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Administrative data

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
April 2021
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2021
Report date:
2021

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
Version / remarks:
April 2004
Deviations:
yes
Remarks:
uncritical deviation: The reference item mix was dissolved in a different solvent than the eluent (metha-nol/water 75/25 % v/v instead of 65/35 % v/v) in the first determination. Deviation had no impact on the retention times.
Qualifier:
according to guideline
Guideline:
other: EU method A.24 “Partition Coefficient (N-OCTANOL/WATER), HIGH PERFORMANCE LIQUID CHROMATOGRAPHY (HPLC) METHOD"
Version / remarks:
December 2015
Deviations:
yes
Remarks:
as above
GLP compliance:
yes (incl. QA statement)
Type of method:
HPLC method
Partition coefficient type:
octanol-water

Test material

Constituent 1
Reference substance name:
Low molecular weight organic substances from fast pyrolysis bio-oil
IUPAC Name:
Low molecular weight organic substances from fast pyrolysis bio-oil
Constituent 2
Reference substance name:
Monomers from fast pyrolysis bio-oil
IUPAC Name:
Monomers from fast pyrolysis bio-oil
Constituent 3
Reference substance name:
Dimers from fast pyrolysis bio-oil
IUPAC Name:
Dimers from fast pyrolysis bio-oil
Constituent 4
Reference substance name:
Trimers from fast pyrolysis bio-oil
IUPAC Name:
Trimers from fast pyrolysis bio-oil
Constituent 5
Reference substance name:
Higher oligomers from fast pyrolysis bio-oil
IUPAC Name:
Higher oligomers from fast pyrolysis bio-oil
Constituent 6
Chemical structure
Reference substance name:
Water
EC Number:
231-791-2
EC Name:
Water
Cas Number:
7732-18-5
Molecular formula:
H2O
IUPAC Name:
water
Test material form:
liquid: viscous
Remarks:
Brown /black highly vicous liquid

Study design

Analytical method:
high-performance liquid chromatography

Results and discussion

Partition coefficientopen allclose all
Type:
log Pow
Partition coefficient:
ca. 1.7 - ca. 3.8
Remarks on result:
other: Peak 1
Type:
log Pow
Partition coefficient:
ca. 3.8 - ca. 5.5
Remarks on result:
other: Peak 2
Type:
log Pow
Partition coefficient:
ca. 5.5 - ca. 5.9
Remarks on result:
other: peak 3
Type:
log Pow
Partition coefficient:
ca. 5.9 - ca. 6.2
Remarks on result:
other: peak 4
Details on results:
The chromatogram of the test item gave a broad signal with several unresolved peaks, which was separated into four sections for evaluation. Since these peaks are very wide, the log k versus log POW calibration function was used to determine the corresponding log POW values of the start and end of the peaks and a log POW range for each peak were determined.
Although area is not necessarily correlated to the absolute concentration, if a UV detector is used, it is assumed that the detected peaks are representative components of the test item.

Discussion
Variations in the retention times of reference items and test item are very small. Therefore a stable configuration of the HPLC-column can be assumed.
A peak in the blank value of methanol/water is a known artifact originating from dissolved air, which has no influence on the retention times of the test item.
The correlation log k/log POW is good: the coefficient of determination r2 was calculated to be 0.9923. This value was considered as sufficiently high to use the calibration function for the determination of the log POW of the test item.
Although area is not necessarily correlated to the absolute concentration, if a UV detector is used, it is assumed that the detected peaks are representative components of the test item.
Since the peaks are very wide, the log k versus log POW calibration function was used to determine the corresponding log POW values of the start and end of the main peaks for determination of a log POW range for each peak.
No observations were made which might cause doubts concerning the validity of the study outcome.

Any other information on results incl. tables

 Measurement Data

The retention times of the test item are presented in the following table: 

Measurement

Start

Peak 1

End *

Peak 1

End *

Peak 2

End *

Peak 3

End

Peak 4

 

min.

min.

min.

min.

min.

