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Hydrolysis

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Reference
Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2010-09-30 - 2010-11-05
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)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Specific details on test material used for the study:
Sponsor's identification: Amine C8
Description: dark brown liquid
Batch number: T7-271109
Date received: 21 September 2010
Expiry date: 31 December 2011
Storage conditions: room temperature in the dark
Radiolabelling:
no
Analytical monitoring:
yes
Details on sampling:
- Preparation of samples
Sample solutions were prepared in stoppered glass flasks at a nominal concentration of 1 g/l in the three buffer solutions.
The test 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.
- Analysis of sample solutions
The 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).
- Samples
Duplicate aliquots (A and B) of sample solution were diluted by a factor of 100 using acetone.
- Standards
Duplicate standard solutions of test item were prepared in acetone:relevant buffer solution (99:1 v/v) covering a nominal concentration range of 1 to 20 mg/l.
- Matrix blanks
Acetone:relevant buffer solution (99:1 v/v).
Buffers:
- Composition of buffer:
Buffer solution (pH) Components Concentration (mol dm-3)
4 Potassium hydrogen phthalate 0.05
7 Disodium hydrogen orthophosphate (anhydrous) 0.03
Potassium dihydrogen orthophosphate 0.02
Sodium chloride 0.02
9 Disodium tetraborate 0.01
Sodium chloride 0.02

The buffer solutions were filtered through a 0.2 µm membrane filter to ensure they were sterile before commencement of the test. Also these solutions were subjected to ultrasonication and degassing with nitrogen to minimise dissolved oxygen content.
Details on test conditions:
Refer to details on sampling and analytical methods.
Duration:
120 h
pH:
4
Initial conc. measured:
1 g/L
Duration:
120 h
pH:
7
Initial conc. measured:
1 g/L
Duration:
120 h
pH:
9
Initial conc. measured:
1 g/L
Number of replicates:
Duplicate aliquots (A and B) of sample solution were diluted by a factor of 100 using acetone.
Positive controls:
no
Negative controls:
no
Statistical methods:
Not specified.
Preliminary study:
The mean peak areas relating to the standard and sample solutions are presented in remarks on results including tables and figures section.
Transformation products:
not specified
Details on hydrolysis and appearance of transformation product(s):
Less than 10% hydrolysis after 5 days at 50°C.
Key result
pH:
4
Temp.:
25 °C
DT50:
1 yr
Type:
not specified
Key result
pH:
7
Temp.:
25 °C
DT50:
1 yr
Type:
not specified
Key result
pH:
9
Temp.:
25 °C
DT50:
1 yr
Type:
not specified
Other kinetic parameters:
None.
Details on results:
At pH4, 7 and 9 there was less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than 1 year at 25°C.

