3-(dimethylamino)propylurea

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

key study

Study period:

2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Qualifier:

no guideline followed

Principles of method if other than guideline:

Testing was not undertaken according to the OECD draft guideline (December 1998), Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid
Chromatography (HPLC), as 3-(dimethylamino) propylurea was deemed unsuitable for the method.
Investigations into the possibility of conducting the test experimentally were performed, using a cyano stationary phase HPLC column and various solvent (methanol or acetonitrile): water mobile phase
compositions. Refractive Index and ultraviolet detectors were used.
It was concluded, after considerable time and method development, that the test material was either interacting with the HPLC column in a specific way or was not eluting from the column at all.
To confirm this, a sample was prepared at approximately 2.50 x 10^4 mg/l in methanol. This was then analysed with and without the analytical column in place.
No test material was detected when the analytical column was in place. This confirmed that the test material was either interacting with the stationary phase of the column, or was not eluting from the column, even
with 100% organic solvent as the mobile phase.
Therefore, estimates of the adsorption coefficient were obtained using computer-based estimation software (PCKOCWIN, Version 1.6, W. Meylan and P. Howard, Syracuse Research Corporation) and Quantitative Structure Activity Relationships (QSAR's), the details of which are provided in the technical guidance-documents in Support of Commission Directive 93/67/EEC on risk assessment for new notified substances.

GLP compliance:

yes (incl. QA statement)

Type of method:

other: PCKOCWIN Estimate

Details on study design: HPLC method:

Testing was not undertaken according to the OECD draft guideline (December 1998): Estimation of the Adsorption Coefficient (Koc) on soil and on sewage sludge using High Performance Liquid Chromatography (HPLC), as 3-(dimethylamino)propylurea was deemed unsuitable for the method.
Investigations into the possibility of conducting the test experimentally were performed, using a cyano stationary phase HPLC column and various solvent
(methanol or acetonitrile): water mobile phase compositions. Refractive Index and ultraviolet detectors were used.
It was concluded, after considerable time and method development, that the test material was either interacting with the HPLC column in a specific way or was not eluting from the column at all.
To confirm this, a sample was prepared at approximately 2.50 x 10^4 mg/l in methanol. This was then analysed with and without the analytical column in place
using the following conditions:
HPLC system: Waters 600E multisolvent delivery system
Waters 410 Differential Refractometer
Waters WISP 700 autosampler
Waters column oven
Column: Luna 5 µm CN (250 x 4.6 mm id)
Column temperature: 40'C
Mobile phase: methanol (100%)
Detector: Differential refractometer
Injection volume: 100 µl

No test material was detected when the analytical column was in place. This confirmed that the test material was either interacting with the stationary phase of the column, or was not eluting from the column, even with 100% organic solvent as the mobile phase.

Key result

Type:

Koc

Value:

1.66 dimensionless

Remarks on result:

not determinable because of methodological limitations

Validity criteria fulfilled:

not specified

Executive summary:

Testing was not undertaken according to the OECD draft guideline (December 1998), Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid

Chromatography (HPLC), as 3-(dimethylamino) propylurea was deemed unsuitable for the method.

Investigations into the possibility of conducting the test experimentally were performed, using a cyano stationary phase HPLC column and various solvent (methanol or acetonitrile): water mobile phase

compositions. Refractive Index and ultraviolet detectors were used.

It was concluded, after considerable time and method development, that the test material was either interacting with the HPLC column in a specific way or was not eluting from the column at all.

To confirm this, a sample was prepared at approximately 2.50 x 10^4 mg/l in methanol. This was then analysed with and without the analytical column in place.

No test material was detected when the analytical column was in place. This confirmed that the test material was either interacting with the stationary phase of the column, or was not eluting from the column, even

with 100% organic solvent as the mobile phase.

Therefore, estimates of the adsorption coefficient were obtained using computer-based estimation software (PCKOCWIN, Version 1.6, W. Meylan and P. Howard, Syracuse Research Corporation) and Quantitative Structure Activity Relationships (QSAR's), the details of which are provided in the technical guidance-documents in Support of Commission Directive 93/67/EEC on risk assessment for new notified substances.

PCKOCWIN estimate: Using the chemical structure as supplied by the sponsor, the adsorption coefficient was estimated to be 46.2, logKoc, Koc 1.66.

Key value for chemical safety assessment

Koc at 20 °C:

1.66