Reaction mass of 5-[[4-[benzylmethylamino]phenyl]azo]-1,4-dimethyl-1H-1,2,4-triazolium methyl sulphate and 3-[[4-[benzylmethylamino]phenyl]azo]-1,4-dimethyl-1H-1,2,4-triazolium methyl sulphate

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

This study was conducted between 08 November 2017 and 26 Novemebr 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

None

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

EC No. 440/82008 of 30 May 2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Version / remarks:

13 April 2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Information as provided by the Sponsor.
Identification: FAT 31016/T
CAS Number: 62163-53-5
Physical state:Dark green iridescent liquid
Batch: AT-0042774700
Purity: 80%
Expiry date: 07 September 2021
Storage conditions: Room temperature, in the dark

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

Duplicate sample solutions were taken initially and from the waterbath at various time points. The pH of each solution was recorded. The concentration of test item in the sample solutions was determined by high performance liquid chromatography (HPLC).

Buffers:

The test system consisted of buffer solutions at pH’s 4, 7 and 9, detailed in the following table:
Table 1 Buffer Solution Specification
Buffer solution (pH) Components Concentration (mol dm-3)
4 Citric acid 0.006
Sodium chloride 0.004
Sodium hydroxide 0.007
7 Disodium hydrogen orthophosphate (anhydrous) 0.003
Potassium dihydrogen orthophosphate 0.002
Sodium chloride 0.002
9 Disodium tetraborate 0.001
Sodium chloride 0.002
The buffer solutions were passed through a 0.2 µm membrane filter to sterilize and subjected to ultrasonication and degassing with nitrogen to minimize dissolved oxygen.

Details on test conditions:

Performance of the Test
Preparation of the Test Solutions
Stock solutions of test item were prepared at a nominal concentration of 4000 mg/L in the three buffer solutions. The stock solutions were split into individual glass vessels, sealed with minimal headspace, for each data point. These sample solutions were shielded from light whilst maintained at the test temperature.

Preliminary Test/Tier 1
Sample solutions at pH 4 and 7 were maintained at 50.0 ± 0.5 °C for a period of 120 hours. Sample solutions at pH 9 were maintained at 50.0 ± 0.5 °C for a period of 212 hours.

Analysis of the Sample Solutions
Duplicate sample solutions were taken initially and from the waterbath at various time points. The pH of each solution was recorded. The concentration of test item in the sample solutions was determined by high performance liquid chromatography (HPLC).

Duration:

120 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

4 000 mg/L

Duration:

120 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

4 000 mg/L

Duration:

212 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

4 000 mg/L

Number of replicates:

2

Positive controls:

no

Negative controls:

no

Test performance:

4.1.5 Validation
The linearity of the detector response with respect to concentration was assessed over the nominal concentration range of 40 to 800 mg/L. The results were satisfactory with a correlation coefficient (r) of ≥0.999 being obtained for all pH’s.

Transformation products:

no

Key result

pH:

4

Temp.:

25 °C

DT50:

> 1 yr

Type:

not specified

Key result

pH:

7

Temp.:

25 °C

DT50:

> 1 yr

Type:

not specified

Key result

pH:

9

Temp.:

25 °C

DT50:

> 1 yr

Type:

not specified

Details on results:

No significant peaks were observed at the approximate retention time of the test item on analysis of any matrix blank solutions.
Greater than 10 % loss of initial test item concentration was observed after 5 days at 50 °C, at pH 9, however no further significant loss was seen after 24 hours. As after the initial decrease in concentration the concentration stabilized, this loss was not attributed to hydrolysis therefore pH 9 reported as a half-life (t ½) of greater than a year.

Preliminary Test/Tier 1

The mean peak areas relating to the standard and sample solutions are shown in the following tables:

Table 2– Preliminary Testing pH 4 at 50.0 ± 0.5 °C

Solution	Mean peak area
Standard 402 mg/L	1.9216 x 10^8
Standard 416 mg/L	1.9430 x 10^8
Initial Sample A, pH 4	1.8749 x 10^8
Initial Sample B, pH 4	1.8765 x 10^8
Standard 411 mg/L	1.9700 x 10^8
Standard 408 mg/L	1.9315 x 10^8
24 Hour Sample A, pH 4	1.8905 x 10^8
24 Hour Sample B, pH 4	1.8928 x 10^8
Standard 402 mg/L	1.8681 x 10^8
Standard 408 mg/L	1.8966 x 10^8
120 Hour Sample A, pH 4	1.8212 x 10^8
120 Hour Sample B, pH 4	1.8382 x 10^8

