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Antonius Kettrup - One of the best experts on this subject based on the ideXlab platform.

  • Influence of methanol on retention of hydrophobic organic chemicals in Soil Leaching column chromatography.
    Chemosphere, 2002
    Co-Authors: Xinmiao Liang, Bingcheng Lin, Karl-werner Schramm, Antonius Kettrup
    Abstract:

    Abstract The influence of methanol in methanol–water mixed eluents on the capacity factor ( k ′ ), an important parameter which could depict Leaching potential of hydrophobic organic chemicals (HOCs) in Soil Leaching column chromatography (SLCC), was investigated. Two reference Soils, GSE 17201 obtained from Bayer Landwirtschaftszentrum, Monheim, Germany and SP 14696 from LUFA, Spencer, Germany, were used as packing materials in Soil columns, and isocratic elution with methanol–water mixtures at different volume fractions of methanol ( ϕ ) were tested. Short-term exposure of the column (packed with the GSE 17201 Soil) to the eluents increased solute retention by a certain (23% log-unit) degree evaluated through a correlation with the retention on the same Soil column but unpreconditioned by methanol-containing eluents. Long-term exposure of Soil columns to the eluents did not influence the solute retention. A log-linear equation, log k ′ =log k ′ w − Sϕ , could well and generally describe the retention of HOCs in SLCC. For the compounds of homologous series, log k ′ w had good linear relationship with S , indicating the hydrophobic partition mechanism existing in the retention process.

  • Retention behavior of hydrophobic organic chemicals as a function of temperature in Soil Leaching column chromatography
    Chemosphere, 2002
    Co-Authors: Xinmiao Liang, Bingcheng Lin, Karl-werner Schramm, Antonius Kettrup
    Abstract:

    Abstract To study the transport mechanism of hydrophobic organic chemicals (HOCs) and the energy change in Soil/solvent system, a Soil Leaching column chromatographic (SLCC) experiment at an environmental temperature range of 20–40 °C was carried out, which utilized a reference Soil (SP 14696) packed column and a methanol–water (1:4 by volume ratio) eluent. The transport process quickens with the increase of column temperature. The ratio of retention factors at 30 and 40 °C (k′30/k′40) ranged from 1.08 to 1.36. The lower enthalpy change of the solute transfer in SLCC (from eluent to Soil) than in conventional reversed-phase liquid chromatography (e.g., from eluent to C18) is consistent with the hypothesis that HOCs were dominantly and physically partitioned between solvent and Soil. The results were also verified by the linear solvation energy relationships analysis. The chief factor controlling the retention was found to be the solute solvophobic partition, and the second important factor was the solute hydrogen-bond basicity, while the least important factors were the solute polarizability–dipolarity and hydrogen-bond acidity. With the increase of temperature, the contributions of the solute solvophobic partition and hydrogen-bond basicity gradually decrease, and the latter decreases faster than the former.

  • Linear solvation energy relationships regarding sorption and retention properties of hydrophobic organic compounds in Soil Leaching column chromatography
    Chemosphere, 2002
    Co-Authors: Xinmiao Liang, Bingcheng Lin, Karl-werner Schramm, Antonius Kettrup
    Abstract:

    The capacity factors of a series of hydrophobic organic compounds (HOCs) were measured in Soil Leaching column chromatography (SLCC) on a Soil column, and in reversed-phase liquid chromatography on a C18 column with different volumetric fractions (phi) of methanol in methanol-water mixtures. A general equation of linear solvation energy relationships, log(XYZ) XYZ0 + mV(I)/100 + spi + bbetam + aalpham, was applied to analyze capacity factors (k'), Soil organic partition coefficients (Koc) and octanol-water partition coefficients (P). The analyses exhibited high accuracy. The chief solute factors that control logKoc, log P, and logk' (on Soil and on C18) are the solute size (V(I)/100) and hydrogen-bond basicity (betam). Less important solute factors are the dipolarity/polarizability (pi*) and hydrogen-bond acidity (alpham). Log k' on Soil and log Koc have similar signs in four fitting coefficients (m, s, b and a) and similar ratios (m:s:b:a), while log k' on C18 and logP have similar signs in coefficients (m, s, b and a) and similar ratios (m:s:b:a). Consequently, logk' values on C18 have good correlations with logP (r > 0.97), while logk' values on Soil have good correlations with logKoc (r > 0.98). Two Koc estimation methods were developed, one through solute solvatochromic parameters, and the other through correlations with k' on Soil. For HOCs, a linear relationship between logarithmic capacity factor and methanol composition in methanol-water mixtures could also be derived in SLCC.

