Anthraquinone acid dye

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted to GLP in compliance with agreed protocols with no deviations from standard test guidelines and/or minor methodological deficiences which do not affect the quality of the relevant results

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Details on test material:

- Name of test material (as cited in study report): INK BH11 M
- Substance type: dark red powder
- Lot/batch No.: MB-1A
- Storage condition of test material: room temperature in the dark

Radiolabelling:

no

Study design

Analytical monitoring:

yes

Details on sampling:

Sample vessels 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 high performance liquid chromatography (HPLC).

Samples
Aliquots of each sample solution were diluted by a factor of 50 using 2.5 mM tetrabutylammonium hydroxide aqueous solution.

Buffers:

- pH: 4
- Type and final molarity of buffer: 0.05 mol dm^-3
- Composition of buffer: potassium hydrogen phthalate

- pH: 7
- Type and final molarity of buffer: 0.03, 0.02, 0.02 mol dm^-3
- Composition of buffer: disodium hydrogen orthophosphate (anhydrous), potassium dihydrogen orthophosphate, sodium chloride

- pH: 9
- Type and final molarity of buffer: 0.01, 0.02 mol dm^-3
- Composition of buffer: disodium tetraborate, sodium chloride

The buffer solutions were filtered through a 0.2 pm 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

Statistical methods:

Sample Solution Concentration

Cspl= (Pspl/ Pstdx Cstdx D) / 1000(equation 1)
Where:
Cspl= sample concentration (g/L)
Pspl= mean peak area of sample solution
Pstd= mean peak area of standard solution, corrected to nominal standard concentration
Cstd= nominal standard solution (100 mg/L)
D = sample dilution factor (10)

Results and discussion

Preliminary study:

Less than 10% hydrolysis after 5 days at 50 C, equivalent to half-life greater than 1 year at 25 C at pH 4, pH 7, and pH 9.

Dissipation DT50 of parent compound

Dissipation DT50 of parent compound 1

pH:

4

Temp.:

25 °C

DT50:

> 1 yr

Dissipation DT50 of parent compound 2

pH:

7

Temp.:

25 °C

DT50:

> 1 yr

Dissipation DT50 of parent compound 3

pH:

9

Temp.:

25 °C

DT50:

> 1 yr

Any other information on results incl. tables

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

 

pH 4 at 50.0 ± 0.5°C

Time (Ho urs)	Concentration (WI)		Mean % of mean initial concentration
	A	B
0	5.21	5.19	100
24	5.15	5.20	99.6
120	5.09	4.73	94.5

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

pH 7 at 50.0 ± 0.5°C

Time (Hours)	Concentration (gll)		Mean % of mean initial concentration
	A	B
0	5.09	5.11	100
24	5.24	5.22	103
120	5.24	5.21	102

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

pH 9 at 50.0 ± 0.5°C

Time (Hours)	Concentration (gll)		Mean % of mean initial concentration
	A	B
0	5.24	5.19	100
24	5.32	5.25	101
120	5.10	5.07	97.6

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

Results from the Preliminary test/Tier 1 showed it was not necessary to undertake further testing at pH 4, pH 7 and pH 9.

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

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

The linearity of the detector response with respect to concentration was assessed over the nominal concentration range of 0 to 200 mg/l in the three buffer matrices. These were satisfactory with correlation coefficients of 1.000 being obtained

Conclusions:

As the test material was determined to be hydrolytically stable under acidic conditions (tai > 1 year at 25°C), no additional testing was performed at pH 1.2, 37.0 ± 0.5°C.

The estimated half-fifes at 25°C of the test material are shown in the following table:

pH Estimated half-fife at 25°C
4 >1 year
7 >1 year
9 >1 year

Executive summary:

In a determination of general physico-chemical properties study (Harlan project number: 0959/0224) the test material

is estimated to have a half life of greater than 1 year at pHs of 4, 7 and 9 at 25°C. The determination was carried out using Method C7 Abiotic Degradation, Hydrolysis as aFunction of pH of Commission Regulation (EC) No 440/2008 of 30 May 2008.