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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:
19 FEB 2010 to 9 NOV 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
Tested according to current guidelines and GLP
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)
Deviations:
no
GLP compliance:
yes
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Analytical method:
high-performance liquid chromatography
Key result
Type:
log Pow
Partition coefficient:
> 0.3 - < 3.93
Temp.:
25 °C
pH:
> 1.1 - < 2
Details on results:
The test substance eluted as seventeen components with retention times corresponding to log Pow values of between <0.3 to 3.93, indicating that the MK92K comprises some components that highly water soluble and others that are fat soluble.
The pH was not adjusted from the natural state of pH 1 - 2

Reference Substance Data for Partition Coefficient

Compound

Purity (%)

Literature value
(Log Pow)

Mass injected (µg)

Formamide

>99

N/A

31.44

2-Butanone

=>99

0.30

257.04

Acetanilide

97

1.00

0.10

Benzonitrile1

99

1.60

0.06

Methyl benzoate

99

2.10

0.16

Ethyl benzoate1

=>99

2.60

0.21

1,4-Dichlorobenzene

=>99

3.40

0.23

Biphenyl

99.5

4.00

1.53

1,2,4-Trichlorobenzene1

>99

4.20

0.78

Test substance

>99

N/A

31.44

1These standards are not used in the calibration line for calculating the partition coefficient

 

Calibration Data for Partition Coefficient

Calibration substance

First estimation

Second estimation

Retention time (min)

Capacity factor (log K)

Retention time (min)

Capacity factor (log K)

Formamide

2.811

N/A

2.812

N/A

2-Butanone

4.319

-0.270

4.308

-0.274

Acetanilide

6.064

0.064

6.037

0.059

Benzonitrile1

7.763

0.246

7.714

0.241

Methyl benzoate

13.489

0.580

13.384

0.575

Ethyl benzoate1

21.585

0.825

22.725

0.850

1,4-Dichlorobenzene

33.561

1.039

33.061

1.032

Biphenyl

66.115

1.353

64.924

1.344

1,2,4-Trichlorobenzene1

70.538

1.382

69.224

1.373

Statistical data:

 

First estimation

Second estimation

Slope

0.4287

0.4300

Intercept

-0.3730

-0.3758

Correlation (R2)

0.9968

0.9967

1These standards are not used in the calibration line for calculating the partition coefficient

 

Analytical Data for Partition Coefficient (First Estimation)

Compound

Retention time (min)

log K mean

log Pow

95% min

95% max

MK92K

3.454

-0.640

-0.621

-0.98

-0.33

3.455

MK92K

3.582

-0.561

-0.441

-0.78

-0.16

3.583

MK92K

4.595

-0.197

0.41

0.16

0.62

4.594

MK92K

5.623

0.000

0.87

0.66

1.05

5.622

MK92K

7.486

0.221

1.39

1.21

1.54

7.483

MK92K

8.457

0.303

1.58

1.41

1.73

8.456

MK92K

8.691

0.321

1.62

1.46

1.77

8.691

MK92K

9.358

0.367

1.73

1.57

1.87

9.358

MK92K

10.275

0.424

1.86

1.71

2.00

10.273

MK92K

11.311

0.481

1.99

1.84

2.14

11.312

MK92K

11.935

0.511

2.06

1.92

2.21

11.939

MK92K

16.016

0.672

2.44

2.29

2.59

16.013

MK92K

25.111

0.899

2.97

2.81

3.14

25.072

MK92K

28.505

0.961

3.11

2.95

3.30

28.507

MK92K

34.456

1.051

3.32

3.15

3.52

34.404

MK92K

60.718

1.313

3.93

3.72

4.19

60.441

1– Retention time < lowest standard. Log Pow to be reported as < 0.3

 

Analytical Data for Partition Coefficent (Second Estimation)