  • Prediction of Soil organic partition coefficients by a Soil Leaching column chromatographic method.
    Journal of environmental quality, 2001
    Co-Authors: Xinmiao Liang, Bingcheng Lin, Karl-werner Schramm, Antonius Kettrup
    Abstract:

    The Soil organic partition coefficient (Koc) is one of the most important parameters to depict the transfer and fate of a chemical in the Soil-water system. Predicting Koc by using a chromatographic technique has been developing into a convenient and low-cost method. In this paper, a Soil Leaching column chromatograpy (SLCC) method employing the Soil column packed with reference Soil GSE 17201 (obtained from Bayer Landwirtschaftszentrum, Monheim, Germany) and methanol-water eluents was developed to predict the Koc of hydrophobic organic chemicals (HOCs), over a log Koc range of 4.8 orders of magnitude, from their capacity factors. The capacity factor with water as an eluent (k'w) could be obtained by linearly extrapolating capacity factors in methanol-water eluents (k'w) with various volume fractions of methanol (symbol in text). The important effects of solute activity coefficients in water on k'w and Koc were illustrated. Hence, the correlation between log Koc and log k'w (and log k') exists in the Soil. The correlation coefficient (r) of the log Koc vs. log k'w correlation for 58 apolar and polar compounds could reach 0.987, while the correlation coefficients of the log Koc -log k' correlations were no less than 0.968, with (symbol in text)ranging from 0 to 0.50. The smaller the (symbol in text), the higher the r. Therefore, it is recommended that the eluent of smaller (symbol in text), such as water, be used for accurately estimating Koc. Correspondingly, the r value of the log Koc -log k'w correlation on a reversed-phase Hypersil ODS (Thermo Hypersil, Kleinostheim, Germany) column was less than 0.940 for the same solutes. The SLCC method could provide a more reliable route to predict Koc indirectly from a correlation with k'w than the reversed-phase liquid chromatographic (RPLC) one.

Xinmiao Liang - One of the best experts on this subject based on the ideXlab platform.

  • Influence of methanol on retention of hydrophobic organic chemicals in Soil Leaching column chromatography.
    Chemosphere, 2002
    Co-Authors: Xinmiao Liang, Bingcheng Lin, Karl-werner Schramm, Antonius Kettrup
    Abstract:

    Abstract The influence of methanol in methanol–water mixed eluents on the capacity factor ( k ′ ), an important parameter which could depict Leaching potential of hydrophobic organic chemicals (HOCs) in Soil Leaching column chromatography (SLCC), was investigated. Two reference Soils, GSE 17201 obtained from Bayer Landwirtschaftszentrum, Monheim, Germany and SP 14696 from LUFA, Spencer, Germany, were used as packing materials in Soil columns, and isocratic elution with methanol–water mixtures at different volume fractions of methanol ( ϕ ) were tested. Short-term exposure of the column (packed with the GSE 17201 Soil) to the eluents increased solute retention by a certain (23% log-unit) degree evaluated through a correlation with the retention on the same Soil column but unpreconditioned by methanol-containing eluents. Long-term exposure of Soil columns to the eluents did not influence the solute retention. A log-linear equation, log k ′ =log k ′ w − Sϕ , could well and generally describe the retention of HOCs in SLCC. For the compounds of homologous series, log k ′ w had good linear relationship with S , indicating the hydrophobic partition mechanism existing in the retention process.

  • Retention behavior of hydrophobic organic chemicals as a function of temperature in Soil Leaching column chromatography
    Chemosphere, 2002
    Co-Authors: Xinmiao Liang, Bingcheng Lin, Karl-werner Schramm, Antonius Kettrup
    Abstract:

