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Cited by 49Per- and polyfluoroalkyl substances researchToxic Organic Pollutants ImpactFluorine in Organic Chemistry

The DOI matches its Crossref record; 42 of the 42 references it cites were found in a registry or an index; 8 of the 51 sources its claims cite were checked for support.

Intermolecular Interactions, Solute Descriptors, and Partition Properties of Neutral Per- and Polyfluoroalkyl Substances (PFAS)

Open access
Endo, Satoshi·2023·Environmental Science & Technology
DOI 10.1021/acs.est.3c07503PMC PMC10653080

Published version of a preprint

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Abstract

The environmental partition properties of per- and polyfluoroalkyl substances (PFAS) must be understood for their transport and fate analysis. In this study, isothermal gas chromatographic (GC) retention times of 60 neutral PFAS were measured using four columns with different stationary phase polarity, which indicated varying polar interactions exerted by these substances. The GC data were combined with partition coefficient data from this study and the literature and used to determine the polyparameter linear free energy relationship (PP-LFER) solute descriptors. A complete set of the solute descriptors was obtained for 47 PFAS, demonstrating the characteristic intermolecular interaction properties such as hydrogen bonding capabilities influenced by the electron-withdrawing perfluoroalkyl group. The partition coefficients between octanol and water, air and water, and octanol and air predicted by the PP-LFER models agreed with those predicted by the quantum chemically based model COSMOtherm, suggesting that both models are highly accurate for neutral PFAS and can fill the current large data gaps in partition property data. A chemical space plot was generated using the PP-LFER-predicted partition coefficients, showing the primary importance of the air phase for the environmental distribution of nonpolar and weakly polar PFAS and the increasing significance of organic phases with increasing PFAS polarity.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

The study measured gas chromatographic retention times for 60 neutral PFAS and new octanol/water partition coefficients to determine polyparameter linear free energy relationship (PP-LFER) solute descriptors, yielding complete descriptors for 47 PFAS. The descriptors show characteristic intermolecular interactions influenced by perfluoroalkyl groups, and PP-LFER-predicted partition coefficients agree with COSMOtherm, with air dominating the environmental distribution of most neutral PFAS.

Key findings

  • Complete PP-LFER solute descriptors were obtained for 47 neutral PFAS; for the remaining 13, S, A, V, and L were available but B was missing due to lack of partition data.
  • FTOHs had higher H-bond donor (A) and lower H-bond acceptor (B) values than nonfluorinated alkan-1-ols; for example, X:1 FTOHs had A = 0.84 ± 0.02 and B = 0.14 ± 0.01, while X:2 FTOHs had A = 0.60 ± 0.01 and B = 0.31 ± 0.01.
  • PP-LFER predictions of log Kow, log Kaw, and log Koa agreed with COSMOtherm, with RMSEs of 0.37, 0.42, and 0.33, respectively; EPI-Suite showed larger discrepancies for log Kaw and log Koa (RMSE 2.50 and 2.56).
  • In the chemical partitioning space plot, air was the preferred phase for most neutral PFAS: equilibrium mass in air was >99% for 16 and at least 1% for 41 of the 47 compounds, while water exceeded 1% for only 10 PFAS.

Methods

  • Isothermal GC retention times were measured for 60 neutral PFAS and 78 nonfluorinated reference compounds on four columns of differing polarity (HP-5ms, DB-200, DB-225ms, SolGel-WAX); 529 and 642 log k data were obtained for PFAS and reference compounds, respectively.
  • Kow was measured for nine PFAS in this study, and these data were combined with existing literature partition data (KHxd/w, Kow, Koa) to determine PP-LFER solute descriptors via iterative calibration of system parameters and solute descriptors.
  • PP-LFER-predicted partition coefficients were compared with COSMOtherm predictions, and a chemical partitioning space plot was generated using predicted log Kaw and log Kow for a hypothetical air/water/organic-phase system.

Limitations

  • The paper states that PP-LFER predictions cannot be considered “fully predicted” because the solute descriptors were calibrated with experimental Kow and Kaw data, and external experimental data for validation were not available.
  • The paper notes that octanol may overestimate environmental organic phases for neutral PFAS, since available FTOH data suggest soil organic carbon/water partition coefficients are ∼2 log units lower than Kow; interfacial adsorption was also not considered in the partitioning space plot.
  • The text makes evident that descriptor determination relied on assumptions, such as sharing S, A, and B among homologues and setting A and/or B to zero for certain PFAS classes, and that relatively high standard deviations (0.1–0.5) were found for PFAs, fluoroethers, and perfluorotrialkylamines.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1021/acs.est.3c07503

Cites

42 of 42 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Verification

Claims the paper makes

8 of 51 cited sources checked · 7 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    The equilibrium partition properties of PFAS remain to be elucidated.

