Reaction mass of 2-(3-{6-[3-(2-Hydroxyethyl)-3-methylureido]hexyl}-1-methylureido)ethanol and 6-[3-(2-Hydroxyethyl)-3-methylureido]hexylamino 3-(methylamino)propionate

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))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Radiolabelling:

no

Details on study design: HPLC method:

Chromatograph: High Performance Liquid Chromatograph, Agilent 1100
Chromatographic conditions:
Column type: length: 250 mm, inner diameter: 4 mm Stationary Phase: LiChrospher 100 CN, particle diameter: 5 μm Supplier: Fa. Merck
Mobile Phase: 415 mL demineralized water (Millipore) + 85 mL buffer pH 6 + 500 mL acetonitrile (isocratic)
Flow rate: 0.5 mL/min Column Temperature: 40 °C Detection: UV, 220 nm Injection volume: 3 μL

Determination of the dead time was performed using sodium nitrate.

Analytical monitoring:

not required

Sample No.:

#1

Type:

log Koc

Value:

ca. 0.5 - ca. 0.9

pH:

7

Temp.:

25 °C

Details on results (HPLC method):

Capacity factor: k’ = (tR - t0)/t0
tR = retention time of substances;
t0 = dead time
Effective correlation: log k’ = a + b log Koc
Linear regression gives:
a = - 0.5020
b = 0.2307
r = 0.9755
where a and b = regression factor and r = correlation factor

Mean value of 3 single values of the test item EGGE 2806-1

	Retention time [tr] = min	Capacity factor k’	Log k’	Log Koc
EGGE 2806-1 peak 1 (main component, 60%)	4.738 +-0.001	0.410	-0.3867	0.500
EGGE 2806-1 peak 2 (minor component, 23%)	5.039 +- 0.001	0.500	- 0.3010	0.871

Validity criteria fulfilled:

yes

Conclusions:

The logKoc of the substance is in the range of about 0.5 to 0.9 (2 peaks). The results are below the logKoc value of the reference substance with the lowest logKoc (1.45). Therefore the extrapolated values were taken for assessment.

Executive summary:

In a test according to OECD 121 (HPLC method) the logKoc of Reaction mass of 2-(3-{6-[3-(2-Hydroxyethyl)-3-methylureido]hexyl}-1-methylureido)ethanol and 6-[3-(2-Hydroxyethyl)-3-methylureido]hexylamino 3-(methylamino)propionate ("EGGE 2806 -1") was determined. The substance consists of 2 isomers which have slighly different retention behaviour under the conditions of the guideline. Individual log Koc value were reported to be 0.5 and 0.9. However the study used only reference substances with a logKoc >1.5. Therefore the study report stated a Koc value of <1.5. Re-evaluation however allows to report the individual values obtained by extrapolation. This is justified as the replicates of retention times were stable (typically +-0.001 min) and the linear regression yielded a correlation coefficient of >0.97.

Description of key information

In a test according to OECD 121 (HPLC method) the logKoc of Reaction mass of 2-(3-{6-[3-(2-Hydroxyethyl)-3-methylureido]hexyl}-1-methylureido)ethanol and 6-[3-(2-Hydroxyethyl)-3-methylureido]hexylamino 3-(methylamino)propionate ("EGGE 2806 -1") was determined. The substance consists of 2 isomers which have slighly different retention behaviour under the conditions of the guideline. Individual log Koc value were reported to be 0.5 and 0.9. However the study used only reference substances with a logKoc >1.5. Therefore the study report stated a Koc value of <1.5. Re-evaluation however allows to report the individual values obtained by extrapolation. This is justified as the 3 replicates of retention times were stable (typically +-0.001 min) and the linear regression yielded a correlation coefficient of >0.97.

The lowest logKoc value was choosen as key information as this reprensents the worst when using EPM for calculating effects values in soil and sediment from aquatic toxicity data.

Key value for chemical safety assessment

Koc at 20 °C:

3.2

Additional information

[LogKoc: 0.5]