Bis(2,6-diisopropylphenyl)carbodiimide

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018-05-08 - 2019-01-15

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to other study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Version / remarks:

2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7840 (Water Solubility)

Version / remarks:

1998

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

column elution method

Water solubility:

< 0.53 µg/L

Conc. based on:

test mat.

Temp.:

20 °C

pH:

ca. 4 - ca. 5

The concentrations of the sample in the fractions were determined by HPLC-MS. Fifteen fractions were collected from column 1 and fourteen fractions from column 2. The data points are listed in the following table including the five fractions with constant concentrations, which were used for the determination of the water solubility (marked in grey). From each fraction 10 mL were collected.

Measurement results of single fractions of both columns:

Column 1			Column 2
Fraktion no.	pH-value	Concentration [µg/L]	Fraction no.	pH-value	Concentration [µg/L]
1	approx. 4 - 5	0.7496	1	approx. 4 - 5	0.3123
2		0.3437	2		0.1100
3		0.4740	3		0.1216
4		0.2589	4		0.1179
5		0.2467	5		0.1610
6		0.1949	6		0.1004
7		0.2432	7		0.0876
8		0.2060	8		0.2748
9		0.2062	9		1.6452
10		0.1662	10		0.0756
11		0.2129	11		0.0700
12		0.1991	12		0.0761
13		0.1864	13		0.0510
14		0.1781	14		0.0681
14		0.5686	-	-	-

Column 1:

Mean value: 0.00020 mg/L

Standard deviation: 0.00001848 mg/L

Relative standard deviation: 9.33 %

Column 2:

Mean value: 0.00012 mg/L

Standard deviation: 0.00002318 mg/L

Relative standard deviation: 18.97 %

Difference between both columns: 25.0 %

All statistical calculations were carried out with values below LoQ!

Because the sample solutions were diluted 1:1 to prevent crystallizing before measurement, the Limit of Quantification is two times the lowest calibration point (0.2624 μg/L, therefore 0.525 μg/L).

The mean value and most measurement values of both columns are lower than LoQ. Therefore the water solubility is < 0.00053 mg/L, corresponding to < 0.53 μg/L

For calibration functions and example chromatograms please refer to the attached background material.

Conclusions:

The water solubility of the test item is stated as: < 0.53 μg/L which is < LoQ.

Executive summary:

The water solubility of the test item was determined by the column elution method according to OECD guideline 105, EU Method A.6 and OPPTS 830.7840 in a GLP-study.

The water solubility of the test item at 20 °C was:

Mean value of both columns: < 0.00053 mg/L (< LoQ), nearly all measured values are below LoQ

Result of the preliminary test: < 0.00053 mg/L (< LoQ from preliminary test)

The lowest calibration point was 0.0002624 mg/L. The samples were diluted 1:1 with acetonitrile and therefore the LoQ for the determination is two times the lowest calibration point.

The water solubility of the test item is stated as: < 0.53 μg/L

Description of key information

The water solubility of the test item was determined by the column elution method according to OECD guideline 105, EU Method A.6 and OPPTS 830.7840 in a GLP-study.

The water solubility of the test item at 20 °C was:

Mean value of both columns: < 0.00053 mg/L (< LoQ), nearly all measured values are below LoQ

Result of the preliminary test: < 0.00053 mg/L (< LoQ from preliminary test)

The lowest calibration point was 0.0002624 mg/L. The samples were diluted 1:1 with acetonitrile and therefore the LoQ for the determination is two times the lowest calibration point.

The water solubility of the test item is stated as: < 0.53 μg/L

Key value for chemical safety assessment

Water solubility:

0.05 mg/L

at the temperature of:

20 °C

Additional information

The test item was investigated via the column elution method for its water solubility (Erstling, 2008) and determined to have a very low solubilty in water (<0.05 mg/L at 20 °C). In addition, the water solubility has been determined to be 0.0001861 mg/L based on an estimated logPow of 8.72 by QSAR estimation [EPIWIN/WSKOW v1.43 by US-EPA (2017)]. From these results, it can be concluded that the test substance is insoluble in water.

Following from an ECHA compliance check it became necessary to improve the value for water solubility. With this a new study was conducted with a better analytical method to determine the water solubility.