    “the equilibrium partition properties of PFAS remain to be elucidated.”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites [1] source
    • cites [2] source
    • cites [3] source
  • Interpretationcitation

    The reason for the inconsistent descriptor values is likely the problem of extrapolation; the system parameters calibrated with only nonfluorinated compounds are not applicable to PFAS.

    “The reason for this is likely the problem of extrapolation; the system parameters calibrated with only nonfluorinated compounds are not applicable to PFAS.9,18”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [9] source
    • cites [18] source

      In Results and Discussion, under “KHxd/air Values Determined by the GC-RT Method” (page not provided), the paper says that calibrating equation 4 only with nonfluorinated reference chemicals required extrapolation to PFAS and produced relatively large errors. This supports extrapolation as a reason for inconsistent values, but the finding concerns that specific equation and measured partition coefficients; it does not establish that system parameters calibrated without PFAS are generally inapplicable to PFAS descriptors. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
  • Premiseown data

    Reliable air/water partition coefficients (Kaw) were available for only a few neutral PFAS with (CF2)≥4 until our group recently reported experimental values for 21 PFAS.

    “reliable air/water partition coefficients (Kaw) were available for only a few neutral PFAS with (CF2)≥4 until our group recently reported experimental values for 21 PFAS.”
    Quote in the paperSubstantial claim1 of 1 sources checked
  • Interpretationcitation

    The current version of COSMOtherm likely slightly overestimates the partitioning of PFAS from air to liquid phases.

    “It is likely that the current version of COSMOtherm slightly overestimates the partitioning of PFAS from air to liquid phases, as reported in previous articles.5,18”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [5] source
    • cites [18] source

      Checked before — its earlier verdict is held back until a new check runs.

  • Premisecitation

    Even basic property data such as octanol/water partition coefficients (Kow) are scarce for PFAS.

    “Even basic property data such as octanol/water partition coefficients (Kow) are scarce for PFAS.”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites [1] source
    • cites [2] source
    • cites [3] source
  • Probably not a substantial claim. 28
  • It may state two separate claims as one. 41

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    Descriptors for very short PFAS (C≤3, mostly refrigerants) have been reported.

    “descriptors for very short PFAS (C≤3, mostly refrigerants) have been reported,13,14”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [13] source
    • cites [14] source

  • Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.

    Study design and conductreasoning

    Kaw for 21 PFAS in ref (5) was not considered here to avoid duplicate data use, as these data were derived from KHxd/w and KHxd/air through the thermodynamic cycle calculation.

    “Note that Kaw for 21 PFAS in ref (5) was not considered here to avoid duplicate data use, as these data were derived from KHxd/w and KHxd/air through the thermodynamic cycle calculation.”
    Quote in the paperNot a substantial claim1 of 1 sources checked

  • Probably not a substantial claim. The authors may not put it forward as true. The paper’s conclusions may not depend on it.

    Premisecitation

    The electron-withdrawing F atoms make the H atom at the terminal methyl group of 6:1 FTI-7H significantly H-bond donating.

    “The electron-withdrawing F atoms were thought to make the H atom at the terminal methyl group of 6:1 FTI-7H significantly H-bond donating.5”
    Quote in the paperNot a substantial claim1 of 1 sources checked

  • It may state two separate claims as one.

    Findingreasoning

    The A and B descriptors for FTOHs are higher and lower, respectively, than those for nonfluorinated alkan-1-ols.

    “The A and B descriptors for FTOHs are higher and lower, respectively, than those for nonfluorinated alkan-1-ols (Figure 2), consistent with previous reports for X:2 FTOHs.9,11,12”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    The S and L values of 6:1 FTI-7H are 0.63 and 3.89, respectively, and are higher than those of 6:1 FTI (0.27 and 3.38, respectively), although the size (V) of the two compounds is similar.

    “The S and L values of 6:1 FTI-7H are 0.63 and 3.89, repectively, and are higher than those of 6:1 FTI (0.27 and 3.38, respectively), although the size (V) of the two compounds is similar.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingreasoning

    Neutral PFAS prefer the air phase; the equilibrium mass in air is >99% for 16 and at least 1% for 41 of the 47 compounds.

