Hexanal

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018-02-19 - 2018-10-24

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)

Version / remarks:

13 April 2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: A.25: 'Partition Coefficient (n-Octanol/water), high performance liquid chromatography (HPLC) method'

Version / remarks:

7 December 2015

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

log Pow

Partition coefficient:

2.3

Temp.:

25 °C

pH:

5

Details on results:

The following deviation from the study plan was observed:
No Laser pointer was used during this study due to an error. This was stated as uncritical, because the prepared solutions were visually clear.
The deviation was assessed and stated by the study director on 15. Nov. 2018.

The retention times of the test item are for

measurement 1: 2.792 min

measurement 2: 2.792 min

measurement 3: 2.792 min.

log P_OW was calculated from the capacity factor

Using the correlation log k / log P_OW, the log P_OW of the peak of test item was calculated as 2.3 ± 0.0 (mean ± standard deviation). Validity criteria are fullfilled.

Conclusions:

With the calibration function log k versus log POW, the corresponding log POW value of the test item peak was determined with: 2.3 ± 0.0.

Executive summary:

The study was performed according to OECD 117 and EU method A.24 under GLP using a HPLC with a C18 column. Eight reference items with different retention times and thiourea for the determination of the dead time were used to produce a calibration curve, since retention time on hydrophobic columns and P_OW are correlated. The reference items were chosen based on the results of the pre-test.

One vial was filled with the reference item mix and one vial with the test item solution. The vials were analysed using the HPLC with the program described below. First one injection from the solvent blank methanol/water 75/25 (v/v) was made. Then three injections were measured from the reference item mix, three injections from the test item and again three injections from the reference item mix.

For each reference item, the capacity factor k was calculated from the retention time of thiourea and the retention time of the respective reference item.

A calibration function (log k versus log P_OW, linear fit) was determined using the literature values for P_OW of the reference items and the retention times in the six determinations.

The chromatogram of the test item gave one peak. With the calibration function log k versus log P_OW, the corresponding log P_OW value of the test item peak was determined with: 2.3 ± 0.0. This value is the mean ± standard deviation of three independent determinations.

Description of key information

The study was performed according to OECD 117 and EU method A.24 under GLP using a HPLC with a C18 column. Eight reference items with different retention times and thiourea for the determination of the dead time were used to produce a calibration curve, since retention time on hydrophobic columns and P_OWare correlated. The reference items were chosen based on the results of the pre-test.

One vial was filled with the reference item mix and one vial with the test item solution. The vials were analysed using the HPLC with the program described below. First one injection from the solvent blank methanol/water 75/25 (v/v) was made. Then three injections were measured from the reference item mix, three injections from the test item and again three injections from the reference item mix.

For each reference item, the capacity factor k was calculated from the retention time of thiourea and the retention time of the respective reference item.

A calibration function (log k versus log P_OW, linear fit) was determined using the literature values for P_OWof the reference items and the retention times in the six determinations. The chromatogram of the test item gave one peak. With the calibration function log k versus log P_OW, the corresponding log P_OWvalue of the test item peak was determined with:

2.3 ± 0.0. This value is the mean ± standard deviation of three independent determinations.

Key value for chemical safety assessment

Log Kow (Log Pow):

2.3

at the temperature of:

25 °C

Additional information

Octanol-water partitition coefficient of hexanal is reported as log Pow = 1.78 based on handbook data. This handbook data is supported by calculation with EPI Suite Log Kow version 1.68 according to the fragments of the molecule. Calculated value is log Pow = 1.7985.

CRC Handbook:

log Pow = 1.78 at 25 °C

EPI Suite:

1.7985