1,2-dimethoxyethane

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2009-12-02 to 2010-03-16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study performed according to OECD guideline and GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

1,2-dimethoxyethane

EC Number:

203-794-9

EC Name:

1,2-dimethoxyethane

Cas Number:

110-71-4

Molecular formula:

C4H10O2

IUPAC Name:

1,2-dimethoxyethane

Details on test material:

- Name of test material: Monoethylenglykoldimethylether
- Molecular formula: C4H10O2
- Molecular weight: 90.12 g/mol
- Physical state: Liquid, colourless
- Analytical purity: 99.9 % (1,2-Dimethoxyethane)
- Storage condition of test material: Room temperature, protected from moisture and light.

Study design

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent/transformation products: Samples were taken at test start (0 h) and test end (120 h)
- Sampling method: The samples were diluted with HPLC water and analysed. The temperature was checked automatically once in an hour.
- Sampling intervals/times for pH measurements: Test start
- Sampling intervals/times for sterility check: Not necessary for 5 d 50 °C testing (no significant transformation)
- Sample storage conditions before analysis: Due to technical reasons, immediate analysis could not be performed. Therefore the samples stored at -20 +/- 2°C were prepared and analysed via SPME GC-MS/MS.

Buffers:

- pH: pH 4, pH 7, pH 8
- Type and final molarity of buffer:
Buffer solution pH 4 45 mL of 0.1 mol/L NaOH were mixed with 250 mL 0.1 mol/L KH2-Citrate and diluted to 500 mL with double distilled water.

Buffer solution pH 7 148.15 mL of 0.1 mol/L NaOH were mixed with 250 mL 0.1 mol/L KH2PO4, diluted to 500 mL with double distilled water.

Buffer solution pH 9 106.5 mL of 0.1 mol/L NaOH were mixed with 250 mL 0.1 mol/L H3BO3 in 0.1 mol/L KCL, diluted to 500 mL with double distilled water.

- Composition of buffer: Buffers were freshly prepared, purged with nitrogen for 5 minutes and the pH was checked to a precision of at least 0.1 at test temperature and adjusted, if necessary. The buffer solutions were sterilised by filtration through 0.20 µm.

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: Sterile amber HPLC vials, volume 4 mL
- Sterilisation method: Autoclaving of double distlled water, sterilisation of buffer solutions by filtration through 0.20 µm.
- Measures taken to avoid photolytic effects: Photolytic effects were avoided by using amber vials.
- If no traps were used, is the test system closed
- Is there any indication of the test material adsorbing to the walls of the test apparatus? No
TEST MEDIUM
- Volume used/treatment: 4 mL
- Kind and purity of water: see above
- Preparation of test medium: Stock solution: 288 µL of the test item were diluted with 10 mL sterile double distilled water.
An aliquot was spiked with a test item stock solution. Aliquots of the test solutions were filled into the vials. After the vials were sealed they were transferred into the laboratory incubator. The time between test item application and transfer to laboratory incubator / analysis did not exceed 30 min.
- Renewal of test solution: None

Duration of test

Duration of test 1

Duration:

120 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

24.7 mg/L

Duration of test 2

Duration:

120 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

26 mg/L

Duration of test 3

Duration:

120 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

25.6 mg/L

Number of replicates:

Two at each sampling interval for immediate analysis, two for reanalysis stored at -20  2°C and two diluted for reanalysis stored at room temperature, if necessary.

Negative controls:

yes

Statistical methods:

No evaluation was necessary, because the test was completed after the preliminary test.

Results and discussion

Preliminary study:

In the preliminary test, the test item was found to be stable at pH 4, 7 and 9, respectively. No further testing was deemed necessary as less than 10 % of the applied test item were hydrolysed after 120 h (5 days) at each of the three pH values

Transformation products:

no

Dissipation DT50 of parent compound

Key result

Remarks on result:

hydrolytically stable based on preliminary test

Remarks:

The test item was found to be stable in the preliminary test at pH 4, 7 and 9 at 50 °C. Reaction rate constants and half lives could not be calculated due to the fact that the test item undergoes no hydrolysis. With regard to the guidelines a half life of > 1 year could be assumed.

Details on results:

TEST CONDITIONS
- pH, sterility, temperature, and other experimental conditions maintained throughout the study: Yes

Any other information on results incl. tables

Hydrolysis Results for Monoethylenglykoldimethyletherat pH 4 and 50 °C

Hydrolysis Time [h]	Replicate	Concentration [mg/L]	Mean	Transformation [%]
0	1	26.5	26.8	-
	2	27.1
120	1	24.4	25.6	4.5
	2	26.8

Hydrolysis Results for Monoethylenglykoldimethyletherat pH 7 and 50 °C

Hydrolysis Time [h]	Replicate	Concentration [mg/L]	Mean	Transformation [%]
0	1	24.5	24.5	-
	2	6.87 *
120	1	25.3	26.0	0.0
	2	26.8

Hydrolysis Results for Monoethylenglykoldimethyletherat pH 9 and 50 °C

Hydrolysis Time [h]	Replicate	Concentration [mg/L]	Mean	Transformation [%]
0	1	25.0	23.9	-
	2	22.8
120	1	23.7	24.7	0.0
	2	25.6

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The test item was found to be stable in the preliminary test at pH 4, 7 and 9 at 50 °C. Reaction rate constants and half lives could not be calculated due to the fact that the test item undergoes no hydrolysis. With regard to the guidelines a half life of > 1 year could be assumed.

Executive summary:

Hydrolysis as a function of pH was determined according to OECD-Guideline No. 111 (2004) for the test item Monoethylenglykoldimethylether(batch number: DEG4071070) from 2009-12-02 to 2010-03-16 at Dr.U.Noack-Laboratorien,31157 Sarstedt, Germany .

The study was conducted with test item concentrations of 25 mg/L in buffer solutions at pH 4, 7 and 9 at a test temperature of 50 °C (preliminary test).

Samples were taken at test start (0 h) and test end (120 h) and analysed via SPME GC-MS using an external standard. Buffer solutions were analysed at test start and test end with no interference with the test item. The analytical method for determination of the test item Monoethylenglykoldimethyletherwas validated and tested with satisfactory results in regard to linearity, accuracy, precision and specificity.

Transformation was calculated as the percentage loss of the test item over the time. In the preliminary test, the test item was found to be stable at pH 4, 7 and 9, respectively. No further testing was deemed necessary as less than 10 % of the applied test item were hydrolysed after 120 h (5 days) at each of the three pH values (Table 1). Reaction rate constants and half lives could not be calculated due to the fact that the test item undergoes no significant hydrolysis. With respect to the guidelines a half life of > 1 year could be assumed for environmental relevant conditions.

Table 1:    Transformation [%] of Monoethylenglykoldimethylether at 50 °C after 120 h

Hydrolysis Time [h]	Transformation [%]
	pH 4	pH 7	pH 9
120	4.5	0.0	0.0