Preliminary test/Tier 1


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


Table 10.2 pH 4






























































































































































































Solution



MeanArea



Peak No.1



Peak No.2



pH 4 blank



ND



ND



Standard 1.03 mg/l



ND



8.093 x 105



Standard 5.17 mg/l



1.120 x 106



4.201 x 106



Standard 10.3 mg/l



2.443 x 106



8.863 x 106



Standard 10.4 mg/l



3.079 x 106



9.482 x 106



Standard 15.5 mg/l



3.597 x 106



1.424 x 107



Standard 20.7 mg/l



5.150 x 106



1.976 x 107



Standard 10.3 mg/l



2.000 x 106



8.876 x 107



Standard 10.4 mg/l



2.269 x 106



9.098 x 107



Initial Sample A, pH 4



2.031 x 106



8.714 x 106



Initial Sample B, pH 4



1.929 x 106



9.040 x 106



2.4-Hour Sample A, pH 4



1.588 x 106



7.988 x 106



2.4-Hour Sample B, pH 4



1.656 x 106



8.179 x 106



pH 4 blank



ND



ND



Standard 1.01 mg/l



ND



6.817 x 105



Standard 5.04 mg/l



ND



3.143 x 106



Standard 10.1 mg/l



9.929 x 105



6.674 x 106



Standard 10.4 mg/l



1.506 x 106



8.108 x 106



Standard 15.1 mg/l



1.831 x 106



1.078 x 107



Standard 20.1 mg/l



3.900 x 106



1.456 x 107



Standard 10.1 mg/l



1.503 x 106



6.527 x 106



Standard 10.4 mg/l



1.442 x 106



6.892 x 106



24-Hour Sample A, pH 4



1.562 x 106



6.446 x 106



24-Hour Sample B, pH 4



8.506 x 105



6.814 x 106



pH 4 blank



ND



ND



Standard 1.11 mg/l



ND



3.206 x 105



Standard 5.54 mg/l



4.974 x 105



2.178 x 106



Standard 11.1 mg/l



1.371 x 106



4.755 x 106



Standard 11.5 mg/l



1.470 x 106



5.030 x 106



Standard 16.7 mg/l



2.300 x 106



7.692 x 106



Standard 22.2 mg/l



3.314 x 106



1.049 x 107



Standard 11.1 mg/l



1.281 x 106



5.076 x 106



Standard 11.5 mg/l



1.431 x 106



5.164 x 106



120-Hour Sample A, pH 4



1.100 x 106



4.513 x 106



120-Hour Sample B, pH 4



9.656 x 105



4.500 x 106




         ND: none detected


 


Table 10.3 pH 7
































































































































































Solution



MeanArea



Peak No.1



Peak No.2



pH 7 blank



ND



ND



Standard 10.3 mg/l[1]



1.064 x 107



6.992 x 106



Standard 10.4 mg/l[1]



1.121 x 107



7.086 x 106



Initial Sample A, pH 7



5.066 x 106



5.550 x 106



Initial Sample B, pH 7



7.476 x 106



6.860 x 106



2.4-Hour Sample A, pH 7



9.218 x 106



7.283 x 106



2.4-Hour Sample B, pH 7



1.060 x 107



6.783 x 106



pH 7 blank



ND



ND



Standard 1.01 mg/l



5.655 x 105



5.659 x 105



Standard 5.04 mg/l



3.418 x 106



3.138 x 106



Standard 10.1 mg/l



9.189 x 106



5.518 x 106



Standard 10.4 mg/l



1.234 x 107



7.218 x 106



Standard 15.1 mg/l



1.643 x 107



8.610 x 106



Standard 20.1 mg/l



1.875 x 107



1.399 x 107



Standard 10.1 mg/l



1.081 x 107



6.399 x 106



Standard 10.4 mg/l



1.077 x 107



6.962 x 106



24-Hour Sample A, pH 7



1.217 x 107



6.771 x 106



24-Hour Sample B, pH 7



1.103 x 107



7.985 x 106



pH 7 blank



ND



ND



Standard 1.11 mg/l



4.020 x 105



3.913 x 105



Standard 5.54 mg/l



3.901 x 106



2.291 x 106



Standard 11.1 mg/l



9.725 x 106



5.085 x 106



Standard 11.5 mg/l



1.021 x 107



5.216 x 106



Standard 16.7 mg/l



1.521 x 107



7.796 x 106



Standard 22.2 mg/l



2.277 x 107



1.138 x 107



Standard 11.1 mg/l



9.523 x 106



4.959 x 106



Standard 11.5 mg/l



9.993 x 106



5.186 x 106



120-Hour Sample A, pH 7



9.574 x 106



4.216 x 106



120-Hour Sample B, pH 7



9.829 x 106



4.300 x 106




         ND: none detected


 


 