    Abstract To study the transport mechanism of hydrophobic organic chemicals (HOCs) and the energy change in Soil/solvent system, a Soil Leaching column chromatographic (SLCC) experiment at an environmental temperature range of 20–40 °C was carried out, which utilized a reference Soil (SP 14696) packed column and a methanol–water (1:4 by volume ratio) eluent. The transport process quickens with the increase of column temperature. The ratio of retention factors at 30 and 40 °C (k′30/k′40) ranged from 1.08 to 1.36. The lower enthalpy change of the solute transfer in SLCC (from eluent to Soil) than in conventional reversed-phase liquid chromatography (e.g., from eluent to C18) is consistent with the hypothesis that HOCs were dominantly and physically partitioned between solvent and Soil. The results were also verified by the linear solvation energy relationships analysis. The chief factor controlling the retention was found to be the solute solvophobic partition, and the second important factor was the solute hydrogen-bond basicity, while the least important factors were the solute polarizability–dipolarity and hydrogen-bond acidity. With the increase of temperature, the contributions of the solute solvophobic partition and hydrogen-bond basicity gradually decrease, and the latter decreases faster than the former.

  • Linear solvation energy relationships regarding sorption and retention properties of hydrophobic organic compounds in Soil Leaching column chromatography
    Chemosphere, 2002
    Co-Authors: Xinmiao Liang, Bingcheng Lin, Karl-werner Schramm, Antonius Kettrup
    Abstract:

    The capacity factors of a series of hydrophobic organic compounds (HOCs) were measured in Soil Leaching column chromatography (SLCC) on a Soil column, and in reversed-phase liquid chromatography on a C18 column with different volumetric fractions (phi) of methanol in methanol-water mixtures. A general equation of linear solvation energy relationships, log(XYZ) XYZ0 + mV(I)/100 + spi + bbetam + aalpham, was applied to analyze capacity factors (k'), Soil organic partition coefficients (Koc) and octanol-water partition coefficients (P). The analyses exhibited high accuracy. The chief solute factors that control logKoc, log P, and logk' (on Soil and on C18) are the solute size (V(I)/100) and hydrogen-bond basicity (betam). Less important solute factors are the dipolarity/polarizability (pi*) and hydrogen-bond acidity (alpham). Log k' on Soil and log Koc have similar signs in four fitting coefficients (m, s, b and a) and similar ratios (m:s:b:a), while log k' on C18 and logP have similar signs in coefficients (m, s, b and a) and similar ratios (m:s:b:a). Consequently, logk' values on C18 have good correlations with logP (r > 0.97), while logk' values on Soil have good correlations with logKoc (r > 0.98). Two Koc estimation methods were developed, one through solute solvatochromic parameters, and the other through correlations with k' on Soil. For HOCs, a linear relationship between logarithmic capacity factor and methanol composition in methanol-water mixtures could also be derived in SLCC.

  • Prediction of Soil organic partition coefficients by a Soil Leaching column chromatographic method.
    Journal of environmental quality, 2001
    Co-Authors: Xinmiao Liang, Bingcheng Lin, Karl-werner Schramm, Antonius Kettrup
    Abstract:

    The Soil organic partition coefficient (Koc) is one of the most important parameters to depict the transfer and fate of a chemical in the Soil-water system. Predicting Koc by using a chromatographic technique has been developing into a convenient and low-cost method. In this paper, a Soil Leaching column chromatograpy (SLCC) method employing the Soil column packed with reference Soil GSE 17201 (obtained from Bayer Landwirtschaftszentrum, Monheim, Germany) and methanol-water eluents was developed to predict the Koc of hydrophobic organic chemicals (HOCs), over a log Koc range of 4.8 orders of magnitude, from their capacity factors. The capacity factor with water as an eluent (k'w) could be obtained by linearly extrapolating capacity factors in methanol-water eluents (k'w) with various volume fractions of methanol (symbol in text). The important effects of solute activity coefficients in water on k'w and Koc were illustrated. Hence, the correlation between log Koc and log k'w (and log k') exists in the Soil. The correlation coefficient (r) of the log Koc vs. log k'w correlation for 58 apolar and polar compounds could reach 0.987, while the correlation coefficients of the log Koc -log k' correlations were no less than 0.968, with (symbol in text)ranging from 0 to 0.50. The smaller the (symbol in text), the higher the r. Therefore, it is recommended that the eluent of smaller (symbol in text), such as water, be used for accurately estimating Koc. Correspondingly, the r value of the log Koc -log k'w correlation on a reversed-phase Hypersil ODS (Thermo Hypersil, Kleinostheim, Germany) column was less than 0.940 for the same solutes. The SLCC method could provide a more reliable route to predict Koc indirectly from a correlation with k'w than the reversed-phase liquid chromatographic (RPLC) one.

