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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:

29 May 2003 to 28 August 2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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))

Version / remarks:

EC Comission Directive 1999/11/EC of 8 March 1999 (Official Journal No L 77/8)

Deviations:

no

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))

Version / remarks:

January 2001

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Radiolabelling:

no

Test temperature:

Temperature: ambient

Details on study design: HPLC method:

PROCEDURE: In order to correlate the measured capacity factor (k) of the test material with its Koc, six reference materials were selected from a list of recommended compounds. These reference compounds were selected to have log10 Koc values between 1.25 and 2.75. A standard (sodium nitrate) with no retention on the HPLC column was used to determine the deadtime of the HPLC system. Duplicate solutions of ca 160 mg/l T-71 in methanol/water, 50/50, v/v were prepared and chromatographed, with solutions of the reference standards, using the following conditions.

DETERMINATION OF DEAD TIME: 1.77 minutes

For details on HPLC standards and the conditions see attachment "T-71 - HPLC standards and conditions adsorption.pdf".

Key result

Type:

log Koc

Value:

< 1.25 dimensionless

Key result

Type:

Koc

Value:

< 17.8 dimensionless

Details on results (HPLC method):

The deadtime (to) was determined as 1.77 minutes. Analytical data for the reference compounds and the test substance are given in attachment "T-71 Analytical data log10Koc by HPLC".
The regression equation produced was:
log10 k = -0.15354 + 0.24135log10 Koc (R= 0.98485)
The mean HPLC retention time of T-71 was 2.38 minutes, which is lower than that obtained for the reference compounds. Therefore the result can be quoted as log10 Koc <1.25, the value of the quickest eluting reference compound (acetanilide).
Duplicate blank solutions showed no peaks in the chromatograms at the characteristic retention time of the test substance.

Description of key information

log10Koc of T-71 was found to be <1.25 (Koc = <17.8) (HPLC method; OECD 121, EU C.19)

Additional information

Koc at ca. 20 °C: <17.8

log10Koc at ca. 20 °C: <1.25