Heptanal, oligomeric reaction products with aniline

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22 July 2016 to 03 November 2016

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

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.2120 (Hydrolysis of Parent and Degradates as a Function of pH at 25°C)

Deviations:

no

GLP compliance:

yes

Radiolabelling:

no

Analytical monitoring:

no

Details on sampling:

Calibration solutions were injected in duplicate. Test samples were analysed by single injection.

Buffers:

Acetate buffer pH 4, 0.01 M
A solution of 16.7% 0.01 M sodium acetate in water
and 83.3% 0.01 M acetic acid in water. The buffer contained 0.0009% (w/v) sodium azide.

Phosphate buffer pH 7, 0.01 M
A solution of 0.01 M potassium di-hydrogenphosphate in water adjusted to pH 7 using 1 N sodium hydroxide.The buffer contained 0.0009% (w/v) sodium azide.

Borate buffer pH 9, 0.01 M
A solution of 0.01 M boric acid in water and 0.01 M potassium chloride in water adjusted to pH 9 using 1 N sodium hydroxide. The buffer contained 0.0009% (w/v) sodium azide.

Details on test conditions:

Performance of the study
The rate of hydrolysis of the test item as a function of pH was determined at pH values normally found in the environment (pH 4-9).

Preliminary test - Tier 1
The buffer solutions were filter-sterilised through a 0.2 μm FP 30/0.2 CA-S filter (Whatman, Dassel, Germany) and transferred into a sterile vessel. To exclude oxygen, nitrogen gas was purged through the solution for 5 minutes. The test item was spiked to the solutions at a target concentration of 200 μg/L using a spiking solution in acetonitrile. For each sampling time, duplicate sterile vessels under vacuum were filled with 6 mL test solution and placed in the dark in a temperature controlled environment at 50.2°C +/- 0.3°C.

Note: the spiking volume was < 1% of the sample volume. Nominal concentrations were not corrected for the spiking volume.

The concentration of the test item in the test samples was determined immediately after preparation (t=0) and after 5 days. The samples taken at t=5 days were cooled to room temperature using running tap water. The samples were diluted in a 1:1 (v:v) ratio with acetonitrile, if necessary diluted with 50:50 (v:v) acetonitrile:buffer and analysed.

Blank buffer solutions containing a similar content of blank spiking solution were treated similarly as the test samples and analysed at t=0. The pH of each of the test solutions (except for the blanks) was determined at each sampling time.

Main study - Tier 2
Test samples were prepared and treated similarly as during the preliminary test.

The concentrations of the test item were determined immediately after preparation (t=0) and after 25 hours (t=1).

Blank buffer solutions were treated similarly as the test samples and analysed at t=0.

The pH of each of the test solutions (except for the blanks) was determined.

The study was performed at the following temperature: 19.9°C +/- 0.2°C

Duration:

5 d

pH:

4

Temp.:

50.2 °C

Initial conc. measured:

200 µg/L

Remarks:

Preliminary test - Tier 1

Duration:

5 d

pH:

7

Temp.:

50.2 °C

Initial conc. measured:

200 µg/L

Remarks:

Preliminary test - Tier 1

Duration:

5 d

pH:

9

Temp.:

50.2 °C

Initial conc. measured:

200 µg/L

Remarks:

Preliminary test - Tier 1

Duration:

25 h

pH:

4

Temp.:

19.9 °C

Initial conc. measured:

200 µg/L

Remarks:

Main study - Tier 2

Duration:

25 h

pH:

7

Temp.:

19.9 °C

Initial conc. measured:

200 µg/L

Remarks:

Main study - Tier 2

Duration:

25 h

pH:

9

Temp.:

19.9 °C

Initial conc. measured:

200 µg/L

Remarks:

Main study - Tier 2

Number of replicates:

Not specified

Positive controls:

no

Negative controls:

no

Statistical methods:

Quadratic regression analysis was performed using the least squares method with a 1/concentration weighting factor.

Preliminary study:

A degree of hydrolysis of ≥ 10% was observed at pH 7 and pH 9 after 5 days. According to the guideline, the higher Tier test was required to determine the half-life time of the test item. At pH 4, the test-item concentration had increased. As this result was unexpected, it was decided to include this pH in the main study, too.

Small responses were detected in the blank buffer solutions. These responses were considered to not to derive from the blank buffer solutions as similar responses were observed in the analytical blanks. This did not impact the study.