  • Influence of organic modifier on the retention behaviour in Soil Leaching column chromatography
    Se pu = Chinese journal of chromatography, 2000
    Co-Authors: Xinmiao Liang, Bingcheng Lin
    Abstract:

    The relationship between capacity factors (k') of 55 nonionic compounds and broad methanol volume percentage (psi) of methanol-water eluent in Soil Leaching column chromatography (SLCC) was systematically investigated. The compounds consist of 11 chlorobenzenes, 14 alkylbenzenes, 22 polyphenyls and polycyclic aromatic hydrocarbons, and 8 pesticides. Reference Soil was dry-packed into a stainless steel chromatographic column (10 mm i.d. x 100 mm) by a homemade pressurizing device, and isocratic methanolwater mixture with psi from 0.0 to 0.80 eluated through the column at a flow-rate of 1 mL.min-1. The column was thermostated at (25.0 +/- 0.1) degree C, and chromatographic peak was monitored by an online ultraviolet detector. The results show that both equations, log k' = log k'w + a psi + b psi 2(1) and log k' = log k'w - S psi (2), well fit the retention values. Equation (2) can be used practically due to few experimental data needed and simpler in formula. Explanation is also given for the existence of the carbon (or chlorine) number rule for two classes of homologous series (i.e. methylbenzenes, n-alkylbenzenes) and weak-polar chlorobenzenes in the SLCC process. The slope and intercept of the rule are also well correlated, and both decreases linearly with increasing eluent psi value.

Bingcheng Lin - One of the best experts on this subject based on the ideXlab platform.

  • Influence of methanol on retention of hydrophobic organic chemicals in Soil Leaching column chromatography.
    Chemosphere, 2002
    Co-Authors: Xinmiao Liang, Bingcheng Lin, Karl-werner Schramm, Antonius Kettrup
    Abstract:

    Abstract The influence of methanol in methanol–water mixed eluents on the capacity factor ( k ′ ), an important parameter which could depict Leaching potential of hydrophobic organic chemicals (HOCs) in Soil Leaching column chromatography (SLCC), was investigated. Two reference Soils, GSE 17201 obtained from Bayer Landwirtschaftszentrum, Monheim, Germany and SP 14696 from LUFA, Spencer, Germany, were used as packing materials in Soil columns, and isocratic elution with methanol–water mixtures at different volume fractions of methanol ( ϕ ) were tested. Short-term exposure of the column (packed with the GSE 17201 Soil) to the eluents increased solute retention by a certain (23% log-unit) degree evaluated through a correlation with the retention on the same Soil column but unpreconditioned by methanol-containing eluents. Long-term exposure of Soil columns to the eluents did not influence the solute retention. A log-linear equation, log k ′ =log k ′ w − Sϕ , could well and generally describe the retention of HOCs in SLCC. For the compounds of homologous series, log k ′ w had good linear relationship with S , indicating the hydrophobic partition mechanism existing in the retention process.

  • Retention behavior of hydrophobic organic chemicals as a function of temperature in Soil Leaching column chromatography
    Chemosphere, 2002
    Co-Authors: Xinmiao Liang, Bingcheng Lin, Karl-werner Schramm, Antonius Kettrup
    Abstract:

    Abstract To study the transport mechanism of hydrophobic organic chemicals (HOCs) and the energy change in Soil/solvent system, a Soil Leaching column chromatographic (SLCC) experiment at an environmental temperature range of 20–40 °C was carried out, which utilized a reference Soil (SP 14696) packed column and a methanol–water (1:4 by volume ratio) eluent. The transport process quickens with the increase of column temperature. The ratio of retention factors at 30 and 40 °C (k′30/k′40) ranged from 1.08 to 1.36. The lower enthalpy change of the solute transfer in SLCC (from eluent to Soil) than in conventional reversed-phase liquid chromatography (e.g., from eluent to C18) is consistent with the hypothesis that HOCs were dominantly and physically partitioned between solvent and Soil. The results were also verified by the linear solvation energy relationships analysis. The chief factor controlling the retention was found to be the solute solvophobic partition, and the second important factor was the solute hydrogen-bond basicity, while the least important factors were the solute polarizability–dipolarity and hydrogen-bond acidity. With the increase of temperature, the contributions of the solute solvophobic partition and hydrogen-bond basicity gradually decrease, and the latter decreases faster than the former.

