Cesium formate

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1998

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

A) The study was conducted according to OECD Guideline 111. B) Well-defined information were provided on: 1. Compositional information of the test substance 2. Test methods used in the study 3. Description of methodologies 4. Test results 5. Definite conclusion

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

no

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent/transformation products: All samples from control at 5°C, control at 50°C and buffer solutions were analysed for total Formate concentration after 5 days.
- Sampling method: No details available
- Sampling methods for the volatile compounds, if any: Not applicable
- Sampling intervals/times for pH measurements: No data on pH measurements
- Sampling intervals/times for sterility check: Not applicable
- Sample storage conditions before analysis: Samples were immediately analysed after the test period of 5 days.
- Other observation, if any (e.g.: precipitation, color change etc.): None

Buffers:

- pH: 4.0
- Type and final molarity of buffer: No data
- Composition of buffer: 2 mL of 0.1 N NaOH and 250 mL of 0.1 M Potassium Biphthalate were mixed and diluted to 500 mL with sterilised deionised water
- pH: 7.0
- Type and final molarity of buffer: No data
- Composition of buffer: 148.2 mL of 0.1 N NaOH and 250 mL of 0.1 M Monopotassium Phosphate were mixed and diluted to 500 mL with sterilised deionised water
- pH: 9.0
- Type and final molarity of buffer: No data
- Composition of buffer: 106.5 mL of 0.1 N NaOH and 250 mL of 0.1 M H3BO3 in 0.1 M KCl were mixed and diluted to 500 mL with sterilised deionised water

Estimation method (if used):

The pH of the buffer solution is estimated by pH meter

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: 100 mL glass volumetric flasks containing 100 mL of the test solution
- Sterilisation method: Autoclaving
- Measures taken to avoid photolytic effects: The water bath was housed in black plastic covered fume hood to avoid photolytic reaction
- Measures to exclude oxygen: All the flasks were sparged with nitrogen gas for 2 min

Duration:

5 d

pH:

4

Initial conc. measured:

ca. 0.008 mol/L

Duration:

5 d

pH:

7

Initial conc. measured:

ca. 0.008 mol/L

Duration:

5 d

pH:

9

Initial conc. measured:

ca. 0.008 mol/L

Duration:

5 d

Temp.:

5 °C

Initial conc. measured:

0.008 mol/L

Duration:

5 d

Initial conc. measured:

ca. 0.008 mol/L

Number of replicates:

Duplicate

Positive controls:

yes

Remarks:

Flasks (in duplicate) containing test solution diluted with deionised water without buffer were kept at 5°C and 50°C for 5 d

Negative controls:

no

Preliminary study:

The mean final concentration of the test substance solution in the control was 0.0086 M, in the blank test substance solution without buffer at 50 °C was 0.0083 M, and in all three buffered test solutions (pH 4.0, 7.0 and 9.0) was 0.0084 M.

Test performance:

The Formate concentrations in the buffered test solutions at 50 °C were very close to the initially added. The relative differences in the Formate concentrations between the buffered test solutions and the control at 5 °C were less than 3%.

Transformation products:

not specified

Details on hydrolysis and appearance of transformation product(s):

Not applicable

% Recovery:

ca. 97

pH:

4

Temp.:

50 °C

Duration:

ca. 5 d

% Recovery:

ca. 97

pH:

7

Temp.:

50 °C

Duration:

ca. 5 d

% Recovery:

ca. 97

pH:

9

Temp.:

50 °C

Duration:

ca. 5 d

Key result

Remarks on result:

hydrolytically stable based on preliminary test

Details on results:

The Formate concentrations in the buffered test solutions at 50°C were very close to that initially added. The relative differences in the Formate concentrations between the buffered test solutions and the control at 5°C were less than 3%.

Table 1. Final concentrations of Formate in the controls and buffered test solutions after 5 days

Test Condition		Final concentration	Final concentration	Relative to Control at 5°C
		(M)	(M)	%
Control	5°C	0.0084	0.0086	-
		0.0087
Control	50°C	0.0082	0.0083	-3.5
		0.0084
Buffer pH 4.0	50 °C	0.0085	0.0084	-2.3
		0.0083
Buffer pH 7.0	50°C	0.0083	0.0084	-2.3
		0.0085
Buffer pH 9.0	50 °C	0.0084	0.0084	-2.3
		0.0084

Validity criteria fulfilled:

not specified

Remarks:

1. Duplicate buffered test solutions were used. 2. Recovery of test material was within recommended range (90-110 %).

Conclusions:

Under the study conditions the test substance solution was considered to be hydrolytically stable.

Executive summary:

A study was conducted to determine the hydrolytic stability of the test substance solution according to OECD Guideline 111. 0.1 M of the test substance solution was mixed with pH 4.0, 7.0 and 9.0 buffered solutions in duplicate 100 mL volumetric flasks and kept in a light-protected water bath at 50±0.1°C for 5 days. Concurrent controls without buffers were also kept at 50±0.1°C and 5°C for 5 days. All samples were analysed in HPLC for total formate concentration immediately after removal from water bath. The relative differences in the formate concentrations between the buffer pH solutions and the control at 5°C were less than 3%. Under the study conditions the test substance solution was considered to be hydrolytically stable (Gibb, 1998).

Additional information

A study was conducted to determine the hydrolytic stability of the test substance solution according to OECD Guideline 111. 0.1 M of the test substance solution was mixed with pH 4.0, 7.0 and 9.0 buffered solutions in duplicate 100 mL volumetric flasks and kept in a light-protected water bath at 50±0.1°C for 5 days. Concurrent controls without buffers were also kept at 50±0.1°C and 5°C for 5 days. All samples were analysed in HPLC for total formate concentration immediately after removal from water bath. The relative differences in the formate concentrations between the buffer pH solutions and the control at 5°C were less than 3%. Under the study conditions the test substance solution was considered to be hydrolytically stable (Gibb, 1998).