Sodium 6,14-diethyl-1,1,1,2,2,18,18,19,19,19-decafluoro-8,12-dioxo-10-({[1-(2,2,3,3,3-pentafluoropropoxy)butan-2-yl]oxy}carbonyl)-4,7,13,16-tetraoxanonadecane-9-sulfonate

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:

05 AUG 2016 - 03 FEB 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to other study

Reason / purpose for cross-reference:

reference to other study

Reason / purpose for cross-reference:

reference to other study

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:

22nd January 2001

Deviations:

no

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:

2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Radiolabelling:

no

Test temperature:

25°C

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: A high performance liquid chromatograph with an UV-VIS detector or MS detector was used. The detection wavelength or MS conditions depended on the characteristics of the test item and the reference items
HPLC-Conditions:
Column: LiChrospher 100 CN (250*4 mm, 5 μm)
Temperature: 25°C


DETERMINATION OF DEAD TIME
- Method: by inert substances which are not retained by the column

REFERENCE SUBSTANCES
- Identity: Acetanilid, Methylbenzoat, Linuron, 1,2,3 Trichlorobenzene, Pyrazophos, Diclofop-methyl, Sodium nitrate

DETERMINATION OF RETENTION TIMES
- Quantity of test substance/reference substance introduced in the column: Injection Volume: 5, 20 or 50 μL. Smaller injection volumes were required to obtained sharp peaks in case of the reference item.
- Intervals of calibration: logKoc 1.25 - 1.8 - 2.59 - 3.16 - 3.65 - 4.2

REPETITIONS
- Number of determinations: 3 replicates

EVALUATION
- Calculation of capacity factors k': The capacity factor was calculated from the retention of the substance concerned (tr) and the unretarded component (t0): k' = (tr - t0) / t0, with tr = retention time [min] and t0 = time a non-sorbed chemical needs to pass the column (dead time) [min], k' = capacity factor
- Calculation of retention times: An inert substance (not retained by the column) was used to determine the dead time. A stock solution of the compound was prepared by dissolution in pure water (1000 mg/L). This stock solution was diluted with pure water and was injected three times to determine the dead time t0 (t0 = retention time of the unretarded component). The retention time of the inert reference item, the test item and acetanilide were determined using MS scan.
- Determination of the log Koc value: The adsorption coefficient Koc is deduced from the capacity factor k’ using a calibration plot of log k’ versus log Koc of selected reference items.

Type:

log Koc

Value:

< 1.25 dimensionless

Temp.:

25 °C

Remarks on result:

other: please refer to 'remarks'

Remarks:

The OECD 121 Guideline might not be applicable for test items with surface active properties. The test item is surface active (20.2 mN/m, see report 20100675.04). Therefore, the calculated values (estimated based on the water solubility or the log Kow were log Koc 2.4 or 3.1 respectively) seem to be more plausible than the log Koc determined by the experimental study.

Type:

log Koc

Value:

2.4 dimensionless

Remarks on result:

other: estimated based on water solubility

Type:

log Koc

Value:

3.1 dimensionless

Remarks on result:

other: estimated based on log Kow

Details on results (HPLC method):

- Retention times of reference substances used for calibration: please refer to attached pdf
- Details of fitted regression line (log k' vs. log Koc): Calibration curve: y = 0.1840* x – 0.0648, regression coefficient r² = 0.9941
- Graph of regression line attached: please refer to attached pdf
- Average retention data for test substance: 1.35 min (LCMS analysis)

Validity criteria fulfilled:

not specified

Conclusions:

The log Koc of the test item was estimated to be below 1.25 using HPLC method.
Theoretical estimations of the log Koc based on the water solubility or the log Kow resulted in a log Koc of 2.4 or 3.1, respectively.

Executive summary:

The study was performed under GLP-conditions and according to OECD Guideline 121 and EU Method C.19 to estimate the adsorption coefficient Koc of the test item using HPLC-method. The measured retention time of the test item was correlated with its adsorption coefficient using a calibration graph.

The present study estimated the log Koc of the test item using HPLC method. Based on calibration curves obtained by correlation of the retention time of 6 structurally heterogeneous reference items with their known adsorption coefficient, the log Koc of the test item was estimated to be below 1.25.

Theoretical estimations of the log Koc based on the water solubility or the log Kow resulted in a log Koc of 2.4 or 3.1, respectively.

All values are generated by estimation and thus a discrepancy of the values may be reasonable. The OECD 121 Guideline might not be applicable for test items with surface active properties. The test item is surface active (20.2 mN/m, Huber, 2011b). Therefore, the calculated values seem to be more plausible than the log Koc determined by the experimental study.

Description of key information

The study was performed under GLP-conditions and according to OECD Guideline 121 and EU Method C.19 to estimate the adsorption coefficient Koc of the test item using HPLC-method. The measured retention time of the test item was correlated with its adsorption coefficient using a calibration graph.

The present study estimated the log Koc of the test item using HPLC method. Based on calibration curves obtained by correlation of the retention time of 6 structurally heterogeneous reference items with their known adsorption coefficient, the log Koc of the test was estimated to be below 1.25.

Theoretical estimations of the log Koc based on the water solubility or the log Kow resulted in a log Koc of 2.4 or 3.1, respectively.

All values are generated by estimation and thus a discrepancy of the values may be reasonable. The OECD 121 Guideline might not be applicable for test items with surface active properties. The test item is surface active (20.2 mN/m, see Huber, 2011b). Therefore, the calculated values seem to be more plausible than the log Koc determined by the experimental study.

Key value for chemical safety assessment

Koc at 20 °C:

251

Additional information

The log Koc was estimated to be below 1.25. However, the OECD 121 Guideline might not be applicable for test items with surface active properties. The test item is surface active (20.2 mN/m, see Huber 2011b). Therefore, the calculated values seem to be more plausible than the log Koc determined by the experimental study. The theoretical estimated log Koc of 3.1 is based on the partition coefficient, which was determined by calculation while the estimated log Koc of 2.4 (Koc = 251) is based on the water solubility, which has been determined according to EU Method A.6, OECD Guideline 105. Thus, the log Koc of 2.4 is most reliable and used as key value.