  • Linear solvation energy relationships regarding sorption and retention properties of hydrophobic organic compounds in Soil Leaching column chromatography
    Chemosphere, 2002
    Co-Authors: Xinmiao Liang, Bingcheng Lin, Karl-werner Schramm, Antonius Kettrup
    Abstract:

    The capacity factors of a series of hydrophobic organic compounds (HOCs) were measured in Soil Leaching column chromatography (SLCC) on a Soil column, and in reversed-phase liquid chromatography on a C18 column with different volumetric fractions (phi) of methanol in methanol-water mixtures. A general equation of linear solvation energy relationships, log(XYZ) XYZ0 + mV(I)/100 + spi + bbetam + aalpham, was applied to analyze capacity factors (k'), Soil organic partition coefficients (Koc) and octanol-water partition coefficients (P). The analyses exhibited high accuracy. The chief solute factors that control logKoc, log P, and logk' (on Soil and on C18) are the solute size (V(I)/100) and hydrogen-bond basicity (betam). Less important solute factors are the dipolarity/polarizability (pi*) and hydrogen-bond acidity (alpham). Log k' on Soil and log Koc have similar signs in four fitting coefficients (m, s, b and a) and similar ratios (m:s:b:a), while log k' on C18 and logP have similar signs in coefficients (m, s, b and a) and similar ratios (m:s:b:a). Consequently, logk' values on C18 have good correlations with logP (r > 0.97), while logk' values on Soil have good correlations with logKoc (r > 0.98). Two Koc estimation methods were developed, one through solute solvatochromic parameters, and the other through correlations with k' on Soil. For HOCs, a linear relationship between logarithmic capacity factor and methanol composition in methanol-water mixtures could also be derived in SLCC.

  • Prediction of Soil organic partition coefficients by a Soil Leaching column chromatographic method.
    Journal of environmental quality, 2001
    Co-Authors: Xinmiao Liang, Bingcheng Lin, Karl-werner Schramm, Antonius Kettrup
    Abstract:

    The Soil organic partition coefficient (Koc) is one of the most important parameters to depict the transfer and fate of a chemical in the Soil-water system. Predicting Koc by using a chromatographic technique has been developing into a convenient and low-cost method. In this paper, a Soil Leaching column chromatograpy (SLCC) method employing the Soil column packed with reference Soil GSE 17201 (obtained from Bayer Landwirtschaftszentrum, Monheim, Germany) and methanol-water eluents was developed to predict the Koc of hydrophobic organic chemicals (HOCs), over a log Koc range of 4.8 orders of magnitude, from their capacity factors. The capacity factor with water as an eluent (k'w) could be obtained by linearly extrapolating capacity factors in methanol-water eluents (k'w) with various volume fractions of methanol (symbol in text). The important effects of solute activity coefficients in water on k'w and Koc were illustrated. Hence, the correlation between log Koc and log k'w (and log k') exists in the Soil. The correlation coefficient (r) of the log Koc vs. log k'w correlation for 58 apolar and polar compounds could reach 0.987, while the correlation coefficients of the log Koc -log k' correlations were no less than 0.968, with (symbol in text)ranging from 0 to 0.50. The smaller the (symbol in text), the higher the r. Therefore, it is recommended that the eluent of smaller (symbol in text), such as water, be used for accurately estimating Koc. Correspondingly, the r value of the log Koc -log k'w correlation on a reversed-phase Hypersil ODS (Thermo Hypersil, Kleinostheim, Germany) column was less than 0.940 for the same solutes. The SLCC method could provide a more reliable route to predict Koc indirectly from a correlation with k'w than the reversed-phase liquid chromatographic (RPLC) one.

  • Influence of organic modifier on the retention behaviour in Soil Leaching column chromatography
    Se pu = Chinese journal of chromatography, 2000
    Co-Authors: Xinmiao Liang, Bingcheng Lin
    Abstract:

