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Adsorption / desorption

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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
15 January 2017 - 27 June 2017
Reliability:
1 (reliable without restriction)
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:
no
GLP compliance:
yes (incl. certificate)
Type of method:
HPLC estimation method
Test temperature:
40°C
Details on study design: HPLC method:
EQUIPMENT
- Apparatus: Agilent Technologies 1200 Series, incorporating autosampler and workstation
- Type, material and dimension of analytical (guard) column: Luna 5 mm Cyano 100Å (150 x 4.6 mm id)
- Detection system: Ultraviolet (UV)

MOBILE PHASES
- Type: A:Methanol:purified water (55:45 v/v), adjusted to pH approx. 7 using sodium hydroxide (0.1M)
B: THF
- Experiments with additives carried out on separate columns: no
- pH: 7.0
- Solutes for dissolving test and reference substances: methanol

DETERMINATION OF DEAD TIME
- Method: The dead time was determined by measuring the retention time of formamide [purity* 99.94%, 601 mg/L solution in methanol: purified water (55:45 v/v)].

REFERENCE SUBSTANCES
- Identity: Acetanilide, Phenol, Atrazine, Isoproturon, Triadimenol, Linuron, Naphthalene, Endosulfan-diol, Fenthion, a-Endosulfan, Phenanthrene, Diclofop-methyl, DDT.



DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: Test item (0.5016 g) was diluted to 50 mL with tetrahydrofuran (THF) to give a concentration of 10.0 g/L.


Key result
Type:
log Koc
Value:
> 5.63 dimensionless
pH:
7
Temp.:
40 °C
Details on results (HPLC method):
As the test item had a high affinity for the stationary phase of the column, the mobile phase was adjusted to 100% THF shortly after the retention time of DDT to elute the sample. As the slope of the calibration curve for the reference standards showed good first order correlation and as the retention times between duplicate injections for each solution was consistent, the HPLC method was considered valid for the determination of adsorption coefficient. Based on the chromatographic data, the test item was considered to be stable during the test procedure.
Validity criteria fulfilled:
yes
Conclusions:
The adsorption coefficient (Koc) of the test item has been determined to be greater than 4.27 x 105, log10 Koc >5.63. This value indicates that the test item is immobile.
Executive summary:

Greater than 4.27 x 105, log10 Koc >5.63. This value indicates that the test item has is immobile. Determination carried out using the HPLC screening method, designed to be compatible with Method 121 of the OECD Guidelines for Testing of Chemicals, 22 January 2001 Method C.19 Adsorption Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008.

Description of key information

Greater than 4.27 x 105, log10 Koc >5.63. This value indicates that the test item has is immobile. Determination carried out using the HPLC screening method,

Key value for chemical safety assessment

Koc at 20 °C:
426 580

Additional information

[LogKoc: 5.63]