    “A general trend is that neutral PFAS prefer the air phase; the equilibrium mass in air is >99% for 16 and at least 1% for 41 of the 47 compounds.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    For each column and compound, log k was linear against 1/T, confirming high measurement consistency over temperature.

    “For each column and compound, log k was linear against 1/T (Figure S6), confirming the high measurement consistency over temperature.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Findingnone given

    The differences from the previous L values were small.

    “The differences from the previous values, however, were small.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Findingown data

    In the DB-225ms and SolGel-WAX data, PFASAs and their N-substituted compounds are farthest from the nonpolar PFAS, reflecting their strong polarity, followed by the moderately polar FTOHs.

    “This is most evident in the DB-225ms and SolGel-WAX data; PFASAs and their N-substituted compounds are farthest from the nonpolar PFAS in the plot, reflecting their strong polarity, followed by the moderately polar FTOHs.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.

    Findingnone given

    The final adjusted solute descriptors for all PFAS are presented in Table S8, and those for selected PFAS are shown in Table 3.

    “The final adjusted solute descriptors for all PFAS are presented in Table S8, and those for selected PFAS are shown in Table 3.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Findingreasoning

    The secondary alcohol 5:2s FTOH has high A and low B values.

    “The secondary alcohol 5:2s FTOH also has high A and low B values.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Findingown data

    The A of 6:1 FTI-7H is positive (0.24) and higher than that of 6:1 FTI (0.13).

    “In fact, the A of 6:1 FTI-7H is positive (0.24) and higher than that of 6:1 FTI (0.13).”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    The RMSE values for log Kow, log Kaw, and log Koa between EPI-Suite and COSMOtherm were 0.27, 2.50, and 2.56, respectively, showing a large discrepancy for Kaw and Koa.

    “The RMSE values for log Kow, log Kaw, and log Koa were 0.27, 2.50, and 2.56, respectively, showing a large discrepancy for Kaw and Koa.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    Other PFAS also tend to have higher A values than their nonfluorinated counterparts, and the opposite is true for B values.

    “Not only FTOHs, but other PFAS also tend to have higher A values than their nonfluorinated counterparts, and the opposite is true for B values.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    For all columns, log k for nonpolar PFAS shows a linear relationship with L and forms a baseline in the log k-L plot.

    “For all columns, log k for nonpolar PFAS (i.e., without a polar functional group, e.g., PFAs, PFAIs, and FTOs) shows a linear relationship with L and forms a baseline in the log k–L plot.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    The correlation between log k for the DB-200 column and L is less good, and a high scatter is evident for the highly polar DB-225ms and SolGel-Wax columns.

    “The correlation between log k for the DB-200 column and L is less good, and a high scatter is evident for the highly polar DB-225ms and SolGel-Wax columns.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Findingown data

    The measured Kow values are presented in Table 2 along with the literature data for three FTOHs.

    “The measured Kow values are presented in Table 2 along with the literature data for three FTOHs.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Findingown data

    Relatively high SDs (0.1-0.5) were obtained only for PFAs, FEs, and perfluorotrialkylamines (PFTAAs), suggesting that the uncertainty of the descriptor values for these PFAS may be high.

    “The relatively high SDs (0.1–0.5) were obtained only for PFAs, FEs, and perfluorotrialkylamines (PFTAAs), suggesting that the uncertainty of the descriptor values for these PFAS may be high.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Findingown data

    COSMOtherm provided, on average, 0.26 (±0.27) and 0.24 (±0.23) higher log Kow and log Koa predictions, respectively, and 0.33 (±0.25) lower log Kaw values than the PP-LFERs.

    “COSMOtherm provided, on average, 0.26 (±0.27) and 0.24 (±0.23) higher log Kow and log Koa predictions, respectively, and 0.33 (±0.25) lower log Kaw values than the PP-LFERs.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingreasoning

    3:1 and 7:1 FTOHs (only one −CH2- spacer) have the highest A and lowest B values of the FTOHs studied.

    “Thus, 3:1 and 7:1 FTOHs (only one −CH2– spacer) have the highest A and lowest B values of the FTOHs studied.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    The relationship for DB-225ms was very slightly concave upward, and it was more so for SolGel-WAX.

