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Environmental fate & pathways

Hydrolysis

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Administrative data

Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
November 17, 2009 - November 19, 2009
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: guideline study conducted under GLP compliance with acceptable restriction

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report date:
2009

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 111 (Hydrolysis as a Function of pH)
GLP compliance:
yes

Test material

Constituent 1
Reference substance name:
MeDONA
IUPAC Name:
MeDONA
Details on test material:
- Name of test material (as cited in study report): MeDONA
- Substance type: single-constituent substance
- Physical state: Clear and colorless liquid
- Analytical purity: 98.9%
- Purity test date: 2/17/2009
- Lot/batch No.::NB 140499-21-8
- Expiration date of the lot/batch :08/25/2014
- Stability under test conditions: Stable
- Storage condition of test material: Frozen
Radiolabelling:
no

Study design

Analytical monitoring:
yes
Details on sampling:
- Sampling intervals for the parent products: Five sampling times for MeDONA in pure water were 18, 23, 27, 32, and 38 minutes. Three sampling times for MeDONA at 397 ppb in pH 2 water were 18, 52, and 87 minutes; Six sampling times for MeDONA at 510 ppb in pH 2 water were 19, 52, 87, 121,156, and 189 minutes,
- Sampling method: inject into GC/MS
- Sampling methods for the volatile compounds, if any: none
- Sampling intervals/times for pH measurements: same as sampling interval for the parent products;
- Sampling intervals/times for sterility check: none
- Sample storage conditions before analysis: no storage
Buffers:
- pH: 2, and unbuffered milli-Q water
- Type and final molarity of buffer: not given
- Composition of buffer: not given
Details on test conditions:
TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: 42 mL vial
- Sterilisation method: None
- Lighting: None
- Measures taken to avoid photolytic effects: None
- Measures to exclude oxygen: None
- Details on test procedure for unstable compounds: None
- Details of traps for volatile, if any: vials were sealed.
- If no traps were used, is the test system closed/open: closed
- Is there any indication of the test material adsorbing to the walls of the test apparatus? not reported

TEST MEDIUM
- Volume used/treatment; 42 mL
- Kind and purity of water: Milli-Q water (18.2 MΩ-cm)
- Preparation of test medium: None.
- Renewal of test solution: None
- Identity and concentration of co-solvent: Acetone

OTHER TEST CONDITIONS
- Adjustment of pH:
- Dissolved oxygen:
Duration of test
Duration:
38 min
Initial conc. measured:
510 ng/L
Number of replicates:
5

Results and discussion

Transformation products:
yes
Identity of transformation products
No.:
#1
Reference
Reference substance name:
Unnamed
IUPAC name:
DONA
Identifier:
other: Short name
Identity:
DONA
Details on hydrolysis and appearance of transformation product(s):
- Formation and decline of each transformation product during test: The test substance MeDONA hydrolyzes to the protonated acid form of DONA.
- Pathways for transformation: CF3OCF2CF2CF2OCFHCF2CO2CH3 + H2O -----> CF3OCF2CF2CF2OCFHCF2CO2H
- Other:
Dissipation DT50 of parent compound
pH:
7
DT50:
>= 1.05 - <= 4.31 min
Type:
(pseudo-)first order (= half-life)
Remarks on result:
other: T1/2 = 0.693/kh where kh = 0.2582 derives from y=0.2582t - 1.1614, R^2 =0.9744 where y = - ln[MeDONA]t/[MeDONA]0
Details on results:
Five samples of MeDONA at about 510 ppb were prepared by spiking 18 µL of MeDONA in acetone into 42 mL of pure water in test vial. The samples were analyzed at 18, 23, 27, 32, and 38 minutes by GC/MS. The hydrolysis half-life was so fast that only three samples were above the LOQ (Table 1). A plot of - In[MeDONA]t/[MeDONA]0 versus time shown in Figure 1. The linearity of the curve was acceptable (R^2 = 0.9744) and kh was determined to be 0.2582. Using the relationship T1/2 = 0.693/kh, the half life of MeDONA in pure water was determined to be 2.68 ±1.63 minutes.

Three samples of MeDONA at 397 ppb in pH 2 water were prepared and analyzed at 18, 52, and 87 minutes; six samples of MeDONA at 510 ppb in pH 2 water were analyzed at 19, 52, 87, 121,156, and 189 minutes. A plot of - In[MeDONA]t/[MeDONA]0 versus time shown in Figure 2. The linearity at the curve was excellent (R^2 = 0.9988) and kh was determined to be 0.0132. Using the relationship T1/2 = O.693/kh , the half life at pH 2 was determined to be 52.50 ± 1.99 minutes.

Any other information on results incl. tables

pH

Time (min)

Initial concentration C0 (ppb)

Concentration at sampling time

Ct (ppb)

-ln(Ct/C0)

Neutral

18

510

17.198

3.38962926

23

510

3.455

4.99472721

27

510

1.725

5.68929383

32

510

<LOQ

 

38

510

<LOQ

 

 

 

 

 

 

2

18

397

425.84

-0.070118

52

397

273.34

0.37320886

87

397

160.78

0.90387443

18

510

500.08

0.01963664

52

510

329.83

0.43582729

87

510

211.64

0.87953818

121

510

134.72

1.33123444

156

510

86.07

1.77997855

189

510

55.031

2.2265177

Applicant's summary and conclusion

Conclusions:
The half-life of MeDONA in pure water and ambient temperature was determined to be 2.68 ± 1.63 minutes.
Executive summary:

About 510 ppb of MeDONA was suspended into unbuffered water at ambient temperature. The quantity of MeDONA was measured from 18 - 38 minutes using GC/MS. In addition, about 397 ppb and 510 ppb of MeDONA were suspended in pH 2 water, and the quantity of MeDONA was measured from 18 -189 minutes. The hydrolysis was measured by the disappearance of parent compound MeDONA. The results showed hydrolysis of MeDONA to form DONA with a half-life of 2.68 ± 1.63 minutes in pure water (laboratory grade 18.2 MΩ water), and 52.5 ± 1.99 minutes at pH 2 water. This is a guideline study conducted under GLP. A rather large error occurs in the half-life, due to the limited number of data points. However, the measured half-life was far less than the regulatory guidance of 1 hour. Therefore, it is considered to be reliable with acceptable restriction.