The mean recovery of the of the test item containing buffer pH4 solutions at t=0 fell within the criterion range of 90-110%.

The mean recoveries of the of the test item containing buffer pH7 and pH9 solutions at t=0 exceeded the criterion range of 90-110%. This was considered acceptable, as a main study was going to be carried out under these conditions. There was no impact on the study.

Transformation products:

not specified

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

Under the conditions of the main study the test item did not degrade hydrolytically at pH 4, 7 and 9

% Recovery:

>= 88 - <= 93

pH:

4

Temp.:

50.2 °C

Duration:

5 d

Remarks on result:

other:

Remarks:

preliminary test

% Recovery:

125

pH:

7.1

Temp.:

50.2 °C

Duration:

5 d

Remarks on result:

other:

Remarks:

preliminary test

% Recovery:

117

pH:

9

Temp.:

50.2 °C

Duration:

5 d

Remarks on result:

other:

Remarks:

preliminary test

% Recovery:

>= 85 - <= 90

pH:

4

Temp.:

20 °C

Duration:

25 h

Remarks on result:

other:

Remarks:

Main test

% Recovery:

>= 88 - <= 93

pH:

8

Temp.:

20 °C

Duration:

5 h

Remarks on result:

other:

Remarks:

Main test

% Recovery:

>= 91 - <= 93

pH:

9

Temp.:

20 °C

Duration:

5 h

Remarks on result:

other:

Remarks:

Main test

Remarks on result:

not measured/tested

Other kinetic parameters:

Not specified

Details on results:

Main Study - Tier 2
pH 4
Small responses were detected in the blank buffer solutions. These responses were considered to not to derive from the blank buffer solutions as similar responses were observed in the analytical blanks. This did not impact the study.

The mean recoveries of the buffer solutions at t=0 fell within the acceptable range of 70-110% for non-labelled chemicals. It demonstrated that the analytical method was adequate to support the hydrolysis study on the test item.

After a testing time of 25 hours, the test-item concentration had increased significantly (i.e. 16% and 20%). Quantifying the test-item concentration based on the transition m/z 380.3 → m/z 252.1 at a retention time of approximately 1.5 min, the test item did obviously not degrade hydrolytically. Accordingly Tier 2 testing at pH 4 was discontinued. The concentration of the investigated component may have increased as a higher-molecular weight component degraded. It was, however, not possible to validate an analytical method for such a higher-molecular-weight component with sufficient sensitivity.

pH 7
Small responses were detected in the blank buffer solutions. These responses were considered to not to derive from the blank buffer solutions as similar responses were observed in the analytical blanks. This did not impact the study.

The mean recoveries of the test item containing buffer solutions at t=0 fell within the criterion range of 90-110%. It demonstrated that the analytical method was adequate to support the hydrolysis study on the test item.

After a testing time of 25 hours, the test-item concentration had increased significantly (i.e. 15% and 22%). Quantifying the test-item concentration based on the transition m/z 380.3 → m/z 252.1 at a retention time of approximately 1.5 min, the test item did obviously not degrade hydrolytically. Accordingly Tier 2 testing at pH 7 was discontinued.

The concentration of the investigated component may have increased as a higher-molecular weight component degraded. It was, however, not possible to validate an analytical method for such a higher-molecular-weight component with sufficient sensitivity

pH 9
Small responses were detected in the blank buffer solutions. These responses were considered to not to derive from the blank buffer solutions as similar responses were observed in the analytical blanks. This did not impact the study.

The mean recoveries of the test item containing buffer solutions at t=0 fell within the criterion range of 90-110%. It demonstrated that the analytical method was adequate to support the hydrolysis study on the test item.

After a testing time of 25 hours, the test-item concentration had increased significantly (i.e. 22% and 26%). Quantifying the test-item concentration based on the transition m/z 380.3 → m/z 252.1 at a retention time of approximately 1.5 min, the test item did obviously not degrade hydrolytically. Accordingly Tier 2 testing at pH 9 was discontinued.