    “However, the relationship for DB-225ms was very slightly concave upward, and it was more so for SolGel-WAX.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    Figure S10 shows that for 134 neutral PFAS, air is the most important phase and the air/organic phase distribution can be an important fate determinant, except for short-chain polar PFAS, which can also be in water.

    “The data points are even more widely distributed, although the plot again shows that air is the most important phase and that the air/organic phase distribution can be an important fate determinant, except for short-chain polar PFAS, which can also be in water.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingreasoning

    Water is often an unpreferred phase for neutral PFAS; the equilibrium mass in water is >1% for only 10 PFAS.

    “In addition, water is often an unpreferred phase; the equilibrium mass in water is >1% for only 10 PFAS.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    The RMSE for log Kow, log Kaw, and log Koa between PP-LFER and COSMOtherm predictions were 0.37, 0.42, and 0.33, respectively, indicating high agreement.

    “The root mean squared errors (RMSE) for log Kow, log Kaw, and log Koa were 0.37, 0.42, and 0.33, respectively, indicating high agreement.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    Although PP-LFER equations in the literature are often not calibrated with PFAS, the predictions of PP-LFERs and COSMOtherm agree within 1 log unit in most cases.

    “Although the PP-LFER equations in the literature are often not calibrated with PFAS, the predictions of PP-LFERs and COSMOtherm agree within 1 log unit in most cases, similar to the results shown in Figure 3.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Findingown data

    Nonpolar PFAS are all >99.9% in the air phase, reflecting their extremely high volatility.

    “Looking at specific classes of PFAS, the nonpolar PFAS are all >99.9% in the air phase, reflecting their extremely high volatility.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Interpretationreasoning

    Both PP-LFER and COSMOtherm models are highly accurate for neutral PFAS.

    “suggesting that both models are highly accurate for neutral PFAS”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Premisecitation

    For polar stationary phases, the contribution of interfacial adsorption to retention, in addition to the bulk partition mechanism, has been shown to be significant in some cases, which may be a reason for the observed nonlinearity.

    “For polar stationary phases, the contribution of interfacial adsorption to retention, in addition to the bulk partition mechanism, has been shown to be significant in some cases,30 which may be a reason for the observed nonlinearity.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [30] source

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Interpretationcitation

    The increased H-bond acidity and decreased H-bond basicity of fluorinated alcohols can be explained by the electron-withdrawing effect of F on the −OH group.

    “The increased H-bond acidity and decreased H-bond basicity of fluorinated alcohols such as 2,2,2-trifluoroethanol and 1,1,1,3,3,3-hexafluoropropan-2-ol have long been known31,32 and can be explained by the electron-withdrawing effect of F on the −OH group.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [31] source
    • cites [32] source

  • Probably not a substantial claim. The paper may give no reason why it holds.

    Premisenone given

    GC retention data are equivalent to partition coefficients, reflecting the intermolecular interactions between the compound and stationary phase.

    “GC retention data are useful because they are relatively easy and fast to measure and are equivalent to partition coefficients, reflecting the intermolecular interactions between the compound and stationary phase.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Interpretationown data

    Nonpolar van der Waals interactions are prevalent with HP-5ms, and additional polar interactions have only minor influences on log k.

    “Clearly, the nonpolar van der Waals interactions are prevalent with HP-5ms, and additional polar interactions have only minor influences on log k.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    Koa, Koil/w, organic carbon/water, and liposome/water partition coefficients can be found in the literature for some FTOHs.

    “Koa, Koil/w, organic carbon/water, and liposome/water partition coefficients can be found in the literature for some FTOHs.9”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [9] source

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    The ABSOLV database stored on the UFZ-LSER website lists descriptor values for several per- and polyfluorinated alkanes and alcohols of unknown origin.

    “the ABSOLV database stored on the UFZ-LSER website10 lists descriptor values for several per- and polyfluorinated alkanes and alcohols of unknown origin.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [10] Ulrich, N.; Endo, S.; Brown, T. N.; Watanabe, N.; Bronner, G.; Abraham, M. H.; Goss, K. U. UFZ-LSER database v 3.2 ; http://www.ufz.de/lserd (accessed on 2023-06-30).

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • It may state two separate claims as one.

    Interpretationreasoning

    Even one or two H substitutions on the perfluoroalkyl chain make the molecule significantly more interactive, reducing the characteristically weak interaction properties of PFAS.

    “Thus, even one or two H substitutions on the perfluoroalkyl chain make the molecule significantly more interactive, reducing the characteristically weak interaction properties of PFAS.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. It may state two separate claims as one.

