Acetic acid, 2,2-difluoro-2-[[2,2,4,5-tetrafluoro-5-(trifluoromethoxy)-1,3-dioxolan-4-yl]oxy]-, ammonium salt (1:1)

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2011-10-13 until 2011-11-04

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)

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Name of test material (as cited in study report): cyclic C6O4 - NH4 Salt
Appearance: liquid, pale amber – yellowish brown, clear
Batch no. 3ac3EV
Expiry date: 2013-12-31
Recommended storage: 18 ± 4°C, humidity < 65%
Storage at test facility: Room temperature, protected from light in the original container
Retention of test item: At least 1g was retained and stored at 6 ± 2°C

Radiolabelling:

no

Analytical monitoring:

yes

Buffers:

Sterile buffer solution at pH 4,7 and 9
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: 296.3 mL of 0.1 mol /L NaOH were mixed with 500 mL 0.1 mol/L KH2PO4 and diluted to 1000 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.
Buffers were prepared, purged with nitrogen for 5 minutes and the pH was checked. Afterwards the buffer solutions were sterilised by filtration through 0.20 um.

Details on test conditions:

Preliminary test: 1 mg of active ingredient/L in buffer solution at pH 4, 7, 9.

Type, material and volume of test flasks, other equipment used: 4 mL amber HPLC vials
Incubation: 120 h
Temperature: 50 +/- 0.5 °C
Lighting: photolytic effects were avoided by using amber vials
Measurements : all samples were diluted with methanol: HPLC/water 50:50 + 5mM NH4COOH and 0.1% formic acid (dilution factor 1:25) before analysis.
Application: the respective sterile buffer solution were spiked to 100ug active ingredient/L with the test item stock solution and filled into the test containers for the 120h sampling, sealed and transferred into the thermostat. The time between test item application and transfer to laboratory incubator/analysis did not exceed 30 min.

Samples were taken at 0h and after 120h. All samples were diluted with methanol: HPLC-water 50:50 + 5 mM NH4COOH and 0.1% formic acid before analysis. All test item containing samples were analysed immediately via LC-MS/MMS.

Duration:

120 h

Temp.:

50 °C

Initial conc. measured:

1 mg/L

Number of replicates:

2 replications

Positive controls:

no

Negative controls:

yes

Remarks:

buffer solutions (pH value 4, 7 and 9)

Preliminary study:

The test item was found to be stable at pH 4, 7 and 9 respectively.

Transformation products:

not specified

% Recovery:

90.4

pH:

4

Temp.:

50 °C

Duration:

120 h

% Recovery:

93.8

pH:

7

Temp.:

50 °C

Duration:

120 h

% Recovery:

100

pH:

9

Temp.:

50 °C

Duration:

120 h

Key result

pH:

4

Temp.:

50 °C

Remarks on result:

hydrolytically stable based on preliminary test

Key result

pH:

7

Temp.:

50 °C

Remarks on result:

hydrolytically stable based on preliminary test

Key result

pH:

9

Temp.:

50 °C

Remarks on result:

hydrolytically stable based on preliminary test

Details on results:

Degradation was calculated as the percentage loss of the test item over the time.
No further testing was deemed necessary as less than 10% of the applied test item were transformed after 120 hrs at each of the three pH values (preliminary study).
Reaction rate constants and half lifes could not be calculated because the test item undergoes no significant hydrolysis. A half life of >1 year could be assumed for ambient temperature conditions in the tested pH range.

Hydrolysis Results for cyclic C6O4-NH4 Salt at pH 4 and 50°C

Hydrolysis Time (hours)	Replicate	Concentration (µg/L)	Mean (µg/L)	Degradation (%)
0	1	1085	1088	-
	2	1090
120	1	966	984	9.6
	2	1002

Hydrolysis Results for cyclic C6O4-NH4 Salt at pH 7 and 50°C

Hydrolysis Time (hours)	Replicate	Concentration (µg/L)	Mean (µg/L)	Degradation (%)
0	1	1058	1075	-
	2	1091
120	1	1030	1008	6.2
	2	986

Hydrolysis Results for cyclic C6O4-NH4 Salt at pH 9 and 50°C

Hydrolysis Time (hours)	Replicate	Concentration (µg/L)	Mean (µg/L)	Degradation (%)
0	1	1029	1004	-
	2	979
120	1	1043	1024	0.0
	2	1005

Validity criteria fulfilled:

yes

Conclusions:

The test item was found to be stable at pH 4, 7 and 9 at 50°C as less of 10% of the applied test item were transformed after 120 h. Reaction rate constants and half-life could not be calculated because the test item undergoes no significant hydrolysis. An half-life of > 1 year could be assumed for ambient temperature conditions in the tested pH range.

Executive summary:

According to OECD-guideline no.111 and Council Regulation (EC) no.440/2008, Method C.7 the study was conducted with test item concentrations of 1 mg active ingredient/L in buffer solutions at pH 4, 7 and 9 at a test temperature of 50°C (preliminary test), analysed with LC-MS/MS on a reversed-phase column in gradient mode using an external standard.

The test item was found to be stable in the preliminary test at pH 4, 7 and 9 at 50°C. No further testing was deemed necessary as less than 10% of the applied test item were transformed after 120 hrs at each of the three pH values. Reaction rate constants and half lives could not be calculated due to the fact that the test item undergoes no significant hydrolysis. With regard to the guideline a half-life of > 1 year could be assumed.

Description of key information

The hydrolysis as function of pH was determined according to OECD TG No.111 and Council Regulation (EC) no.440/2008, Method C.7. The preliminary test was conducted under GLP without deviations with test item concentration of 1 mg of active ingredient/L in buffer solution at pH 4, 7, 9 at temperature of 50°C.

Since the test item was found to be stable in the preliminary test (less than 10% of the applied test item was transformed after 120 hrs at each of the three pH values), no further testing was deemed necessary.

Reaction rate constants and half lives could not be calculated due to the fact that the test item undergoes no significant hydrolysis. According to the OECD TG No. 111 a half-life of > 1 year is assumed.