(4E)-4-(3,3,4-trimethylcyclopentylidene)butanal

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experimental Dates (main test): September 23 to October 2, 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study was conducted according to an internationally recognised method, with some adaptation as recommended by ECHA conducted according to scientific principles, and under GLP. The substance is adequately characterised. Therefore full validation applies.

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

27 July 1995
with slow-stirring adaptation, according to the findings of Letinski et al (2002)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Version / remarks:

Regulation (EC) No 440/2008, with last update to the A6 method by Regulation (EU) No 260/2014)
and slow-stirring adaptation, according to the findings of Letinski et al (2002)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

signed on 15 Nov. 2018

Type of method:

flask method

Remarks:

with slow-stirring adaptation

Specific details on test material used for the study:

Actual storage conditions: Ambient temperature.

Key result

Water solubility:

50.3 mg/L

Conc. based on:

test mat.

Loading of aqueous phase:

1.02 g/L

Incubation duration:

24 - 168 h

Temp.:

20 °C

pH:

4.87 - 5.65

Preliminary test

A preliminary test was carried out as a range finding test prior to the main test. The concentration range obtained gave an indication on the necessary analytical method sensitivity.

Increasing volumes of water were added at room temperature to 20.8 mg of the test sample in a 100 mL flask. After each addition of an amount of water, the mixture was shaken for 10 minutes and was visually checked for any undissolved parts of the sample.

The test item (20.8 mg) was not solubilized by a water volume of 100 mL after 24 h, corresponding to a solubility inferior to 0.197 g/L (taking purity into account).

After that, the contents of the flask were poured into a 1 L flask. The test item was solubilized by a water volume of 1 L, corresponding to a solubility between 19.7 mg/L and 197 mg/L.

It was observed, during this preliminary test and the ecotoxicity tests, that the test item is less dense than water.

Estimates of water solubility were also obtained from estimation program. For the test item, using (Q)SAR methods, predictions of 111 mg/L (ChemAxon’s solubility predictor) and 35 mg/L (Kreatis, data provided by the study monitor) were obtained.

Main test

Concentrations profiles

The following table presents the concentrations (in mg/L) obtained during the study for the vessel 1:

Equilibration time (h)	Replicate 1	Replicate 2	Mean
Preparation (T0)	-	-	-
ca 24h	49.787	47.644	48.716
ca 48h	55.491	53.651	54.571
ca 72h	51.590	54.621	53.106
ca 96h	46.597	52.651	49.624
ca 168h	51.346	50.599	50.973

Sampling in vessels 2 and 3 occurred after ca 168 h. The concentrations measured (in mg/L) for these two vessels were:

	Replicate 1	Replicate 2	Mean
Vessel 2	46.514	50.407	48.461
Vessel 3	51.132	52.032	51.582

The pH values measured in the three systems were:

- 5.18 in vessel 1 and 5.70 in vessels 2 and 3 at the beginning of the experiment;

- 5.30 in vessel 1, 5.65 in vessel 2 and 4.87 in vessel 3 at the end of the experiment.

The pH controlled with the indicator strips for each specimen was 5 for all the samples taken from the three vessels.

The temperature variations were included in the range 19.7 °C - 20.3 °C.

Equilibrium demonstration

From the t-test, the equilibrium state can be declared for the vessel 1 between 48h and 168h equilibration time.

The maximum difference observed in the 5 last samples was 9.5%.

Since the two conditions were fulfilled, the equilibrium state was declared at 168h for the vessel 1.

Water solubility calculation

The mean of the two samples at the equilibrium state declaration after 168h was:

- 50.973 mg/L for vessel 1.

The means of the two other vessels, obtained at the equilibration time, after ca 168h, were:

- 48.461 mg/L for vessel 2.

- 51.582 mg/L for vessel 3.

The maximum difference observed between these three determinations is 6 %, which proves that an acceptable repeatability is obtained (the OECD 105 acceptability criterion for the maximum difference between two tests by the column elution method is 30 % and 15 % for the shake flask method).

The test item solubility in water is given by the mean of the values obtained for the three vessels: 50.3 ± 1.4 mg/L.

Executive summary:

The water solubility of the test substance was measured under GLP according OECD 105 guideline, modified with slow-stirring adaptation from Lentinski et al (2002).

Three vessels were prepared, at 20°C. Quantification was performed with a validated HPLC-DAD method. The first vessel was used to determine the equilibration time. When achieved, the test item concentration was determined in the other two vessels.

The water solubility was calculated as the average of the three vessels at the final sampling time: 50.3 mg/L (at 20°C and pH ca 5.3).

Description of key information

Considered as slightly soluble, with equilibrium reached from 48h.

pH of saturated solution: 4.9 - 5.7.

Key value for chemical safety assessment

Water solubility:

50.3 mg/L

at the temperature of:

20 °C

Additional information

A fully reliable experimental study, conducted according to a recognized OECD/EC method and under GLP, is available. Therefore, it is considered as a key study, and the result is retained as key value.