Table 10.4 pH 9






























































































































































































Solution



MeanArea



Peak No.1



Peak No.2



pH 9 blank



ND



ND



Standard 1.03 mg/l



ND



ND



Standard 5.17 mg/l



2.678 x 106



2.690 x 106



Standard 10.3 mg/l



1.134 x 107



6.616 x 106



Standard 10.4 mg/l



1.013 x 107



6.499 x 106



Standard 15.5 mg/l



1.706 x 107



1.110 x 107



Standard 20.7 mg/l



2.452 x 107



1.682 x 107



Standard 10.3 mg/l



1.002 x 107



5.612 x 106



Standard 10.4 mg/l



1.104 x 107



7.402 x 106



Initial Sample A, pH 9



1.199 x 107



7.355 x 106



Initial Sample B, pH 9



1.075 x 107



7.104 x 106



2.4-Hour Sample A, pH 9



9.028 x 106



7.896 x 106



2.4-Hour Sample B, pH 9



1.038 x 107



6.823 x 106



pH 9 blank



ND



ND



Standard 1.01 mg/l



9.192 x 105



ND



Standard 5.04 mg/l



2.199 x 106



3.073 x 106



Standard 10.1 mg/l



8.950 x 106



7.033 x 106



Standard 10.4 mg/l



7.256 x 106



6.712 x 106



Standard 15.1 mg/l



1.458 x 107



1.042 x 107



Standard 20.1 mg/l



2.003 x 107



1.226 x 107



Standard 10.1 mg/l



7.808 x 106



6.695 x 106



Standard 10.4 mg/l



8.851 x 106



5.999 x 106



24-Hour Sample A, pH 9



1.062 x 107



7.383 x 106



24-Hour Sample B, pH 9



1.001 x 107



6.273 x 106



pH 9 blank



ND



ND



Standard 1.11 mg/l



ND



3.479 x 105



Standard 5.54 mg/l



2.542 x 106



2.123 x 106



Standard 11.1 mg/l



7.300 x 106



4.838 x 106



Standard 11.5 mg/l



8.182 x 106



5.024 x 106



Standard 16.7 mg/l



1.344 x 107



7.897 x 106



Standard 22.2 mg/l



2.039 x 107



1.101 x 107



Standard 11.1 mg/l



7.425 x 106



4.634 x 106



Standard 11.5 mg/l



8.057 x 106



4.897 x 106



120-Hour Sample A, pH 9



8.574 x 106



4.211 x 106



120-Hour Sample B, pH 9



8.745 x 106



4.210 x 106




         ND: none detected


 


Equations of the calibration curve and correlation coefficients for the analyses are shown in the following table:


Table 10.5















































































































































Analysis



Correlation Coefficient



Equation of the Curve[2]



A



B



C



pH 4, Initial, 2.4-Hour, Peak 1



0.997



2.64 x 104



1.83 x 105



3.12 x 103



pH 4, Initial, 2.4-Hour, Peak 2



1.000



-3.45 x 104



7.99 x 105



7.69 x 103



pH 4, 24-Hour Peak 1



0.972



5.47 x 104



5.23 x 104



6.45 x 103



pH 4, 24-Hour Peak 2



0.996



-3.46 x 104



6.41 x 105



4.33 x 103



pH 4, 120-Hour Peak 1



0.999



-3.69 x 104



9.80 x 104



2.43 x 103



pH 4, 120-Hour Peak 2



0.999



-1.03 x 105



4.23 x 105



2.53 x 103



pH 7, Initial, 2.4-Hour Peak 1[3]



0.972



3.00 x 105



1.21 x 106



3.61 x 104



pH 7, Initial, 2.4-Hour Peak 2[3]



1.000



-7.67 x 104



8.40 x 105



5.62 x 103



pH 7, 24-Hour Peak 1[4]



0.984



-1.61 x 105



1.02 x 106



-



pH 7, 24-Hour Peak 2



0.990



9.72 x 104



5.45 x 105



6.17 x 103



pH 7, 120-Hour Peak 1



0.999



-2.32 x 105



7.27 x 105



1.37 x 104



pH 7, 120-Hour Peak 2



1.000



-1.464 x 104



3.89 x 105



5.47 x 103



pH 9, Initial, 2.4-Hour Peak 1



0.994



-6.41 x 105



8.88 x 105



1.64 x 104



pH 9, Initial, 2.4-Hour Peak 2



0.996



-1.88 x 104



4.46 x 105



1.78 x 104



pH 9, 24-Hour Peak 1



0.993



-1.54 x 105



5.94 x 105



2.14 x 104



pH 9, 24-Hour Peak 2[4]



0.991



1.01 x 105



6.32 x 105



-



pH 9, 120-Hour Peak 1



0.999



-1.91 x 105



4.55 x 105



2.15 x 104



pH 9, 120-Hour Peak 2



1.000



-5.33 x 104



3.69 x 105



5.96 x 103




 




[1] The calibration curve was not used in this analysis since a significant change in response occurred after the calibration. Thus the Initial and 2.4-Hour, pH 7 samples were calculated on this set of standards which followed the samples. See Discussion section.




