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Administrative data

adsorption / desorption: screening
Type of information:
calculation (if not (Q)SAR)
Migrated phrase: estimated by calculation
Adequacy of study:
key study
Study period:
October 4, 2007 - January 15, 2008
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study has been performed according to OECD guidelines and according to GLP principles.

Data source

Reference Type:
study report
Report Date:

Materials and methods

Test guidelineopen allclose all
according to
OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))
according to
EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))
GLP compliance:
yes (incl. certificate)
Type of method:
HPLC estimation method

Test material

Details on test material:
- Name of test material (as cited in study report): Corsair Clear #12
- Substance type: Soft waxy beige solid
- Physical state: Solid
- Stability under test conditions: stable
- Storage condition of test material: At room temperature in the dark

Study design

Test temperature:

HPLC method

Details on study design: HPLC method:
According to the guidelines, the determination of the Koc for test substances that are ionized for at least 10% within pH 5.5 to 7.5 should be performed with both the ionized and non-ionized form. Therefore, the pKa values of the test substance were calculated using the Perrin calculation method (pKalc 5.0, module in Pallas 3.0, CompuDrug International San Francisco, CA, USA). Based on the calculations, the HPLC analysis was performed at neutral pH.
Analytical conditions
Instrument: Alliance Separation Module 2695 (Waters, Milford, MA, USA)
Detector (reference substances): Photodiode Array Detector 2996 (Waters)
Detector (test substance): ELSD 2000 ES (Alltech, Deerfield, IL, USA)
Column: Hypersil BDS-CN, 150 mm x 4.6 mm i.d., dp = 5 µm (Thermo, San Jose, CA, USA)
Column temperature: 35°C ± 1.0°C
Mobile phase A: 55/45 (v/v) methanol/Milli-Q water
Mobile phase B: Methanol
Mobile phase C: Tetrahydrofuran
Time (min) Flow (ml/min) A (%) B(%) C(%)
0 1.0 100 - -
20 1.0 100 - -
20.1 1.0 - 100 -
40 1.0 - 100 -
40.1 1.0 - - 100
55 1.0 - - 100
55.1 1.0 100 - -
70 1.0 100 - -

Flow: 1 ml/min
Injection volume: 10 µl
UV detection: 210 nm
ELSD detection:
Temperature: 84.8°C
Nebuliser gas: nitrogen
Nebuliser gas flow: 2.3 l/min
Impactor: off

Results and discussion

Adsorption coefficient
log Koc
> 5.4

Results: HPLC method

Details on results (HPLC method):
Using the recommended mobile phase and isocratic elution, a test substance peak was not observed in the chromatograms of the test substance solution. Therefore, the analytical method was adjusted to gradient elution with 100% methanol for 20 minutes and subsequently 100% tetrahydrofuran for 15 minutes. Yet, the test substance could not be eluted from the analytical column. From this it was concluded that the HPLC method cannot be used for the determination of the Koc of Corsair Clear #12.

Any other information on results incl. tables

Since it was not possible to determine the Kocand log Koc values of the test substance using the HPLC method, the QSAR calculation method was applied. Based on the water solubility of the test substance (< 2.82 x 10-4 g/l) the compound was classified as “predominantly hydrophobic”. For this chemical class, the log Koc is given as: log Koc = 0.81 log Pow + 0.10.       

Using the HPLC method the partition coefficient, Pow, of Corsair Clear #12 was determined to be > 3.2 x 106 (log Pow > 6.5).

When applying this log Pow value to the above given equation, the log Koc of Corsair Clear #12 was calculated to be > 5.4.

Applicant's summary and conclusion

Validity criteria fulfilled:
not applicable
The log Koc of Corsair Clear #12 was calculated to be > 5.4, as the HPLC method could not be used.