Estradiol

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

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))

Deviations:

no

Qualifier:

equivalent or similar 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:

not applicable

GLP compliance:

yes

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Radiolabelling:

no

Test temperature:

25 °C

Details on study design: HPLC method:

HPLC CONDITIONS:
- Instrumentation: liquid chromatograph series Agilent 1100 with autosampler and diode array detector
- Column: stainless steel [ISO x 4.6 mm (length x i.d.)]
- Stationary phase: Zorbax SB-CN, 5 µm
- Eluent: methanol/0.01 M citrate buffer pH 6; 55 : 45 (by volume before mixing); the pH was determined in the aqueous phases with a calibrated glass electrode (Knick pH-meter 766 Calimatic)
- Flow rate: 1.0 mL/ min
- Injection volume: 5 µL n-alkyl methyl ketones; 5 µL reference substances; 5 µL test substance
- Substance concentrations: n-alkylmethyl ketones (approx. 3-5 mg/mL); reference substances (approx. 0.01-0.08 mg/mL); test substance 0.11 mg/mL (ketones in methanol/water mixtures. reference and test substances in methanol/eluent buffer)
-Detection: n-alkyl methyl ketones (UV 280 nm); reference substances (UV 210 nm); test substance (UV 210nm)
-Retention time determination: chromatography evaluation system (Millennium 4.0) for online recorded chromatograms (LD/LDV, Schering AG)

TEST SEQUENCE:
- 2 injections ofn-alkylmethyl ketone mixture
- 2 injections of reference substance mixture
- 3 injections of the test substance
- 2 injections of reference substance mixture
- 2 injections ofn-alkyl methyl ketone mixture
- 1 injection of test substance in acetonitrile (for test of stability under test conditions, only (0.10 mg/mL)

Analytical monitoring:

yes

Details on matrix:

Cyanopropyl phase

Sample No.:

#1

Duration:

6.5 min

Initial conc. measured:

0.11 other: mg/mL

pH:

6

Temp.:

25 °C

Remarks:

Test substance (UV 210 nm)

Sample no.:

#1

Duration:

6.5 min

Conc. of adsorbed test mat.:

0.11 other: mg/mL

pH:

6

Temp.:

25 °C

Remarks:

Test substance (UV 210 nm)

Key result

Sample No.:

#1

Type:

Koc

Value:

3.4

pH:

6

Temp.:

25 °C

Matrix:

Zorbax SB-CN, 5 µm

Remarks on result:

other: (95% confidence limits 3.1 to 3.7)

Transformation products:

not specified

Validity criteria fulfilled:

yes

Conclusions:

The soil adsorption coefficient (Koc) of 3.4 was determined at pH 6 and 25 °C. The 95% confidence limit was between 3.1 and 3.7.

Executive summary:

The soil adsorption coefficient Koc of 3.4 (95% confidence limits 3.1 to 3.7) was determined according to EU Testing Guideline C.l9 (HPLC method based) at pH 6 and 25 °C. The method is based on the correlation of the HPLC retention data of the test compound on a cyanopropyl phase with those of reference compounds with known log Koc values.

Description of key information

The soil adsorption coefficient (Koc) of 3.4 was determined at pH 6 and 25 °C. The 95% confidence limit was between 3.1 and 3.7.

Key value for chemical safety assessment

Koc at 20 °C:

3.4

Additional information

"Should read: 3.4 at 25 °C"