Compound

Retention time (min)

log K mean

log Pow

95% min

95% max

MK92K

3.453

-0.645

-0.631

-0.99

-0.31

3.446

MK92K

3.580

-0.566

-0.441

-0.79

-0.16

3.573

MK92K

4.581

-0.204

0.40

0.15

0.62

4.561

MK92K

5.602

-0.006

0.87

0.65

1.05

5.569

MK92K

7.439

0.213

1.38

1.20

1.54

7.377

MK92K

8.414

0.296

1.57

1.41

1.73

8.334

MK92K

8.637

0.313

1.61

1.45

1.76

8.550

MK92K

9.303

0.360

1.72

1.56

1.87

9.204

MK92K

10.242

0.418

1.86

1.70

2.01

10.121

MK92K

11.238

0.473

1.99

1.84

2.13

11.112

MK92K

11.846

0.503

2.06

1.91

2.20

11.680

MK92K

15.897

0.664

2.43

2.29

2.59

15.688

MK92K

24.882

0.891

2.96

2.80

3.14

24.463

MK92K

28.251

0.952

3.11

2.94

3.30

27.763

MK92K

34.113

1.042

3.32

3.14

3.52

33.482

MK92K

56.053

1.268

3.85

3.63

4.10

53.893

MK92K

59.857

1.302

3.93

3.71

4.19

58.566

1– Retention time < lowest standard. Log Pow to be reported as < 0.3

 

Back-Calculated Partition Coefficient Values

Compound

Retention time (min)

log K mean

log Pow

95% min

95% max

First estimation

2-Butanone

4.319

-0.270

0.24

-0.03

0.47

Acetanilide

6.064

0.064

1.02

0.82

1.19

Methyl benzoate

13.489

0.580

2.22

2.08

2.37

Biphenyl

66.115

1.353

4.03

3.80

4.29

Second estimation

2-Butanone

4.308

-0.274

0.24

-0.04

0.47

Methyl benzoate

13.384

0.575

2.23

2.08

2.37

1,4-Dichlorobenzene

33.061

1.032

3.29

3.12

3.50

Biphenyl

64.924

1.344

4.02

3.80

4.29

 

Conclusions:
The test substance eluted as seventeen componenets with retention times corresponding to log Pow values of between <0.3 to 3.93.
Executive summary:

The compound MK92K eluted as multiple peaks, and with two exceptions these all exhibited retention times within the range of retention times of the calibration substances. Therefore the results of the estimation may be expected to be realistic, as the results were calculated by interpolation rather than extrapolation. It was possible to establish the calibration line with five different calibration compounds. For the components with retention times shorter than that of the lowest standard (2-butanone) the partition coefficient was considered to be less than that of the lowest standard.

There were only minimal differences between the replicates of retention times for each of the calibration and test substances, and between the two injection sequences. For both runs a peak with a retention time shorter than formamide was observed. The resultant calculated values differed only to a small extent, therefore the results may be considered as acceptable for regulatory purposes.

The test substance eluted as seventeen components with retention times corresponding to log Pow values of between <0.3 to 3.93, indicating that the MK92K comprises some components that are highly water soluble and others that are fat soluble.

Description of key information

The test substance eluted as seventeen components with retention times corresponding to log Pow values of between <0.24 to 3.93, indicating that the MK92K comprises some components that highly water soluble and others that are fat soluble.

A headline figure of Log 3 is used for the Chesar export

Key value for chemical safety assessment

Log Kow (Log Pow):
3
at the temperature of:
25 °C

Additional information

The octanol water partition coefficient was determined according to OECD Guideline 117 (Partition Coefficient [n-octanol/water], HPLC method) and EU Method A.8 (Partition Coefficient).

The dead time T0 was measured using formamide (in solution in mobile phase) as a non-retained solute (void volume marker). Two series of injections were made, each series consisted of duplicate injections of the test substance, eight calibration substances (only five of which were used in the calibration) (including a mixed standard), and triplicate injections of formamide, injected in a random order. The test substance was dissolved in mobile phase and the mean retention time recorded.

Whilst is acknowledged that the test substance is surface active (as determined in this study) the HPLC simlulation was considered the most appropriate option for this test due to the complex multi-component nature of the material making analysis of solutions difficult. For this reason the results of the simulation should be regarded as indicative values rather than absolute figures.