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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:
2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
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
GLP compliance:
yes (incl. QA statement)
Type of method:
HPLC estimation method
Specific details on test material used for the study:
EC name: tert-pentyl peroxypivalate
Chemical name: tert-Amyl peroxypivalate
Trade name: Trigonox 125-C75
CAS: 29240-17-3
Batch/Lot no.: 1205442102
Composition: see CoA
Appearance: Colorless clear liquid
Storage: approx. -25°C
Expiry date: January 1, 2017
Radiolabelling:
no
Details on study design: HPLC method:
For each reference substance and the test substance a stock solution was prepared by weighing an accurate amount of substance on an analytical balance and transferring it into a 25 mL measuring flask and filling it up to the mark with methanol. The reference substance and test substance solutions, to be injected into the HPLC system, i.e. reference solution, test substance solution, as well as mixtures of these, were prepared by transferring an amount of stock solution to a HPLC vial and adding methanol and HPLC grade water so the final solution had the same methanol-water ratio as used for the mobile phase. In the same way as described for the reference substances a stock solution and test solution of thiourea was prepared.
In order to determine the retention time, the prepared solutions of the test substance and reference substances were injected separately as well as in mixtures into the HPLC.
Key result
Type:
log Koc
Value:
1.92
Details on results (HPLC method):
Average retention times of the reference substances and test substance
Substance log Koc Avg Avg net Avg log Koc
theoretical ret. time ret. time log k’ calculated
(min) (min)
Thiourea (dead time) 2.64 0
Acetanilide 1.25 3.14 0.51 -0.72
Methyl benzoate 1.80 3.61 0.98 -0.43
Aniline 2.07 3.39 0.76 -0.54
Naphthalene 2.75 5.25 2.62 0.00
1,2,3-Trichlorobenzene 3.16 5.04 2.41 -0.04
Phenanthrene 4.09 10.40 7.76 0.47
Test substance T15037 3.53 0.89 -0.47 1.92
Conclusions:
In the test, the average log Koc value for the test substance was calculated with the retention time of two injections, using the calibration plot of log k’ versus log Koc of the selected reference substances. The average measured log Koc value for the test substance, as determined from the test, was calculated to be 1.92. The test substance had a Koc of 83.
Executive summary:

The adsorption coefficient (Koc) of the test substance was estimated using the High Performance Liquid Chromatography (HPLC) method. The Koctest was performed in accordance with the OECD guideline 121.The data on Koccan be used to predict the potential of the test substance to partition to soil, sediment or sewage sludge.

The average log Kocvalue for the test substance calculated from the test was 1.92, which is equal to a Kocof 83.

Description of key information

The adsorption coefficient (Koc) of the test substancewas estimated using the High Performance Liquid Chromatography (HPLC) method. The Koc test was performed in accordance with the OECD guideline 121.The data on Koc can be used to predict the potential of the test substance to partition to soil, sediment or sewage sludge.

The average log Koc value for the test substance calculated from the test was 1.92, which is equal to a Koc of 83.

Key value for chemical safety assessment

Koc at 20 °C:
83

Additional information

[LogKoc: 1.92]