Measurement 1

0.893

5.435

17.132

22.255

27.413

Measurement 2

0.924

5.420

17.127

22.279

27.289

Measurement 3

0.875

5.462

17.152

22.145

26.958

Mean

0.897

5.439

17.137

22.226

27.220

Standard Deviation

0.024

0.021

0.013

0.071

0.235

* The end time of one peak is identical with the start time of the following peak

Peak Areas Test Item

Measurement

Relative Area
Peak 1

Relative Area
Peak 2

Relative Area
Peak 3

Relative Area
Peak 4

 

%

%

%

%

Measurement 1

79.11

17.53

2.02

1.35

Measurement 2

79.21

17.61

1.95

1.23

Measurement 3

78.81

17.51

2.32

1.36

Mean

79.04

17.55

2.10

1.31

RSD

0.26

0.28

9.32

5.42

 

Calculated Values

The calculated values are presented in the following table:

Peak

Measurement No.

k

log k

log POW

1 (Start)

1

-0.3739

n.c.*

n.c.*

2

-0.3527

n.c.*

n.c.*

3

-0.3867

n.c.*

n.c.*

Mean

 

 

n.c.*

Standard Deviation

 

 

n.c.*

1 (End)

= 2 (Start)

1

2.8093

0.4486

3.812

2

2.7989

0.4470

3.807

3

2.8280

0.4515

3.820

Mean

 

 

3.813

Standard Deviation

 

 

0.007

2 (End)

= 3 (Start)

1

11.0072

1.0417

5.543

2

11.0039

1.0415

5.542

3

11.0213

1.0422

5.544

Mean

 

 

5.543

Standard Deviation

 

 

0.001

3 (End)

= 4 (Start)

1

14.5981

1.1643

5.901

2

14.6146

1.1648

5.902

3

14.5210

1.1620

5.894

Mean

 

 

5.899

Standard Deviation

 

 

0.004

4 (End)

1

18.2135

1.2604

6.181

2

18.1260

1.2583

6.175

3

17.8946

1.2527

6.159

Mean

 

 

6.172

Standard Deviation

 

 

0.012

*n.c. = not calculable, log POW was not able to be calculated from the capacity factor because the factor was negative.

 

log POWwas calculated from the capacity factor as follows:

 

log POW= (log k + 0.8574) / 0.3426

 

Validity

The validity criteria and results are presented in the following table:

Peak

Parameter

Criterion

Found

Assessment

1 (start)

Range (Max – Min. log POW)

< 0.1

n.c.*

not valid

Retention time within Range of
Reference Items

2.143 -
29.770

0.897

not within range

1 (end)
=2 (Start)

Range (Max – Min. log POW)

< 0.1

0.013

valid

Retention time within Range of
Reference Items

2.143 -
29.770

5.439

within range

2

(end)
=3 (Start)

Range (Max – Min. log POW)

< 0.1

0.002

valid

Retention time within Range of
Reference Items

2.143 -29.770

17.137

within range

3 (end)
=4 (Start)

Range (Max – Min. log POW)

< 0.1

0.008

valid

Retention time within Range of
Reference Items

2.143 -
29.770

22.226

within range

4 (end)

Range (Max – Min. log POW)

< 0.1

0.022

valid

Retention time within Range of
Reference Items

2.143 -
29.770

27.220

within range

* n.c. = not calculable

Applicant's summary and conclusion

Conclusions:
the log POW range of the test item components is <1.7 – 6.2
Executive summary:

The study was performed using a HPLC with a C18 column, according to OECD guideline 117. Seven reference items with different retention times and thiourea for the determination of the dead time were used to produce a calibration curve, since retention time on hydrophobic columns and POW are correlated. The reference items were chosen based on the results of the pre-test.

The chromatogram of the test item gave four peaks. Since the peaks are very wide, the log k versus logPOW calibration function is used to determine the corresponding logPOW values of the start and end of the peaks and a logPOW range for each peak were determined:

 

Peak

Relative Area

Retention Time start

Retention Time end

Log POW

± Standard Deviation

 

[%]

[min]

 

 

1

79.04

0.897

5.439

< 1.7* - 3.8±0.01

2

17.55

5.439

17.137

3.8±0.01 – 5.5±0.00

3

2.10

17.137

22.226

5.5±0.00 – 5.9±0.00

4

1.32

22.226

27.220

5.9±0.00 – 6.2±0.01

*Peak start lay within the dead time of the method and not within the range of log POW values of the reference items. Therefore, the corresponding log POW value should be stated as < 1.7

These values are the means ± standard deviations of three independent determinations.

Although area is not necessarily correlated to the absolute concentration, if a UV detector is used, it is assumed that the detected peaks are representative components of the test item, indicating that the logPOW range of the test item components is <1.7 – 6.2.