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Hydrolysis

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Reference
Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 11 sept 2012 to 22 jan 2013
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 111 (Hydrolysis as a Function of pH)
Deviations:
no
GLP compliance:
yes
Radiolabelling:
no
Analytical monitoring:
yes
Details on sampling:
Analysis of the test solutions for trifluoromethanesulfonic acid concentration was performed on days 0, 1 and 5.
The pH of the test solutions was measured on test day 0 (before and after dosing) and day 5.
The Quality Control samples were freshly prepared on days 1 and 5 and were analyzed along with the test samples.
Buffers:
pH 4.0:
180 mL of a 0.01 M sodium acetate solution (0.6806 g of sodium acetate trihydrate dissolved and brought to a volume of 500 mL with purified reagent water) was combined with 820 mL of a 0.01 M acetic acid solution (0.576 mL of acetic acid brought to a volume of 1000 mL with purified reagent water) for a final total volume of 1000 mL. The pH of the resulting solution was 4.01 and required no adjustment.

pH 7.0:
195 mL of a 0.02 M sodium phosphate monobasic solution (1.5608 g of sodium phosphate monobasic dihydrate dissolved and brought to a volume of 500 mL with purified reagent water) was combined with 305 mL of a 0.02 M sodium phosphate dibasic solution (1.7888 g of sodium phosphate dibasic dihydrate dissolved and brought to a volume of 500 mL with purified reagent water) and brought to a final volume of 1000 mL with purified reagent water. The pH of the resulting solution was 7.06 and required no adjustment.

pH 9.0:
20 mL of a 0.5 M boric acid solution (3.1059 g of boric acid dissolved and brought to a volume of 100 mL with purified reagent water) was brought to a final volume of 1000 mL with purified reagent water. The pH of the resulting solution was adjusted to 9.01 with 1N sodium hydroxide.

Buffers were autoclaved in a Consolidated autoclave (Model SSR-3A-E, S.N. 072710) at approximately 121°C at 15 psi for 50 minutes. Prior to dosing, the buffer solutions were purged with sterile nitrogen for approximately 5 minutes to exclude oxygen. The pH of the sterile, nitrogen purged buffer solutions was verified to be 4.0 ± 0.1, 7.0 ± 0.1 and 9.0 ± 0.1 prior to dosing.

The sterility of the prepared buffer solutions was confirmed on day 0 and on days 0 and 5 for the hydrolysis samples. Sterility was evaluated using 3M Petrifilm Aerobic Count Plates. A 0.5-mL aliquot of each dosed sample was pipetted onto the center of the bottom film and spread using a spreader. Plates were incubated at room temperature for at least 48 hours and then observed for microbial growth on days 0 and 5. Plates were interpreted as positive, indicating the presence of microbial growth, or as negative, indicating the absence of microbial colony formation
Details on test conditions:
Individual 10-mL amber vials (10 vials per buffer solution) were filled with 10 mL of the appropriate buffer solution (i.e., pH 4.0, 7.0 or 9.0). To each 10-mL vial was added 60 µL of the 5.00 mg/mL primary stock solution to provide a nominal concentration of 30 mg/L. After being flushed with a sterile nitrogen stream for 10 seconds, the vials were capped with aluminum crimp caps fitted with Teflon®-lined rubber septa and vortexed for 20 seconds. The vials were placed in a water bath with cover (dark condition) designed to maintain a temperature of 50.0 +/- 0.5°C for a period of 5 days. Analysis of the test solutions for trifluoromethanesulfonic acid concentration was performed on days 0, 1 and 5.

At each sampling interval, duplicate samples for each pH were removed from the water bath, cooled under tap water, vortexed for 20 seconds and then transferred into 15-mL plastic test tubes prior to IC analysis.

Preparation of Calibration Standards
Calibration standards (1.50, 2.50, 5.00, 10.0, 20.0 and 35.0 mg/L) were prepared in purified reagent water. The 1.50, 2.50 and 5.00 mg/L calibration standards were prepared by dosing purified reagent water with 15, 25 and 50 µL, respectively, of the 1.00 mg/mL secondary stock solution. The 10.0, 20.0 and 35.0 mg/L calibration standards were prepared by dosing purified reagent water with 20, 40 and 70 µL, respectively, of the 5.00 mg/mL primary stock solution. All calibration standards were diluted to a final volume of 10 mL in volumetric flasks and then transferred into 15-mL plastic test tubes. The standards were analyzed by ion chromatography (IC) with suppressed conductivity detection.
Duration:
5 d
Temp.:
25 °C
Initial conc. measured:
30 mg/L
Number of replicates:
2
Positive controls:
no
Negative controls:
no
Preliminary study:
Less than 10% degradation of trifluoromethanesulfonic acid was observed after 5 days incubation at 50.0  0.5 C in sterile pH 4.0, pH 7.0 and pH 9.0 buffer samples. The test substance was considered to be hydrolytically stable (estimated half-life greater than 1 year at 25 °C) and no additional testing was performed.
Transformation products:
no
Key result
Remarks on result:
hydrolytically stable based on preliminary test
Details on results:
The temperature of the water bath used to control the temperature of the test solutions ranged from 49.7ºC to 50.1ºC. Measurements of pH recorded in the test solutions showed that the buffering capacity had not been decreased.

