(3-methoxy-2-methylpropyl)benzene

Partition coefficient

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015-02-04 to 2015-02-05

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study was conducted according to OECD/EC guideline, and under GLP. No deviation was reported. Test substance is adequately specified with purity. Therefore full validation applies.

Qualifier:

according to guideline

Guideline:

OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

inspected on June 3 to 5, 2013 / signed on November 5, 2013

Type of method:

shake-flask method to: flask method

Partition coefficient type:

octanol-water

Analytical method:

other: UPLC-DAD

Key result

Type:

log Pow

Partition coefficient:

3.32

Temp.:

20.2 °C

pH:

6

Details on results:

Method Validation
The analytical method on test substance was validated with satisfactory results regarding linearity, limit of quantification, accuracy, precision and specificity.

Linearity
LOD = 0.15 mg/L
System quantification limit = 0.5 mg/L
Range: 0.5 – 100 mg/L with r2 = 0.999932 (n=9)

Limit of Quantification
Nominal target concentration = 0.6 mg/L for the aqueous phase, 50 mg/L for the n-octanol phase

Accuracy and Precision
Recovery rates were:
aqueous phase 97 % for the 1 x LOQ (RSD=5.4%) and 93 % for the 5 x LOQ (RSD=3.2 %)
octanol phase 99 % for the 1 x LOQ (RSD=3.5%) and 100 % for the 10 x LOQ (RSD=2.8 %)

Specificity
Analyses were performed with DAD (diode array detection) as selective detector. Spectra of sample peaks were compared automatically by the software against spectra obtained from standard peaks. For all samples above the system quantification limit, a maximum spectra match angle of 16.243 was observed, the maximum observed match threshold was 23.731 and the spectral match angle was lower than the match threshold for all samples. For the control samples, no significant signal could be detected, showing that blank values were lower than 30 % of the LOQ.

Table 4.7/1: Concentrations in n-Octanol- and Aqueous Phase, log Pow

 

n-octanol / water ratio	Repl.	Meas. cont. in n-octanol [mg/L]	Meas. cont. in aq. phase [mg/L]	Pow	Log Pow
						Mean	SD	Diff. (max-min)
2:1	1	1774	0.806	2200	3.34	3.32	0.02	0.04
	2	1637	0.808	2027	3.31
1:1	1	1696	0.805	2106	3.32
	2	1695	0.803	2110	3.32
1:2	1	1668	0.839	1989	3.30
	2	1672	0.804	2079	3.32

 

Test Temperature: 20.2 ± 0.2 °C

pH-Value: 6.016 ± 0.162

Mass Balance for the Test Item in n-Octanol- and Aqueous Phase: 99-107%

 

Results of the Reference Test

The partition coefficient (n-octanol/water) of the reference item Benzophenone was determined to be 1573, corresponding to a decadic logarithm of 3.20 (log Kow), being in good correspondence with the literature value of 3.2.

 

Validity Criteria

The obtained log Pow values fell within a range of ± 0.3 units.

The temperature was kept constant at ± 1 °C

Conclusions:

The substance has low potential to bioaccumulate in the environment, according to CLP classification criteria for aquatic chronic toxicity (log Kow < 4).

Executive summary:

The partition coefficient of the test substance was measured under GLP according to the OECD 107 guideline, shake-flask method.

The test was conducted at a temperature range of 20 - 21 °C. Three runs with n-octanol/water ratios of 1:1, 1:2 and 2:1 were performed. Both phases were analysed for the test item in duplicates via UPLC-DAD.

 

The analytical method for the determination of the test item was validated and tested with satisfactory results in regard to linearity, accuracy, precision and specificity for both test media. The six determined log Kow values did not differ for more than 0.04, thus the validity criterion (log Kow should not differ for more than 0.3) was fulfilled.

 

The partition coefficient (n-octanol/water) of the test item was determined at a mean temperature of 20.2 °C to be: 3.32 ± 0.02 (pH 6.0).

Reference 2

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

From August 18 to 27, 1997

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study was conducted according to OECD/EC guideline, and under GLP. The substance is considered to be adequately characterised with its purity. Therefore full validation applies.

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient)

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

log Pow

Partition coefficient:

3.38

Temp.:

25 °C

pH:

7

Table 4.7/1: Partition coefficient – results

 

	Temperature (°C)	pH	retention time (min)	Capacity factor (k)	Log k	Log Pow
Benzene	25	7	5.567	1.47	0.168	2.1
Toluene	25	7	7.958	2.54	0.404	2.7
Bromobenzene	25	7	8.851	2.93	0.467	3.0
Naphthalene	25	7	11.281	4.01	0.604	3.6
Diphenyl	25	7	17.539	6.80	0.832	4.0
Phenanthrene	25	7	27.924	11.41	1.057	4.5

	Temperature (°C)	pH	Injected quantity (µg)	retention time (min)	Capacity factor (k)	Log k	Log Pow interpolated	Pow interpolated
Test 1	25	7	2.5	11.75	4.222	0.625	3.38	2399
Test 2	25	7	2.5	11.73	4.213	0.625	3.38	2399
Mean	25	7		11.74	4.218	0.625	3.38	2399

 

The mean of two determinations for the log Pow is 3.38

This is in agreement within ± 0.1 log units as described in OECD Guideline No.117.

Conclusions:

The substance has low potential to bioaccumulate in the environment, according to CLP classification criteria for aquatic chronic toxicity (log Kow < 4).

Executive summary:

The partition coefficient of the test substance was measured under GLP according to the OECD 117/EU A8 guideline, HPLC method. The system was calibrated with six reference substances, and duplicate determination was performed for the test item. The mean result was retained.

Partition coefficient (log Pow) = 3.38.

Description of key information

The data is relevant for classification in aquatic chronic toxicity hazard class, according to CLP criteria. The substance has low potential for bioaccumulation (log Kow<4).

Key value for chemical safety assessment

Log Kow (Log Pow):

3.32

at the temperature of:

20.2 °C

Additional information

Two reliable studies, conducted according to recognized OECD/EC methods and under GLP, are available, and provide consistent results. The INERIS 1998 study was performed with the HPLC method, based on comparative elution versus standards, the choice of which leading to minor restrictions on accuracy. The more recent one (Noack 2015) was performed with the shake-flask method, which is considered of higher quality, as based on actual phase partitioning and analysis. Therefore the shake-flask result is preferred and retained as key data, rather than the mean value.