    Premisecitation

    Previous studies have shown that A values for 4:2, 6:2, and 8:2 FTOHs are higher than those of nonfluorinated alkyl alcohols and that B has the opposite relationship.

    “previous studies have shown that A values for 4:2, 6:2, and 8:2 FTOHs are higher than those of nonfluorinated alkyl alcohols and that B has the opposite relationship.9,11,12”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [9] source
    • cites [11] source
    • cites [12] source

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    Similar to PFAS, organosilicon compounds have weak van der Waals interaction properties.

    “Similar to PFAS, organosilicon compounds have weak van der Waals interaction properties9”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [9] source

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Interpretationreasoning

    This is not a problem specific to the PP-LFER models.

    “This is not a problem specific to the PP-LFER models.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    The increased H-bond acidity and decreased H-bond basicity of fluorinated alcohols such as 2,2,2-trifluoroethanol and 1,1,1,3,3,3-hexafluoropropan-2-ol have long been known.

    “The increased H-bond acidity and decreased H-bond basicity of fluorinated alcohols such as 2,2,2-trifluoroethanol and 1,1,1,3,3,3-hexafluoropropan-2-ol have long been known31,32”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [31] source
    • cites [32] source

  • It may state two separate claims as one.

    Premisecitation

    The B values of alkyl acrylates and methacrylates in the ABSOLV database are 0.42-0.55 and those of 1-iodoalkanes are 0.14-0.17.

    “For example, the B values of alkyl acrylates and methacrylates in the ABSOLV database are 0.42–0.55 and those of 1-iodoalkanes are 0.14–0.17.10”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [10] Ulrich, N.; Endo, S.; Brown, T. N.; Watanabe, N.; Bronner, G.; Abraham, M. H.; Goss, K. U. UFZ-LSER database v 3.2 ; http://www.ufz.de/lserd (accessed on 2023-06-30).

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    In a previous article, it was shown that 6:1 FTI-7H has a relatively high affinity for water compared to 6:1 FTI.

    “In a previous article,5 it was shown that 1H,1H,7H-perfluoroheptyl iodide (6:1 FTI-7H) has a relatively high affinity for water compared to 6:1 FTI.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [5] source

      Checked before — its earlier verdict is held back until a new check runs.

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Study design and conductown data

    Dimethylformamide, 1-pentylamine, dimethylsulfoxide, and dodecamethylcyclohexasiloxane (D6) were removed from the log k data sets because they frequently appeared as outliers (>3 SD) of the PP-LFER model fit.

    “Dimethylformamide, 1-pentylamine, dimethylsulfoxide, and dodecamethylcyclohexasiloxane (D6) were removed from the log k data sets, because they frequently appeared as outliers (>3 SD) of the PP-LFER model fit.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. It may state two separate claims as one.

    Study design and conductown data

    The iterative calculation of system parameters and PFAS solute descriptors was repeated 20 times, which was sufficient to obtain stable results.

    “This cycle was repeated 20 times, which was sufficient to obtain stable results.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim.

    Premisecitation

    In a previous study, our group measured KHxd/air for 64 neutral PFAS to elucidate their nonpolar interaction properties.

    “In a previous study, our group measured the values of KHxd/air, the decadic logarithm of which is L in eq 1, for 64 neutral PFAS to elucidate their nonpolar interaction properties.18”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [18] source

      Checked before — its earlier verdict is held back until a new check runs.

  • Probably not a substantial claim.

    Premisecitation

    L can be explained by summing the contributions from the fluorinated and nonfluorinated parts of the molecule.

    “The study showed that L can be explained by summing the contributions from the fluorinated and nonfluorinated parts of the molecule.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [18] source

      Checked before — its earlier verdict is held back until a new check runs.

  • Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.

    Premisecitation

    Endo and Goss recalibrated the solute descriptors for FTOHs, which were evaluated again by Abraham and Acree.

    “Later, Endo and Goss9 recalibrated the solute descriptors for FTOHs, which were evaluated again by Abraham and Acree.12”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [9] source
    • cites [12] source

  • It may state two separate claims as one.

    Premisecitation

    Solute descriptors are available for several thousand compounds but are rarely available for PFAS.

