Thiophene, tetrahydro-, 1,1-dioxide, 3-(C9-11-isoalkyloxy) derivs., C10-rich

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Testing was conducted between 27 October 2011 and 9 November 2011.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. The study report was conclusive, done to a valid guideline and the study was conducted under GLP conditions.

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

Analysis of sample solutions
Duplicate sample solutions were taken from the water bath at various times and the pH of each solution recorded. The concentration of the sample solution was determined by gas chromatography (GC).

Buffers:

Due to the tabular nature of this information please see Any other information on materials and methods incl. tables section.

Details on test conditions:

Preparation of samples
Stock solutions were prepared in glass flasks at a nominal concentration of 2.5 x 10-2g/l in the three buffer solutions. A 1% co-solvent of tetrahydrofuran was used to aid solubility.
The stock solutions were split into individual vessels for each data point.
The solutions were shielded from light whilst maintained at the test temperature.

Preliminary test/Tier 1
Sample solutions at pH 4, 7 and 9 were maintained at 50.0 ± 0.5°C for a period of 120 hours.

Samples
An aliquot of sample solution was diluted by a factor of 2 using tetrahydrofuran.

Standards
Duplicate standard solutions of test item were prepared in tetrahydrofuran:water (1:1 v/v) at a nominal concentration of 12.5 mg/l.

Matrix blanks
Tetrahydrofuran:water (1:1 v/v).

Duration:

120 h

pH:

4

Temp.:

50

Initial conc. measured:

12.5 mg/L

Duration:

120 h

pH:

7

Temp.:

50

Initial conc. measured:

12.5 mg/L

Duration:

120 h

pH:

9

Temp.:

50

Initial conc. measured:

12.5 mg/L

Number of replicates:

Duplicate standard solutions of test item were prepared in tetrahydrofuran:water (1:1 v/v) at a nominal concentration of 12. 5 mg/I.

Positive controls:

no

Negative controls:

no

Test performance:

The linearity of the detector response with respect to concentration was assessed over the nominal concentration range of 5 to 50 mg/l. This was satisfactory with a correlation coefficient (r2) of 0. 991 being obtained.

Transformation products:

not specified

pH:

4

Temp.:

50 °C

Duration:

0 h

% Recovery:

107

pH:

4

Temp.:

50 °C

Duration:

72 h

% Recovery:

93.1 - 96.5

pH:

4

Temp.:

50 °C

Duration:

120 h

pH:

7

Temp.:

50 °C

Duration:

0 h

% Recovery:

105 - 108

pH:

7

Temp.:

50 °C

Duration:

72 h

% Recovery:

99.5 - 102

pH:

7

Temp.:

50 °C

Duration:

120 h

pH:

9

Temp.:

50 °C

Duration:

0 h

% Recovery:

103 - 104

pH:

9

Temp.:

50 °C

Duration:

72 h

% Recovery:

90.6 - 94.2

pH:

9

Temp.:

50 °C

Duration:

120 h

Temp.:

25 °C

DT50:

> 1 yr

Type:

not specified

Remarks on result:

other: The estimated half-life of the test item at pH 4, pH 7 and pH 9 was greater than 1 year at 25°C.

Details on results:

Due to the tabular nature of this information & to retain the integrity & coherence of the original Harlan Laboratories Ltd. Study report please see section “Any other information on results including tables”

Results The mean total peak areas relating to the standard and sample solutions are shown in the following table:

Solution	Mean total Peak Area
Standard 12.5 mg/l	7.164 x 10^5
Standard 12.7 mg/l	7.122 x 10^5
Initial Sample A, pH 4	8.720 x 10^5
Initial Sample B, pH 4	7.148 x 10^5
Initial Sample A, pH 7	6.873 x 10^5
Initial Sample B, pH 7	7.051 x 10^5
Initial Sample A, pH 9	7.006 x 10^5
Initial Sample B, pH 9	6.843 x 10^5
Standard 12.8 mg/l	7.317 x 10^5
Standard 12.5 mg/l	7.380 x 10^5
72 Hour Sample A, pH 4	7.893 x 10^5
72 Hour Sample B, pH 4	7.865 x 10^5
72 Hour Sample A, pH 7	7.750 x 10^5
72 Hour Sample B, pH 7	7.507 x 10^5
72 Hour Sample A, pH 9	7.301 x 10^5
72 Hour Sample B, pH 9	7.407 x 10^5
Standard 13.2 mg/l	6.101 x 10^5
Standard 12.6 mg/l	5.999 x 10^5
120 Hour Sample A, pH 4	5.521 x 10^5
120 Hour Sample B, pH 4	5.721 x 10^5
120 Hour Sample A, pH 7	5.745 x 10^5
120 Hour Sample B, pH 7	5.866 x 10^5
120 Hour Sample A, pH 9	5.409 x 10^5
120 Hour Sample B, pH 9	5.205 x 10^5

The test item concentrations at the given time points are shown in the following tables:

      pH 4 at 50°C

Time (Hours)	Concentration (g/l)		% of initial concentration
	A	B	A	B
0	3.08 x 10^-2*	2.52 x 10^-2	-	-
72	2.71 x 10^-2	2.70 x 10^-2	107	107
120	2.35 x 10^-2	2.44 x 10^-2	93.1	96.5

     pH 7 at 50°C

Time (Hours)	Concentration (g/l)		% of initial concentration
	A	B	A	B
0	2.43 x 10^-2	2.49 x 10^-2	-	-
72	2.66 x 10^-2	2.58 x 10^-2	108	105
120	2.45 x 10^-2	2.50 x 10^-2	99.5	102

      pH 9 at 50°C

Time (Hours)	Concentration (g/l)		% of initial concentration
	A	B	A	B
0	2.47 x 10^-2	2.42 x 10^-2	-	-
72	2.51 x 10^-2	2.54 x 10^-2	103	104
120	2.30 x 10^-2	2.22 x 10^-2	94.2	90.6

Result: Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than 1 year at 25°C.

*Not used in further calculations as considered high and inconsistent

Validity criteria fulfilled:

yes

Conclusions:

The estimated half-life of the test item at pH 4, pH 7 and pH 9 was greater than 1 year at 25°C.

Executive summary:

The estimated half-life of the test item at pH 4, pH 7 and pH 9 was greater than 1 year at 25°C. Assessnt of hydrolytic stability was carried out using a procedure designed to be compatible with Method C7 Abiotic Degradation, Hydrolysis as a Function of pH of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 111 of the OECD Guidelines for Testing of Chemicals, 13 April 2004.

Description of key information

The estimated half-life of the substance at pH 4, pH 7 and pH 9 was greater than 1 year at 25°C; study conducted in accordance with OECD 111 and EU Method C.7; Fox and White (2011)

Additional information

In a GLP compliant hydrolysis study conducted in accordance with standardised guidelines, the hydrolysis of the test substance was determined. Under the conditions of the test, the half-life of the substance at pH 4, pH 7 and pH 9 was determined to be greater than one year at 25ºC.