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Administrative data

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
March 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
Chemical structure
Reference substance name:
1,6-anhydro-β-D-glucose
EC Number:
207-855-0
EC Name:
1,6-anhydro-β-D-glucose
Cas Number:
498-07-7
Molecular formula:
C6H10O5
IUPAC Name:
(1R,2S,3S,4R,5R)-6,8-dioxabicyclo[3.2.1]octane-2,3,4-triol
Constituent 2
Chemical structure
Reference substance name:
Glycollaldehyde
EC Number:
205-484-9
EC Name:
Glycollaldehyde
Cas Number:
141-46-8
Molecular formula:
C2H4O2
IUPAC Name:
2-hydroxyacetaldehyde
Constituent 3
Reference substance name:
Organic acids
IUPAC Name:
Organic acids
Constituent 4
Reference substance name:
Ketones
IUPAC Name:
Ketones
Constituent 5
Reference substance name:
Phenols
IUPAC Name:
Phenols
Constituent 6
Reference substance name:
Water
EC Number:
231-791-2
EC Name:
Water
Cas Number:
7732-18-5
Molecular formula:
H2O
IUPAC Name:
water
Constituent 7
Reference substance name:
Oligomers of sugars and anhydrosugars
IUPAC Name:
Oligomers of sugars and anhydrosugars
Test material form:
liquid: viscous

Study design

Analytical method:
high-performance liquid chromatography

Results and discussion

Partition coefficientopen allclose all
Type:
log Pow
Partition coefficient:
< 0.3
Remarks on result:
other: Peak 1
Type:
log Pow
Partition coefficient:
ca. 1.2 - ca. 2.3
Remarks on result:
other: Peak 2
Type:
log Pow
Partition coefficient:
ca. 2.3 - ca. 2.4
Remarks on result:
other: peak 3
Type:
log Pow
Partition coefficient:
ca. 2.4 - ca. 3.4
Remarks on result:
other: peak 4
Details on results:
The chromatogram of the test item gave three major and one minor peaks.
Since the peaks are very wide, the log k versus log POW calibration function is used to determine the corresponding log POW values of the start and end of the main peaks and a log POW range for each peak were determined.
As peak 3, show a relative area < 5%, they is considered as minor peak and is not taken into account in the determination of 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.

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 0.9714. This value was considered as sufficiently high to use the calibration function for the determination of the log POW of the test item Pyrolytic Sugar.
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

0.872

2.460

4.125

4.347

9.009

Measurement 2

0.900

2.457

4.117

4.372

9.322

Measurement 3

0.892

2.442

4.100

4.364

9.060

Mean

0.888

2.453

4.114

4.361

9.130

Standard Deviation

0.014

0.010

0.013

0.013

0.168

* 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

69.97

23.86

0.95

5.21

Measurement 2

68.46

24.85

1.04

5.65

Measurement 3

68.03

25.10

1.17

5.70

Mean

68.82

24.60

1.05

5.52

RSD

1.48

2.65

10.20

4.87

Calculated Values

The calculated values are presented in the following table:

Peak

Measurement No.

k

log k

log POW

1 (Start)

1

-0.3914

n.c*

n.c.*

2

-0.3718

n.c.*

n.c.*

3

-0.3775

n.c.*

n.c.*

Mean

 

 

n.c.*

Standard Deviation

 

 

n.c.*

1 (End)

= 2 (Start)

1

0.7172

-0.1443

1.227

2

0.7148

-0.1458

1.223

3

0.7044

-0.1522

1.208

Mean

 

 

1.219

Standard Deviation

 

 

0.010

2 (End)

= 3 (Start)

1

1.8794

0.2740

2.266

2

1.8735

0.2727

2.263

3

1.8620

0.2700

2.256

Mean

 

 

2.262

Standard Deviation

 

 

0.005

3 (End)

= 4 (Start)

1

2.0341

0.3084

2.352

2

2.0515

0.3121

2.361

3

2.0458

0.3109

2.358

Mean

 

 

2.357

Standard Deviation

 

 

0.005

4 (End)

1

5.2880

0.7233

3.382

2

5.5066

0.7409

3.426

3

5.3241

0.7262

3.389

Mean

 

 

3.399

Standard Deviation

 

 

0.023

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

log POW was calculated from the capacity factor as follows:

 

log POW = (log k + 0.6383) / 0.4026

 

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

1.883 - 15.779

0.888

not within range

1 (end)
=2 (Start)

Range (Max – Min. log POW)

< 0.1

0.019

valid

Retention time within Range of Reference Items

1.883 - 15.779

2.453

within range

2

(end)
=3 (Start)

Range (Max – Min. log POW)

< 0.1

0.010

valid

Retention time within Range of Reference Items

1.883 - 15.779

4.114

within range

3 (end)
=4 (Start)

Range (Max – Min. log POW)

< 0.1

0.009

valid

Retention time within Range of Reference Items

1.883 – 15.779

4.361

within range

4 (end)

Range (Max – Min. log POW)

< 0.1

0.044

valid

Retention time within Range of Reference Items

1.883 - 15.779

9.130

within range

* n.c. not calculable

Applicant's summary and conclusion

Conclusions:
the log POW range of the test item components is < 0.3 – 3.4
Executive summary:

The study was performed using a HPLC with a C18 column according to OECD guideline 117.

Eight 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 three major and one minor 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 main peaks and a logPOW range for each peak were determined:

 

Peak

Relative Area

Retention Time start

Retention Time end

Log POW

± Standard Deviation

 

[%]

[min]

[min]

 

1

68.82

0.888

2.453

< 0.3* – 1.2±0.01

2

24.60

2.453

4.114

1.2±0.01 – 2.3±0.01

3

1.05

4.119

4.361

2.3±0.01 – 2.4±0.01

4

5.52

4.361

9.130

2.4±0.01 – 3.4±0.02

*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 POWvalue should be stated as < 0.3

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 log POW range of the test item components is < 0.3 – 3.4.