetic atmospheric particulate matter. The collection of RM was achieved by filter- and sorbent-based methods. Analyses of the RM collected on the filters and sorbents were performed using thermal extraction combined with cold vapor atomic fluorescence spectroscopy (CVAFS), allowing direct measurement of the RM load on the substrates. Laboratory measurements of the gas-particle partitioning coefficients of RM to atmospheric aerosol particles revealed a strong dependence on aerosol composition, with partitioning coefficients that varied by orders of magnitude depending on the composition of the particles. Particles of sodium nitrate and the chlorides of potassium and sodium had high partitioning coefficients, shifting the RM partitioning toward the particle phase, while ammonium sulfate, levoglucosan, and adipic acid caused the RM to partition toward the gas phase and, therefore, had partitioning coefficients that were lower by orders of magnitude.

Linking biosensor responses to Cd, Cu and Zn partitioning in soils

International Nuclear Information System (INIS)

Dawson, J.J.C.; Campbell, C.D.; Towers, W.; Cameron, C.M.; Paton, G.I.

2006-01-01

Soils bind heavy metals according to fundamental physico-chemical parameters. Bioassays, using bacterial biosensors, were performed in pore waters extracted from 19 contrasting soils individually amended with Cd, Cu and Zn concentrations related to the EU Sewage Sludge Directive. The biosensors were responsive to pore waters extracted from Zn amended soils but less so to those of Cu and showed no toxicity to pore water Cd at these environmentally relevant amended concentrations. Across the range of soils, the solid-solution heavy metal partitioning coefficient (K d ) decreased (p d values. Gompertz functions of Cu and Zn, K d values against luminescence explained the relationship between heavy metals and biosensors. Consequently, biosensors provide a link between biologically defined hazard assessments of metals and standard soil-metal physico-chemical parameters for determining critical metal loadings in soils. - Biosensors link biological hazard assessments of metals in soils with physico-chemical partitioning

Semivolatile organic compounds in indoor environments

DEFF Research Database (Denmark)

Weschler, Charles J.; Nazaroff, W.W.

2008-01-01

Semivolatile organic compounds (SVOCs) are ubiquitous in indoor environments, redistributing from their original sources to all indoor surfaces. Exposures resulting from their indoor presence contribute to detectable body burdens of diverse SVOCs, including pesticides, plasticizers, and flame ret...... remarkably well with levels measured in dermal hand wipes for SVOCs possessing a wide range of octanol-air partition coefficients....

Water isotope partitioning and ecohydrologic separation in mixed conifer forest explored with a centrifugation water extraction method

Science.gov (United States)

Bowers, W.; Mercer, J.; Pleasants, M.; Williams, D. G.

2017-12-01

Isotopic partitioning of water within soil into tightly and loosely bound fractions has been proposed to explain differences between isotopic water sources used by plants and those that contribute to streams and ground water, the basis for the "two water worlds" hypothesis. We examined the isotope ratio values of water in trees, bulk soil, mobile water collected from soil lysimeters, stream water, and GW at three different hillslopes in a mixed conifer forest in southeastern Wyoming, USA. Hillslopes differed in aspect and topographic position with corresponding differences in surface energy balance, snowmelt timing, and duration of soil moisture during the dry summer. The isotopic results support the partitioning of water within the soil; trees apparently used a different pool of water for transpiration than that recovered from soil lysimeters and the source was not resolved with the isotopic signature of the water that was extracted from bulk soil via cryogenic vacuum distillation. Separating and measuring the isotope ratios values in these pools would test the assumption that the tightly bound water within the soil has the same isotopic signature as the water transpired by the trees. We employed a centrifugation approach to separate water within the soil held at different tensions by applying stepwise increases in rotational velocity and pressures to the bulk soil samples. Effluent and the remaining water (cryogenically extracted) at each step were compared. We first applied the centrifugation method in a simple lab experiment using sandy loam soil and separate introductions of two isotopically distinct waters. We then applied the method to soil collected from the montane hillslopes. For the lab experiment, we predicted that effluents would have distinct isotopic signatures, with the last effluent and extracted water more closely representing the isotopic signature of the first water applied. For our field samples, we predicted that the isotopic signature of the

Antibacterial Activity of Long-Chain Fatty Alcohols against Staphylococcus aureus

