Registration Dossier

Administrative data

Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2012-04-11 - 2012-05-24
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report Date:
2012

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))
Version / remarks:
(2008)
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))
Version / remarks:
(2001)
Deviations:
no
GLP compliance:
yes
Type of method:
HPLC estimation method
Media:
soil/sewage sludge

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
solid: particulate/powder
Specific details on test material used for the study:
CYANOX® 1790 Antioxidant
IUPAC nomenclature - Tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate
Synonym - [tris(4-t-butyl-3-hydroxy-2,6-dimethyl-benzyl)-s-triazine-2,4,6-(1H,3H,5H) trione]
Lot WP1031901
Appearance - White powder, odorless
CAS No. 40601-76-1
Molecular Formula - C42H57N3O6
Molecular Weight - 699.92 g/mole
Purity > 96%
Radiolabelling:
no

Study design

HPLC method

Details on study design: HPLC method:
CALCULATION OF PKA
The following pKa values in the pH range of 1 - 14 were calculated (Perrin calculation method (pKalc 5.0, module in Pallas 3.0, CompuDrug International San Francisco, CA, USA)): pKa acidic: 11.1, 11.6 and 12.1; pKa basic: none.

HPLC METHOD CONDITIONS
Instrument:  Alliance Separation Module 2695 (Waters, USA)
Detector:  Dual λ Absorbance Detector 2487 (Waters)
Column: Hypersil-BDS-CN, 150 mm x 4.6 mm i.d., dp= 5 µm (Thermo Fisher Scientific, USA)
Column temperature:  35°C ± 1°C
Mobile phase gradient*: 
- 0 minutes: 55% methanol / 45% water
- 15 minutes: 55% methanol / 45% water
- 25 minutes: 100% methanol / 0% water
- 30 minutes: 55% methanol / 45% water
- 35 minutes: 55% methanol / 45% water
Flow: 1 ml/min
Injection volume: 10 µl
UV detection: 210 nm

* the reference substance solution was analysed from 0-15 minutes.

REFERENCE SUBSTANCES
4,4’-DDT, 98.2%, CAS 50-29-3, log Koc 5.63 (value according to the OECD 121 guideline based on soil adsorption data)

PREPARATION OF SOLUTIONS
A stock solution of the reference substance at a concentration of approximately 1 g/l in methanol was diluted to obtain an end solution of 55/45 (v/v) methanol/water.

A 1008 mg/l stock solution of the test substance was prepared in methanol (ultrasonication for 5 minutes). The stock solution was diluted to obtain an end solution of 55/45 (v/v) methanol/water. Final test substance concentration: 50.4 mg/l.

PERFORMANCE OF THE STUDY
The reference substance and test substance solutions were injected in duplicate. Blank solution (55/45 (v/v) methanol/water) was analysed by single injection. The test substance results were compared with the results of reference substance 4,4’-DDT. 

Results and discussion

Adsorption coefficient
Type:
log Koc
Value:
> 5.63 dimensionless
Remarks on result:
other: Koc > 4.3 x 10^5

Results: HPLC method

Details on results (HPLC method):
In the HPLC chromatogram of the test solution, one peak with a retention time of 21.1 minutes was observed. This retention time indicates that the test substance elutes within the gradient to 100% methanol. Using the isocratic part of the chromatographic method, the retention time of reference substance 4,4’-DDT (log Koc = 5.63) was 6.3 minutes. Hence, it was concluded that the log Koc of the test substance at neutral pH was > 5.63 (Koc > 4.3x10^5).

Applicant's summary and conclusion

Conclusions:
The HPLC method using soil-adsorption-reference data was applied for the determination of the adsorption coefficient of the substance, resulting in a log Koc of > 5.63 (Koc > 4.3x10^5).
Executive summary:

The HPLC method at neutral pH using soil-adsorption-reference data was applied for the determination of the adsorption coefficient (Koc) of the substance. The mobile phase was 55/45 (v/v) methanol/water (gradient). The column temperature was 35°C. The HPLC chromatogram of the test solution, showed one peak. The retention time of this peak indicates that the test substance elutes within the gradient to 100% methanol. Using the isocratic part of the chromatographic method, the retention time of reference substance 4,4’-DDT (log Koc = 5.63) was 6.3 minutes. Hence, it was concluded that the log Koc of the test substance at neutral pH was > 5.63 (Koc > 4.3 x 10^5). The study was performed in accordance with EC C.9 and OECD 121 and according to the principles of GLP.