Molybdenum, bis(N,N-dibutylcarbamodithioato-κS,κS')dioxodi-μ-thioxodi-, stereoisomer

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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))

Version / remarks:

May 2008

Deviations:

no

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))

Version / remarks:

January 2001

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Radiolabelling:

no

Test temperature:

35°C ± 1°C (column temperature)

Details on study design: HPLC method:

EQUIPMENT
- Apparatus:
- Type: ultra performance liquid chromatography (UPLC)
- Type, material and dimension of analytical (guard) column: Acquity UPLC HSS Cyano, 100 mm x 2.1 mm i.d., dp = 1.8 µm
- Detection system: UV set at 210 nm (and 280 nm for confirmation)

MOBILE PHASES
- Type:
Solvent A: Water
Solvent B: Methanol
Gradient: A gradient was applied in order to elute components with log Pow > 5.63 from the column. The reference compound was eluted in the isocratic part of the method and the gradient step was not applied for these injections.
0 min: 45% A / 55% B
10 min: 45% A / 55% B
10.5 min: 0% A / 100% B
16.0 min: 0% A / 100% B
16.5 min: 45% A / 55% B
21.0 min: 45% A / 55% B

- Experiments with additives carried out on separate columns: no additives used
- pH: The pKa values of the test item 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 method was performed at neutral pH.
- Solutes for dissolving test and reference substance:
test substance: 1 g/L stock solution in DMF, diluted to 10 mg/L with methanol
reference substance: about 1 g/L stock solution in methanol, diluted with water to 0.55 g/L (55/45 (v/v) methanol/water).
Blank solutions: 1% DMF in methanol or 55/45 (v/v) methanol/water
Reference substance and test item solutions were injected in duplicate. Blank solutions were analyzed by single injection.

DETERMINATION OF DEAD TIME
- Method: not necessary

REFERENCE SUBSTANCES
- Identity and known logKoc values: 4,4'-DDT, LogKoc: 5.63; 4,4'-DDT was chosen based on soil adsorption data.

DETERMINATION OF RETENTION TIMES
- Quantity of test and reference substances introduced in the column (μg): 0.05 µg and approx. 3 µg, respectively.

REPETITIONS
- Number of determinations: two

EVALUATION
Comparison of retention times

Key result

Type:

log Koc

Value:

> 5.63 dimensionless

Any other information on results incl. tables

The test item eluted as one peak with retention times of 12.415 and 12.416 minutes in the two runs (see background material "S-600 - Adsorption oefficient.pdf"). Under the same analytical conditions, the retention time of 4,4’-DDT (log Koc = 5.63) was 7.9 minutes. Thus, it was concluded that the log Koc of test item was > 5.63.

Validity criteria fulfilled:

not applicable

Description of key information

Log Koc at 35 °C (column temparature): >5.63 (HPLC method; OECD 121, EU C.19)

Additional information

Log Koc at 35 °C (column temparature): >5.63