REAKTIV-GELB F-68 072 FW

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24 March 1993 to 15 July 1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: Richtlinie 84/449/EWG Anhang V, Teil C: Methoden zur Bestimmung der Ökotoxizität; C. 10: Abbaubarkeit - Abiotischer Abbau - Hydrolyse in Abhängigkeit vom pH

Deviations:

yes

Remarks:

see below

Principles of method if other than guideline:

"Reactive"-dyes rapidly turn into their "reactive" vinyl derivative (-S02CH=CH2) in alkaline solution. In the testing facility the abiotic hydrolysis data of more than 20 reactive-dyes were determined according to the cited guideline. The half-life period at pH 9 and 25 deg C each time was less than one day. Applying these results to the present test substance Reaktiv-Gelb F-68072, there is no need for hydrolysis tests at pH 9:

Half life (Reaktiv-Gelb F-68072, pH 9, 25 °C) < 1 d

GLP compliance:

yes

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Not applicable.

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

Choice of Concentration
The optimal concentration of test substance required for the HPLC analysis is about 200 mg/l. This value is less than the solubility in water and thus satisfies the requirements of the guidelines.

Preparation of Test Samples
Solutions were usually prepared by weighing ca. 20 mg of the test substance in a 100 ml volumetric flasks and dissolving it in the relevant buffer.
The time between dissolution of the test substance and placing it into the thermostatic water bath (thermostated at the required hydrolysis temperature) was kept as short as possible.

Buffers:

pH 4 buffer solution (citric acid - monohydrate)
pH 7 buffer solution (potassium dihydrogenphosphate)

Estimation method (if used):

Not applicable.

Details on test conditions:

See Details on analytical methods

Number of replicates:

See tabulated data below

Positive controls:

no

Negative controls:

no

Preliminary study:

The reaction rate constant and the resulting half-life period at 25 °C are determined by extrapolating the results of tests 1 and 3 using the Arrhenius equation

Test performance:

The reaction rate constant and the resulting half-life period at 25 °C are determined by extrapolating the results of tests 1 and 3 using the Arrhenius equation

Transformation products:

yes

No.:

#1

Details on hydrolysis and appearance of transformation product(s):

Assessment of hydrolysis products are attached below.

pH:

4

Temp.:

25 °C

DT50:

2.2 yr

Remarks on result:

other: extrapolated from the results of test 1 and 3

pH:

7

Temp.:

25 °C

DT50:

1.8 d

Remarks on result:

other: extrapolated from the results of test 1 and 3

pH:

9

Temp.:

25 °C

DT50:

< 1 d

Remarks on result:

other: derived from hydrolysis investigations with substances of the same class

Details on results:

As detailed below.

Results of Analyses and Extrapolation

 

The reaction rate constant and the resulting half-life period at 25⁰C are determined by extrapolating the results of test 1 and 3 using the Arrhenius equation.

 

pH 7:

Temp. (⁰C)	Kobs(h^-1)	t½(h)	t½(d)
50	0.21477	3.2	0.1	Test 1
35	0.04717	14.7	0.6	Test 3
25	0.01578	43.9	1.8	Extrapolation

 

pH 4:

Temp. (⁰C)	Kobs(h^-1)	t½(h)	t½(d)
85	0.02541	27.3	1.1	Test 3
75	0.01140	60.8	2.5	Test 3
60	0.00220	315.2	13.1	Test 1 (run 2)
25	0.00004	19349.1	806.2 d = 2.2 a	Extrapolation

Validity criteria fulfilled:

yes

Conclusions:

The half-life periods of Reaktiv-Gelb F-68072 FW at 25 °C are
2.2 years at pH 4 (extrapolated from the results of test 1 and 3)
1.8 days at pH 7 (extrapolated from the results of test 1 and 3)
< 1 day at pH 9 (derived from hydrolysis investigations with substances of the same class)

Executive summary:

The objective of this study was the determination of the abiotic degradation of the test substance (the main compound), i.e. the determination of the hydrolysis rate as a function of the pH-value according to 84/449/EEC Part C.10 using the HPLC method. Study conducted in compliance with GLP.

The half-life periods of Reaktiv-Gelb F-68072 FW at 25 °C are

2.2 years at pH 4 (extrapolated from the results of test 1 and 3)

1.8 days at pH 7 (extrapolated from the results of test 1 and 3)

< 1 day at pH 9 (derived from hydrolysis investigations with substances of the same class)

Assessment of hydrolysis products was undertaken as an additional report. This is enclosed as additional supporting information, but is not considered to have an impact on the overall results.

 

Description of key information

The half-life periods of Reaktiv-Gelb F-68072 FW at 25 °C are
2.2 years at pH 4 (extrapolated from the results of test 1 and 3)
1.8 days at pH 7 (extrapolated from the results of test 1 and 3)
< 1 day at pH 9 (derived from hydrolysis investigations with substances of the same class).

Key value for chemical safety assessment

Half-life for hydrolysis:

1.8 d

at the temperature of:

25 °C

Additional information

The objective of this study was the determination of the abiotic degradation of the test substance (the main compound), i.e. the determination of the hydrolysis rate as a function of the pH-value according to 84/449/EEC Part C.10 using the HPLC method. Study conducted in compliance with GLP.