Disodium C-isodecyl sulphonatosuccinate

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

December 18, 2013 - July 17, 2014

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study was performed in accordance with OECD guideline 111. Non-GLP study.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2014

Report date:

2014

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Version / remarks:

(2004)

GLP compliance:

not specified

Remarks:

no information

Test material

Test material information

Constituent 1

Reference substance name:

Disodium C-isodecyl sulphonatosuccinate

EC Number:

253-452-8

EC Name:

Disodium C-isodecyl sulphonatosuccinate

Cas Number:

37294-49-8

Molecular formula:

C14H26O7S.2Na

IUPAC Name:

disodium 4-[(2-methylnonyl)oxy]-4-oxo-3-sulfonatobutanoate

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

Name of test material (as cited in study report): Disodium Isodecyl Sulfosuccinate
Description: white powder
Storage conditions of test material: at room temperature in well-sealed container
The substance was tested as received.

Radiolabelling:

no

Study design

Analytical monitoring:

yes

Details on sampling:

A sample (5 mL) was taken and diluted to 10.0 mL with methanol in a volumetric flask. The resulting solution was shaken well before HPLC analysis. Blank buffer solutions and standard solutions were treated in the same way.

Buffers:

pH 4 buffer solution - potassium acid phthalate
pH 7 buffer solution - potassium phosphate monobasic and sodium hydroxide, chlorine titrimeter reagent
pH 9 buffer solution - boric acid, potassium chloride, and sodium hydroxide

The buffers were filtered through a 0.1 µm syringe filter and degassed by ultrasonication.

Details on test conditions:

-Tier 1 preliminary test at pH 4, 7 and 9 and 50°C
-Tier 2 main study at pH 9 and 65°C, 50°C and 20°C
-The test solutions were incubated in a liquid bath or incubator in the dark at the specific test temperature (± 0.5°C).
-Each sample was injected in triplicate into the HPLC system.
-All equipment and glassware was sterilized.

Details Tier 1 preliminary test
-Test substance solutions were prepared (in duplicate) in the buffer solutions pH 4, 7 and 9 at concentrations ranging from 2.9 and 3.5 g/L.
-Samples were taken from the test substance solutions after 120 h incubation at 50°C.
-Standards were prepared in buffer solution pH 4, 7 and 9 at a concentration of 3 g/L.
-The standards were treated in the same way as the test samples (see Details on sampling).
-The mean (n=3) peak area of each standard or sample was multiplied by the correction factor '3.0/concentration prepared' (see table below) in order to be able to compare the peak areas of the samples with the standards and to calculate the '% of mean initial concentration'.

Details Tier 2 main study
-Test substance solutions were prepared at nominal 3 g/L (two solutions per test temperature).
-Samples were taken from the test substance solution after preparation and after 15, 24, 46, 66, 72, 139 and 216 h of incubation at 65°C.
-Samples were taken from the test substance solution after preparation and after 15, 24, 46, 72, 139, 216 h and 689.5 h of incubation at 50°C.
-Samples were taken from the test substance solution after preparation and after 48, 196, 263, 426.5 h, 719 h and 744 h of incubation at 20°C.
-On each day of analysis standards were prepared in buffer solution pH 9 at a concentration of 3 g/L.
-The standards were treated in the same way as the test samples (see Details on sampling).
-The mean (n=3) peak area of each standard or sample was multiplied by the correction factor '3.0/concentration prepared' (see table below).
-The % peak area relative to the peak area of the fresh standard was calculated (=% of mean initial concentration) (see table below).
-Ct=Concentration at time t = 3.0 x '% of mean of initial concentration' (see table below).

Duration of test

Duration of test 1

Duration:

216 h

pH:

9

Temp.:

65 °C

Initial conc. measured:

2.99 - 3.01 g/L

Duration of test 2

Duration:

689.5 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

2.99 - 3.01 g/L

Duration of test 3

Duration:

744 h

pH:

9

Temp.:

20 °C

Initial conc. measured:

2.99 - 3.02 g/L

Number of replicates:

two (A and B)

Positive controls:

no

Negative controls:

no

Results and discussion

Preliminary study:

At pH 4 and pH 7, hydrolysis < 10% was observed after 5 days. This corresponds with a half-life time at 25°C of > 1 year (half-life time at 25°C is > 1 year). According to the guideline, no further tests were required at pH 4 and pH 7.

A degree of > 10% of hydrolysis was observed after 5 days at pH 9 and 50°C. In accordance with the guideline, a Tier 2 test was performed at pH 9.

