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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:
08 January 2015
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
The study was conducted according to an internationally recognised method, and under GLP. However the choice of the standards could bring lack of acccuracy. The substance is considered to be adequately characterised with its purity. Therefore validation applies with restrictions.
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)
Qualifier:
according to
Guideline:
EPA OPPTS 830.7570 (Partition Coefficient, n-octanol / H2O, Estimation by Liquid Chromatography)
GLP compliance:
yes
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
- Storage condition of test material: In refrigerator (2-8°C) protected from light, container flushed with nitrogen
- Stability at higher temperatures: Yes, maximum temperature: 40°C, maximum duration: 10 days
Analytical method:
high-performance liquid chromatography
Type:
Pow
Partition coefficient:
6 200
Temp.:
35 °C
pH:
ca. 7
Key result
Type:
log Pow
Partition coefficient:
3.8
Temp.:
35 °C
pH:
ca. 7

Calculation of the Pow: The Pow of the test substance was calculated to be 1.6 × 10^3 (log Pow 3.2) using the Rekker calculation method.

Calculation of the pKa: No pKa values for acidic and basic groups in the molecular structure of the test substance in the logarithm range of 1 − 14 were calculated.

Results:

Substance

tr,1 [min]

tr, 2 [min]

mean tr (n=2)

log Pow

Pow

Formamide (t0)

0.559

0.558

0.559

-

-

Nitrobenzene

0.890

0.892

-

1.9

Bromobenzene

1.471

1.472

-

3.0

1,4-Dichlorobenzene

1.827

1.828

-

3.4

Biphenyl

2.445

2.444

-

4.0

1,2,4-Trichlorobenzene

2.824

2.822

-

4.2

Dibenzyl

4.048

4.044

-

4.8

Test substance

2.182

2.183

2.183

3.8

6.2 x 103

The equation of the regression line was: log k’ = 0.349 × log Pow – 0.860 (r = 0.998, n = 12).

In the chromatogram of the test solution, one test substance peak was observed.

Conclusions:
The substance has low potential to bioaccumulate in the environment, according to CLP classification criteria for aquatic chronic toxicity (log Kow <4).
Executive summary:

The partition coefficient of the test substance was measured, under GLP, according to the OECD 117 guideline, HPLC method.

The system was calibrated with 6 reference substances, between log Kow 1.9 and 4.8, and the result for the sample was interpolated from the linear regression.

The partition coefficient (log Kow) of the test substance has been determined to be 3.8 (at 35°C, and neutral pH).

Description of key information

The substance has low potential for bioaccumulation, according to CLP classification criteria for aquatic chronic toxicity (log Kow <4).

It should also be of no concern for PBT assessment.

Key value for chemical safety assessment

Log Kow (Log Pow):
3.8
at the temperature of:
35 °C

Additional information

A reliable experimental study, conducted according to a recognized OECD/EC method (HPLC) and under GLP, is available. Despite minor restrictions on accuracy, it is considered as a key study. The result is retained as key data.