2,5-bis(1,1,3,3-tetramethylbutyl)hydroquinone

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)

Qualifier:

according to guideline

Guideline:

other: EU Method A.24 (Partition Coefficient (n-octanol/water), HPLC method)

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

5.814

Temp.:

25 °C

pH:

>= 5 - <= 6

Remarks on result:

other: 5.81 ± 0.004.

Details on results:

log POW should be regarded as 5.81 ± 0.004 (mean ± standard deviation).

Measurement Data    

The retention times of the test item are presented in the following table:

Peak 2 was eluted during a purge step with 100 % methanol

Retention Times (RT) Test Item

Measurement	RT 1	RT 2
	min.	min.
Measurement 1	25.804	57.318
Measurement 2	25.851	57.338
Measurement 3	25.969	57.379
Mean	25.874	57.345
Standard Deviation	0.085	0.031

 

Peak Areas Test Item

Measurement	Area Peak 1	Relative Area Peak 1	Area Peak 2	Relative Area Peak 2
	mAU*min	%	mAU*min	%
Measurement 1	70.9515	99.48	0.3708	0.52
Measurement 2	69.6470	99.63	0.2616	0.37
Measurement 3	65.8469	99.55	0.2979	0.45
Mean	68.8151	99.55	0.3101	0.45
Relative Standard Deviation	3.854 %	0.073 %	17.928 %	16.255 %

As peak 2, showed a relative area < 5%, it was considered as minor peak.

Calculated values    

The calculated values are presented in the following table:

Capacity Factor, log Capacity Factor, log P_OWTest Item Peaks

Peak	Measurement No.	k	log k	log POW
1	1	16.562	1.219	5.802
	2	16.593	1.220	5.804
	3	16.674	1.222	5.810
	Mean			5.805
	Standard Deviation			0.004
2	1	38.009	1.580	6.816
	2	38.023	1.580	6.816
	3	38.051	1.580	6.817
	Mean			6.817
	Standard Deviation			0.001

 

log P_OWwas calculated from the capacity factor as follows:

log P_OW= (log k + 0.8447) / 0.3557

Result    

As peak 2 showed a relative area < 5 %, it was considered as minor peak.

Although area is not necessarily correlated to absolute concentration if a UV detector is used, it is assumed that the test item consists mainly of the peak 1

Using the correlation log k / log P_OW, the log P_OWof the major component of test itemAF‑317was calculated as 5.81 ± 0.004 (mean ± standard deviation).

Validity    

The validity criteria and results are presented in the following table:

Validity Criteria and Results

Peak	Parameter	Criterion	Found	Assessment
1	Range (Max – Min. log POW)	< 0.1	0.008	valid
	Value within Range of Reference Items	1.70 - 6.20	5.63	valid
2	Range (Max – Min. log POW)	< 0.1	0.001	valid
	Value within Range of Reference Items	1.70 - 6.20	6.59	not valid*

*Peak 2 eluted later than DDT as the reference item with the highest log P_OW. Because the log P_OW of DDT is 6.2, the log P_OW of test item peak 2 is stated as > 6.2.

Variations in the retention times of reference items and test item are very small. Therefore, a stable configuration of the HPLC-column can be assumed.

The correlation log k/log POW is good: the coefficient of determination r2 was calculated with 0.9942. This value was considered as sufficiently high to use the calibration function for the determination of the log POW of the test item AF-317.

As peak 2 showed a relative area < 5 %, it was considered as minor peak. Although area is not necessarily correlated to absolute concentration if UV detection is used, it is as-sumed that the test item AF-317 consists mainly of the peak 1, indicating that the log POW should be regarded as 5.81 ± 0.004 (mean ± standard deviation).

No observations were made which might cause doubts concerning the validity of the study outcome.

Description of key information

log Kow = 5.814 at 25 °C, at pH 5-6 (OECD 117, HPLC)

 

Key value for chemical safety assessment

Log Kow (Log Pow):

5.814

at the temperature of:

25 °C