Registration Dossier

Administrative data

Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2010-01-21 to 2010-01-26
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: study performed according OECD guidline 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:
OECD Guideline 111 (Hydrolysis as a Function of pH)
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Diethylenglykoldimethylether
- Molecular formula: C6H14O3
- Molecular weight: 134.18 g/mol
- Physical state: Liquid, colourless
- Analytical purity: 99.9 % (Bis(2-methoxyethyl)ether)
- Storage condition of test material: Room temperature, protected from moisture and light.
Radiolabelling:
no

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: All test item containing samples were diluted with HPLC water and analysed immediately (max. 30 min for preparation and start of analyses) via SPME GC-MS.
Due to analytical difficulties analysis of pH 7 samples at test end were performed from reserve samples (frozen samples).
- Sample storage conditions before analysis: Additionally backup samples were collected. 2 samples stored at -20  2°C and 2 prepared samples stored at room temperature. The bath temperature was checked at least twice every working day.
- Other observation, if any (e.g.: precipitation, color change etc.): None
Buffers:
- pH:
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 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.
Estimation method (if used):
None
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: Filtration, Autoclav
- Lighting: None
- Measures taken to avoid photolytic effects: Photolytic effects were avoided by using amber vials.
- Measures to exclude oxygen: Buffers were purged with nitrogen for 5 minutes
- 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? None
TEST MEDIUM
- Volume used/treatment 4 mL
- Kind and purity of water: sterile, double distilled water
- Preparation of test medium: 169 µL of the test item were diluted with 10 mL sterile double distilled water; an aliquot of the respective buffer was spiked with the test item stock solution. Aliquots of the test solutions was filled into the vials, sealed and transferred into the water bath. The time between test item application and transfer to water bath/analysis did not exceed 30 min.
- Renewal of test solution: No
- Identity and concentration of co-solvent: None
OTHER TEST CONDITIONS
- Adjustment of pH: if necessary prior to test start
- Dissolved oxygen: not measured
Duration of testopen allclose all
Duration:
120 h
pH:
7
Initial conc. measured:
16.5 mg/L
Duration:
120 h
pH:
9
Initial conc. measured:
16.3 mg/L
Duration:
120 h
pH:
4
Initial conc. measured:
14.8 mg/L
Number of replicates:
2 at each sampling interval for immediate analysis and 2 for reanalysis
Positive controls:
no
Negative controls:
yes
Remarks:
Buffer solution (pH value 4, 7 and 9)

Results and discussion

Transformation products:
no
Total recovery of test substance (in %)
% Recovery:
> 94.5
pH:
9
Temp.:
50 °C
Duration:
120 h
Details on results:
TEST CONDITIONS
- pH, sterility, temperature, and other experimental conditions maintained throughout the study: Yes



MAJOR TRANSFORMATION PRODUCTS
At pH5:
- Range of maximum concentrations in % of the applied amount and day(s) of incubation when observed:
- Range of maximum concentrations in % of the applied amount at end of study period:
on the - the and -th day of incubation, respectively. At the end of the study period, the corresponding concentrations were - and -- % of the applied amount, respectively.


At pH7:
- Range of maximum concentrations in % of the applied amount and day(s) of incubation when observed:
- Range of maximum concentrations in % of the applied amount at end of study period:
on the - the and -th day of incubation, respectively. At the end of the study period, the corresponding concentrations were - and -- % of the applied amount, respectively.


At pH9:
- Range of maximum concentrations in % of the applied amount and day(s) of incubation when observed:
- Range of maximum concentrations in % of the applied amount at end of study period:
on the - the and -th day of incubation, respectively. At the end of the study period, the corresponding concentrations were - and -- % of the applied amount, respectively.


MINOR TRANSFORMATION PRODUCTS
Maximum concentrations in % of the applied amount
- at pH5:
- at pH7:
- at pH9:


MINERALISATION (distinguish between dark and irradiated samples)
- % of applied radioactivity present as CO2 at end of study:


INDICATION OF UNSTABLE TRANSFORMATION PRODUCTS:


VOLATILIZATION (at end of study)
- Evolved CO2 in % of the applied: .. at pH 5, .. at pH 7, .. at pH 9
- Total volatile organics in % of the applied: .. at pH 5, .. at pH 7, .. at pH 9


UNIDENTIFIED RADIOACTIVITY (at end of study)
- at pH5:
- at pH7:
- at pH9:


PATHWAYS OF HYDROLYSIS
- Description of pathwayS:
- Figures of chemical structures attached: Yes/No


SUPPLEMENTARY EXPERIMENT (if any): RESULTS:

Any other information on results incl. tables

Hydrolysis Results for Diethylenglykoldimethyletherat pH 4 and 50 °C

Hydrolysis Time

[hours]

Replicate

Concentration

[mg/L]

Mean

Degradation

[%]

0

1

15.4

14.8

-

2

14.1

120

1

15.2

15.5

0.0

2

15.7

Hydrolysis Results for Diethylenglykoldimethyletherat pH 7 and 50 °C

Hydrolysis Time

[hours]

Replicate

Concentration

[mg/L]

Mean

Degradation

[%]

0

1

14.8

16.5

-

2

18.2

120

1

16.1

16.3

1.2

2

16.4

Hydrolysis Results for Diethylenglykoldimethyletherat pH 9 and 50 °C

Hydrolysis Time

[hours]

Replicate

Concentration

[mg/L]

Mean

Degradation

[%]

0

1

16.5

16.3

-

2

16.0

120

1

15.4

15.4

5.5

2

15.4

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 (Table 10). 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.
Degradation [%] of Diethylenglykoldimethylether at 50 °C after 120 Hours

Hydrolysis Time
[hours] Degradation [%]
pH 4 pH 7 pH 9
120 0.0 1.2 5.5
Executive summary:

Hydrolysis as a function of pH was determined according to OECD-Guideline No. 111 (2004) for the test item Diethylenglykoldimethylether(batch number: DEG4071791) from 2010-01-21 to 2010-01-26 at Dr.U.Noack-Laboratorien, 31157 Sarstedt , Germany .

The study was conducted with test item concentrations of 16 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 hours) and test end (120 hours) 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 Diethylenglykoldimethyletherwas validated and tested with satisfactory results in regard to linearity, repeatability of injections, accuracy, precision and specificity.

Degradation 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 hours (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 all test conditions.

Degradation [%] of Diethylenglykoldimethyletherat 50 °C after 120 Hours

Hydrolysis Time

[hours]

Degradation [%]

pH 4

pH 7

pH 9

120

0.0

1.2

5.5