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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
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Analytical method:
high-performance liquid chromatography
Key result
Type:
log Pow
Partition coefficient:
4.8
Temp.:
25 °C
pH:
7.2
Type:
log Pow
Partition coefficient:
4.5
Remarks on result:
other: calculated
Remarks:
KOWWIN v. 1.68
Details on results:
In order to ensure a stable performance of the HPLC column, the column temperature was set to 40 °C. The reference Pow-values in the OECD guideline presumably refer to 25 °C. Even though the column temperature was 40 °C, this temperature has no influence on the result of the determination. Therefore the Pow-value of the test item determined within this study also refers to 25 °C.

The pKa values, calculated with the software ACD/Labs/Percepta 14.0.0 Release 2012, were:

  • pKa(Acid): No acid pKa
  • First pKa(Base): - 4.3 ± 0.2
  • Second pKa(Base): 0.5 ± 0.2S

Therefore the undissociated form (nonionic from) of Macrolex Rot 5B exists at a pH value > 1.5 and the test was carried out in buffered water at pH > 2.

Conclusions:
The partition coefficient (logPow) of Macrolex Rot 5B was determined to be 4.8 at 25 °C (pH 7).
Executive summary:

For Macrolex Rot 5B the partition coefficient was determined by the HPLC-method according to OECD TG 117. The partition coefficient was determined to be 4.8 at 25°C. All validity criteria were met.

Description of key information

The partition coefficient (logPow) of Solvent Red 52 was determined to be 4.8 at 25 °C (pH 7).

Key value for chemical safety assessment

Log Kow (Log Pow):
4.8
at the temperature of:
25 °C

Additional information

In order to ensure a stable performance of the HPLC column, the column temperature was set to 40 °C. The reference Pow-values in the OECD guideline presumably refer to 25 °C. Even though the column temperature was 40 °C, this temperature has no influence on the result of the determination. Therefore the Pow -value of the test item determined within this study also refers to 25 °C.