m,m'-[carbonylbis[imino(3-methoxy-p-phenylene)azo]]bis(benzenesulphonic) acid, compound with 2,2'-iminodiethanol (1:2)

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

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 111 (Hydrolysis as a Function of pH)

Qualifier:

equivalent or similar to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Remarks:

HPLC

Details on sampling:

The hydrolysis test solutions were analyzed by HPLC at defined time intervals.

Buffers:

Buffer pH 4: Citric acid/NaOH/NaCl; Fluka, order no.: 33643
Buffer pH 7: KH2PO4/Na2HPO4, Fluka, order no.: 33646
Buffer pH 9: Na2B4O7/HCl, Fluka, order no.: 33648

Details on test conditions:

Preparation and procedure of the tests
- All buffer solutions were filled in glass bottles and purged with N2 for five minutes
- Afterwards the buffer solutions were sterilized at 120 °C for 20 minutes
- Before the beginning of the tests the solutions are tempered and the temperature was checked.
- All glassware was purged with N2 before and after filling in the test item and the buffer solutions
- The test solutions were overlain with N2

Hydrolysis at pH 4 (50 °C)
Preparation of the test solution
- 12.8 mg of the test item was dissolved in 120 mL buffer pH 4 resulting in a test item concentration of 95.6 mg/L (0.0001 mol/L)
- Aliquots of the test solution were directly filled into brown glass sample vials to obtain individual samples for each test point
- Preparation was carried out under nitrogen as flushing gas to avoid oxygen
- The vials were closed and incubated at 50 °C in a heat regulator with electronic temperature control to the exclusion of light to avoid any photolytic effects
- The temperature was checked during the experiment using a digital precision thermometer


Preparation of a test item stock solution
- weighing 80.6 mg of the test item in a 50 mL volumetric flask and filling it to the mark with demineralized water, which results in a final concentration of 1444.35 mg/L

Preparation of the calibration solutions
The stock solution was diluted with appropriate volumes to obtain calibration solutions between 28.89 and 144.44 mg/L in demin. water.

Preparation of the solution used for verification of the system suitability
51.7 mg of the test item were weighed into a 50 mL volumetric flask and filled up to the mark with demin. water to obtain a control solution of 926.46 mg/L. To obtain the control solution it was diluted by the factor of 10. This control solution was used for verification of the system suitability before analyzing the test solutions.

Preparation of the hydrolysis test solutions
For each pH separate hydrolysis test solutions were prepared in the corresponding buffer systems. Test item concentrations of approx. 100 mg/L were obtained. Aliquots of the stock solutions were taken without further treatment to prepare individual vials for every test point.

- pH-determination was done with a pH-meter equipped with a calibrated single-rod glass electrode

Preparation and procedure of the tests
All buffer solutions were filled in glass bottles and purged with N2 for five minutes.
Afterwards the buffer solutions were sterilized at 120 °C for 20 minutes. Before the beginning of the tests the solutions are tempered and the temperature was checked.
All glassware was purged with N2 before and after filling in the test item and the buffer solutions. The test solutions were overlain with N2.

Solubility and test concentration
According to OECD TG 111 the concentration of the test item should not exceed 0.01 M or half of the saturation concentration of the water solubility.
Consequently, the test item was applied as aqueous buffer solution with a concentration of approx. 100 mg/L which fulfills the requirements of OECD

Duration:

5 d

pH:

4

Temp.:

50 °C

Initial conc. measured:

102.815 mg/L

Duration:

5 d

pH:

7

Temp.:

50 °C

Initial conc. measured:

85.802 mg/L

Duration:

5 d

pH:

9

Temp.:

50 °C

Initial conc. measured:

93.573 mg/L

Number of replicates:

6 replicates for each pH-value

Preliminary study:

A preliminary test at 50 °C at pH 4, 7 and 9 was conducted according to OECD Guideline 111. Based on these results, the substance is hydrolytically stable.

Transformation products:

not measured

% Recovery:

95.26

pH:

4

Temp.:

50 °C

Duration:

5 d

Remarks on result:

hydrolytically stable based on preliminary test

% Recovery:

94.52

pH:

7

Temp.:

50 °C

Duration:

5 d

Remarks on result:

hydrolytically stable based on preliminary test

% Recovery:

92.63

pH:

9

Temp.:

50 °C

Duration:

5 d

Remarks on result:

hydrolytically stable based on preliminary test

Remarks on result:

hydrolytically stable based on preliminary test

Remarks:

at all three pH-values

Details on results:

As agreed with the sponsor only the main compound was used to observe hydrolysis behaviour in this study.

Validity criteria fulfilled:

yes

Conclusions:

Bayscript Yellow GGN is found to be stable at 50 °C at pH 4,7 and 9. Therefore it can be assumed that the test item is also stable at 25 °C and no half-life times and hydrolysis rates were calculated.

Executive summary:

The tests were performed according to OECD Guidelines for Testing of Chemicals, Section 1 – Physical-Chemical Properties, OECD TG 111, Council Regulation (EC) No 440/2008, Guideline Part C – Methods for the Determination of Ecotoxicity, C.7. “Abiotic Degradation: Hydrolysis as a Function of pH”.

The hydrolysis behaviour of Bayscript gelb GGN was investigated at 50 °C at pH values of 4, 7 and 9 over a period of five days. The stability was monitored by HPLC analysis using UV-detection. No abiotic degradation of the test item exceeding 10 % was observed.

Bayscript gelb GGN is found to be stable at 50 °C at all three pH-values. Therefore it can be assumed that the test item is also stable at 25 °C and no half-life times and hydrolysis rates were calculated.

Description of key information

Bayscript gelb GGN is found to be stable at 50 °C at all pH 4,7 and 9. Therefore it can be assumed that the test item is also stable at 25 °C and no half-life times and hydrolysis rates were calculated.