9-[2-(ethoxycarbonyl)phenyl]-3,6-bis(ethylamino)-2,7-dimethylxanthylium chloride

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Version / remarks:

2014

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

column elution method

Key result

Water solubility:

77.9 g/L

Conc. based on:

test mat.

Temp.:

20 °C

pH:

2.8

Preliminary Test

The preliminary test at room temperature showed, that the water solubility of the test item was between 28.8 g/L and 64.9 g/L. Therefore, the flask method was performed.

Main Test (flask method)

For the main test three flasks were prepared with an amount of test item and water, and one flask only with water. After stirring and centrifugation the aqueous phases were measured by means of HPLC. The solution of each flask has been measured twice. The results of these measurements are shown in Table 3. The values represented in the table are rounded values. The calculation was carried out with the original not rounded values.

Table 3: Results of the flask method

Flask	1a	2a	3a	4a**
Measured value [g/L]	0.767 / 0.781	0.787 / 0.792	0.770 / 0.776	0 / 0
Aliquot of the flask	0.1	0.1	0.1	0.1
Total volume after 1^stdilution [mL]	10	10	10	10
Water solubility [g/L]*	76.7/ 78.1	78.7/ 79.2	77.0 7 77.6	0 / 0
Average water solubility [g/L]	77.4	78.9	77.3	0
Mean value of the water solubility [g/L]	77.9			0
Standard deviation [g/L]	0.9			-
Relative standard deviation [%]	1.2			-

* Under consideration of the dilution factor 100

** blank measurement

To verify the accuracy of the analytical method a fresh prepared standard solution (prepared with the test item) was measured in between the samples of the flask method. The results of these measurements are shown in Table 4.

Table 4: Measurement of a standard solution

Standard solution (nominal value [g/L]	Measured value [g/L]	Repeatability [%]
Ü-1 (0.57)	0.57	100.9
	0.55	96.7
Ü-2 (1.40)	1.40	99.6
	1.41	100.7

The recovery rate of the measured standard solutions was in the range from 96.7 % to 100.9 %, which shows a good accuracy of the analytical method.

Conclusions:

The water solubility of the test item Basic Red 1 was determined to be 77.9 g/L (RSD = 1.2%) at 20 °C and pH 2.8.

Executive summary:

The water solubility of the test item Basic Red 1 was determined by the column elution method according to OECD guideline 105 and EU method A.6. The water solubility of the test item was determined to be 77.9 g/L (RSD = 1.2%) at 20 °C and pH 2.8.

Description of key information

The water solubility of the test item Basic Red 1 was determined to be 77.9 g/L (RSD = 1.2%) at 20 °C and pH 2.8.

Key value for chemical safety assessment

Water solubility:

77.9 g/L

at the temperature of:

20 °C

Additional information

The water solubility of the test item Basic Red 1 was determined by the column elution method according to OECD guideline 105 and EU method A.6. The water solubility of the test item was determined to be 77.9 g/L (RSD = 1.2%) at 20 °C and pH 2.8.