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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:
2010-09-30 - 2010-11-05
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
comparable to guideline study
Qualifier:
equivalent or similar to guideline
Guideline:
EU Method A.8 (Partition Coefficient)
GLP compliance:
yes (incl. QA statement)
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
Sponsor's identification: Amine C8
Description: dark brown liquid
Batch number: T7-271109
Date received: 21 September 2010
Expiry date: 31 December 2011
Storage conditions: room temperature in the dark
Analytical method:
high-performance liquid chromatography
Key result
Type:
log Pow
Partition coefficient:
< 0.3
Temp.:
20 °C
pH:
12
Remarks on result:
other: For 88.4% of the test item
Type:
log Pow
Partition coefficient:
0.565
Temp.:
20 °C
pH:
12
Remarks on result:
other: For 11.6% of the test item

Preliminary estimate

The test item was observed to be fully miscible with water. 

The test item was observed to be partly soluble in n-octanol at concentrations of 10 to 95% w/w. The mixtures were observed to be a single phase liquid but were cloudy and tested positive for the Tyndall effect. Since the test item was a complex mixture, it was considered that test item was mostly soluble in octanol but contained some less soluble fractions.

Approximate Pow: <1
Log10Pow: <0

For definitive test - see overall remarks and attachments.

Conclusions:
The partition coefficient (Pow) of the test item has been determined to be in the range <2.00 to 3.67. The log10 Pow of the test item is <0.3 and 0.565 for the approximate percentage composition of 88.4% and 11.6% of test item respectively.
Executive summary:

Partition Coefficient. 

The partition coefficient was determined to range from <2.00 to 3.67, log10Pow <0.3 to 0.565 using the HPLC method, designed to be compatible with Method A8 Partition Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008. The log10 Pow of the test item has been reported as follows: 

Percentage of Test Item (%)

Log10Pow

88.4

<0.3

11.6

0.565

Description of key information

The partition coefficient of the test substance was determined to be logPow < 0.3 (corresponding to 88.4% of the test item) and logPow = 0.565 (corresponding to 11.6% of the test item) at 20 °C using the HPLC method, designed to be compatible with EC test method A.8, under GLP conditions (Butler and White, 2010).

Key value for chemical safety assessment

Log Kow (Log Pow):
0.565
at the temperature of:
20 °C

Additional information

The test was performed at pH 12 at which the test item is predominantly in its non-dissociated form. Due to the nature of the substance (UVCB) a single octanol/water partition coefficient is not defined.


Testing was performed at pH ~12 to obtain the main test item components in their non-ionised form. However, no correction has been made since the test item was a complex mixture and it was not possible to assign the peaks with any one component of the test item. However, it can be assumed that at the environmentally relevant pH (pH 7), the partition coefficients of the main components will be less than 3.67 (log10Pow0.565), this value (logPow = 0.565) is advised for use in the CSA.


The retention times, capacity factors and log10Powvalues determined for the sample are shown in the following table:


 




















































































































































Peak Number(s)


 

Injection


 

Retention Time (mins)


 

Capacity Factor (k)


 

Log10k


 

Log10Pow


 

Mean Log10Pow


 

Mean % Area


 

1


 

1


 

1.535


 

<0.343


 

<-0.465


 

<0.3


 

<0.3


 

0.760


 
 

2


 

1.536


 

<0.343


 

<-0.465


 

<0.3


 

2


 

1


 

1.914


 

<0.343


 

<-0.465


 

<0.3


 

<0.3


 

22.1


 
 

2


 

1.915


 

<0.343


 

<-0.465


 

<0.3


 

3


 

1


 

2.057


 

<0.343


 

<-0.465


 

<0.3


 

<0.3


 

65.5


 
 

2


 

2058


 

<0.343


 

<-0.465


 

<0.3


 

4


 

1


 

2.526


 

0.399


 

-0.399


 

0.565


 

0.565


 

11.6


 
 

2


 

2.527


 

0.400


 

-0.398


 

0.566


 

Mean log10Pow:      In the range <0.3 to 0.565
Partition coefficient:In the range <2.00 to 3.67