7,7-dimethyl-3-oxa-6-azaoctan-1-ol

Adsorption / desorption

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

adsorption / desorption

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Study period:

Not applicable.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: EPI Suite is a reliable QSAR established by the EPA for analysis of certain environmental end points.

Justification for type of information:

QSAR prediction: migrated from IUCLID 5.6

Qualifier:

no guideline required

Principles of method if other than guideline:

The Koc of the substance was predicted using EPI Suite v3.20 program.

GLP compliance:

no

Type:

log Koc

Value:

1

Details on results (HPLC method):

A QSAR prediction using EPI Suite v3.20 estimated the Log Koc to be 1.

Validity criteria fulfilled:

not applicable

Conclusions:

A QSAR prediction using EPI Suite v3.20 estimated the Log Koc to be 1.

Reference 2

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

04 July to 05 July 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted to GLP and in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not effect the quality of the relevant results.

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

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Radiolabelling:

no

Test temperature:

Column temperature: 19ºC (+/- 1ºC)

Details on study design: HPLC method:

Sample preparation:
Mobile phase buffered to pH 7.0

The test material was dispersed in pH7 buffered mobile phase and injected in duplicate (99.1 mg in 10 ml). The quantities injected were 198.2 μg.


EQUIPMENT
Instrumentation:
HPLC pump: Perkin Elmer series 200 Quaternary pump
Detectors: Perlcin Elmer 785A UVIVIS @225nm (channel A)
Perkin Elmer LC25 Refractive Index (RI) (channel B)
Interface box: PE Nelson 950A
Computer: Compuadd e series Pl20
Software: PE Nelson Turbochrom , Version 4.1 <2FI2>
Injector: Perlcin Elmer Series 200 autosampler

HPLC conditions:
Mobile phase: 55:45 Methanol:aqueous buffer (pH 7.0)
Flow rate: 1 ml/min
UV detectors: 1.0V/AU
Injection volume: 20 μl (standard) and 20 μl (sample and blank)
Analytical column: Hypersil CP5, 5μ, 25cm
Guard column: Not used
Column heater: Not used
Column temperature: 19ºC (laboratory air conditioning).


DETERMINATION OF DEAD TIME
The system dead time (t0) is the average retention time of a non-retained material. The dead time is taken as the retention time of the sodium nitrate peak (or the solvent front when the sodium nitrate and solvent coelute).


REFERENCE SUBSTANCES
- Identity: phenol, atrazine, naphthalene, 1,2,3-trichlorobenzene, dichlofop-methyl, DDT, sodium nitrate (t0)


DETERMINATION OF RETENTION TIMES
Retention time of the sodium nitrate peak (or the solvent front when the sodium nitrate and solvent coelute).


EVALUATION
- Calculation of capacity factors k':
The adsorption coefficient is derived from the capacity factor k, given by the expression:

k = tR - t0 / t0

Where tR is the retention time of the test material (or a component) and t0 is the dead-time.

Calibration graphs are generated for log k against log Koc, (the adsorption coefficient), for the reference compounds.

The HPLC method enables adsorption coefficients to be estimated in the log Koc, range between 1.5 and 5.0.

Type:

log Koc

Value:

0 - 4.28

Details on results (HPLC method):

The pKa value was not known for the test substance, therefore the analysis was perfonned at pH 7.0.

Eight peaks were detected UV detection at 225nm and one with RI detection. The log Koc, values range from <0.0 to 4.28.

The large negative peak noted in the UV chromatogram, for the test substance, was found to be reproducible and has been included in the report. A negative peak is generated when a component has less absorbance than the mobile phase.

The test substance was scanned between 190 and 350nrn. A λ max was noted at 225nm

The peak for DDT in the attached RI chromatogram was missing. This is due to the fact that it was not wholly soluble under the conditions of the mixed standard. Preliminary work with the standards individually prepared gave better chromatography and confirmation of peak identity.

See attached background results for results tables and chromatograms.

Validity criteria fulfilled:

yes

Conclusions:

The log Koc values range from <0.0 to 4.28.

Executive summary:

This report contains a description of the methods used and the results obtained during a study to evaluate the Adsorption Coefficient(s) of thetest substance.

This experimental method uses HPLC for the estimation of the adsorption coefficient Koc, in soil and sewage sludge (following OECD guideline 121).

The pKa value was not known for the test substance, therefore the analysis was perfonned at pH 7.0.

Eight peaks were detected UV detection at 225nm and one with RI detection. The log Koc, values range from <0.0 to 4.28.

Description of key information

Key Study: Log Koc = 0-4.28 (Drake, 2001); OECD 121

Key value for chemical safety assessment

Koc at 20 °C:

21.88

Additional information

In a study conducted in accordance with OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and Sewage Sludge), multiple peaks were observed in test chromatograam produced in the study, many of which are considered insignificant to the test item (i.e. <1 % of overall peak area). Thus the given range of Koc reported in Drake (2001) is perhaps misleading with respect to the potential adsorption of the sub stance to soil and sewage sludge. The major peaks in this study occured at 3.3, 3.5 and 3.9 minutes, indicating a log Koc range of -0.5 to 1.34 which is more representative of the substance tested. Therefore a Koc of 21.88 and a log Koc of 1.34 have been presented as values for use in the chemical safety assessment.

[LogKoc: 1.34]

[LogKoc: 1.34]