The hydrolysis was performed in pH 4.0, pH 7.0 and pH 9.0 sterile aqueous buffer solutions at an application rate of 30 mg/L (30 ppm). At selected intervals (days 0, 1 and 5), duplicate samples were analyzed by ion chromatography (IC) with suppressed conductivity detection to quantify the test substance present in the aqueous samples.

Less than 10% degradation of trifluoromethanesulfonic acid was observed after 5 days incubation at 50.0  0.5 C in sterile pH 4.0, pH 7.0 and pH 9.0 buffer samples. The test substance was considered to be hydrolytically stable (estimated half-life greater than 1 year at 25 °C) and no additional testing was performed.

Analysis of QC samples resulted in measured concentrations that were consistent with the acceptable range. Based on these results, it was established that the appropriate precision and quality control was maintained during the analysis of the test solutions.

Concentrations of trifluoromethanesulfonic acid measured in the test and QC samples at 50 ºC during the hydrolysis test.

Sample

Target Concentration (mg/L)

Response

(Area)

Concentration (mg/L)

Recovery

(% of Nominal)

 pH 4 buffer

 

 

 

 

Day 0

30.0

199.23

28.38

94.60

Day 0

30.0

203.11

28.92

96.42

 

 

 

Average

95.51

Day 1

30.0

195.24

27.82

92.72

Day 1

30.0

188.01

26.80

89.32

 

 

 

Average

91.02

Day 5

30.0

194.09

27.65

92.18

Day 5

30.0

198.10

28.22

94.06

 

 

 

Average

93.12

 pH 7 buffer

 

 

 

 

Day 0

30.0

196.70

28.02

93.40

Day 0

30.0

201.88

28.75

95.84

 

 

 

Average

94.62

Day 1

30.0

198.83

28.32

94.41

Day 1

30.0

193.11

27.51

91.72

 

 

 

Average

93.06

Day 5

30.0

189.02

26.94

89.79

Day 5

30.0

195.90

27.91

93.03

 

 

 

Average

91.41

 pH 9 buffer

 

 

 

 

Day 0

30.0

206.63

29.42

98.07

Day 0

30.0

211.73

30.14

100.47

 

 

 

Average

99.27

Day 1

30.0

205.35

29.24

97.47

Day 1

30.0

204.31

29.10

96.98

 

 

 

Average

97.23

Day 5

30.0

198.02

28.21

94.03

Day 5

30.0

197.13

28.08

93.60

 

 

 

Average

93.82

 QC sample

 

 

 

 

Day 1

30.0

199.85

28.47

94.89

Day 1

30.0

196.51

28.00

93.32

Day 5

30.0

198.52

28.28

94.26

Day 5

30.0

191.39

27.27

90.91

 

Validity criteria fulfilled:
yes
Conclusions:
Less than 10% degradation of the test substance was observed after 5 days (half-life is estimated to be greater than 1 year at 25 °C) in the sterile pH 4.0, pH 7.0 and pH 9.0 buffer samples. The test substance was considered to be hydrolytically stable at pH 4.0, 7.0 and 9.0 .
Executive summary:

The hydrolysis of trifluoromethanesulfonic acid was studied in accordance with the OECD Testing Guideline 111 and under the GLP. The samples were incubated for 5 days at 50±0.5°C at pH 4.0, pH 7.0 and pH 9.0 sterile aqueous buffer solutions at a nominal concentration of 30.0 mg/L in dark conditions. At selected intervals, duplicate samples were analyzed by ion chromatography (IC) with suppressed conductivity detection to quantify the test substance present in the aqueous samples.

Less than 10% degradation of the test substance was observed after 5 days (half-life is estimate to be greater than 1 year at 25 °C) in the sterile pH 4.0, pH 7.0 and pH 9.0 buffer samples. The test substance was considered to be hydrolytically stable at pH 4.0, 7.0 and 9.0 and no additional testing was required or performed. 

Description of key information

Trifluoromethanesulfonic acid was found to be stable in an OECD TG 111 study. 

Key value for chemical safety assessment

Half-life for hydrolysis:
1 yr
at the temperature of:
25 °C

Additional information

The hydrolysis of trifluoromethanesulfonic acid was studied in accordance with the OECD Testing Guideline 111 and under the GLP. The samples were incubated for 5 days at 50±0.5°C at pH 4.0, pH 7.0 and pH 9.0 sterile aqueous buffer solutions at a nominal concentration of 30.0 mg/L in dark conditions. At selected intervals, duplicate samples were analyzed by ion chromatography (IC) with suppressed conductivity detection to quantify the test substance present in the aqueous samples.

Less than 10% degradation of the test substance was observed after 5 days (half-life is estimate to be greater than 1 year at 25 °C) in the sterile pH 4.0, pH 7.0 and pH 9.0 buffer samples. The test substance was considered to be hydrolytically stable at pH 4.0, 7.0 and 9.0 and no additional testing was required or performed.