Sodium hydrogen m-sulphonatobenzoate

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

31. May 2008

Deviations:

yes

Remarks:

The temperature range 50 ± 0.5 °C was not held during the incubation phase. This was considered uncritical because the deviation of the average temperature was small, and the test item showed no signs of degradation at all three pH values.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Version / remarks:

13. Apr. 2004

Deviations:

yes

Remarks:

The temperature range 50 ± 0.5 °C was not held during the incubation phase. This was considered uncritical because the deviation of the average temperature was small, and the test item showed no signs of degradation at all three pH values.

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Batch no.: 170103
Appearance: White crystalline powder
CAS No.: 17625-03-5
EINECS-No.: 241-602-5
Molecular formula: C7H5SO5Na
Molecular weight: 224.17 g/mol
Purity: > 99.0% (Titration with NaOH, Glass indicating electrode, Calomel reference electrode)
Homogeneity: totally homogeneous
Stability: H2O: 96 h; EtOH: unknown; acetone: unknown; CH3CN: unknown; DMSO: unknown
Solubility: H2O: >1 g/L; EtOH: unknown; acetone: unknown; CH3CN: unknown; DMSO: unknown
Expiry date: 14. Feb. 2024
Storage: Room Temperature (20 ± 5°C), keep away from humidity

Radiolabelling:

no

Analytical monitoring:

yes

Buffers:

Water
Deionised water was used for the test item stock solution and for the preparation of the buffer solutions.

pH Buffer Solutions
The following solutions were used unsterile:
Compound Molecular Formula Concentration
Acetic acid CH3COOH 2 M
Sodium acetate CH3COONa 1 M
Sodium hydroxide NaOH 2 M

Buffer-Solutions, pH 4
CH3COOH, 2 M - 16 mL
CH3COONa - 8 mL
Demineralised water ad 200 mL
Final pH value = 4.03

Buffer-Solution, pH 7
KH2PO4 - 1.7430 g
Demineralised water - 50 mL
NaOH, 2 M - 2.98 mL
Demineralised water ad 200 mL
Final pH value (adjusted with NaOH) = 7.01

Buffer-Solution, pH 9
H3BO3 - 0.6193 g
KCl - 0.7465 g
Demineralised water - 100 mL
NaOH, 2 M - 2.15 mL
Demineralised water ad 200 mL
Final pH value (adjusted with NaOH) = 9.04

Estimation method (if used):

Not used.

Details on test conditions:

Glass Material
All glassware was sterilized before use.
Vials with PTFE septa were used. A large head space above the liquid was avoided.

Incubation Chamber
Memmert Tv30u

Instruments and Devices
The following instruments and devices were used for the performance of the study:
• Autoclave 3870 ELV-B, Tuttnauer
• pH-Meter pH 540 GLP, wtw
• Analytical scales XS205DU, Mettler Toledo
• Adjustable pipettes with one-way tips, Rainin ®, Mettler Toledo
• Repeater pipettes Autorep E, Mettler Toledo
• Syringe sterile filters, 0.2 µm PTFE
• Carbon analyser TOC multi N/C 2100S, Analytik Jena
• Refrigerator
• Temperature data loggers, ebro
Usage and calibration followed the corresponding SOP in the current edition.
Standard laboratory material (e.g. glassware) was also used in the performance of the study

Analytical Determination
An analytical method using HPLC-UV was validated and is fully described in the valida-tion report VB17042002G926.

Analytical Instrument
Identification: HPLC 6
Components:
- HPLC Ultimate3000:
- Solvent Rack
- Pump LPG-3400SD
- Autosampler WPS-3000TSL
- Column Compartment TCC-3200 with
- 6-fold motorized HPLC valve
- UV-Detector MWD-3000
Manufacturer: Thermo Fisher Scientific
Software: CHROMELEON 6.80 SR15b Build 4981

Usage and calibration followed SOP 11400529 in the current edition.

