Dibenzylbenzene, ar-methyl derivative

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008-11-27 to 2008-12-04

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

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:

> 6

Temp.:

22 °C

pH:

ca. 7

Details on results:

see below

Individual results

Peak 1

Measurement	RT in minutes	K	log POW
1	50.157	39.0828	6.284
2	49.929	38.9006	6.279
3	50.053	38.9997	6.282
		Mean ± Stand. dev.:	6.282 ± 0.002

Peak 2

Measurement	RT in minutes	K	log POW
1	51.962	40.5253	6.319
2	51.711	40.3247	6.315
3	51.885	40.4638	6.318
		Mean ± Stand. dev.:	6.317 ±  0.002

Peak 3

Measurement	RT in minutes	K	log POW
1	55.407	43.2784	6.384
2	55.164	43.0842	6.379
3	55.329	43.2160	6.382
		Mean ± Stand. dev.:	6.382  ± 0.002

Peak 4

Measurement	RT in minutes	K	log POW
1	57.285	44.7792	6.417
2	57.027	44.5730	6.412
3	57.208	44.7176	6.416
		Mean ± Stand. dev.:	6.415  ± 0.002

Peak 5

Measurement	RT in minutes	K	log POW
1	62.765	49.1585	6.508
2	62.450	48.9068	6.503
3	62.704	49.1097	6.507
		Mean ± Stand. dev:	6.506  ± 0.003

Assessment / Conclusion

Retention times of all peaks of the test substance are above the range of reference substances and

out of the range of the method.

Hence, it can be assumed, that log P_OW of benzyltoluene is greater than six.

Final Result

log P_OW > 6

Conclusions:

Retention times of all peaks of the test substance are above the range of reference substances and
out of the range of the method.
Hence, it can be assumed, that log POW of benzyltoluene is greater than six.

Executive summary:

The study was performed using a HPLC with a C18 column. Six reference items with different retention times were used to produce a calibration curve, since retention time on hydrophobie columns and Pow are correlated. The reference items were chosen on behalf of the retention time of the test item on the column.
First, a solution of the reference items was analysed with HPLC, then a solution of the test item and finally again the solution with the reference items. Each analysis was performed three times, totalling to nine runs.
For each reference item, the capacity factor K was calculated from the retention time of thio urea and the retention time of the respective reference item.
A calibration function (log K versus log Pow, linear fit) was determined using the literature values for log Pow of the reference items and the retention times in the six determinations.
The chromatogram of the test item gave five peaks, three main peaks and two shoulders. With the help of the calibration function log K versus log Pow, the corresponding log Pows were determined as:

Peak	Mean retention time [min]	Log Pow +/-sd
1 2 3 4 5	50.046 51.853 55.300 57.173 62.640	6.282 +/- 0.002 6.317 +/- 0.002 6.381 +/- 0.002 6.415 +/- 0.002 6.506 +/- 0.003

These values are the mean ± standard deviation of three independent  determinations
Ali peaks lay outside the range of reference items and the range of the method. Therefore they should be stated as > 6.0.

Description of key information

Log Pow Dibenzylbenzene, ar-methyl derivative: > 6 at 22°C

Key value for chemical safety assessment

Log Kow (Log Pow):

6

at the temperature of:

22 °C

Additional information

Retention times of all peaks of the test substance were above the range of reference substances and out of the range of the method.