(2E)-2-methyl-3-(4-methylphenyl)prop-2-en-1-ol

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

06-12-2010 to 16-12-2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study performed under GLP. All relevant validity criteria were met.

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

inspected: May 2009; signature: July 2009

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

log Pow

Partition coefficient:

2.39

Temp.:

30 °C

pH:

6

Type:

Pow

Partition coefficient:

245

Temp.:

30 °C

pH:

6

Preliminary estimate

A preliminary assessment of the partition coefficient was made based on the KOWIN calculation method (Epiwin® v3.10, for Microsoft Windows c/William Meylan, 1994,1995) using the structure of the test item.

 

Preparation of sample solution

The test material (0.100 g) was diluted to 50 mL with mobile phase.

 

Preparation of reference solutions

The dead time was determined by measuring the retention time of the injection peak. A solution of reference standards (0.100 g/each) see table below was prepared with the mobile phase (50 mL)

 

Reference items

Standard	Purity (%)	Concentration (g/L)
Anisole	99.7	2.0
Ethyl Benzoate	99 +	2.0
Toluene	99.7	2.0
Ethyl Benzene	99.0	2.0
Cumene	98.0	2.0
Biphenyl	99.5	2.0

 

Determination of retention time

The sample and reference standard solutions were injected in qun-tuplicate using the following HPLC parameters:

HPLC: PerkinEimer Series 200LC, incorporating autosampler and Turbochrom 6.2

Column: Nucleosil EC 100-5 C 18 (250 x 4.6 mm id)

Column temperature: 30°C

Mobile phase: methanol:water (75:25 v/v)

pH of mobile phase: 6.0

Flow-rate: 0.8 mL/min

RI detector: RI-4 Varian

Injection volume: 10 uL

Run time: 30 min

 

Construction of calibration curve

A calibration curve was constructed from the retention time data of the injection peak and the reference standard solutions. The capacity factors (k) for the reference standards were calculated. Log Pow values of the reference standards are those quoted in EU Method A.8.

 

Partition coefficient of sample

The capacity factor was calculated using the following equation and the log Pow value determined with reference to the calibration curve.

k = tr – t0 / t0

Where:

k = capacity factor

tr = retention time (min)

t0 = dead time (min)

 

Preliminary test

A preliminary assessment of the partition coefficient was made based by the KOWWIN calculation method (Epiwin® v3.10, for Microsoft Windows c/William Meylan,1994,1995) using the structure of the test item.

Log Pow estimate: 2.94

Approximate Pow: 871

 

Definitive test

Calibration

The retention times, capacity factors (k) and log Pow values for the reference standards and test item are shown in the following tables:

Table 1

	RT1	RT2	RT3	RT4	RT5	Mean RT	STD	CV%	K	Log K	Log Pow
	min	min	min	Min	min	min
(T0) Dead time	3.70	3.70	3.70	3.70	3.70	3.70	0.00	0.00	0.00	-	-
Anisole	8.99	8.98	8.99	8.99	8.99	8.99	0.00	0.05	1.43	0.155	2.10
Ethyl Benzoate	11.01	11.01	11.01	11.01	11.02	11.01	0.00	0.04	1.98	0.296	2.60
Toluene	12.79	12.78	12.79	12.78	12.79	12.79	0.01	0.04	2.46	0.390	2.70
Ethyl Benzene	17.38	17.38	17.38	17.39	17.39	17.38	0.01	0.03	3.70	0.568	3.20
Cumene	23.05	23.04	23.04	23.04	23.06	23.06	0.01	0.04	5.23	0.718	3.70
Biphenyl	26.68	26.67	26.67	26.69	26.70	26.68	0.01	0.05	6.21	0.793	4.00
Test Item	10.37	10.36	10.38	10.38	10.37	10.37	0.01	0.08	1.803	0.256	2.39

 

Test item:

Mean log Pow: 2.39

Partition coefficient: Pow: 245

Conclusions:

The partition coefficient of the test item was determined to be Pow = 245 and log Pow = 2.39 at 30 °C and pH 6

Executive summary:

The n-octanol-water partition coefficient was determined using the HPLC method of EU Method A.8 and OECD Method 117 under GLP. The partition coefficient of the test item was determined to be Pow = 245 and log Pow = 2.39 at 30 °C and pH 6.

Applicant assessment indicates: As the test item contains no relevant dissociating functional groups, were testing to be carried out at neutral pH by expert judgement, the results would not be anticipated as being different to the results presented at pH 6. Pow = 245 and log Pow = 2.39 at 30 °C and pH 7.

Description of key information

n-octanol/water: Pow = 245 and log Pow = 2.39 @ 30 °C and pH 7, EU Method A.8 – HPLC method, 2010

Key value for chemical safety assessment

Log Kow (Log Pow):

2.39

at the temperature of:

30 °C

Additional information

The n-octanol-water partition coefficient was determined using the HPLC method of EU Method A.8 and OECD Method 117 under GLP. The partition coefficient of the test item was determined to be Pow = 245 and log Pow = 2.39 at 30 °C and pH 6.

Applicant assessment indicates: As the test item contains no relevant dissociating functional groups, were testing to be carried out at neutral pH by expert judgement, the results would not be anticipated as being different to the results presented at pH 6. Pow = 245 and log Pow = 2.39 at 30 °C and pH 7.