C-M5

Partition coefficient

Administrative data

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted to GLP and in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do no effect the quality of the relevant results.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

shake-flask method to: flask method

Partition coefficient type:

octanol-water

Test material

Reference

Name:

Unnamed

Type:

Constituent

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Study design

Analytical method:

photometric method

Results and discussion

Partition coefficient

Type:

log Pow

Partition coefficient:

< -4.37

Temp.:

23 °C

pH:

7

Details on results:

The partition coefficient of the test material has been determined to be <4.31 x 10-5 at 23.0 ± 0.5 degC, log10 Pow <-4.37.

Any other information on results incl. tables

Results

Preliminary estimate

Approximate solubility in n-octanol: 9.2 x 10 ^-3 g/l

Approximate solubility in water:       >515 g/l
Approximate P_ow:   1.79 x 10ResultsPreliminary estimateApproximate solubility in n-octa^-5
Log₁₀P_ow:   -4.75

         Definitive test

The absorbances obtained for the standard, stock and sample solutions are shown in the following two tables:

Organic Phase

Solution	Absorbance*
Standard 0.226 mg/l	1.720 x 10^-3
Standard 0.452 mg/l	3.790 x 10^-3
Standard 0.510 mg/l	4.790 x 10^-3
Standard 0.678 mg/l	7.350 x 10^-3
Standard 0.904 mg/l	9.770 x 10^-3
Standard 1.13 mg/l	1.403 x 10^-2
Sample 1	-0.00176993
Sample 2	-0.00171993
Sample 3	-0.00157973
Sample 4	-0.00190003
Sample 5	-0.00184003
Sample 6	-0.00198003

* corrected for organic blank (water saturated n-octanol:dimethylsulfoxide (1:1))

Aqueous Phase

Solution	Absorbance
Standard 10.2 mg/l	0.390
Standard 10.3 mg/l	0.382
Sample 1	0.400
Sample 2	0.396
Sample 3	0.390
Sample 4	0.390
Sample 5	0.393
Sample 6	0.383
Stock solution A	0.382
Stock solution B	0.391

* corrected for organic blank (water saturated n-octanol:dimethylsulfoxide (1:1))

The total weights (mg) and analysed concentration (mg/l) of the respective phases are shown in the following table:

Sample Number	Volume of Water Saturated n-octanol (ml)	Volume of Stock Solution (ml)	Total Weight (mg)*	Organic Phase		Aqueous Phase
				Analysed Concentration (mg/l)	Weight (mg)†	Analysed Concentration (mg/l)	Weight (mg)†	pH
1	110	11	113	0.438	4.82 x 10^-2	1.06 x 10^4	117	7.2
2	110	11	113	0.438	4.82 x 10^-2	1.05 x 10^4	115	7.3
3	110	22	225	0.438	4.82 x 10^-2	1.03 x 10^4	227	7.2
4	130	26	266	0.438	5.69 x 10^-2	1.03 x 10^4	269	7.4
5	110	44	451	0.438	4.82 x 10^-2	1.04 x 10^4	458	7.4
6	110	44	451	0.438	4.82 x 10^-2	1.02 x 10^4	447	7.2

pH of n-octanol saturated water:           7.5
pH of stock solution:                             7.4
Temperature:                                        23.0 ± 0.5°C

The partition coefficient determined for each sample is shown in the following table:

Sample Number	n-Octanol/Water Volume Ratio	Partition Coefficient	Log10Pow
1	10 : 1	4.13 x 10^-5	-4.38
2		4.17 x 10^-5	-4.38
3	5 : 1	4.24 x 10^-5	-4.37
4		4.24 x 10^-5	-4.37
5	5 : 2	4.20 x 10^-5	-4.38
6		4.31 x 10^-5	-4.37

Overall P_ow :4.31 x 10^-5                     log₁₀P_ow: <-4.37

* from analysis of the stock solution

† from analysis of the respective phase

Validation

The linearity of the detector response with respect to concentration was assessed over the nominal concentration range of 0 to 20 mg/l for the aqueous samples.  This was satisfactory with a correlation coefficient of 1.00 being obtained.

Discussion

The limit value for the organic phase samples was obtained from the lowest detectable standard within the experimentally determined linearity of response range.

Substances having a log₁₀P_owof greater than 3 are regarded as having the potential to bioaccumulate in the environment.

The test material contained benzene sulphonic acid sodium salt groups and therefore pKa values outside the environmentally relevant pH range for the determination of partition coefficient.  As a result of this, testing was performed at pH 7 using the shake-flask method as recommended for salts.

Conclusion

The partition coefficient of the test material has been determined to be 4.31 x 10^-5at 23.0 ± 0.5°C, log₁₀P_ow -4.37.

Applicant's summary and conclusion

Conclusions:

The partition coefficient of the test material has been determined to be <4.31 x 10-5 at 23.0 ± 0.5°C, log10 Pow <-4.37.

Executive summary:

The determination for substance C-M5 in project number 0345 -0889 was carried out using the shake-flask method, Method A8 of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC), Method 107 of the OECD Guidelines for Testing of Chemicals, 27 July1995.The partition coefficient of the test material has been determined to be <4.31 x 10^-5at 23.0 +/- 0.5 ˚c, log10 Pow <-4.37.