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Physical & Chemical properties

Partition coefficient

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Reference
Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
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)
Version / remarks:
April 2004
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method A.8 (Partition Coefficient - HPLC Method)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 830.7570 (Partition Coefficient, n-octanol / H2O, Estimation by Liquid Chromatography)
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:
ca. 5.6
Temp.:
35 °C
pH:
ca. 7

The results obtained with the reference substance are given below:

Reference substance Log Pow retention time run 1 (min) retention time run 2 (min) mean retention time (min) k  log k
Thiourea   2.120 2.120 2.12    
Benzyl alcohol 1.1 2.619 2.618 2.62 0.235 -0.629
Benzene 2.1 3.732 3.731 3.73 0.760 -0.119
Toluene 2.7 4.626 4.625 4.63 1.182 0.073
1,4-dichlorobenzene 3.4 5.689 5.689 5.69 1.683 0.226
Cumene 3.7 6.857 6.857 6.86 2.234 0.349
1,2,4-trichlorobenzene 4.2 8.493 8.494 8.49 3.006 0.478
Fluoranthene 5.1 14.190 14.202 14.20 5.696 0.756
Triphenylamine 5.7 16.847 16.864 16.86 6.951 0.842
4,4'-DDT 6.5 20.940 20.962 20.95 8.883 0.949

The correlation coefficient was 0.9831.

The test item was injected twice:

Run retention time (min) k log k log Pow
1 17.035 7.0354 0.8473 5.6
2 17.006 7.0217 0.8464 5.6
Mean 17.021 7.0285 0.8469 5.6
Conclusions:
The partition coefficient n-octanol/water of the test substance was determined to be log Pow = 5.6 at 35°C and pH 7.
Executive summary:

In the current study the partition coefficient (n-octanol/water) of the test item was determined according to OECD Guideline 117 (2004).

The test was performed with a concentration of 10 mg test item in 25 mL methanol/20 mM potassium phosphate buffer (pH 7) 75:25 volume). Samples were analysed via HPLC on a C18 column with a refractive index detection.

Calibration was performed using 9 reference items with known log Pow values. The dead time was determined using thiourea. After calibration, the calibration mixture containing the 9 reference items and thiourea was measured, followed by by the test substance twice and the calibration mixture again.The validity criteria were reached.

From the two retention times derived for the test item, a mean retention time was calculated from which subsequently the log Pow value was derived.

The partition coefficient n-octanol/water of the test item, log Pow was determined to be 5.6 at 35 °C and pH7.

Description of key information

For this endpoint, one study is available in which the partition coefficient is assessed according to OECD 117, HPLC method. The partition coefficient n-octanol/water of the test item, log Pow was determined to be 5.6 at 35 °C and pH7.

Key value for chemical safety assessment

Log Kow (Log Pow):
5.6
at the temperature of:
35 °C

Additional information

From the two retention times derived for the test item, a mean retention time was calculated from which subsequently the log Pow value was determined to be 5.6 at 35°C and pH7.