    “While solute descriptors are available for several thousand compounds,10 they are rarely available for PFAS.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [10] Ulrich, N.; Endo, S.; Brown, T. N.; Watanabe, N.; Bronner, G.; Abraham, M. H.; Goss, K. U. UFZ-LSER database v 3.2 ; http://www.ufz.de/lserd (accessed on 2023-06-30).

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.

    Interpretationnone given

    COSMOtherm is a theoretical model and may have the potential to provide accurate predictions without an additional empirical calibration.

    “COSMOtherm is a theoretical model and may have the potential to provide accurate predictions without an additional empirical calibration.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. It may state two separate claims as one.

    Interpretationreasoning

    These features are well expected due to the weak van der Waals interactions with any phase and the high cavity energy in water of PFAS.

    “These features are well expected due to the weak van der Waals interactions with any phase and the high cavity energy in water of PFAS.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: PFAS have weak van der Waals interactions with any phase and high cavity energy in water.

  • Probably not a substantial claim. It may be too vague to check against evidence. The paper’s conclusions may not depend on it.

    Interpretationreasoning

    It may be beneficial to include organosilicon compounds in reference data sets.

    “and it may be beneficial to include them in reference data sets.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.

    Premisecitation

    PFASAs and FASAs are weak acids and may ionize in water and partition more into water.

    “Note that PFASAs and FASAs are weak acids and may ionize in water and partition more into water,5 which is not accounted for in the plot.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [5] source

      Checked before — its earlier verdict is held back until a new check runs.

  • It may state two separate claims as one.

    Premisereasoning

    At least one solvent/water or air/water partition coefficient is required to determine B because there is no commonly used GC phase that is a significant H-bond donor.

    “In particular, at least one solvent/water or air/water partition coefficient is required to determine B because there is no commonly used GC phase that is a significant H-bond donor.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    Goss et al. determined solute descriptors for four fluorotelomer alcohols (FTOHs) and four fluorotelomer olefins (FTOs).

    “In the past, Goss et al.11 determined solute descriptors for four fluorotelomer alcohols (FTOHs) and four fluorotelomer olefins (FTOs).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [11] source

  • It may state two separate claims as one.

    Premisecitation

    Key to the accurate determination of the polar interaction descriptors is the availability of K data for partition systems with water as a partition phase because water is a strong H-bond donor and acceptor phase and thus the corresponding K values are sensitive to the H-bonding properties of the solute.

    “Key to the accurate determination of the polar interaction descriptors is the availability of K data for partition systems with water as a partition phase because water is a strong H-bond donor and acceptor phase and thus the corresponding K values are sensitive to the H-bonding properties of the solute.27”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [27] source

  • It may state two separate claims as one.

    Premisecitation

    None of the variously substituted benzenesulfonamides have an A value greater than 1 or a B value less than 0.7.

    “None of the variously substituted benzenesulfonamides have an A value greater than 1 or a B value less than 0.7, suggesting that the A (1.15) and B (0.26) values for PFASAs obtained in this work are significantly influenced by the perfluoroalkyl structure.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [10] Ulrich, N.; Endo, S.; Brown, T. N.; Watanabe, N.; Bronner, G.; Abraham, M. H.; Goss, K. U. UFZ-LSER database v 3.2 ; http://www.ufz.de/lserd (accessed on 2023-06-30).

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • It may state two separate claims as one.

    Study design and conductreasoning

    Since linearity is a prerequisite for PP-LFER model fitting, the log k data for SolGel-WAX were not used for solute descriptor determination.

    “Since linearity is a prerequisite for PP-LFER model fitting, the log k data for SolGel-WAX were not used for solute descriptor determination.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim.

    Premisenone given

    To determine the three descriptors S, A, and B, a minimum of three k and K data are required for a given PFAS compound.

    “To determine the three descriptors, a minimum of three k and K data are required for a given PFAS compound.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Premisereasoning

    In the data set, KHxd/w is sensitive to both A and B and Kow is sensitive to B.

    “In the data set, KHxd/w is sensitive to both A and B and Kow is sensitive to B.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Premisecitation

    For neutral organic compounds, PP-LFERs with Abraham's solute descriptors can quantify the energetic contributions of the relevant intermolecular interactions and describe partition coefficients in general.

    “For neutral organic compounds, polyparameter linear free energy relationships (PP-LFERs) with Abraham’s solute descriptors can quantify the energetic contributions of the relevant intermolecular interactions and describe partition coefficients in general.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [7] source

  • Probably not a substantial claim.

    Study design and conductown data

    Repeated measurements showed that the k variation was typically within 0.01 log unit.

