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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:
27 to 28 October 2016
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)
Qualifier:
according to
Guideline:
EU Method A.8 (Partition Coefficient - HPLC Method)
GLP compliance:
yes (incl. certificate)
Remarks:
Staatliches Gewerbeaufsichtsamt Hildesheim, Germany
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Key result
Type:
log Pow
Partition coefficient:
3.11
Temp.:
22.7 °C
Remarks on result:
other: pH not measured, not relevant for the substance.
Remarks:
weighted mean of four test item signals.
Key result
Type:
log Pow
Partition coefficient:
>= 3.04 - <= 3.16
Temp.:
22.7 °C
Remarks on result:
other: pH not measured, not relevant for the substance.
Remarks:
range based on four test item signals.

Determination of the Void Time

The HPLC void time (t0) was determined by threefold injection of a solution of 5 mg/L NaNO3. The results are provided in the following table.

 

Serial no.

t0[min]

1

0.743

2

0.724

3

0.721

Mean

0.729

 

 

Calibration

In the following table, the retention time data of the reference items used for calibration are given.

 

Reference item

log POW

1st Calibration

2nd Calibration

tR1

[min]

k

log k

tR2

[min]

k

log k

4-Acetylpyridine

0.5

1.303

0.787

-0.104

1.304

0.788

-0.104

Acetanilide

1.0

1.570

1.15

0.0617

1.572

1.16

0.0627

Benzonitrile

1.6

2.282

2.13

0.328

2.287

2.14

0.330

Nitrobenzene

1.9

3.561

3.88

0.589

3.570

3.89

0.590

Toluene

2.7

8.925

11.2

1.05

8.986

11.3

1.05

Ethylbenzene

3.2

15.169

19.8

1.30

15.275

19.9

1.30

Isopropylbenzene

3.7

24.272

32.3

1.51

24.421

32.5

1.51

 

The calculated slope, Y-intercept and correlation coefficient for the first and second calibration of the reference items are shown in the following table. The correlation coefficient r for both calibrations was > 0.9.

 

 

1st Calibration

2nd Calibration

slope

1.864

1.865

Y-intercept

0.8249

0.8230

r2

0.9926

0.9927

r

0.9963

0.9964

r Correlation Coefficient

r2 Coefficient of determination

 

 

Results of Test Item Analysis

The substance is UVCB, with four components accounting for 51.3 % of the composition (sum of four major peaks). For each of the four test item signals, two individual log POW values were derived under consideration of the first and second calibration and a mean value was calculated from these individual log POW values. Finally, a weighted average mean based on the peak area percentage of the respective signals was calculated. The results are summarized in the following tables.

Retention Times, Capacity Factors and Partition Coefficients of Signal 1

SIGNAL 1

tR

[min]

k

log k

log POW

1st Calibration

2nd Calibration

11.942

15.4

1.19

3.04 ± 0.06

2.90 to 3.19 (95% Cl)

3.04 ± 0.06

2.90 to 3.18 (95 % Cl)

11.945

15.4

1.19

Mean

11.944

15.4

1.19

3.04

 

Retention Times, Capacity Factors and Partition Coefficients of Signal 2

SIGNAL 2

tR

 [min]

k

log k

log POW

1st Calibration

2nd Calibration

12.284

12.284

12.284

3.06 ± 0.06

2.92 to 3.21 (95 % Cl)

3.06 ± 0.06

2.92 to 3.20 (95 % Cl)

12.286

12.286

12.286

Mean

12.285

12.285

12.285

3.06

 

Retention Times, Capacity Factors and Partition Coefficients of Signal 3

SIGNAL 3

tR

 [min]

k

log k

log POW

1st Calibration

2nd Calibration

13.414

13.414

13.414

3.14 ± 0.06

2.99 to 3.29 (95 % Cl)

3.14 ± 0.06

2.99 to 3.28 (95 % Cl)

13.412

13.412

13.412

Mean

13.413

13.413

13.413

3.14

 

Retention Times, Capacity Factors and Partition Coefficients of Signal 4

SIGNAL 4

tR

 [min]

k

log k

log POW

1st Calibration

2nd Calibration

13.778

13.778

13.778

3.16 ± 0.06

3.00 to 3.31 (95 % Cl)

3.16 ± 0.06

3.01 to 3.30 (95 % Cl)

13.780

13.780

13.780

Mean

13.779

13.779

13.779

3.16

Conclusion

For each of the four test item signals, two individual log POW values were derived under consideration of the first and second calibration and a mean value was calculated from these individual log POW values. Finally, a weighted average mean based on the peak area of the respective signals was calculated (results reported in the following table). The mean column temperature was determined to be 22.7 °C during the course of the study.

 

log POW

Area

[%]

1st Calibration

2nd Calibration

Mean

Signal 1

3.04 ± 0.06

2.90 to 3.19 (95 % Cl)

3.04 ± 0.06

2.90 to 3.18 (95% Cl)

3.04

19.7

Signal 2

3.06 ± 0.06

2.92 to 3.21 (95 % Cl)

3.06 ± 0.06

2.92 to 3.20 (95 % Cl)

3.06

24.9

Signal 3

3.14 ± 0.06

2.99 to 3.29 (95 % Cl)

3.14 ± 0.06

2.99 to 3.28 (95 % Cl)

3.14

10.9

Signal 4

3.16 ± 0.06

3.00 to 3.31 (95 % Cl)

3.16 ± 0.06

3.01 to 3.30 (95 % Cl)

3.16

44.4

 

 

Weighted Mean

3.11

 

Conclusions:
A log Kow of 3.11 at 22.7 °C was determined for the test substance according to OECD 117.

Description of key information

Log Kow: 3.11 at 22.7 °C (EU Method A.8, HPLC Method)

Key value for chemical safety assessment

Log Kow (Log Pow):
3.11
at the temperature of:
22.7 °C

Additional information

The substance is UVCB, with four main components with Log POW of 3.04, 3.06, 3.14 and 3.16. A weighted mean Log POW, based on the peak area percentage of the respective signals, was calculated for substance as a whole.