Table3– Preliminary Testing pH 7 at 50.0 ± 0.5 °C

Solution	Mean peak area
Standard 402 mg/L	1.9226 x 10^8
Standard 416 mg/L	1.9322 x 10^8
Initial Sample A, pH 7	1.6055 x 10^8
Initial Sample B, pH 7	1.5938 x 10^8
Standard 411 mg/L	1.9626 x 10^8
Standard 408 mg/L	1.9280 x 10^8
24 Hour Sample A, pH 7	1.7567 x 10^8
24 Hour Sample B, pH 7	1.7600 x 10^8
Standard 402 mg/L	1.8624 x 10^8
Standard 408 mg/L	1.8886 x 10^8
120 Hour Sample A, pH 7	1.4853 x 10^8
120 Hour Sample B, pH 7	1.4751 x 10^8

Table4– Preliminary Testing pH 9 at 50.0 ± 0.5 °C

Solution	Mean peak area
Standard 402 mg/L	1.5920 x 10^8
Standard 416 mg/L	1.6844 x 10^8
Initial Sample A, pH 9	1.8911 x 10^8
Initial Sample B, pH 9	1.8888 x 10^8
Standard 411 mg/L	1.6234 x 10^8
Standard 408 mg/L	1.6283 x 10^8
24 Hour Sample A, pH 7	1.1978 x 10^8
24 Hour Sample B, pH 7	1.1977 x 10^8
Standard 402 mg/L	1.5464 x 10^8
Standard 408 mg/L	1.5956 x 10^8
120 Hour Sample A, pH 9	1.1112 x 10^8
120 Hour Sample B, pH 9	1.1191 x 10^8
Standard 400 mg/L	1.6696 x 10^8
Standard 404 mg/L	1.6949 x 10^8
144 Hour Sample A, pH 9	1.1036 x 10^8
144 Hour Sample B, pH 9	1.1036 x 10^8
Standard 400 mg/L	1.6113 x 10^8
Standard 403 mg/L	1.6041 x 10^8
212 Hour Sample A, pH 9	1.1017 x 10^8
212 Hour Sample B, pH 9	1.1031 x 10^8

  The test item concentrations at the given time points are shown in the following tables:

Table 5            pH 4 at 50.0 ± 0.5 ºC

Time (Hours)	Concentration (g/L)		% of mean initial concentration
	A	B	A	B
0	3.97	3.97	-	-
24	3.97	3.98	100	100
120	3.92	3.96	99	100

 

Result:            Less than 10% hydrolysis after 5 days at 50 °C, equivalent to a half-life greater than 1 year at 25 °C.

Table 6            pH 7 at 50.0 ± 0.5 ºC

Time (Hours)	Concentration (g/L)		% of mean initial concentration
	A	B	A	B
0	3.41	3.38	-	-
24	3.70	3.71	109	109
120	3.21	3.19	94	94

 

Result:            Less than 10% hydrolysis after 5 days at 50 °C, equivalent to a half-life greater than 1 year at 25 °C.

Table 7            pH 9 at 50.0 ± 0.5 ºC

Time (Hours)	Concentration (g/L)		% of mean initial concentration
	A	B	A	B
0	4.73	4.72	-	-
24	3.02	3.02	64	64
120	2.87	2.89	61	61
144	2.64	2.64	56	56
212	2.75	2.76	58	58

 

Result:            Greater than10% loss after 5 days at 50 °C,however no further significant loss was seen after 24 hours. Therefore no hydrolysis is indicated by the results, providing a hydrolysis equivalent to a half-life greater than 1 year at 25 °C.

Validity criteria fulfilled:

yes

Conclusions:

The estimated rate constant and half-life at 25 °C of the test item are shown in the following table:
Table
pH Estimated Half-Life at 25 °C
4 > 1 year
7 > 1 year
9 > 1 year

Executive summary:

The hydrolysis as a function of pH of FAT 31016/T has been determined. The results are summarized below:

Abiotic Degradation, Hydrolysis as a Function of pH. Assessment of hydrolytic stability was carried out using a procedure designed to be compatible with Method C.7 Abiotic Degradation, Hydrolysis as a Function of pH of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 111 of the OECD Guidelines for Testing of Chemicals, 13 April 2004. The results are as follows:

pH	Estimated half-life at 25 °C
4	>1 year
7	>1 year
9	>1 year

Description of key information

FAT 31016/T TE was found to be hydrolytically stable, with half life of >1 year at 25 °C.

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C

Additional information

Assessment of hydrolytic stability was carried out using a procedure designed to be compatible with Method C.7 Abiotic Degradation, Hydrolysis as a Function of pH of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 111 of the OECD Guidelines for Testing of Chemicals, 13 April 2004. The estimated rate constant and half-life at 25 °C of the test item were determined as follows:

pH    Estimated Half-Life at 25 °C

4       > 1 year

7       > 1 year

9       > 1 year