    The relationship between capacity factors (k') of 55 nonionic compounds and broad methanol volume percentage (psi) of methanol-water eluent in Soil Leaching column chromatography (SLCC) was systematically investigated. The compounds consist of 11 chlorobenzenes, 14 alkylbenzenes, 22 polyphenyls and polycyclic aromatic hydrocarbons, and 8 pesticides. Reference Soil was dry-packed into a stainless steel chromatographic column (10 mm i.d. x 100 mm) by a homemade pressurizing device, and isocratic methanolwater mixture with psi from 0.0 to 0.80 eluated through the column at a flow-rate of 1 mL.min-1. The column was thermostated at (25.0 +/- 0.1) degree C, and chromatographic peak was monitored by an online ultraviolet detector. The results show that both equations, log k' = log k'w + a psi + b psi 2(1) and log k' = log k'w - S psi (2), well fit the retention values. Equation (2) can be used practically due to few experimental data needed and simpler in formula. Explanation is also given for the existence of the carbon (or chlorine) number rule for two classes of homologous series (i.e. methylbenzenes, n-alkylbenzenes) and weak-polar chlorobenzenes in the SLCC process. The slope and intercept of the rule are also well correlated, and both decreases linearly with increasing eluent psi value.

Karl-werner Schramm - One of the best experts on this subject based on the ideXlab platform.

  • Influence of methanol on retention of hydrophobic organic chemicals in Soil Leaching column chromatography.
    Chemosphere, 2002
    Co-Authors: Xinmiao Liang, Bingcheng Lin, Karl-werner Schramm, Antonius Kettrup
    Abstract:

    Abstract The influence of methanol in methanol–water mixed eluents on the capacity factor ( k ′ ), an important parameter which could depict Leaching potential of hydrophobic organic chemicals (HOCs) in Soil Leaching column chromatography (SLCC), was investigated. Two reference Soils, GSE 17201 obtained from Bayer Landwirtschaftszentrum, Monheim, Germany and SP 14696 from LUFA, Spencer, Germany, were used as packing materials in Soil columns, and isocratic elution with methanol–water mixtures at different volume fractions of methanol ( ϕ ) were tested. Short-term exposure of the column (packed with the GSE 17201 Soil) to the eluents increased solute retention by a certain (23% log-unit) degree evaluated through a correlation with the retention on the same Soil column but unpreconditioned by methanol-containing eluents. Long-term exposure of Soil columns to the eluents did not influence the solute retention. A log-linear equation, log k ′ =log k ′ w − Sϕ , could well and generally describe the retention of HOCs in SLCC. For the compounds of homologous series, log k ′ w had good linear relationship with S , indicating the hydrophobic partition mechanism existing in the retention process.

  • Retention behavior of hydrophobic organic chemicals as a function of temperature in Soil Leaching column chromatography
    Chemosphere, 2002
    Co-Authors: Xinmiao Liang, Bingcheng Lin, Karl-werner Schramm, Antonius Kettrup
    Abstract:

    Abstract To study the transport mechanism of hydrophobic organic chemicals (HOCs) and the energy change in Soil/solvent system, a Soil Leaching column chromatographic (SLCC) experiment at an environmental temperature range of 20–40 °C was carried out, which utilized a reference Soil (SP 14696) packed column and a methanol–water (1:4 by volume ratio) eluent. The transport process quickens with the increase of column temperature. The ratio of retention factors at 30 and 40 °C (k′30/k′40) ranged from 1.08 to 1.36. The lower enthalpy change of the solute transfer in SLCC (from eluent to Soil) than in conventional reversed-phase liquid chromatography (e.g., from eluent to C18) is consistent with the hypothesis that HOCs were dominantly and physically partitioned between solvent and Soil. The results were also verified by the linear solvation energy relationships analysis. The chief factor controlling the retention was found to be the solute solvophobic partition, and the second important factor was the solute hydrogen-bond basicity, while the least important factors were the solute polarizability–dipolarity and hydrogen-bond acidity. With the increase of temperature, the contributions of the solute solvophobic partition and hydrogen-bond basicity gradually decrease, and the latter decreases faster than the former.

  • Linear solvation energy relationships regarding sorption and retention properties of hydrophobic organic compounds in Soil Leaching column chromatography
    Chemosphere, 2002
    Co-Authors: Xinmiao Liang, Bingcheng Lin, Karl-werner Schramm, Antonius Kettrup
    Abstract:

