Reaction products of disodium 3,5-diamino-2-[(2-sulfonatophenyl)diazenyl]benzoate and  diazotised sodium 2-[(4-aminophenyl)sulfonyl]ethyl sulfate

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experiment start date - 25 February 2003; Experiment end date - 21 May 2003; Study completion date - 23 July 2003.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

no

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)

Specific details on test material used for the study:

Identity: FAT 40810/A
Batch: WP 6/02
Purity: approx. 75 %
Appearance: Solid, dark brownish powder
Expiration date: 12 December 2010
Storage: At room temperature at about 20 °C

Analytical monitoring:

yes

Details on sampling:

After incubation 10 µL aliquots of the test solutions at each pH value were analysed without dilution by measuring the UV/VIS signal of FAT 40810/A after HPLC separation of the injected sample solution.

Buffers:

Buffer pH 4, Biphthalate
Buffer pH 7, Phosphate
Buffer pH 9, Borate
Acetonitrile
Water
Tetrabutylammoniumbromid (TBAB)
The buffer solutions were sterilized for 25 minutes in an autoclave prior to first use. Nitrogen was passed through the buffer solutions for 3 minutes except when freshly sterilized.

Details on test conditions:

Principle of the Test
The study was conducted as described in the guidelines and in accordance with the RCC Ltd Standard Operating Procedures. The test item was dissolved in the buffer solutions and incubated at 50 °C with the water bath kept constant at ± 0.1 °C, usually. The concentration of the test item was determined as a function of time at each pH.

Performance of the Test
A preliminary test was performed at 50 °C ± 0.5 °C for pH 4.0, pH 7.0 and pH 9.0. Aliquots of each test solution were analysed in time intervals using the analytical method as described later in this report. Analysis was performed before incubation, after 2.4 hours and after 120 hours. A main study was not performed, according to the results found during the preliminary test.

Duration:

120 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

>= 91.87 - <= 97.92 mg/L

Duration:

2.4 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

>= 138.4 - <= 141.77 mg/L

Number of replicates:

2 replicates per pH solution were tested.

Positive controls:

no

Negative controls:

no

Statistical methods:

not applied as test was terminated following pre-test.

Preliminary study:

The results of pH 4.0 showed no significant degradation of FAT 40810/A at 50 °C. The degradation of FAT 40810/A was less than 10 % after 5 days. According to the EEC Directive 92/69, Section C.7, it can be concluded, that the estimated half-life time is higher than one year under representative environmental conditions (25 °C). Therefore, FAT 40810/A was considered to be hydrolytically stable at pH 4.0, and no further testing was necessary at pH 4.0.

The results of pH 7.0 showed significant degradation of FAT 40810/A at 50 °C. The degradation of the main peak of FAT 40810/A was more than 50 % after 2.4 hours. According to the EEC Directive 92/69, Section C.7, it can be concluded, that the estimated half-life time is shorter than one day under representative environmental conditions (25 °C). Therefore, FAT 40810/A was considered to be hydrolytically unstable at pH 7.0, and no further testing was necessary at pH 7.0.
The results of pH 9.0 showed significant degradation of FAT 40810/A at 50 °C. It can be concluded from the chromatograms that the main component of the test item degrades immediately after dissolving FAT 40810/A in buffer solution pH 9.0. The peak of the main component could not be detected before incubation at 50 °C. Therefore, it was not possible to follow degradation and according to the EEC Directive 92/69, Section C.7, it can be concluded, that the estimated half-life time is shorter than one day under representative environmental conditions (25 °C). Therefore, FAT 40810/A was considered to be hydrolytically unstable at pH 9.0, and no further testing was necessary at pH 9.0.

Test performance:

At pH 9.0 apparently the substance immediately hydrolysed at time of solution (no main peak of the test item detectable) and thus stability testing could not be performed

Transformation products:

not measured

pH:

4

Temp.:

25 °C

DT50:

> 1 yr

pH:

7

Temp.:

25 °C

DT50:

< 2.4 h

pH:

9

Temp.:

25 °C

DT50:

< 2.4 h

The results of pH 4.0, showed no significant degradation of the test item at 50 °C. The degradation of the test item was less than 10 % after 5 days. According to the EEC Directive 92/69, Section C.7 it can be concluded, that the estimated half-life time is higher than one year under representative environmental conditions (25 °C). Therefore, the test item was considered to be hydrolytically stable at pH 4.0, and no further testing was necessary. The results of pH 7.0 and pH 9.0 showed significant degradation of the test item at 50 °C. The degradation of the test item was more than 50 % after 2.4 hours. According to the EEC Directive 92/69, Section C.7 it can be concluded, that the estimated half-life time is shorter than one day under representative environmental conditions (25 °C). Therefore, the test item was considered to be hydrolytically unstable at pH 7.0 and pH 9.0, and no further testing was necessary.

Validity criteria fulfilled:

yes

Conclusions:

FAT 40810/A was considered to be hydrolytically stable at pH 4.0 (half-life >1 year) and unstable at pH 7 and 9 (half-life <1 day).

Executive summary:

The hydrolysis determination of FAT 40810/A, at different pH values was based on the OECD Guideline No. 111, "Hydrolysis as a Function of pH"; adopted May 12, 1981 and on the EEC Directive 92/69, Section C.7, "Abiotic Degradation: Hydrolysis as a Function of pH", L383 A, December 1992. The results of pH 4.0, showed no significant degradation of the test item at 50 °C. The degradation of the test item was less than 10 % after 5 days. According to the EEC Directive 92/69, Section C.7 it can be concluded, that the estimated half-life time is higher than one year under representative environmental conditions (25 °C). Therefore, the test item was considered to be hydrolytically stable at pH 4.0, and no further testing was necessary. The results of pH 7.0 and pH 9.0 showed significant degradation of the test item at 50 °C. The degradation of the test item was more than 50 % after 2.4 hours. According to the EEC Directive 92/69, Section C.7 it can be concluded, that the estimated half-life time is shorter than one day under representative environmental conditions (25 °C). Therefore, the test item was considered to be hydrolytically unstable at pH 7.0 and pH 9.0, and no further testing was necessary.

Description of key information

The hydrolysis determination of FAT 40810/A, at different pH values was based on the OECD Guideline No. 111, "Hydrolysis as a Function of pH"; adopted May 12, 1981 and on the EEC Directive 92/69, Section C.7, "Abiotic Degradation: Hydrolysis as a Function of pH", L383 A, December 1992. The results of pH 4.0, showed no significant degradation of the test item at 50 °C. The degradation of the test item was less than 10 % after 5 days. According to the EEC Directive 92/69, Section C.7 it can be concluded, that the estimated half-life time is higher than one year under representative environmental conditions (25 °C). Therefore, the test item was considered to be hydrolytically stable at pH 4.0, and no further testing was necessary. The results of pH 7.0 and pH 9.0 showed significant degradation of the test item at 50 °C. The degradation of the test item was more than 50 % after 2.4 hours. According to the EEC Directive 92/69, Section C.7 it can be concluded, that the estimated half-life time is shorter than one day under representative environmental conditions (25 °C). Therefore, the test item was considered to be hydrolytically unstable at pH 7.0 and pH 9.0, and no further testing was necessary.

Key value for chemical safety assessment

Half-life for hydrolysis:

1 d

at the temperature of:

25 °C