Benzene, mono-C10-13-alkyl derivs., distn. residues, sulfonated, barium salts

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-10-31 - 2018-01-11

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7570 (Partition Coefficient, n-octanol / H2O, Estimation by Liquid Chromatography)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)

Version / remarks:

adopted 13 April 2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient - HPLC Method)

Version / remarks:

Annex to Commission Directive 92/69/EEC. 1992.

Deviations:

no

GLP compliance:

yes

Remarks:

US EPA (40 CFR Part 792); OECD (ENV/MC/CHEM(98); Japan MAFF)

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

ca. -3.8 - ca. 5.2

Temp.:

40 °C

pH:

6.5

Details on results:

Injections of a matrix blank sample (75% ACN: 25% reagent water (v/v)) and reagent blank sample (75% ACN: 25% reagent water: 2% THF (v/v/v)) showed that the reagents used for preparation of the reference standard solutions and sample solutions were free of any potentially interfering contaminants.
The mean retention time of the duplicate thiourea standard injections was 0.832 minutes. Seven reference standard solutions were analyzed after each thiourea injection, five of which were used to establish a calibration curve. The additional two standards, sodium nitrate and 1-phenyltetradecane, were injected to give a more accurate estimation for the lowest-retaining test substance peak and to bracket any test substance peaks that eluted after DDT, respectively, and were not included in the calibration curve.
The three 51.0 mg/L sample solutions were sequentially injected. Sample eluted as four distinct peaks. A fourth test substance solution at 204 mg/L was subsequently injected to verify that all four of the peaks were correctly attributed to the test substance. The mean retention times of the four peaks were 0.671 minutes, 1.193 minutes, 1.625 minutes, and 2.722 minutes. The first test substance peak eluted prior to the retention time for sodium nitrate, and since the test substance peak was non-retained with a calculated negative capacity factor, a corresponding Log POW could not be extrapolated. The Log POW of the test substance peak was therefore reported as less than the Log POW for sodium nitrate (i.e., <-3.8). The corresponding Log POW values for peaks two, three, and four were 2.5, 3.8, and 5.2, respectively.

Conclusions:

Under the chromatographic conditions specified, the test item eluted as four discrete peaks. The mean retention times of the test substance peaks were 0.671 minutes, 1.193 minutes, 1.625 minutes, and 2.722 minutes. The corresponding mean n-octanol/water partition coefficients (Log POW) for the test item was a range from less than sodium nitrate (i.e., < -3.8) to 5.2.

Executive summary:

The objective of this study was to experimentally estimate the n-octanol/water partition coefficient of the test substance by a reverse-phase high performance liquid chromatography method. The study was conducted in compliance with GLP standards and according to EU Method A.8, OECD guideline #117 and to US EPA OPPTS 830.7570.

Under the chromatographic conditions specified, the test item eluted as four discrete peaks. The mean retention times of the test substance peaks were 0.671 minutes, 1.193 minutes, 1.625 minutes, and 2.722 minutes. The corresponding mean n-octanol/water partition coefficients (Log POW) for the test item was a range from less than sodium nitrate (i.e., < -3.8) to 5.2 at a temperature of 40 °C and a pH of 6.5.

Description of key information

The objective of this study was to experimentally estimate the n-octanol/water partition coefficient of the test substance by a reverse-phase high performance liquid chromatography method. The study was conducted in compliance with GLP standards and according to EU Method A.8, OECD guideline #117 and to US EPA OPPTS 830.7570.

Under the chromatographic conditions specified, the test item eluted as four discrete peaks. The mean retention times of the test substance peaks were 0.671 minutes, 1.193 minutes, 1.625 minutes, and 2.722 minutes. The corresponding mean n-octanol/water partition coefficients (Log POW) for the test item was a range from less than sodium nitrate (i.e., < -3.8) to 5.2 at a temperature of 40 °C and a pH of 6.5.

In addition, the partition coefficient of the calcium sulfonate read across substance CAS 70024 -69 -0 was estimated to be > 2.95E5, logPow > 5.47 and the one of the calcium sulfonate read across substance CAS 61789 -86 -4 has been estimated to be > 4.43E6 , logPow > 6.65.

Key value for chemical safety assessment

Log Kow (Log Pow):

4.76

at the temperature of:

40 °C

Additional information

The four different log Kow's for the substance are:

Peak 1: < -3.8 (This peak eluted prior to sodium nitrate, therefore an extrapolation cannot be determined. The log Pow of this peak is less than the cited log Pow value of sodium nitrate. For CSA -3.8 was assumed)

Peak 2: 2.5

Peak 3: 3.8

Peak 4: 5.2

The corresponding Kow values are:

Peak 1: 0.00015849

Peak 2: 316.228

Peak 3: 6309.573

Peak 4: 158489.319

Regarding the peak-area, this area is different for each peak:

Peak 1: 4.7 %

Peak 2: 4.5 %

Peak 3: 43 %

Peak 4: 27 %

Therefore the weighted mean (Xmean = (sum products of weighting * value) / (sum of weightings))

weighted mean: (0.047*0.00015849 + 0.045*316.228 + 0.43*6309.573 + 0.27*158489.319) / (0.047 +0.045 +0.43 +0.27) = 57474.069

lg (weighted mean) = 4.76

For CSA the lg of the weighted mean of the different Kow-values was chosen: 4.76