Directory of Open Access Journals (Sweden)

Yoshihiro Inoue

2007-02-01

Full Text Available The antibacterial activity against Staphylococcus aureus of long-chain fatty alcohols was investigated, with a focus on normal alcohols. The antibacterial activity varied with the length of the aliphatic carbon chain and not with the water/octanol partition coefficient. 1-Nonanol, 1-decanol and 1-undecanol had bactericidal activity and membrane-damaging activity. 1-Dodecanol and 1-tridecanol had the highest antibacterial activity among the long-chain fatty alcohols tested, but had no membrane-damaging activity. Consequently, it appears that not only the antibacterial activity but also the mode of action of long-chain fatty alcohols might be determined by the length of the aliphatic carbon chain.

Partitioning of L-methionine in aqueous two-phase systems containing poly(propylene glycol) and sodium phosphate salts

International Nuclear Information System (INIS)

Salabat, Alireza; Sadeghi, Rahmat; Moghadam, Somayeh Tiani; Jamehbozorg, Bahman

2011-01-01

Highlights: → Thermodynamics parameters for partitioning of L-methionine in ATPS. → Investigation of different effects on partition coefficient of the amino acid. → Propose the best condition for L-methionine partitioning. - Abstract: The partitioning behavior of L-methionine has been studied in aqueous two-phase systems of (poly(propylene glycol) + sodium phosphate salts + H 2 O) at different temperatures. The salts used were sodium di-hydrogen phosphate (NaH 2 PO 4 ), di-sodium hydrogen phosphate (Na 2 HPO 4 ) and tri-sodium phosphate (Na 3 PO 4 ). The effects of tie line length, salt type, and temperature on the partition coefficient of this amino acid have been studied. In addition, thermodynamic parameters (ΔH o , ΔS o and ΔG o ) as a function of temperature were calculated. The results showed that increasing tie line length led to decreasing of the partition coefficient. We also showed that the partition coefficients of the amino acid in the systems containing Na 3 PO 4 are greater than the other two salts. Moreover, it is verified that increasing temperature led to decreasing the partition coefficient. The experimental partition coefficient data are correlated using a modified virial-type model.

A flow-through aqueous standard generation system for thin film microextraction investigations of UV filters and biocides partitioning to different environmental compartments

International Nuclear Information System (INIS)

Ahmadi, Fardin; Sparham, Chris; Pawliszyn, Janusz

2017-01-01

In this paper problems associated with preparation of aqueous standard of highly hydrophobic compounds such as partial precipitation, being lost on the surfaces, low solubility in water and limited sample volume for accurate determination of their distribution coefficients are addressed. The following work presents two approaches that utilize blade thin film microextraction (TFME) to investigate partitioning of UV filters and biocides to humic acid (dissolved organic carbon) and sediment. A steady-state concentration of target analytes in water was generated using a flow-through aqueous standard generation (ASG) system. Dialysis membranes, a polytetrafluoroethylene permeation tube, and a frit porous (0.5 μm) coated by epoxy glue were basic elements used for preparation of the ASG system. In the currently presented study, negligible depletion TFME using hydrophilic-lipophilic balance (HLB) and octadecyl silica-based (C18) sorbents was employed towards the attainment of free concentration values of target analytes in the studied matrices. Thin film geometry provided a large volume of extraction phase, which improved the sensitivity of the method towards highly matrix-bound analytes. Extractions were performed in the equilibrium regime so as to prevent matrix effects and with aims to reach maximum method sensitivity for all analytes under study. Partitioning of analytes on dissolved organic carbon (DOC) was investigated in ASG to facilitate large sample volume conditions. Binding percentages and DOC distribution coefficients (Log K DOC ) ranged from 20 to 98% and 3.71–6.72, respectively. Furthermore, sediment-water partition coefficients (K d ), organic-carbon normalized partition coefficients (Log K OC ), and DOC distribution coefficients (Log K DOC ) were investigated in slurry sediment, and ranged from 33 to 2860, 3.31–5.24 and 4.52–5.75 Lkg -1 , respectively. The obtained results demonstrated that investigations utilizing ASG and TFME can yield reliable

Partitioning of water flux in a Sierra Nevada ponderosa pine plantation