1,1'-{(phenylmethanediyl)bis[(3-substituted benzene-4,1-diyl)diazene-2,1-diyl{1-[3-(dimethylamino)propyl]-2-hydroxy-4-methyl-6-oxo-1,6-dihydropyridine-5,3-diyl}]}dipyridinium chloride lactate salts

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

February 04-March 05, 2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study compliant with TG guideline and conducted under GLP in recognized contract research organization.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

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

Media:

soil/sewage sludge

Test material

Reference

Name:

Unnamed

Type:

Constituent

Radiolabelling:

no

Study design

Test temperature:

35°C ± 1°C (column temperature)

HPLC method

Details on study design: HPLC method:

EQUIPMENT
- Apparatus:
- Type: Alliance Separation Module 2695 (Waters, Milford, MA, USA)
- Type, material and dimension of analytical column: 150 mm x 4.6 mm i.d. Hypersil BDS-CN; dp = 5 µm (Thermo, San Jose, CA, USA)
- Detection system: Dual Lambda Absorbance Detector 2487 (Waters) , 210 and 472 nm

MOBILE PHASES
- Type:
A: 55/45 (v/v) methanol/water
B: 100% methanol
Since it proved not possible to elute the test substance under isocratic conditions with a mobile phase of 55/45 (v/v) methanol/water as described in the guideline, a gradient was applied directly after the isocratic run in attempts to rinse the test substance off the column with methanol (see Table 1).
- Experiments with additives carried out on separate columns: no
- pH: neutral; the test substance is a mixture of components of which the main constituent is a salt. Salts consist of a cationic and anionic part and there is not a pH at which both parts are not ionized. Therefore, the HPLC analysis was only performed at neutral pH.
- Solutes for dissolving test and reference substances: stock solutions were prepared in me-thanol and diluted with 55/45 (v/v) methanol/water.

DETERMINATION OF DEAD TIME
- Method: not indicated
REFERENCE SUBSTANCES
- Identity: 2,4-DDT

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 0.146 µg
- Quantity of reference substances: 0.1054 µg
- Intervals of calibration: not indicated

REPETITIONS
- Number of determinations: two

EVALUATION
- Determination of the log Koc value: Solutions of the reference substance and the test sub-stance were analysed. Based on the retention times of the compounds the Koc and log Koc values of the test substance were determined.

Batch equilibrium or other method

Analytical monitoring:

yes

Results and discussion

Adsorption coefficient

Adsorption coefficient 1

Type:

Koc

Value:

> 430 000

Adsorption coefficient 2

Type:

log Koc

Value:

> 5.63

Results: HPLC method

Details on results (HPLC method):

- Retention times of reference substances used for calibration: 5.29 min
- Details of fitted regression line (log k' vs. log Koc): not applicable
- Graph of regression line attached: not applicable
- Average retention data for test substance: >45 min

Applicant's summary and conclusion

Validity criteria fulfilled:

not applicable

Remarks:

no criteria given by the test guideline OECD Guideline 121