Transformation products:

not measured

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

In general carboxylic esters hydrolyze to the carboxylic acid and an alcohol. Proposed hydrolysis product: Sulphonatosuccinate anion; C4H5O7S.

Dissipation DT50 of parent compound

Dissipation DT50 of parent compound 1

pH:

9

Temp.:

65 °C

Hydrolysis rate constant:

0.013 h-1

DT50:

53.8 h

Type:

(pseudo-)first order (= half-life)

Remarks on result:

other: y= -0.0129x + 1.0064; r2=0.9905

Dissipation DT50 of parent compound 2

pH:

9

Temp.:

50 °C

Hydrolysis rate constant:

0.003 h-1

DT50:

226.5 h

Type:

(pseudo-)first order (= half-life)

Remarks on result:

other: y= -0.00306+1.0692;r2=0.9984

Dissipation DT50 of parent compound 3

pH:

9

Temp.:

20 °C

Hydrolysis rate constant:

0 h-1

DT50:

5 338 h

Type:

(pseudo-)first order (= half-life)

Remarks on result:

other: Y= -0.00013x + 1.1322; r2=0.5396

Dissipation DT50 of parent compound 4

pH:

9

Temp.:

25 °C

Hydrolysis rate constant:

0 h-1

DT50:

2 874.6 h

Type:

other: from the Arrhenius plot

Remarks on result:

other: t1/2= 120 days

Details on results:

No significant peaks were observed at the approximate retention time of the test substance on analysis of any matrix blank solutions.

Any other information on results incl. tables

Table: Results of the preliminary (Tier 1) test at pH 4, 7 and 9 at 50°C

pH	Solution	Concentration prepared (g/L)	Mean (n=3) peak area	Corrected peak area	% of Mean Initial Concentration
4	Standard A	3.4	786.6	684.0	100
	Sample 1 (120 h)	3.0	726.3	719.1	105.1
	Sample 2 (120 h)	2.9	692.9	729.4	106.6
7	Standard B	3.5	795.9	684.2	100
	Sample 3 (120 h)	3.5	796.3	692.5	101.2
	Sample 4 (120 h)	3.3	796.7	715.6	104.6
9	Standard C	3.0	670.2	667.9	100
	Sample 5 (120 h)	3.0	485.6	482.4	72.2
	Sample 6 (120 h)	3.2	509.0	465.6	69.7

Table: Tier 2 results of the test at pH 9 and 65°C

Solution	Mean (n=3) peak area	Corrected peak area	% of Mean Initial Concentration
Initial sample A, 3.01 mg/mL	1061.7	1055.9
Initial sample B, 2.99 mg/mL	1085.3	1088.4
Standard 1, 3.02 mg/mL	1041.6	1033.3
15 hrs, sample A	807.9	803.5	77.8
15 hrs, sample A	805.8	808.1	78.2
24 hrs, sample A	714.1	710.2	68.7
24 hrs, sample B	716.8	718.8	69.6
Standard 2, 3.02 mg/mL	1017.9	1009.9
46 hrs, sample A	504.8	502.0	49.7
46 hrs, sample B	588.6	590.2	58.4
Standard 3, 3.02 mg/mL	996.9	990.3
66 hrs, sample A	364.1	362.1	36.6
66 hrs, sample B	364.2	365.3	36.9
72 hrs, sample A	349.3	347.4	35.1
72 hrs, sample B	339.2	340.2	34.4
Standard 4, 3.04 mg/mL	1017.8	1004.4
139 hrs, sample A	137.2	136.1	13.6
139 hrs, sample B	130.8	130.4	13.1
Standard 5, 3.00 mg/mL	1006.9	1005.6
216 hrs, sample A	59.8	59.3	5.9
216 hrs, sample B	65.8	65.5	6.6