Duration:

120 h

pH:

4

Temp.:

49.2 °C

Initial conc. measured:

488.53 mg/L

Duration:

120 h

pH:

7

Temp.:

49.3 °C

Initial conc. measured:

524.62 mg/L

Duration:

120 h

pH:

9

Temp.:

49.3 °C

Initial conc. measured:

486.56 mg/L

Number of replicates:

2 for blank at each pH values and 6 for each sample and for each pH value.

Positive controls:

no

Negative controls:

no

Statistical methods:

Not relevant.

Preliminary study:

After five days (120 hours), the concentrations of the test item lay slightly above 100 % of the start concentration at pH values 4 and 9, indicating that the test item is hydrolytically stable. As the starting value of pH 7 was much higher than expected (> 120 % of the nominal concentration) but in the same concentration range as the other two pH values at the end of the incubation period, a sample preparation error at t = 0 was assumed and Tier 1 was repeated for pH 7.
In the repeated experiment at pH 7, the change in test item concentration was + 0.4 % compared to the starting concentration. The test item is considered hydrolytically stable also at pH 7.

Transformation products:

not measured

pH:

4

Temp.:

49.2 °C

Duration:

120 h

Remarks on result:

hydrolytically stable based on preliminary test

pH:

7

Temp.:

49.3 °C

Duration:

120 h

Remarks on result:

hydrolytically stable based on preliminary test

pH:

9

Temp.:

49.2 °C

Duration:

120 h

Remarks on result:

hydrolytically stable based on preliminary test

pH:

4

Temp.:

49.2 °C

Remarks on result:

hydrolytically stable based on preliminary test

pH:

7

Temp.:

49.3 °C

Remarks on result:

hydrolytically stable based on preliminary test

pH:

9

Temp.:

49.2 °C

Remarks on result:

hydrolytically stable based on preliminary test

Tier 1

Measured Concentrations, Decrease

The measured concentrations and the decrease in tier 1 are presented in the following table.

 

Table. Measured Concentrations t = 0 h.

Sample Name	Peak Area [mAU*min]	Dilution Factor	Concentration [mg/L]	Mean Concentration [mg/L]
Blank pH 4t=0 h	n.a.	none	< LOQ	< LOQ
	n.a.	none	< LOQ
pH 4 t=0 h	7.1701	50	485.39	488.53
	7.2615	50	491.66
Blank pH 7t=0 h	n.a.	none	< LOQ	< LOQ
	n.a.	none	< LOQ
pH 7 t=0 ht=0 h	8.4491	50	573.19	607.29^1
	8.5520	50	580.25
Blank pH 9t=0 h	n.a.	none	< LOQ	< LOQ
	n.a.	none	< LOQ
pH 9 t=0 ht=0 h	7.2073	50	487.94	486.56
	7.1671	50	485.18

¹Including matrix correction factor 1.0530

 

Table. Measured Concentrations t = 0 h, repeated experiment.

Sample Name	Peak Area [mAU*min]	Dilution Factor	Concentration [mg/L]	Mean Concentration [mg/L]
Blank pH 7t=0 h	n.a.	none	< LOQ	< LOQ
	n.a.	none	< LOQ
pH 7 t=0 ht=0 h	5.6604	50	496.95	524.62^1
	5.6890	50	499.48

¹Including matrix correction factor 1.0530

  

