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Environmental fate & pathways

Hydrolysis

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Reference
Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2nd October to 13th November, 2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study performed according to OECD Guidelines and with GLP compliance
Reason / purpose:
reference to same study
Qualifier:
according to
Guideline:
OECD Guideline 111 (Hydrolysis as a Function of pH)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Radiolabelling:
no
Analytical monitoring:
yes
Details on sampling:
At the begining gof the test and after five days (=120 hours), samples of each test vessel are analysed and the areas resp. the amounts of the test item are compared.
Samples were measured directly after sampling. Filtration was not necessary as the solutions in all incubation vials were clear.
Buffers:
Deionised water was used for the solution of the test item and for the preparation of the buffer solutions.
Composition was taken from the annex of the OECD method (buffer solutions pH 7 and pH 9) resp. Küster et al. (buffer solution pH 4). All chemicals used were of analytical grade. The pH was measured with a pH-meter with an uncertainty of 0.01 units and pH was ad-justed to the nominal pH value ± 0.02 units :
- Acetic acid, 2-m
- Buffer-Solution, pH 4
- Potassium dihydrogenphosphate
- Sodiumhydroxide solution, 0.1-m
- Buffer-Solution, pH 7
- Boric acid
- Potassium chloride
- Buffer-Solution, pH 9
- Argon, free form O2
Estimation method (if used):
Concentrations were calculated as follows
Cm = (Area - Intercept) / Slope
with
cm = measured concentration
Area = measured area by UVD
Slope and Intercept are the coefficients of the calibration function.
All measured concentrations cm were multiplied by the dilution factor, which is always 100, and the correction factor, given by the measured standards.
C = Cm x 100 x Sr / Sm
with
C = corrected concentration
sr = nominal concentration of standard
sm = measured concentration of standard
Details on test conditions:
For tier 1, a solution of the test item was prepared by dissolving 80 mg test item in 100 mL demineralised water (resulting concentration 800 mg/L). This solution was mixed 1:1 with the appropriate buffer solution, giving a concentration of 400 mg/L.
The hydrolysis solutions were sterile filtrated into sterile HPLC vials using 0.2 µm sterile syringe filters. The tubes then were purged with sterile argon to remove oxygen. The tubes were closed using teflon seals. Three replicates for each pH value were incubated at 50 °C and one aliquot was analysed directly after sterile filtration.
At the 120 h sampling time point, the incubation vials were opened and recapped with an HPLC autosampler cap.
Duration:
5 d
pH:
4
Initial conc. measured:
400 mg/L
Duration:
5 d
pH:
7
Initial conc. measured:
400 mg/L
Duration:
5 d
pH:
9
Initial conc. measured:
400 mg/L
Number of replicates:
Three replicates for each pH value were incubated at 50 °C and one aliquot was analysed directly after sterile filtration
Positive controls:
no
Negative controls:
no
Preliminary study:
After five days (120 hours), the concentrations of the test item lay slightly above 100% of the nominal start concentration at all three pH values. The test item can be regarded as hydrolytically stable. Performance of tier 2 is therefore not required.
At pHs 4, 7 and 9, no signs of hydrolysis were observed in tier 1. Therefore, the test item can be considered as hydrolytically stable at these pH values.
Transformation products:
not measured
% Recovery:
102.9
pH:
4
Temp.:
50 °C
Duration:
5 d
% Recovery:
101.8
pH:
7
Temp.:
50 °C
Duration:
5 d
% Recovery:
101.3
pH:
9
Temp.:
50 °C
Duration:
5 d
Remarks on result:
hydrolytically stable based on preliminary test

Measured concentrations Tier 1:

Standards

 

 

 

 

Hours

Nominal Concentration crin mg/L

Measured Concentration cmin mg/L

sr/sm

 

0

200

201.00

1.0050

 

120

200

201.72

1.0086

 

pH

4.00

 

 

 

Hours

Nominal Concentration crin mg/L

Mean[abdeh1] Measured Concentration cmin mg/L

Residue in %

Increase in %

0

400

395.67

 

 

120

400

407.23

102.9%

+ 2.9 %

pH

7.00

 

 

 

 Hours

Nominal Concentration crin mg/L

Mean Measured Concentration cmin mg/L

Residue in %

Increase in %

0

400

400.00

 

 

120

400

407.08

101.8% %

+ 1.8 %

pH

9.01

 

 

 

 Hours

Nominal Concentration crin mg/L

Mean Measured Concentration cmin mg/L

Residue in %

Increase in %

0

400

402.00

 

 

120

400

407.07

101.3%

+ 1.3 %

Validity criteria fulfilled:
yes
Conclusions:
At the three ph tested (4, 7 and 9), no degradation of the Reaction mass of N-[2-(2-Oxoimidazolidin-1-yl)ethyl]methacrylamide and methacrylic acid was observed. The test item can be regarded as hydrolytically stable.
Executive summary:

The determination of hydrolysis was carried out according to OECD Guideline 111 and EU Method C7 (Abiotic Degradation, Hydrolysis as a function of pH). A deviation from the study plan was observed on not washed Argon (used to remove oxygen), but was stated as uncritical. No deviation from the guideline was observed.

The test system uses sterile buffer solutions at pH 4.0, 7.0 and 9.0. The test item Reaction mass of N-[2-(2-Oxoimidazolidin-1-yl)ethyl]methacrylamide and methacrylic acid was dissolved in an aqueous solution at specific pH value and was determined as a function of time, using HPLC-UV validated method. No degradations were observed at three differents pH (recovery ca 100%). Therefore, the test item can be regarded as hydrolytically stable. The estimated half-life at 25°C at differents pH has been shown to be greater than one year.

Description of key information

At the three pH tested (4, 7 and 9), no degradation of the Reaction mass of N-[2-(2-Oxoimidazolidin-1-yl)ethyl]methacrylamide and methacrylic acid was observed. The test item can be regarded as hydrolytically stable.

Key value for chemical safety assessment

Half-life for hydrolysis:
1 yr
at the temperature of:
50 °C

Additional information

The determination of hydrolysis was carried out according to OECD Guideline 111 and EU Method C7 (Abiotic Degradation, Hydrolysis as a function of pH). A deviation from the study plan was observed on not washed Argon (used to remove oxygen), but was stated as uncritical. No deviation from the guideline was observed.

The test system uses sterile buffer solutions at pH 4.0, 7.0 and 9.0. The test item Reaction mass of N-[2-(2-Oxoimidazolidin-1-yl)ethyl]methacrylamide and methacrylic acid was dissolved in an aqueous solution at specific pH value and was determined as a function of time, using HPLC-UV validated method. No degradations were observed at three differents pH (recovery ca 100%). Therefore, the test item can be regarded as hydrolytically stable. The estimated half-life at 25°C at differents pH has been shown to be greater than one year.