4,4'-[2,2,2-trifluoro-1-(trifluoromethyl)ethylidene]diphenol; bisphenol AF

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11 August 2017 - 11 December 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Study was conducted in accordance with international guidelines and in accordance with GLP. All guideline validity criteria were met.

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Regulation (EC) 440/2008 of 30 May 2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Version / remarks:

13 April 2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent/transformation products:
- Sampling method:
At each sampling time 2 mL acetonitrile were added through the septum (dilution factor 2) using a Hamilton syringe. The samples were homogenised by shaking. Two vials were prepared for each pH and each sampling date.


- Sampling methods for the volatile compounds, if any:
Not applicable


- Sampling intervals/times for pH measurements:
120 hours.


- Sampling intervals/times for sterility check:
Not applicable.


- Sample storage conditions before analysis:
The samples taken at t0 hours were stored deep frozen (≤ - 18 °C) until the sampling date after 5 days. The nominal content of the test item in the measuring solution was 50 mg/L.


- Other observation, if any (e.g.: precipitation, color change etc.):
Not applicable.

Buffers:

- pH: 4
- Type and final molarity of buffer: citrate buffer, 0.05 M
- Composition of buffer: Per 2 L ultra-pure grade water, 21.018 g citric acid monohydrate and 117 mL of sodium hydroxide solution (1 M) was added to reach pH 4.


- pH: 7
- Type and final molarity of buffer: phosphate buffer, 0.05 M
- Composition of buffer: Per 2 L ultra-pure grade water 13.612 g Potassium dihydrogenphosphate and 57 mL of sodium hydroxide solution (1 M) was added to reach pH 7.


- pH: 9
- Type and final molarity of buffer: borate buffer, 0.05 M
- Composition of buffer: Per 2 L ultra-pure grade water 6.186 g boric acid, 7.453 g potassium chloride and 42 mL of sodium hydroxide solution (1 M) was added to reach pH 9.


The pH values of the buffer solutions used during the test were determined with a calibrated pH meter with a precision of 0.01 pH units.

Estimation method (if used):

Not applicable.

Duration:

120 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

>= 98.5 - <= 99.8 mg/L

Remarks:

Mean Determined Content of the test item in Sample = 99.2 mg/l

Duration:

120 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

>= 97 - <= 99 mg/L

Remarks:

Mean Determined Content of the test item in Sample = 97.5 mg/l

Duration:

120 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

>= 100 - <= 100.2 mg/L

Remarks:

Mean Determined Content of the test item in Sample = 100.1 mg/l

Number of replicates:

Two replicates of each preliminary test were performed at pH 4, 7 and 9.

Positive controls:

no

Negative controls:

no

Preliminary study:

The hydrolysis of the test item is negligible at pH 4, pH 7 and pH 9. The degradation of the test item was less than 10 % at pH 4, pH 7 and pH 9 at 50 °C over a period of 120 hours. Therefore, the corresponding half-life time can be estimated to be longer than one year at 25 °C.

Test performance:

A main test was not performed due to negligible hydrolysis of the test item of the test item during the preliminary test.

Transformation products:

not measured

Remarks:

No main test was conducted.

Key result

Remarks on result:

hydrolytically stable based on preliminary test

Preliminary Test (Tier 1):

The time courses of the test item concentration at 50 °C and three different pH values were determined. The determined temperatures during the entire period of the test were in the range of 50.0 °C ± 0.5 °C. Two samples were taken at each pH and each sampling date.

 

Samples were taken at the beginning of the test and after 120 hours at pH 4, pH 7 and pH 9. The concentrations in buffer solutions were determined by HPLC-UV analysis. At pH 4, pH 7 and pH 9 less than 10 % of the test item were hydrolysed within 120 hours at 50 °C.

 

Table 2:          Time course of test item concentration at pH 4 at 50 °C

Time (h)	pH value	Determined Content of Test Item in Sample (mg/l).*	Mean Determined Content of Test Item in Sample (mg/l)	Actual concentration in % of initial concentration
0	4.04	98.5	99.2	100.0
		99.8
120	4.02	98.1	98.3	99.1
		98.4

*Dilution factor of 2.

 

 

Table 3:          Time course of test item concentration at pH 7 at 50 °C

Time (h)	pH value	Determined Content of Test Item in Sample (mg/l).*	Mean Determined Content of Test Item in Sample (mg/l)	Actual concentration in % of initial concentration
0	7.05	97.0	97.5	100.0
		98.0
120	7.06	97.4	97.4	99.9
		97.4

*Dilution factor of 2.

 

 

Table 4:          Time course of test item concentration at pH 9 at 50 °C

Time (h)	pH value	Determined Content of Test Item in Sample (mg/l).*	Mean Determined Content of Test Item in Sample (mg/l)	Actual concentration in % of initial concentration
0	9.06	100.0	100.1	100.0
		100.2
120	9.05	99.7	99.6	99.5
		99.5

*Dilution factor of 2.

 

 

Main Test (Tier 2):

No main test was performed due to negligible hydrolysis of the test item of the test item during the preliminary test.

 

 

Validity criteria fulfilled:

yes

Remarks:

Recoveries was from 90 to 110% in mixed buffer solution and the relative standard deviation was <20%. Repeatability of the analytical method was checked by duplicate analysis of the same buffer solutions. The analytical method was sufficiently sensitive.

Conclusions:

The estimated half life of the test item is > 1 year at 25 °C.

Executive summary:

EU Method C.7. –  The hydrolysis of the test item as a function of pH was determined using a procedure designed to be compatible with Method C.7., Degradation - Abiotic Degradation: Hydrolysis as a Function of pH, of Commission Regulation (EC) No 440/2008 of 30 May 2008.

 

At three pHs, standard solutions of test item were prepared using sterilised citrate (pH 4), phosphate (pH 7) and borate (pH 9) buffer solutions (all 0.05 M).  Under an inert (argon) atmosphere, aliquots of each solution were transferred into 6 mL vials and sealed.  Two vials were prepared for each pH and each sampling point (t0 h and t120 h).  Samples taken at t0 were stored deep frozen (≤ - 18 °C) until the sampling date after 5 days.  The test item concentration of these samples was determined using HPLC-UV and a method validated according to guideline SANCO/3029/99 rev. 4.

 

The hydrolysis of the test item was negligible (< 10 %) at pH 4, pH 7 and pH 9. Therefore, the half-life of test item was estimated to be longer than one year at 25 °C.

Description of key information

Hydrolysis: Half-life > 1 year at 25.0°C; EU Method C.7.; C Bär (2017)

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C

Additional information

EU Method C.7. –  The hydrolysis of the test item as a function of pH was determined using a procedure designed to be compatible with Method C.7., Degradation - Abiotic Degradation: Hydrolysis as a Function of pH, of Commission Regulation (EC) No 440/2008 of 30 May 2008.

 

At three pHs, standard solutions of test item were prepared using sterilised citrate (pH 4), phosphate (pH 7) and borate (pH 9) buffer solutions (all 0.05 M).  Under an inert (argon) atmosphere, aliquots of each solution were transferred into 6 mL vials and sealed.  Two vials were prepared for each pH and each sampling point (t0 h and t120 h).  Samples taken at t0 h were stored deep frozen (≤ - 18 °C) until the sampling date after 5 days.  The test item concentration of these samples was determined using HPLC-UV and a method validated according to guideline SANCO/3029/99 rev. 4.

 

The hydrolysis of the test item was negligible (< 10 %) at pH 4, pH 7 and pH 9. Therefore, the half-life of test item was estimated to be longer than one year at 25 °C.