Table. Measured Concentrations t = 120 h.
Sample Name	Peak Area [mAU *min]	Concentration [mg/L]	Dilution Factor	Mean Concentration [mg/L]
Blank pH 4^1 t = 120 h	n.a.	< LOQ	none	< LOQ
	n.a.	< LOQ	none
pH 4 t=120 h^1	7.4350	503.57	50	506.05
	7.4658	505.69	50
	7.5151	509.07	50
	7.4219	502.67	50
	7.5364	510.53	50
	7.4525	504.77	50
Blank pH 7 t = 120 h^2	n.a.	< LOQ	none	< LOQ
	n.a.	< LOQ	none
pH 7 t=120 h^2	7.3407	497.10	50	531.32^1
	7.4791	506.60	50
	7.4853	505.17	50
	7.3265	496.13	50
	7.5673	512.66	50
	7.5260	509.82	50
Blank pH 9 t = 120 h^3	n.a.	< LOQ	none	< LOQ
	n.a.	< LOQ	none
pH 9 t=120 h^3	7.5122	508.87	50	499.90
	7.3722	499.26	50
	7.3495	497.70	50
	7.4075	501.69	50
	7.3372	496.86	50
	7.3102	495.01	50

¹Including matrix correction factor 1.0530

 

Table. Measured Concentrations t = 120 h (repeated experiment).
Sample Name	Peak Area [mAU *min]	Concentration [mg/L]	Dilution Factor	Mean Concentration [mg/L]
Blank pH 7 t = 120 h	n.a.	< LOQ	None	< LOQ
	n.a.	< LOQ	None
pH 7 t=120 h^1	5.7610	500.99	50	526.68^1
	5.7675	501.56	50
	5.7462	499.70	50
	5.8156	505.77	50
	5.7047	496.06	50
	5.7149	496.96	50

¹Including matrix correction factor 1.0530

 

Assessment

The measured change in concentration at each pH value is summarised in Table below.

Table. Measured Concentrations Tier 1.

	Mean Concentrations [mg/L]
	pH 4	pH 7*	pH 9	pH 7, repeated
Average temperature [°C]	49.2	49.2	49.2	49.3
t = 0 h	488.53	607.29	486.56	524.62
t = 120 h	506.05	531.32	499.90	526.68
Recovery after 120 h [%]	103.6	87.5	102.7	99.6
Change over 120h[%]	+ 3.6	- 12.5	+ 2.7	+ 0.4

* The starting concentration was implausible (too high), therefore the test at pH 7 was repeated

Validity criteria fulfilled:

yes

Conclusions:

Sodium 3-sulfobenzoate is hydrolytically stable after five days (120 hours) at pH values of 4, 7 and 9 and 50°C.

Executive summary:

The determination of pH-dependent Hydrolysis in Water of sodium 3-sulfobenzoate has been performed according to OECD Guideline 111 and EU Method C.7.

Tier 1

A test item solution in demineralised water was mixed with buffer solutions (pH values: 4; 7; and 9). The resulting solutions were sterile filtered and incubated at 50 °C for a period of five days. Samples were analysed at the beginning and after five days. The analysis of the samples (performed with HPLC) showed no decrease > 10 % in the test item concentration within five days.

 

pH	% of start concentration after 5 days	% change within 5 days
4	103.6	+ 3.6
7*	87.5	- 12.5
9	102.7	+ 2.7
7, repeated	99.6	- 0.4

* The starting concentration was implausible (too high), therefore the test at pH 7 was repeated

 

The test item was considered hydrolytically stable at the tested pH values.

Description of key information

The determination of pH-dependent Hydrolysis in Water of sodium 3-sulfobenzoate has been performed according to OECD Guideline 111 and EU Method C.7.

Tier 1

A test item solution in demineralised water was mixed with buffer solutions (pH values: 4; 7; and 9). The resulting solutions were sterile filtered and incubated at 50 °C for a period of five days. Samples were analysed at the beginning and after five days. The analysis of the samples (performed with HPLC) showed no decrease > 10 % in the test item concentration within five days.

pH	% of start concentration after 5 days	% change within 5 days
4	103.6	+ 3.6
7*	87.5	- 12.5
9	102.7	+ 2.7
7, repeated	99.6	- 0.4

* The starting concentration was implausible (too high), therefore the test at pH 7 was repeated

 

The test item was considered hydrolytically stable at the tested pH values.