Reaction products of 7-amino-4-hydroxynaphthalene-2-sulfonic acid reacted with 2-((1,3,5-triazin-2-yl)amino)ethan-1-ol, coupled with diazotised 3-amino-4-hydroxybenzenesulfonic acid, subsequently coupled with diazotised 2-amino-5-methoxybenzenesulfonic acid, chelated with copper, sodium salt

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 1991-04-08 to 1991-06-28

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

- Sampling method: Solutions of the test substance were prepared in buffer solutions of pH 4, 7 and 9. The solutions were maintained at 50 °C and the concentration of the test material was monitored over five days by high performance liquid chromatography. The samples were not further diluted.
- Preparation of the standards: Standard solutions were prepared in each buffer solution at a nominal concentration of 500 µg/mL.

Buffers:

- pH: 4,7, 9

COMPOSITION OF THE BUFFER:
pH 4
Citric acid: 0.05 mol/L
Sodium hydroxide: 0.10 mol/L
Hydrochloric acid.0.05 mol/L

pH 7
Potassium dihydrogen orthophosphate 6.8 g
Sodium hydroxide: 1.18 mol/L
Mercuric potassium iodide: 0.02 g
Water to 1L

pH 9
Orthoboric acid 3.095 g
Potassium chloride 3.725 g
Sodium hydroxide 0.848 g
Mercuric potassium iodide 0.02g
Water to 1L

Duration:

24 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

512 mg/L

Duration:

48 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

522 mg/L

Duration:

68 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

517 mg/L

Preliminary study:

A preliminary test was performed on the substance at 50 ± 0.1°C at each of pH 4.0, 7.0 and 9.0. After 5 days less than 10 per cent abiotic degradation was observed (t1/2 > 1 year), and the test substance was considered hydrolytically stable and no additional testing was required.

Transformation products:

no

% Recovery:

99.8

pH:

4

Temp.:

50 °C

Duration:

120 h

Remarks on result:

hydrolytically stable based on preliminary test

% Recovery:

100

pH:

7

Temp.:

50 °C

Duration:

120 h

Remarks on result:

hydrolytically stable based on preliminary test

% Recovery:

99.8

pH:

9

Temp.:

50 °C

Duration:

120 h

Remarks on result:

hydrolytically stable based on preliminary test

pH:

4

Temp.:

50 °C

Remarks on result:

hydrolytically stable based on preliminary test

pH:

7

Temp.:

50 °C

Remarks on result:

hydrolytically stable based on preliminary test

pH:

9

Temp.:

50 °C

Remarks on result:

hydrolytically stable based on preliminary test

Details on results:

Direct Red 83:1 has been determined to undergo less than 10 % hydrolysis in pH 4, 7 and 9 buffer solutions after 5 days at 50.0 ± 0.5 °C.

Solution	Solution pH	Peak height (units)
Standard 509 mg/L	4	1.854x10^5
Standard 502 mg/L	4	1.828x10^5
Initial sample	4	1.864x10^5
2.4 hour sample	4	1.869x10^5
Standard 499 mg/L	7	1.842x10^5
Standard 497 mg/L	7	1.827x10^5
Initial sample	7	1.923x10^5
2.4 hour sample	7	1.921x10^5
Standard 507 mg/L	9	1.945x10^5
Standard 502 mg/L	9	1.882x10^5
Initial sample	9	1.962x10^5
2.4 hour sample	9	1.970x10^5
Standard 505 mg/L	4	97.8 mm
Standard 496 mg/L	4	95.3 mm

24 hour sample	4	99.2 mm
Standard 500 mg/L	7	96.5 mm
Standard 498 mg/L	7	95.4 mm
24 hour sample	7	101,3 mm
Standard 502 mg/L	9	94,9 mm
Standard 504 mg/L	9	95.8 mm
24 hours	9	97.1 mm

The peak heights relating to the standard and sample solutions have been detailed above.

