Thiocyanic acid, (1,3,8,10-tetrahydro-1,3,8,10-tetraoxoanthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-2,9-diyl)di-3,1-phenylene ester, reaction products with sodium sulfide (Na2(Sx))

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-04-06 to 2017-05-17

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

July 27, 1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Version / remarks:

2014

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7840 (Water Solubility)

Version / remarks:

March 1998

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Other quality assurance:

ISO/IEC 17025 (General requirements for the competence of testing and calibration laboratories)

Type of method:

flask method

Key result

Water solubility:

0.35 mg/L

Conc. based on:

test mat.

Loading of aqueous phase:

3.33 g/L

Incubation duration:

>= 24 - <= 72 h

Temp.:

20 °C

pH:

>= 3.18 - <= 3.26

Details on results:

The calibration solutions were prepared in 0.1 – 10 µg/mL range.
The calibration samples were analysed by spectrophotometric method with three replicates from each.
Concentration of Leuco Sulfur Red 14 was calculated with the help of the calibration equation.

Results of the test and measured concentrations of Leuco Sulfur Red 14 are presented in the following table. The measured concentrations are constant within ± 15 % and thus within the range required by the guidelines.

Results of the Method Validation

Measurement repeatability (7 parallels)	CV% < 2 %
Repeatability of the Preparation (n=5)	< 5 %
Linear range	0.1 - 10 µg/mL
Correlation coefficients	≥ 0.999
Limit of Quantification	0.1 µg/mL
Limit of Detection	0.05 µg/mL
Recovery from ISO medium	92 %
Recovery from20X AAPmedium	94 %
Recovery from ultra-pure water	97 %
Accuracy	≤ 6 %
Precision	≤ 9 %
Stability of the test item inISO mediumat the temperature 18-22°C for 2 days	Stable at the test conditions
Stability of the test item in20X AAPmediumat the temperature 22-26°C for 7 days	78 % at the test conditions
Stock solution stability (1 mg/mL) , after dissolution, dye complexation and color development	for at least 3 days at 5±3 °C

Results of the determination of Leuco Sulfur Red 14 concentrations

Sampling time	Measured concentrationofLeuco Sulfur Red 14(mg/L )		Measured pH
	Test vessels	Mean withthe 95% confidence intervals
After 24h	0.37	0.36 ± 0.02	3.25
	0.36		3.26
	0.35		3.25
After 48h	0.35	0.34 ± 0.04	3.18
	0.35		3.18
	0.32		3.18

Results of the determination of Leuco Sulfur Red 14 concentrations (continued)

Sampling time	Measured concentrationofLeuco Sulfur Red 14(mg/L )				Measured pH
	Test vessels		Mean withthe 95% confidence intervals
After 72h	0.36		0.35 ± 0.03		3.18
	0.33				3.20
	0.35				3.19
Solubility ofthe test item (mg/L)	0.35 ± 0.01	-
RSD%	4	-
Ultra-pure water			< LOQ	6.51

Conclusions:

The water solubility of Leuco Sulfur Red 14 was determined to be 0.35 +/- 0.01 mg/L (95% confidence interval) at 20 °C ± 1 °C using the shake-flask method.

Executive summary:

The solubility of the test item in water was measured according to OECD Guideline 105 (shake-flask method), EU Method A.6 and US EPA OPPTS 830.7840 and in compliance with GLP principles. The substance was dissolved in water at a temperature somewhat above the test temperature of 20 ± 1 °C. When saturation was achieved the mixture was cooled and kept at the test temperature, stirring as long as necessary to reach equilibrium. Subsequently, the mass concentration of the substance in the aqueous solution was determined by a suitable analytical method. In result, the water solubility of the test item was determined to be 0.35 +/- 0.01 mg/L (95% confidence interval)  at 20 °C ± 1 °C using the shake-flask method for the performance.

 

 

Description of key information

The solubility of the test item in water was measured to be 0.35 +/- 0.01 mg/L (95% confidence interval)  at 20 °C ± 1 °C.

Key value for chemical safety assessment

Water solubility:

0.35 mg/L

at the temperature of:

20 °C

Additional information

The solubility of the test item in water was measured according to OECD Guideline 105 (shake-flask method) and in compliance with GLP principles. The substance was dissolved in water at a temperature somewhat above the test temperature of 20 ± 1 °C. When saturation was achieved the mixture was cooled and kept at the test temperature, stirring as long as necessary to reach equilibrium. Subsequently, the mass concentration of the substance in the aqueous solution was determined by a suitable analytical method. In result, the water solubility of the test item was determined to be 0.35 +/- 0.01 mg/L (95% confidence interval)  at 20 °C ± 1 °C using the shake-flask method for the performance.