[2] 2ndorder calibration y = A + Bx + Cx2, where y = area, x = concentration (mg/l)




[3] Calibration curve not used to calculate the sample concentrations. Post sample standards used due to a significant change in instrument response during analysis. See Discussion Section.




[4] 1storder calibration y = A + Bx,where y = area, x = concentration (mg/l)


 


 


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


Table 10.5   pH 4 at 50.0 ± 0.5ºC Peak No.1














































Time (Hours)



Mean Concentration (g/l)



% of mean initial concentration (g/l)



A



B



A



B



0



0.945



0.903



-



-



2.4



0.757



0.786



81.9



85.0



24



1.17



0.776



126



84.0



120



0.940



0.845



102



91.5




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


Table 10.6   pH 4 at 50.0 ± 0.5ºC Peak No.2














































Time (Hours)



Mean Concentration (g/l)



% of mean initial concentration (g/l)



A



B



A



B



0



1.03



1.05



-



-



2.4



1.00



1.02



90.8



92.7



24



0.897



1.04



93.4



98.5



120



1.03



1.03



101



101




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


Table 10.7   pH 7 at 50.0 ± 0.5ºC Peak No.1














































Time (Hours)



Mean Concentration (g/l)



% of mean theoretical[1]concentration (g/l)



A



B



A



B



0



0.480



0.709



-



-



2.4



0.874



1.00



86.9



99.8



24



1.21



1.10



120



109



120



1.12



1.14



111



113




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




Table 10.8   pH 7 at 50.0 ± 0.5ºC Peak No.2














































Time (Hours)



Mean Concentration (g/l)



% of mean theoretical[2]concentration (g/l)



A



B



A



B



0



0.816



1.01



-



-



2.4



1.07



0.998



107



99.2



24



1.09



1.26



108



125



120



0.958



0.975



95.2



96.9




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


Table 10.9   pH 9 at 50.0 ± 0.5ºC Peak No.1














































Time (Hours)



Mean Concentration (g/l)



% of mean initial concentration (g/l)



A



B



A



B



0



1.17



1.07



-



-



2.4



0.928



1.04



82.9



93.0



24



1.25



1.19



112



107



120



1.22



1.24



109



111




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


Table 10.10 pH 9 at 50.0 ± 0.5ºC Peak No.2














































Time (Hours)



Mean Concentration (g/l)



% of mean initial peak area



A



B



A



B



0



1.14



1.11



-



-



2.4



1.20



1.07



107



95.5



24



1.15



0.977



103



87.1



120



0.996



0.996



88.8



88.8




Result:         Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than 1 year at 25°C[3]





[1] The theoretical value of test item concentration has been used to determine the degree of hydrolysis. See Discussion section.




[2] The theoretical value of test item concentration has been used to determine the degree of hydrolysis. See Discussion section.




[3] Variation in the reported concentration data for pH 9 Peak No.2. Based on percentage of theoretical concentration (98%), <10% hydrolysis is indicated.






 

Validity criteria fulfilled:
yes
Conclusions:
The test item was determined to be hydrolytically stable at pH 4, 7 and 9, with estimated half-lives of greater than 1 year at 25°C.
Executive summary:

Abiotic Degradation.  Assessment 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. The test item was determined to be hydrolytically stable at pH 4, 7 and 9, with estimated half-lives of greater than 1 year at 25°C.

Description of key information

The assessment of hydrolytic stability of the substance was carried out according to the EU Method C.7 (Butler & White, 2010). The test item was determined to be hydrolytically stable at pH 4, 7 and 9, with estimated half-lives greater than 1 year at 25°C.  The study is given a Klimisch score of 1, was conducted under GLP and is considered as the key study for endpoint coverage.

Key value for chemical safety assessment

Half-life for hydrolysis:
1 yr
at the temperature of:
25 °C

Additional information