    The capacity factors of a series of hydrophobic organic compounds (HOCs) were measured in Soil Leaching column chromatography (SLCC) on a Soil column, and in reversed-phase liquid chromatography on a C18 column with different volumetric fractions (phi) of methanol in methanol-water mixtures. A general equation of linear solvation energy relationships, log(XYZ) XYZ0 + mV(I)/100 + spi + bbetam + aalpham, was applied to analyze capacity factors (k'), Soil organic partition coefficients (Koc) and octanol-water partition coefficients (P). The analyses exhibited high accuracy. The chief solute factors that control logKoc, log P, and logk' (on Soil and on C18) are the solute size (V(I)/100) and hydrogen-bond basicity (betam). Less important solute factors are the dipolarity/polarizability (pi*) and hydrogen-bond acidity (alpham). Log k' on Soil and log Koc have similar signs in four fitting coefficients (m, s, b and a) and similar ratios (m:s:b:a), while log k' on C18 and logP have similar signs in coefficients (m, s, b and a) and similar ratios (m:s:b:a). Consequently, logk' values on C18 have good correlations with logP (r > 0.97), while logk' values on Soil have good correlations with logKoc (r > 0.98). Two Koc estimation methods were developed, one through solute solvatochromic parameters, and the other through correlations with k' on Soil. For HOCs, a linear relationship between logarithmic capacity factor and methanol composition in methanol-water mixtures could also be derived in SLCC.

  • Prediction of Soil organic partition coefficients by a Soil Leaching column chromatographic method.
    Journal of environmental quality, 2001
    Co-Authors: Xinmiao Liang, Bingcheng Lin, Karl-werner Schramm, Antonius Kettrup
    Abstract:

    The Soil organic partition coefficient (Koc) is one of the most important parameters to depict the transfer and fate of a chemical in the Soil-water system. Predicting Koc by using a chromatographic technique has been developing into a convenient and low-cost method. In this paper, a Soil Leaching column chromatograpy (SLCC) method employing the Soil column packed with reference Soil GSE 17201 (obtained from Bayer Landwirtschaftszentrum, Monheim, Germany) and methanol-water eluents was developed to predict the Koc of hydrophobic organic chemicals (HOCs), over a log Koc range of 4.8 orders of magnitude, from their capacity factors. The capacity factor with water as an eluent (k'w) could be obtained by linearly extrapolating capacity factors in methanol-water eluents (k'w) with various volume fractions of methanol (symbol in text). The important effects of solute activity coefficients in water on k'w and Koc were illustrated. Hence, the correlation between log Koc and log k'w (and log k') exists in the Soil. The correlation coefficient (r) of the log Koc vs. log k'w correlation for 58 apolar and polar compounds could reach 0.987, while the correlation coefficients of the log Koc -log k' correlations were no less than 0.968, with (symbol in text)ranging from 0 to 0.50. The smaller the (symbol in text), the higher the r. Therefore, it is recommended that the eluent of smaller (symbol in text), such as water, be used for accurately estimating Koc. Correspondingly, the r value of the log Koc -log k'w correlation on a reversed-phase Hypersil ODS (Thermo Hypersil, Kleinostheim, Germany) column was less than 0.940 for the same solutes. The SLCC method could provide a more reliable route to predict Koc indirectly from a correlation with k'w than the reversed-phase liquid chromatographic (RPLC) one.

Phillip Sollins - One of the best experts on this subject based on the ideXlab platform.

  • Biodegradation and regeneration of water-soluble carbon in a forest Soil: Leaching column study
    Biology and Fertility of Soils, 2002
    Co-Authors: Rota Wagai, Phillip Sollins
    Abstract:

    We hypothesized that water-soluble C is a major substrate for microbial activity and studied the susceptibility of water-soluble C both to Leaching and to microbial degradation. Soil columns, consisting of A-horizon top Soil with and without tree seedlings, were leached every 2 weeks for 20 weeks. Water-soluble material was extracted from the Soils before and after the 20-week study. Biodegradability of dissolved organic C (DOC) was assessed by solution incubation. DOC in leachates was constant over the 20 weeks and the extractable C pool declined by 31–40% between the start and end of the experiment. The amount and biodegradability of both leachates and extracts were lower in the presence of seedlings. Water extracts contained 8–17 times more DOC than leachates. Percentage biodegradable DOC was 13–16% in leachates and 18–27% in extracts. A Soil C destabilization model was proposed based on the measured pools (particulate, water-extractable, and leachable C) and estimates of Soil respiration and microbial biomass from the same Soil. Leaching loss accounted for 8–14% of the total C destabilized. Due to its low concentration and biodegradability, we concluded that leachable C was not a significant substrate for heterotrophic Soil respiration in the studied system. The role of water-extractable C as a major substrate was less clear, as the regeneration rate of the extractable C in Soil is still unknown.