3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl)pyrrolidine-2,5-dione

Adsorption / desorption

Link to relevant study record(s)

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))

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))

Principles of method if other than guideline:

The guideline was not applicable for the determination of the adsorption coefficient (Koc) of the test substance on soil and on sewage sludge because the log Koc of the test item is outside the scope of this guideline.

GLP compliance:

yes

Type of method:

HPLC estimation method

Media:

other: HPLC eluent

Radiolabelling:

no

Details on study design: HPLC method:

Test system:
Analytical HPLC-column (based on silica matrix) packed with a cyanopropyl solid phase containing non-polar and polar moieties coupled to DAD. Acetonitrile and 20 mM KH2PO4 at pH 7 in a ratio 65 : 35 was used as mobile phase. A buffer was needed because the test item is a base.
Reasons for the selection: The selection of the test system was based on the guidelines. HPLC coupled to DAD is a useful method for estimation of the adsorption coefficient Koc. The Koc indicates the binding capacity of the test item on soil or sewage sludge and allows comparing the adsorption behaviour of different chemicals.

Analytical monitoring:

not required

Details on test conditions:

HPLC-DAD-System: HPLC AGILENT 1100 consisting of
Auto sampler: G1329A
Auto sampler thermostat: G1330B
Degasser: G1322A
Column oven: G1316A
Detector (test system): G1315B
Pump: G1312A
Software: Empower 2 (Build No: 2154), WATERS

Reagents:
Acetonitrile, super gradient, VWR
HPLC water, for HPLC, VWR
Potassium dihydrogen orthophosphate, 99.8 %, VWR

HPLC column:
YMC-Pack Cyano, 250 x 4.0 mm, S-5 µm, 120 Angström
Gel. Lot 11334, YMC Europe GmbH

Additional Equipment:
Analytical balance
Top pan balance
Direct displacement pipettes, Microman, Gilson
Piston stroke pipettes, Finnpipette, Thermo Scientific
Laboratory glassware

Mobile phase:
Acetonitrile and 20 mM KH2PO4 at pH 7 in a ratio 65 : 35
Buffered mobile phase was used for pH stabilisation due to the basic properties of the test item.
Column temperature: 22 °C
Flow: 1 mL/min
Test item: Hostavin 3055
Stock solution: 2000 mg/L in Acetonitrile
Test concentration: 100 mg/L
Dilution: With acetonitrile and 20 mM KH2PO4 (at pH 7) to mobile phase ratio
Replicates: Single (one injection)
Detection: with DAD

Reference items:
Sodium nitrate was used for determination of dead time of the test system. Phenyl benzoate, Phenanthrene and 4,4'-DDT were used as further reference items.
Test concentrations: 5 mg/L
Replicates: single with one injection

Conditions of analysis: see 'Any other information on materials and methods incl. tables'

Key result

Sample No.:

#1

Type:

log Koc

Value:

> 5.63 dimensionless

pH:

7

Temp.:

22 °C

Matrix:

Analytical HPLC-column (based on silica matrix) packed with a cyanopropyl solid phase containing non-polar and polar moieties

Remarks on result:

other: retention time was higher than that of the standard with the highest log Koc ( 4,4'-DDT; log Koc = 5.63)

Sample No.:

#1

Phase system:

other: Acetonitrile and 20 mM KH2PO4 in a ratio 65 : 35

Type:

log Kp

Value:

other: not detectable

Temp.:

22 °C

pH:

7

Remarks on result:

not determinable

Details on results (HPLC method):

The guideline was not applicable for the determination of the adsorption coefficient (Koc) of the test substance on soil and on sewage sludge because the log Koc of the test item is outside the scope of this guideline.

Transformation products:

no

Retention Times of the Reference Items and Test Item

Reference item	Retention time	log Koc, soil	log Koc, sewage sludge
Sodium nitrate (dead time)	1.676	-	-
Phenyl benzoate	3.538	2.87	3.26
Phenanthrene	3.915	4.09	4.35
4,4'-DDT	4.891	5.63	-
Test item	15.068	-	-

Validity criteria fulfilled:

yes

Conclusions:

The guideline was not applicable for the determination of the adsorption coefficient (Koc) of the test substance on soil and on sewage sludge because the log Koc of the test item is outside the scope of this guideline.

Executive summary:

Preliminary investigations for the determination of the adsorption coefficient Koc of the test substance on soil and on sewage sludge using high performance liquid chromatography (HPLC) were performed according to OECD 121 and Council Regulation (EC) No. 440/2008, Method C.19.

The results of these experiments showed that this guideline is not applicable for the determination of the adsorption coefficient (KOC) of the test substance on soil and on sewage sludge because the test item has a higher retention time than 4,4'-DDT. 4,4'-DDT is the reference compound given in the guideline with the highest log Koc value of 5.63. A determination of the log Koc value would be only possible by extrapolation, which provides significant inaccuracy for the study endpoint.

Description of key information

No definitive conclusion on log Koc possible based on HPLC-screening test (OECD 121; pH 7; RL1): retention time was considerably higher than that of the standard with the highest log Koc ( 4,4'-DDT; log Koc = 5.63).

Conclusion: log Koc (test item) > 5.63

Key value for chemical safety assessment

Koc at 20 °C:

426 580

Additional information

Preliminary investigations for the determination of the adsorption coefficient Koc of the test substance on soil and on sewage sludge using high performance liquid chromatography (HPLC) were performed according to OECD 121 and Council Regulation (EC) No. 440/2008, Method C.19, compliant with GLP (RL1; NOACK, 2016). The test was performed at neutral pH using buffered mobile phase (pH 7).

No definitive conclusion with regard to the Koc value of the submission substance could be drawn: the test item showed a pronouncedly higher retention time than 4,4'-DDT. 4,4'-DDT is the reference compound given in the guideline with the highest log Koc value of 5.63. A determination of the log Koc value would have been only possible by extrapolation, which provides significant inaccuracy for the study endpoint.

Therefore, the conclusion for the test item is:

log Koc (OECD 121; pH 7) > 5.63

[LogKoc: 5.63]

[LogKoc: 5.63]