    “Only one injection was performed for each compound because repeated measurements showed that the k variation was typically within 0.01 log unit.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. It may state two separate claims as one.

    Interpretationreasoning

    Any empirical model requires high-quality data on PFAS to accurately predict PFAS properties, but such data are often lacking.

    “Any empirical model requires high-quality data on PFAS to accurately predict PFAS properties, but such data are often lacking.”
    Quote in the paperSubstantial claim
60 of 60

  • The paper relies on this without support.

    The equilibrium partition of organic compounds is determined by the intermolecular interactions with the surrounding phases, including polar (e.g., hydrogen-bonding) and nonpolar (i.e., van der Waals) interactions.

    “The equilibrium partition of organic compounds is determined by the intermolecular interactions with the surrounding phases, including polar (e.g., hydrogen (H)-bonding) and nonpolar (i.e., van der Waals) interactions.”

  • The paper relies on this without support.

    GC retention data are equivalent to partition coefficients, reflecting the intermolecular interactions between the compound and stationary phase.

    “GC retention data are useful because they are relatively easy and fast to measure and are equivalent to partition coefficients, reflecting the intermolecular interactions between the compound and stationary phase.”

  • The authors state this as an assumption.

    PFAS that have the same nonfluorinated structure and differ only in the perfluoroalkyl chain length share the values of S, A, and B.

    “First, PFAS that have the same nonfluorinated structure and differ only in the perfluoroalkyl chain length share the values of S, A, and B.”

  • The authors state this as an assumption.

    A and/or B are zero if the compound does not have a functional group that can form an H-bond in the respective manner.

    “Second, A and/or B were set to 0 if the compound did not have a functional group that can form an H-bond in the respective manner.”

  • The paper relies on this without support.

    The PP-LFER and COSMOtherm models are based on completely different principles.

    “Since the two prediction models are based on completely different principles, the agreement increases the reliability of both models.”

  • The paper relies on this without support.

    PFAS have weak van der Waals interactions with any phase and high cavity energy in water.

    “These features are well expected due to the weak van der Waals interactions with any phase and the high cavity energy in water of PFAS.”
6 of 6

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Claimed fluorotelomer B-value increase conflicts with Table 3

    Minor

    The text says the B values of nonfluorinated alkyl acrylates and methacrylates (0.42-0.55) are about 0.1 lower than those of their fluorotelomer counterparts. Table 3 instead gives B values of 0.40 and 0.39 for the fluorotelomer acrylates and methacrylates.

  • PFASA B value differs between the text and Table 3

    Minor

    The text gives a B value of 0.26 for PFASAs, while Table 3 reports 0.23 ± 0.02.

  • Kaw data described as both excluded and used for calibration

    Minor

    The methods say Kaw data were not used to determine the descriptors, but the comparison section says the descriptors were calibrated with experimental Kaw data.

3 of 3

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Related

Metadata

Authors
Endo, S.
Affiliations
National Institute for Environmental Studies (JP)
Corresponding author
Endo, Satoshi
ORCID
Endo, Satoshi
Venue
Environmental Science & Technology
Publisher
American Chemical Society (ACS)
Published
2023-11-01
Volume
57
Issue
45
Pages
17534-17541
ISSN
  • 0013-936X (ISSN-L)
  • 1520-5851
DOI
10.1021/acs.est.3c07503
PMC
PMC10653080
OpenAlex
W4388129954
Semantic Scholar
00000a919f96e27214c974f39c97c26a46c41a26
Cited by
48
References
42
Citations by year
2026: 23 · 2025: 13 · 2024: 12
FWCI
4.14
Type
journal article
Language
en
Open access
Licence
Locations
  • Environmental Science & Technology (publishedVersion, cc-by)
  • ChemRxiv (acceptedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
Funders
Environmental Restoration and Conservation Agency (JPMEERF20213002)
Topics
  • Physical Sciences › Environmental Science › Environmental Chemistry › Per- and polyfluoroalkyl substances research
  • Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Toxic Organic Pollutants Impact
  • Physical Sciences › Chemistry › Organic Chemistry › Fluorine in Organic Chemistry
Keywords
per- and polyfluoroalkyl substances, partition coefficient, octanol-water partition coefficient, air-water partition coefficient, solute descriptors, intermolecular interactions, hydrogen bonding, gas chromatographic retention, environmental fate
MeSH terms
Octanols, Fluorocarbons, Water

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Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

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