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Environmental fate & pathways

Adsorption / desorption

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Administrative data

Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))
Qualifier:
according to
Guideline:
EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))
GLP compliance:
yes
Type of method:
HPLC estimation method
Media:
other: HPLC column

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
Batch No. 0712002519
Radiolabelling:
no

Study design

Test temperature:
Column temperature 35 °C

HPLC method

Details on study design: HPLC method:
EQUIPMENT
- Apparatus: Alliance Separation Module 2695
- Detection system: Dual lambda absorbance detector 2487

MOBILE PHASES
- Type: 30/70 methanol/water (neutral); 30/70 methanol/phosphate buffer (pH 2.0)
- Solutes for dissolving test and reference substances: water (lactic acid); methanol (phenol)

DETERMINATION OF DEAD TIME
- Method: by means of homologous series / by inert substances which are not retained by the column

REFERENCE SUBSTANCES
- Identity: Phenol

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 10 µl; 209 ng (neutral), 135 ng (pH 2)
- Quantity of reference substances: 10 µl; 100 ng

REPETITIONS
- Number of determinations: all samples were measured in duplicate; controls were injected once

EVALUATION
- Calculation of capacity factors k': Not calculated
- Calculation of retention times: Not given other than in (single) chromatogram run printouts
- Determination of the log Koc value: <1.32 (i.e. < phenol log Koc)

Results and discussion

Adsorption coefficientopen allclose all
Key result
Type:
Koc
Value:
< 20.9 dimensionless
Type:
log Koc
Value:
< 1.32 dimensionless

Results: HPLC method

Details on results (HPLC method):
Lactic acid eluted before phenol; phenol has a designated Koc of < 20.9 (log Koc < 1.32). No relevant differences in the results were observed at neutral pH and pH 2.0.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The Koc of lactic acid is < 20.9 (log Koc < 1.32).
Executive summary:

The adsorption coefficient (Koc) of lactic acid on soil and on sewage sludge was determined using high performance liquid chromatography (HPLC).

The Koc and log Koc value of the test substance at neutral pH and at pH 2 was < 20.9 and < 1.32, respectively.