Diallylamine

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experimental Starting Date: 05 August 2015 Experimental Completion Date: 29 October 2015

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)

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

Preparation of the Sample Solutions
Stock solutions were prepared in glass flasks at a nominal concentration of 900 mg/L in the three buffer solutions. The stock solutions were split into individual glass headspace vials and sealed with no headspace to reduce the potential for volatization of the test item for each data point. The sample solutions were shielded from light whilst maintained at the test temperature.

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

Analysis of the Sample Solutions
The sample solutions were taken from the water bath at various times and the pH of each solution recorded. The concentration of test item in the stock solutions and sample solutions was determined by high performance liquid chromatography (HPLC).

Samples
An aliquot of each sample was diluted by a factor of 2 using acetonitrile.

Standards
Duplicate standard solutions of test item were prepared in acetonitrile:relevant buffer (1:1 v/v) at a nominal concentration of 450 mg/L.

Matrix blanks
Acetonitrile:relevant buffer (1:1 v/v).

Buffers:

The determination of hydrolysis as a function of pH was carried out using a procedure designed to be compatible with Method C7 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 test system used sterile buffer solutions at pH’s 4, 7 and 9.

Table 3.1 – Buffer Solution Specification

Buffer solution
(pH) Components Concentration
(mol dm-3)
4 Citric acid 0.06
Sodium chloride 0.04
Sodium hydroxide 0.07
7 Disodium hydrogen orthophosphate (anhydrous) 0.03
Potassium dihydrogen orthophosphate 0.02
Sodium chloride 0.02
9 Disodium tetraborate 0.01
Sodium chloride 0.02

These solutions were subjected to ultrasonication and degassing with nitrogen to minimize the dissolved oxygen content.

The glassware used to hold the sample solutions and standards was silanized with dichlorodimethylsilane to prevent adsorption of the cationic test item to the glass.

Details on test conditions:

Refer to details on sampling and analytical methods.

Duration:

120 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

0.903 other: g/L - Sample A

Duration:

120 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

0.893 other: g/L - Sample B

Duration:

120 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

0.915 other: g/L - Sample A

Duration:

120 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

0.916 other: g/L - Sample B

Duration:

120 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

0.875 other: g/L - Sample A

Positive controls:

no

Negative controls:

no

Statistical methods:

Not specified.

Preliminary study:

The mean peak heights relating to the standard and sample solutions are shown in table 3.2 (please see remarks on results including tables and figures section).

Test performance:

The linearity of the detector response with respect to concentration for all three solution matrices was assessed over the nominal concentration range of 35 to 850 mg/L. These were satisfactory with a correlation coefficient (r) of at least 0.998 being obtained.

Transformation products:

not specified

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

Less than 10% hydrolysis after 5 days at 50°C.

pH:

4

Temp.:

50 °C

DT50:

> 1 yr

pH:

7

Temp.:

50 °C

DT50:

> 1 yr

pH:

9

Temp.:

50 °C

DT50:

> 1 yr

Other kinetic parameters:

None.

Details on results:

The estimated half-life of the test item at 25 °C for pH 4, 7 and 9 has been shown to be greater than 1 year.

Results Please see Attachment 1 of this Summary for the Typical Chromatography. The mean peak areas relating to the standard and sample solutions are shown in the following table:

 

Table 3.2

 

Solution	Mean Peak Area
Standard 483 mg/L	3.6915 x 10^6
Standard 468 mg/L	3.5213 x 10^6
Initial Sample A, pH 4	3.4212 x 10^6
Initial Sample B, pH 4	3.3839 x 10^6
24 hours Sample A, pH 4	3.4849 x 10^6
24 hours Sample B, pH 4	3.4552 x 10^6
120 hours Sample A, pH 4	3.3506 x 10^6
120 hours Sample B, pH 4	3.3828 x 10^6
Standard 483 mg/L	3.4664 x 10^6
Standard 468 mg/L	3.3391 x 10^6
Initial Sample A, pH 7	3.2706 x 10^6
Initial Sample B, pH 7	3.2740 x 10^6
24 hours Sample A, pH 7	3.3943 x 10^6
24 hours Sample B, pH 7	3.8616 x 10^6
120 hours Sample A, pH 7	3.2961 x 10^6
120 hours Sample B, pH 7	3.3331 x 10^6
Standard 483 mg/L	3.4265 x 10^6
Standard 468 mg/L	3.3429 x 10^6
Initial Sample A, pH 9	3.1121 x 10^6
Initial Sample B, pH 9	-*
24 hours Sample A, pH 9	2.7741 x 10^6
24 hours Sample B, pH 9	2.9420 x 10^6
120 hours Sample A, pH 9	3.0742 x 10^6
120 hours Sample B, pH 9	3.1210 x 10^6

*Contained a large interfering peak. Therefore the sample was not used in any calculations.

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

 

Table 3.3       pH 4 at 50 ºC

 

Time (Hours)	Concentration (g/L)		% of initial concentration
	A	B	A	B
0	0.903	0.893	101	99.5
24	0.920	0.912	102	102
120	0.884	0.893	98.5	99.4

 

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

 

Table 3.4       pH 7 at 50 ºC

 

Time (Hours)	Concentration (g/L)		% of initial concentration
	A	B	A	B
0	0.915	0.916	99.9	100
24	0.949	1.08	104	118
120	0.922	0.932	101	102

 

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

 

Table 3.5       pH 9 at 50 ºC

 

Time (Hours)	Concentration (g/L)		% of initial concentration*
	A	B	A	B
0	0.875	-[1]	100	-
24	0.780	0.827	89.1	94.5
120	0.864	0.877	98.8	100

 

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

 

The results from the Preliminary Test/Tier 1 showed the test item was stable to hydrolysis and therefore it was not necessary to undertake further testing at pH 4, 7 and 9.

 

*The initial concentration was based on Sample A of the 0 hour time point only.

[1] Contained a large interfering peak. Therefore the sample was not used in any calculations.

Validity criteria fulfilled:

yes

Conclusions:

The estimated half-life of the test item at 25 °C for pH 4, 7 and 9 has been shown to be greater than 1 year.

Executive summary:

The determination of hydrolysis as a function of pH was carried out using a procedure designed to be compatible with Method C7 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 test system used sterile buffer solutions at pH’s 4, 7 and 9.

 

Table 3.1– Buffer Solution Specification

 

Buffer solution (pH)	Components	Concentration (mol dm^-3)
4	Citric acid	0.06
	Sodium chloride	0.04
	Sodium hydroxide	0.07
7	Disodium hydrogen orthophosphate (anhydrous)	0.03
	Potassium dihydrogen orthophosphate	0.02
	Sodium chloride	0.02
9	Disodium tetraborate	0.01
	Sodium chloride	0.02

 

These solutions were subjected to ultrasonication and degassing with nitrogen to minimize the dissolved oxygen content.

 

The glassware used to hold the sample solutions and standards was silanized with dichlorodimethylsilane to prevent adsorption of the cationic test item to the glass.

Conclusion

The estimated half-life of the test item at 25 °C for pH 4, 7 and 9 has been shown to be greater than 1 year.

Description of key information

The determination of hydrolysis as a function of pH was carried out using a procedure designed to be compatible with Method C7 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 half-life of the test item at 25 °C for pH 4, 7 and 9 has been shown to be greater than 1 year.

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C