The concentration of the investigated component may have increased as a higher-molecular weight component degraded. It was, however, not possible to validate an analytical method for such a higher-molecular-weight component with sufficient sensitivity

Preliminary test–hydrolysis of the test item at pH 4, pH 7 and pH 9

pH	Sampling time	Analysed concentration [μg/L]	Degree of hydrolysis [%]		Actual pH
			Individual	Mean
4	0 hours	177			4.0
		185			4.0
	5 days	253	-40	-39	4.1
		250	-38		4.1
7	0 hours	250			7.1
		251			7.1
	5 days	195	22	21	7.1
		199	20		7.1
9	0 hours	231			9.0
		236			9.0
	5 days	135	42	43	9.0
		129	45		9.0

 

Preliminary test–recoveries

pH	Nominal concentration [μg/L]	Analysed concentration [μg/L]	Recovery [%]	Mean recovery [%]
4	200	177	88	90
	200	185	93
7	200	250	125	125
	200	251	125
9	200	231	116	117
	200	236	118

 

Main test–hydrolysis of the test item at pH 4 and 20°C

Sampling time [hours]	Analysed concentration [μg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0	171	97	1.99	4.0
0	181	103	2.01	4.0
25	204	116	2.07	4.1
25	212	120	2.08	4.1

 

Main test–Recoveries (at pH 4 and 20°C)

Temperature (°C)	Nominal concentration [μg/L]	Analysed concentration [μg/L]	Recovery [%]	Mean recovery [%]
20	200	171	85	88
	200	181	90

 

Main test–hydrolysis of the test item at pH 7 and 20°C

Sampling time [hours]	Analysed concentration [μg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0	175	97	1.99	7.0
0	786	103	2.01	7.0
25	208	115	2.06	7.0
25	219	122	2.08	7.0

 

Main test – Recoveries (at pH 7 and 20°C)

Temperature (°C)	Nominal concentration [μg/L]	Analysed concentration [μg/L]	Recovery [%]	Mean recovery [%]
20	200	175	88	90
	200	186	93

 

Main test–hydrolysis of the test item at pH 9 and 20°C

Sampling time [hours]	Analysed concentration [μg/L]	Relative concentration [%]	Logarithm relative concentration	Actual pH
0	182	98	1.99	8.9
0	189	102	2.01	8.9
25	227	122	2.09	8.9
25	234	126	2.10	8.9

 

Main test – Recoveries (at pH 9 and 20°C)

Temperature (°C)	Nominal concentration [μg/L]	Analysed concentration [μg/L]	Recovery [%]	Mean recovery [%]
20	200	182	91	93
	200	189	94

 

Validity criteria fulfilled:

yes

Conclusions:

No hydrolytic degradation for the monitored component for Hepteen Base (R) when tested at 20°C for 25 hours at pH 4,7 and 9.

The concentration of the investigated component may have increased as a higher-molecular-weight component degraded. It was, however, not possible to validate an analytical method for such a higher-molecular-weight component with sufficient sensitivity.

Executive summary:

The preliminary test (Tier 1) and main study (Tier 2) were performed for the determination of the rate of hydrolysis of Hepteen Base® at pH values normally found in the environment (pH 4-9).

After a testing time of 25 hours, the test-item concentration had increased significantly (i.e. 22% and 26%) at all pHs. Based on the monitored component, the test item did obviously not degrade hydrolytically. Accordingly Tier 2 testing was discontinued.

The concentration of the investigated component may have increased as a higher-molecular weight component degraded. It was, however, not possible to validate an analytical method for such a higher-molecular-weight component with sufficient sensitivity.

Description of key information

The preliminary test (Tier 1) and main study (Tier 2) were performed for the determination of the rate of hydrolysis of Hepteen Base® at pH values normally found in the environment (pH 4-9).

After a testing time of 25 hours, the test-item concentration had increased significantly (i.e. 22% and 26%) at all pHs. Based on the monitored component, the test item did obviously not degrade hydrolytically. Accordingly Tier 2 testing was discontinued. The concentration of the investigated component may have increased as a higher-molecular-weight component degraded. It was, however, not possible to validate an analytical method for such a higher-molecular-weight component with sufficient sensitivity.

Additional information

A study was conducted to determine the hydrolysis rate of Hepteen Base®. The study was conducted in accordance with the following test guidelines:

European Community (EC), EC no. 440/2008, Part C: Methods for the Determinationof Ecotoxicity, Guideline C.7: “Degradation- Abiotic Degradation: Hydrolysis as aFunction of pH”, Official Journal of the European Union no. L142, May 31, 2008.

 

Organization for Economic Co-operation and Development (OECD), OECDGuidelines for the Testing of Chemicals no. 111: “Hydrolysis as a Function of pH",April 13, 2004.

 

United States Environmental Protection Agency (EPA), Fate, Transport and Transformation Test Guidelines no. OPPTS 835.2120: "Hydrolysis", October 2008.