3-(methylthio)propionaldehyde

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

01-11-26 - 02-02-08

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)

Version / remarks:

Cited as Directive 92/69/EEC, C.7

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

no

Analytical monitoring:

yes

Buffers:

- pH: 4
Standard-buffer-solution pH 4. Bernd Kraft GmbH. Art.-No.: 03083.3000

- pH: 7
Standard-buffer-solution pH 7. Bernd Kraft GmbH. Art.-No.: 03086.3000

- pH: 9
Standard-buffer-solution pH 9. Riedel-de Haen. Art.-No.: 33548

Details on test conditions:

TEST SYSTEM (Prelimenary test)
- Type, material and volume of test flasks, other equipment used: HPLC vials
- Measures taken to avoid photolytic effects: vials were protected from light
- If no traps were used, is the test system closed/open: performed in closed HPLC vials

TEST MEDIUM
- Volume used/treatment: 100 mL
- Kind and purity of water: Reagent water generated by the Millipore system "Milli Q"
- Preparation of test medium: Amounts of the test substance were weighed exactly into volumetric flasks (100 mL). The test substance was dissolved and subsequently adjusted to the mark using the corresponding buffer solution.

TEST SYSTEM (Main test)
- Type, material and volume of test flasks, other equipment used: HPLC vials
- Measures taken to avoid photolytic effects: vials were protected from light
- If no traps were used, is the test system closed/open: performed in closed HPLC vials

TEST MEDIUM
- Volume used/treatment: 100 mL
- Kind and purity of water: Reagent water generated by the Millipore system "Milli Q"
- Preparation of test medium: 82.32 mg of the test substance were weighed into a 100 mL volumetric flask and filled up to the mark with standard buffer solution.

Duration:

5 d

pH:

4

Temp.:

50 °C

Initial conc. measured:

759.5 mg/L

Remarks:

Preliminary test

Duration:

5 d

pH:

7

Temp.:

50 °C

Initial conc. measured:

606.5 mg/L

Remarks:

Preliminary test

Duration:

5 d

pH:

9

Temp.:

50 °C

Initial conc. measured:

562.3 mg/L

Remarks:

Preliminary test

Duration:

101 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

782.08 mg/L

Remarks:

Main test

Duration:

5 890 min

pH:

7

Temp.:

55 °C

Initial conc. measured:

624.57 mg/L

Remarks:

Main test

Duration:

3 060 min

pH:

7

Temp.:

65 °C

Initial conc. measured:

645.03 mg/L

Remarks:

Main test

Duration:

580 min

pH:

9

Temp.:

50 °C

Initial conc. measured:

757.19 mg/L

Remarks:

Main test

Duration:

3 055 min

pH:

9

Temp.:

39 °C

Initial conc. measured:

639.21 mg/L

Remarks:

Main test

Number of replicates:

2 replicates

Positive controls:

no

Negative controls:

yes

Preliminary study:

After 5 days less than 10% had been hydrolysed. The determined degradation of the substance at pH 4 and 50 °C corresponded to a half-life time of more than one year under outdoor conditions. The determined half-life at pH 7 and pH 9 at 50 °C was > 2.4 d. Thus, in accordance with EU method C.7, the main test was performed at pH 7 and pH 9 only.

Transformation products:

not measured

% Recovery:

64.44

pH:

7

Temp.:

50 °C

Duration:

101 h

% Recovery:

58.28

pH:

7

Temp.:

55 °C

Duration:

98.17 h

% Recovery:

48.03

pH:

7

Temp.:

65 °C

Duration:

51 h

% Recovery:

31.78

pH:

9

Temp.:

50 °C

Duration:

9.7 h

% Recovery:

20.98

pH:

9

Temp.:

39 °C

Duration:

50.92 h

pH:

4

Temp.:

25 °C

DT50:

> 1 yr

Remarks on result:

other: determined in preliminary test

pH:

7

Temp.:

25 °C

Hydrolysis rate constant:

0 h-1

DT50:

75.4 d

Type:

(pseudo-)first order (= half-life)

Remarks on result:

other: extrapolated from results at 50 - 65 °C

pH:

9

Temp.:

25 °C

Hydrolysis rate constant:

0.004 h-1

DT50:

6.5 d

Type:

(pseudo-)first order (= half-life)

Remarks on result:

other: extrapolated from results at 50 and 39 °C

Details on results:

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

Validity criteria fulfilled:

not applicable

Conclusions:

The half-life time at pH 7 and 25 °C was extrapolated from the measured values at 50, 55 and 65 °C. The half-life time was 1810 h (appr. 75 days).
The half-life time at pH 9 and 25 °C was extrapolated from the measured values at 50 and 39 °C. The half-life time was 156 h (appr. 6.5 days).

Description of key information

DT50: appr. 75 days at pH 7 and 25 °C

Key value for chemical safety assessment

Half-life for hydrolysis:

75 d

at the temperature of:

25 °C

Additional information

The hydrolysis of the substance was tested in a study following Directive 92/69/EEC, C.7 (GLP). A preliminary test was set up testing the hydrolysis at pH 4, 7 and 9 at a temperature of 50 °C. An extrapolation of the results for pH 4 and 50 °C resulted in a half-life > 1 year under environmentally relevant conditions. The determined half-life at pH 7 and pH 9 at 50 °C was > 2.4 days. Thus, in accordance with EU method C.7, the main test was performed at pH 7 (50, 55 and 65 °C ) and pH 9 (50 °C, 39 °C) only.  From the results in the main test a half-life of appr. 75 days was extrapolated for pH 7 and 25 °C. For pH 9 and 25 °C a half-life of appr. 6.5 days was extrapolated.