Hexane, 1,6-diisocyanato-, homopolymer, 2-hydroxyethyl acrylate- and propylene glycol monoacrylate-blocked

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:

From February 21, 2017 to February 27, 2017

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

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

Radiolabelling:

no

Test temperature:

Temperature was held constant at 25 ± 0.5°C using a HPLC column oven.

Details on study design: HPLC method:

- Equipment: Degasser: G1379A, Quaternary pump: G1311A, Autosampler G1313A, Column compartment: G1316A, UV/VIS-Detector: MWD G1365B, Manufacturer: Agilent Technologies, Software: CHROMELEON 6.8 SR11d, Build 3302, HPLC column with a cyanopropyl chemical bound resin on a silica base.

- Details of HPLC parameters:
Gradient: Methanol/Water 55/45% (v/v) or Methanol
Flow rate: 0.8 mL/min
Injection volume: 20 µL
Column: Reprosil PurCN 125 x 4.6 mm, with pre-column Phenomenex Securi-tyGuard CN, 4x3 mm
Column temperature: 25 ± 0.5°C
Evaluation reference Mix: UV, 220 nm
Evaluation test substance: UV, 200 nm

- Mobile Phases:
A mixture of 55% methanol/45% water, isocratic, was used. The mix was produced by mixture of 225 mL water and 275 mL methanol, pH of the eluent was approximately 7. Further mixtures were: 135 mL water and 165 mL methanol, and 225 mL water and 275 mL methanol.

- Test substance solution 1 for the pre-test and of main test 1:
21.0 mg of the test substance was weighed into a 10 mL flask and filled up to 10.5 mL with methanol. 0.55 mL of this solution were mixed with 0.45 mL water, resulting in a solution with a concentration of 1100 mg/L.

- Test substance solution 2 for the measurements of main test 2:
21.5 mg of the test substance was weighed into a 10 mL flask and filled up to 10.75 mL with methanol. 0.55 mL of this solution were mixed with 0.45 mL water, resulting in a solution with a concentration of 1100 mg/L. pH of this solution was approximately 7, measured with pH paper.

- Reference substance: Sodium nitrate, phenol, methylbenzoate, naphtalene, 1,2,3-trichlorobenzene, phenanthrene and 4,4'-DDT

The measurements are performed on moderately polar analytical columns packed with a cyanopropyl solid phase containing lipophilic and polar moieties. This allows for interaction of a molecule in the test system in a similar way as is the case for organic matter in soil or sewage sludge matrices. The peaks of the test substance are retained in proportion to their adsorption coefficient Koc. The retention times of the peaks of the test substance are compared with retention times of reference substances with known adsorption coefficients Koc.

Analytical monitoring:

no

Computational methods:

- Retention times saved and measurement of the capacity factors
- Correlation between k' and log Koc values (with linear regression)

Key result

Type:

log Koc

Value:

> 1.86 - < 5.63 other: dimensionless

pH:

7

Temp.:

20 °C

Details on results (HPLC method):

The chromatogram of the test substance produced 10 peaks, out of which three peaks showed an area of <5%. Hence, they were considered minor peaks and were not considered for determination of the log Koc of the test substance. Based on the areas of the remaining seven peaks and the corresponding log Koc of these peaks, the adsorption coeffecient (log Koc) of the test substance was determined to be in the range of 1.860-5.63.

Validity criteria fulfilled:

yes

Conclusions:

Under the study conditions, the adsorption coefficient log Koc of the test substance was determined to be within the range of 1.860 - 5.63 at pH 7.

Executive summary:

A study was conducted to determine the adsorption coefficient of the test substance on soil and on sewage sludge according to OECD Guideline 121 and EU Method C.19, in compliance with GLP. The study was performed using a HPLC with a cyanopropyl chemical-bound resin on a silica base column at neutral pH. For the determination of the Koc, solutions of the test substance and of the reference substances with known log Koc values based on soil adsorption data were analysed. The capacity factor (k’) of each compound was calculated from its retention time and sodium nitrate retention time. The log k’ values of the reference substances were plotted against the known log Koc values. A calibration function was set up using the literature values for Koc of the reference substances and the mean capacity factor of the six determinations. Linear regression analysis was performed using the least squares method. The coefficient of correlation (r) was calculated. With the help of the calibration function log k’ versus log Koc, the corresponding log Koc values were determined. Under the study conditions, the adsorption coefficient (log Koc) of the test substance was determined to be within the range of 1.86 - 5.63 at pH 7 (Brinkmann, 2017).

Key value for chemical safety assessment

Koc at 20 °C:

426 580

Additional information

A study was conducted to determine the adsorption coefficient of the test substance on soil and on sewage sludge according to OECD Guideline 121 and EU Method C.19, in compliance with GLP. The study was performed using a HPLC with a cyanopropyl chemical-bound resin on a silica base column at neutral pH. For the determination of the Koc, solutions of the test substance and of the reference substances with known log Koc values based on soil adsorption data were analysed. The capacity factor (k’) of each compound was calculated from its retention time and sodium nitrate retention time. The log k’ values of the reference substances were plotted against the known log Koc values. A calibration function was set up using the literature values for Koc of the reference substances and the mean capacity factor of the six determinations. Linear regression analysis was performed using the least squares method. The coefficient of correlation (r) was calculated. With the help of the calibration function log k’ versus log Koc, the corresponding log Koc values were determined. Under the study conditions, the adsorption coefficient (log Koc) of the test substance was determined to be within the range of 1.86 - 5.63 at pH 7 (Brinkmann, 2017).

[LogKoc: 5.63]