Corsair Clear #12

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption: screening

Type of information:

calculation (if not (Q)SAR)

Remarks:

Migrated phrase: estimated by calculation

Adequacy of study:

key study

Study period:

October 4, 2007 - January 15, 2008

Reliability:

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

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Test material

Reference

Name:

Unnamed

Type:

Constituent

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

Radiolabelling:

no

Study design

Test temperature:

35°C

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
Gradient:
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

Type:

log Koc

Value:

> 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 K_ocand log K_oc 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 K_oc is given as: log Koc = 0.81 log Pow + 0.10.       

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

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

Applicant's summary and conclusion

Validity criteria fulfilled:

not applicable

Conclusions:

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