Results:

Concentration of the test substance as weighed (g/L)	0.514	0.520	0.522
Concentration of the test substance found initially (g/L)	0.512	0.522	0.517
Concentration of the test substance found at 2.4 hrs (g/L) expressed as % of initial	0.513   100	0.521     99.8	0.519   100
Concentration of the test substance found at 24 hrs (g/L) expressed as % of initial	0.514   100	0.527   101	0.512   99.0
Concentration of the test substance found at 48 hrs (g/L) expressed as % of initial	0.519   100	0.520   99.6	0.512   101
Concentration of the test substance found at 68 hrs (g/L) expressed as % of initial	0.512   100	0.523   100	0.524   101
Concentration of the test substance found at 120 hrs (g/L) expressed as % of initial	0.511   99.8	0.527   101	0.516   99.8
pH	4	7	9

Validity criteria fulfilled:

yes

Conclusions:

KAYARUS SUPRA RUBINE BLN (Direct Red 83:1) has been determined to undergo less than 10% hydrolysis in pH 4, 7 and 9 buffer solutions after 5 days at 50.0 ± 0.5 °C. The Half-life (t1/2) is considered to be greater than 1 year, and therefore the test substance was considered hydrolytically stable.

Executive summary:

The hydrolysis behaviour of Direct Red 83:1 was assessed at pH-values normally found in the environment i.e. (pH 4 -9).

In the environment, chemicals usually occur in dilute solution, which means that water is present in large excess, and, therefore, that the concentration of water remains essentially constant during hydrolysis. Hence the testing of substances for hydrolysis is relevant to their persistence. Hydrolysis is one of the most common reactions controlling abiotic degradation and is therefore one of the main

Degradation paths of substances in the environment.

Table 1: Results Synopsis:

pH	Temperature (°C)	Description of The incubation system used	Test duration	Test design	Details on Buffer solutions	Amount of the test substance applied	Method for (separation and quantification)	Results and discussions
4	50 ± 0.1°C		5 days		Citric acid: 0.05 mol/L Sodium hydroxide: 0.10 mol/L Hydrochloric acid.0.05 mol/L	500 µg/L (nominal in Buffer solutions)	HPLC	The substance has been determined to undergo less than 10% hydrolysis in pH 4, 7 and 9 buffer solutions after 5 days at 50.0   ± 0.5 °C.
7	50 ± 0.1°C		5 days		Potassium dihydrogen orthophosphate 6.8 g Sodium hydroxide: 1.18 mol/L Mercuric potassium iodide: 0.02 g Water to 1L	500 µg/L (nominal in Buffer solutions)	HPLC
9	50 ± 0.1°C		5 days		Orthoboric acid 3,095 g Potassium chloride 3.725 g Sodium hydroxide 0.848 g Mercuric potassium iodide 0.02g Water to 1L	500 µg/L (nominal in Buffer solutions)	HPLC

 

 

Description of key information

The read across substance Direct Red 83:1 has been determined to undergo less than 10% hydrolysis in pH 4, 7 and 9 buffer solutions after 5 days at 50.0 ± 0.5 °C.  The Half-life (t1/2) is considered to be greater than 1 year, and therefore the  test substance was considered  hydrolytically stable.

Additional information

The hydrolysis behaviour of the read across substance Direct Red 83:1 was assessed at pH-values normally found in the environment i.e. (pH 4 -9).

In the environment, chemicals usually occur in dilute solution, which means that water is present in large excess, and, therefore, that the concentration of water remains essentially constant during hydrolysis. Hence the testing of substances for hydrolysis is relevant to their persistence. Hydrolysis is one of the most common reactions controlling abiotic degradation and is therefore one of the main Degradation paths of substances in the environment.

Table 1: Results Synopsis:

pH	Temperature (°C)	Description of The incubation system used	Test duration	Test design	Details on Buffer solutions	Amount of the test substance applied	Method for (separation and quantification)	Results and discussions
4	50 ± 0.1°C		5 days		Citric acid: 0.05 mol/L Sodium hydroxide: 0.10 mol/L Hydrochloric acid.0.05 mol/L	500 µg/L (nominal in Buffer solutions)	HPLC	The substance has been determined to undergo less than 10% hydrolysis in pH 4, 7 and 9 buffer solutions after 5 days at 50.0  ± 0.5 °C.
7	50 ± 0.1°C		5 days		Potassium dihydrogen orthophosphate 6.8 g Sodium hydroxide: 1.18 mol/L Mercuric potassium iodide: 0.02 g Water to 1L	500 µg/L (nominal in Buffer solutions)	HPLC
9	50 ± 0.1°C		5 days		Orthoboric acid 3,095 g Potassium chloride 3.725 g Sodium hydroxide:0.848 g Mercuric potassium iodide 0.02 g Water to 1L	500 µg/L (nominal in Buffer solutions)	HPLC