Table: Tier 2 results of the test at pH 9 and 50°C

pH 9 Buffer Solution	Mean (n=3) peak area	Corrected peak area	% of Mean Initial Concentration
Initial sample A, 3.01 mg/mL	1061.7	1055.9
Initial sample B, 2.99 mg/mL	1085.3	1088.4
Standard 1, 3.02 mg/mL	1041.6	1033.3
15 hrs, sample A	989.1	983.7	95.2
15 hrs, sample A	975.2	977.9	94.6
24 hrs, sample A	929.9	924.8	89.5
24 hrs, sample B	944.0	946.7	91.6
Standard 2, 3.02 mg/mL	1017.9	1009.9
46 hrs, sample A	876.1	871.3	86.3
46 hrs, sample B	868.1	870.5	86.2
Standard 3, 3.02 mg/mL	996.9	990.3
72 hrs, sample A	776.2	772.0	78.0
72 hrs, sample B	739.7	741.8	74.9
Standard 4, 3.04 mg/mL	1017.8	1004.4
139 hrs, sample A	634.3	628.9	62.6
139 hrs, sample B	636.3	634.2	63.1
Standard 5, 3.00 mg/mL	1006.9	1005.6
216 hrs, sample A	505.8	503.1	50.0
216 hrs, sample B	471.6	472.9	47.0
Standard 7, 3.03 mg/mL	931.6	921.8
689.5 hrs, sample A	113.8	113.2	12.3
689.5 hrs, sample B	106.1	106.4	11.5

Table: Tier 2 results of the test at pH 9 and 20°C

pH 9 Buffer Solution	Mean (n=3) peak area	Corrected Peak area	% of Mean Initial Concentration
Initial sample C, 2.99 mg/mL	959.2	960.6
Initial sample D 3.02 mg/mL	993.2	993.7
Standard 8, 3.05 mg/mL	948.2	932.0
48 hrs, sample C	923.8	925.2	99.3
48 hrs, sample D	980.5	981.0	105.3
Standard 9, 3.07 mg/mL	893.4	873.6
196 hrs, sample C	877.4	878.7	100.6
196 hrs, sample D	930.1	930.6	106.5
Standard 10, 3.04 mg/mL	965.2	952.5
263 hrs, sample C	909.5	910.8	95.6
263 hrs, sample D	955.6	956.1	100.4
Standard 11, 3.06 mg/mL	936.6	918.2
263 hrs, sample C	873.4	874.7	95.3
263 hrs, sample D	911.5	912.0	99.3
Standard 12, 3.07 mg/mL	976.4	954.8
426.5 hrs, sample C	902.8	904.1	94.7
426.5 hrs, sample D	938.9	939.4	98.4
Standard 13, 2.98 mg/mL	948.1	953.2
719 hrs, sample C	881.3	882.6	92.6
719 hrs, sample D	936.7	937.2	98.3
Standard 14, 3.03 mg/mL	1002.1	991.5
744 hrs, sample C	895.7	897.0	90.5
744 hrs, sample D	944.6	945.1	95.3

Table: Tier 2 results at pH 9 and 65°C

t [h]	lnCt (Ct in g/L)
15	0.85
15	0.85
24	0.72
24	0.74
46	0.40
46	0.56
66	0.09
66	0.10
72	0.05
72	0.03
139	-0.90
139	-0.94
216	-1.73
216	-1.63

Table:  Tier 2 results at pH 9 and 50°C

t [h]	lnCt (Ct in g/L)
15	1.05
15	1.04
24	0.99
24	1.01
46	0.95
46	0.95
72	0.85
72	0.81
139	0.63
139	0.64
216	0.41
216	0.34
689.5	-1.00
689.5	-1.06

Table: Tier 2 results at pH 9 and 20°C

t [h]	lnCt (Ctin g/L)
48	1.09
48	1.15
196	1.10
196	1.16
263	1.05
263	1.10
426.5	1.05
426.5	1.09
575	1.04
575	1.08
719	1.02
719	1.08
744	1.00
744	1.05

Applicant's summary and conclusion

Conclusions:

The substance is hydrolytically stable at pH 4 and 7 (half-life time at 25°C of > 1 year). Hydrolysis of the test substance at pH 9 shows a pseudo-first order behaviour. Half-life time at 25°C and pH 9 was determined to be 120 days.

Executive summary:

The rate of hydrolysis of the substance at pH values normally found in the environment (pH 4-9) was determined in a OECD TG 111 study. At pH 4 and 7, a degree of < 10% of hydrolysis was observed after 5 days at 50 °C. This corresponds with a half-life time at 25°C of > 1 year. The substance can be considered hydrolytically stable at pH 4 and 7.

 

At pH 9 and 50°C, a degree of ca. 30% of hydrolysis was observed after 5 days and therefore a Tier 2 study was performed at pH 9. Hydrolysis rates of the substance at 65, 50 and 20°C were determined from which the hydrolysis rate at 25°C was calculated. The test substance was shown to degrade by a pseudo-first order behaviour. Half-life time at 25°C and pH 9 was determined to be 120 days.