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Environmental fate & pathways

Adsorption / desorption

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Administrative data

Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
2008-07-09 - 2008-11-19
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study perforemd acccording to relevant guidelines and compliant to GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report Date:
2008

Materials and methods

Test guidelineopen allclose all
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))
Deviations:
yes
Remarks:
Because of poor solubility of test item in solvents, the solvents for dissolving the test item differed from the mobile phase used on HPLC.
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))
GLP compliance:
yes (incl. certificate)
Remarks:
Swiss Ordinance on Good Laboratory Practice, adopted on 18th May 2005 (OGLP, SR 813.112.1] based on OECD-GLP 1997 [C(97)186/Final]
Type of method:
HPLC estimation method
Media:
soil/sewage sludge

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
not applicable
Radiolabelling:
no

Study design

Test temperature:
25°C

HPLC method

Details on study design: HPLC method:
Test Item Solutions

The test item (tip of a spatula) was dissolved in Dimethylacetamide (about 2 mL). This mixture was ultrasonificated for about 5 minutes and submitted to a 0.2 µm filtration. This solution was diluted with 2 mL of a solvent mixture of water and methanol (45:55; v/v). This test item solution was injected.

The test item (tip of a spatula) was dissolved in methanol (about 2 mL). This mixture was ultrasonificated for about 5 minutes and centrifugation for at about 4000 rpm for 10 min. This supernatant was injected.

TKP 50089 (EXPERIMENTAL PINK 23161B) (21.02 mg) was dissolved in 10 mL Dimethylacetamide. This mixture was ultrasonificated for 15 minutes. This turbid solution was diluted with a solvent mixture of water and acetonitrile (45:55; v/v) in a ratio 1:1 and submitted to a 0.2 µm filtration. This test item solution was injected.


HPLC-Conditions
The tests to determine the adsorption coefficient (Koc) of TKP 50089 (EXPERIMENTAL PINK 23161B) were performed with a solvent mixture of methanol/water or acetonitrile and water. These mixtures were not sufficient to elute the test item from the column. Therefore, the change to 100% acetonitrile after 1 h with water and acetonitrile (45:55; v/v) was tried. During these runs no test item peak was detected.

Apparatus:
Varian autosampler 9095
Varian pump 9012
Varian UV/VIS detector 9050
Jones column oven 7990

Column: LiChrospher CN, particle size 5 µm, 250 mm x 4 mm

HPLC Eluent: Water / acetonitrile (45:55; v/v) for 60 min; then 100% acetonitrile for 50 min, after that during 1 min it was changed to back to water / acetonitrile (45:55; v/v)

Detection: Test item: 285 nm
Temperature: 25 °C
Injection Volume: 10 µL
Flow: 1.0 mL/min
Run Time: 119 minutes
Retention Times: none

Batch equilibrium or other method

Analytical monitoring:
not required
Computational methods:
Not applicable

Results and discussion

Results: HPLC method

Details on results (HPLC method):
The elution of the test item was not possible with the criteria given in the guideline.

lt was not possible to dissolve the test item completely in dimethylacetamide or methanol.

The tests to determine the adsorption coefficient (Koc) of the test item were performed with a solvent mixture of methanol/water or acetonitrile and water. These mixtures were not sufficient to elute the test item from the column. Therefore, the change to 100% acetonitrile after 1 h with water and acetonitrile (45:55; v/v) was tried. During these runs no test item peak was detected.

The elution of the test item from the column was not possible by using different eluents:
- Methanol/Water (55:45; v/v)
- Acetonitrile/Water (55:45; v/v)
- Acetonitrile 100%

Results: Batch equilibrium or other method

Statistics:
not applicable

Applicant's summary and conclusion

Validity criteria fulfilled:
not applicable
Remarks:
Due to adherence of the test item to the column following the test protocol further on was impossible
Conclusions:
To estimate the adsorption coefficient Koc of the test item, the HPLC-method according to OECD technical guideline no. 121 had been applied (reliability category 1, GLP compliance). The poor solubility of the test item in water as well as in other solvents precluded the deduction of useful results. Using different sovent mixtures, partial dissolution of the test item had been possible. Elution from the HPLC-column, however, proved to be impossible in spite of different solvent systems used. Most probably, the test item had precipitated on the column. Therefore, Koc for the test item cannot be determined using the estimation method based on HPLC.
Executive summary:

An attempt was made to determine the adsorption coefficient (Koc) of the test item according to OECD Guideline for the Testing of Chemicals, No. 121, Estimation of the Adsorption Coefficient (Koc) on Soil and Sewage Sludge using High Performance Liquid Chromatography (HPLC), January, 2001 and the EC Directive 2001/59, C.19. It was not possible to dissolve the test item completely in dimethylacetamide or methanol. The elution of the test item from the column was not possible by using different eluents:

- Methanol/Water (55:45; v/v)

- Acetonitrile/Water (55:45; v/v)

- Acetonitrile 100%