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Partition coefficient

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Reference
Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method A.8 (Partition Coefficient - HPLC Method)
Deviations:
no
GLP compliance:
no
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
Identification: 1-Phenyl-3-methyl-4-(p-dodecylphenylazo)-5-pyrazolone
Appearance/Physical state: dark red semi solid
Batch: ZA07202016
Purity: >99%
Expiry date: 19 July 2019
Storage conditions: room temperature in the dark
Analytical method:
high-performance liquid chromatography
Key result
Type:
log Pow
Partition coefficient:
> 6.5
Temp.:
30 °C
pH:
6.92
Remarks on result:
other: The mobile phase was mixed on the instrument, the pH of a mixture of 80:20 MeOH:water was taken as a typical pH of the mobile phase.

Preliminary Estimate Results:

The log10Powwas calculated to be:    approximately 8 to 13

Definitive Test Results:

Calibration:

The retention times of the dead time and the retention times, capacity factors (k') and log10Powvalues for the reference standards are shown in the following tables:

Dead Time

Retention Time (mins)

Mean Retention Time (mins)

Injection 1

Injection 2

Thiourea

0.914

0.914

0.914

Standard

Retention Time (mins)

Capacity Factor (k')

Log10k'

Log10Pow

Injection 1

Injection 2

Mean

Benzene

1.453

1.453

1.453

0.590

-0.229

2.1

Toluene

1.701

1.696

1.698

0.859

-6.60 x 10-2

2.7

Naphthalene

1.798

1.798

1.798

0.968

-1.41 x 10-2

3.6

Phenanthrene

2.308

2.303

2.306

1.52

0.183

4.5

Triphenylamine

4.184

4.184

4.184

3.58

0.554

5.7

DDT

5.199

5.199

5.199

4.69

0.671

6.5

Partition coefficient of sample:

The retention times, capacity factor and log10Powvalue determined for the sample are shown in the following table:

Peak

Injection

Retention Time (mins)

Capacity Factor (k')

Log10k'

Log10Pow

Mean
Log10Pow

1

1

13.698

14.0

1.15

> 6.5

> 6.5

2

13.727

14.0

1.15

> 6.5

2

1

14.577

15.0

1.17

> 6.5

> 6.5

2

14.572

15.0

1.17

> 6.5

3

1

14.728

15.1

1.18

> 6.5

> 6.5

2

14.733

15.1

1.18

> 6.5

4

1

15.258

15.7

1.20

> 6.5

> 6.5

2

15.253

15.7

1.20

> 6.5

5

1

15.593

16.1

1.21

> 6.5

> 6.5

2

15.603

16.1

1.21

> 6.5

6

1

15.753

16.2

1.21

> 6.5

> 6.5

2

15.753

16.2

1.21

> 6.5

7

1

16.093

16.6

1.22

> 6.5

> 6.5

2

16.088

16.6

1.22

> 6.5

8

1

16.365

16.9

1.23

> 6.5

> 6.5

2

16.361

16.9

1.23

> 6.5

9

1

16.783

17.4

1.24

> 6.5

> 6.5

2

16.783

17.4

1.24

> 6.5

10

1

16.978

17.6

1.25

> 6.5

> 6.5

2

16.978

17.6

1.25

> 6.5

 Overall log10Pow:                   greater than 6.5
Overall Partition coefficient: greater than 3.16 x 106

Discussion:

The result from the preliminary test indicated that the HPLC method was suitable for determination of partition coefficient for this test item.

Due to the high affinity of the test item to the column the mobile phase solvent content was increased to 80%, slightly over that recommended by the test guidelines. This was not considered to impact the validity of the results.

Conclusions:
The partition coefficient of the test item has been determined to be greater than 3.16 x 10^6, log10 Pow > 6.5.
Executive summary:

Partition Coefficient (n-octanol/water). Greater than 3.16 x 106, log10Pow> 6.5, using the HPLC method, designed to be compatible with Method A.8 Partition Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 117 of the OECD Guidelines for Testing of Chemicals, 13 April 2004.

Description of key information

Partition Coefficient (n-octanol/water). Greater than 3.16 x 106, log10Pow> 6.5, using the HPLC method, designed to be compatible with Method A.8 Partition Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 117 of the OECD Guidelines for Testing of Chemicals, 13 April 2004.

Key value for chemical safety assessment

Log Kow (Log Pow):
6.5
at the temperature of:
30 °C

Additional information

Partition Coefficient (n-octanol/water). Greater than 3.16 x 106, log10Pow> 6.5.