Registration Dossier

Administrative data

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was performed according to guideline under GLP conditions. The test substance was analytical monitored by a substance specific method. The analytical method was validated with respect to linearity and precision

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)
Deviations:
no
Qualifier:
equivalent or similar to
Guideline:
other: Publication: "Structural determination of zinc dithiophosphates in lubricating oils by gas chromatography-mass spectrometry with electron impact and electron-capture negative ion chemical ionization" Journal of Chromatography A. 905 (2001) 207-222.
Deviations:
not applicable
GLP compliance:
yes
Type of method:
shake-flask method to: flask method
Partition coefficient type:
octanol-water

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
-Substance type: is a mixture of coordinations compound consisting of a zinc metal complex bonded to dialkyldithiophosphate ligands.
- Stability under test conditions: A Tier 1, preliminary hydrolysis studies conducted on the substance at 50 deg. C and pH 4, 7 and 9, indicated the dialkyl dithiophosphate ligands are hydrolytically stable ( <10% change in concentration of dialkyldithiophosphate ligand).

Study design

Analytical method:
other: GC-MS (gas chromatography-mass spectrometry)

Results and discussion

Partition coefficient
Type:
log Pow
Partition coefficient:
0.56
Temp.:
22 °C
pH:
ca. 5
Details on results:
Values for logPow were between 0.21 and 0.98 with a mean value of 0.56 ( ± 0.26). Sample recovery was 63.6 % (± 19.5%).

The compositions of the aqueous and octanol phases were compared by GC (gas chromatography on derivatized substance). The chromatograms show ZDDP (zinc dialkyldithiophosphate) components were distributed between both phases with a higher proportion of lower molecular weight dithiophosphate ligands containing the C3 (isopropyl) alkyl group (peak eluting at 8.17 min) in the aqueous phase. The chromatogram of the octanol phases shows a higher proportion of the higher molecular weight dithiophosphate ligands containing all C6 (1,3-dimethyl butyl) and ligands containing a mixture of C3/C6 alkyl chains.

Any other information on results incl. tables

Table 7. Results of Partition Coefficient Test

 

Octanol/Water Ratio

Replicate

Aqueous Phase

Octanol Phase

Pow

logPow

Mean  Pow

Mean logPow

Std Dev logPow

Sum GC Peak Areas

Conc in Water ug/mL)

Sum GC Peak Areas

Conc in Octanol (ug/mL)

2/1

1

140800

174

19634

686

3.94

0.60

3.34

0.51

0.16

2

191368

231

13068

479

2.08

0.32

3

87329

111

11923

443

3.99

0.60

1/1

1

359065

409

18987

665

1.63

0.21

2.17

0.32

0.16

2

109864

137

9588

370

2.70

0.43

3

284803

333

9286

360

*1.08

*0.03

1/2

1

45639

60

9385

363

6.05

0.78

7.33

0.85

0.11

2

59946

77

13443

491

6.38

0.80

3

29218

39

9673

372

9.55

0.98

                                                                          Overall Mean logPow

0.56

 

                                                                       Standard Deviation in logPow

0.26

 

Table 8. Method Accuracy (% of nominal concentration)

Nominal (mg/L)

SumAreas

Dilution

Conc.        (mg/L)

% Recovery

0.2

13943

1

0.09

50.70%

0.2

28351

1

0.19

95.80%

0.2

17176

1

0.12

60.90%

                                                       Mean

69.10%

                                                    SD

23.70%

                                                         %RSD

34.3

1.00

147628

1

0.95

90.80%

1.00

137278

1

0.89

84.80%

1.00

182920

1

1.16

111.00%

                                                       Mean

95.60%

                                                    SD

13.70%

                                                         %RSD

14.3

4.00

927012

1

4.38

105.90%

4.00

1071352

1

4.72

114.80%

4.00

1105295

1

4.79

116.70%

                                                       Mean

112.50%

                                                    SD

5.80%

                                                         %RSD

5.1

Table 9. Sample Recovery

Octanol/Water Ratio

Replicate

Aqueous Phase Mass (ug)

Octanol Phase Mass (ug)

Total Mass
    (ug)

Initial Mass (ug)

%  Recovery

Mean % Recovery

2/1

1

521

4114

4636

6000

77

62.3

2

694

2876

3570

6000

60

3

332

2660

2991

6000

50

1/1

1

1839

2994

4833

4500

107

75.7

2

619

1663

2282

4500

51

3

1498

1620

3118

4500

69

1/2

1

359

1090

1448

3000

48

52.7

2

464

1473

1938

3000

65

3

237

1117

1353

3000

45

                                                                                     Mean % Recovery

63.6

                                                                                      Standard Deviation

19.5

Applicant's summary and conclusion

Conclusions:
The test substance has a partition coefficient value, logPow, of 0.56 ± 0.26. The distribution of this multicomponent substance between the organic and aqueous phases is dependent on the alkyl chain lengths of the alkyldithiophosphate ligands


Executive summary:

Partitioning of the test substance between n-octanol and water was performed by the shake flask method equivalent to OECD 107. Test mixtures were prepared in triplicate under three different conditions where the octanol/water volume ratios were varied ( 1/2 , 2/1, and 1/1). Test mixtures were shaken for 5 min at 22 degrees C and the n-octanol and water phases separated by centrifugation. 

 

The concentration of ZDDP in each phase was determined by GC-MS following reaction with pentafluorobenzyl bromide to form halogenated derivatives according to a procedure described in the publication: "Structural determination of zinc dithiophosphates in lubricating oils by gas chromatography-mass spectrometry with electron impact and electron-capture negative ion chemical ionization"in Journal of Chromatography A. 905 (2001) 207-222.   

 

The following partition coefficient values were determined: Pow = 4.54   and logPow = 0.56.