Registration Dossier

Environmental fate & pathways

Adsorption / desorption

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
July 10, 2013
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
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))
Version / remarks:
(2008)
Deviations:
no
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))
Version / remarks:
(2001)
Deviations:
no
GLP compliance:
yes
Type of method:
HPLC estimation method
Media:
soil
Radiolabelling:
no
Details on study design: HPLC method:
CALCULATION OF PKA
The following pKa values in the pH range of 1 - 14 were calculated using the Perrin calculation method (pKalc 5.0, module in Pallas 3.0, CompuDrug International San Francisco, USA): pKa acidic: 2.83 and 3.43; pKa basic: none

HPLC METHOD CONDITIONS
Justification: based on the pKa calculations, the HPLC method was performed at pH 2 which is the lowest pH that can be used with a cyanopropyl column, and at pH 7. At pH 2, major part of the test substance will be in its non-ionised form. At pH 7, the test substance will be fully ionised.

Instrument: Acquity UPLC system (Waters, USA)
Detector: Acquity UPLC TUV detector (Waters)
Column: Acquity UPLC HSS Cyano, 100 mm × 2.1 mm i.d., dp = 1.8 μm (Waters)
Column temperature:  35°C ± 1°C
Mobile phase pH 2: 30/70 (v/v) methanol/water adjusted to pH 2 using H3PO4
Mobile phase pH 7: 30/70 (v/v) methanol/phosphate buffer pH 7, 0.01 M
Flow: 0.4 mL/min
Injection volume: 5 µL
UV detection:
acquisition: 210 nm and 265 nm
evaluation: 210 nm

Reference substance(s): Acetanilide (CAS number 103-84-4; log Koc: 1.26 according to OECD 121 based on soil adsorption data)

PREPARATION OF SOLUTIONS
- pH 2:
A stock solution of the reference substance at a concentration of approximately 1 g/L in methanol was diluted to obtain an end solution of 30/70 (v/v) methanol/water adjusted to pH 2 using H3PO4.
A 836 mg/L stock solution of the test substance was prepared in methanol. In order to dissolve the test substance the stock solution was ultrasonicated for 5 minutes. The ultrasonicated stock solution was diluted to obtain an end solution of 30/70 (v/v) methanol/water adjusted to pH 2 using H3PO4. The final concentration of the test substance solution was 41.8 mg/L.
- pH 7:
A stock solution of the reference substance at a concentration of approximately 1 g/L in methanol was diluted to obtain an end solution of 30/70 (v/v) methanol/phosphate buffer pH 7, 0.01 M.
A 836 mg/L stock solution of the test substance was prepared in methanol. In order to dissolve the test substance the stock solution was ultrasonicated for 5 minutes. The ultrasonicated stock solution was diluted to obtain an end solution of 30/70 (v/v) methanol/phosphate buffer pH 7, 0.01 M. The final concentration of the test substance solution was 41.8 mg/L.

PERFORMANCE OF THE STUDY
- The reference substance and test substance solutions were injected in duplicate
- Blank solutions (30/70 (v/v) methanol/phosphate buffer pH 7, 0.01 M and 30/70 (v/v) methanol/water adjusted to pH 2 using H3PO4) were analysed by single injection
- The test substance results were compared with the results of the reference substance
Type:
log Koc
Value:
< 1.26
Remarks on result:
other: At pH 2, as well as at pH 7
Type:
Koc
Value:
< 18
Remarks on result:
other: At pH 2, as well as at pH 7
Details on results (HPLC method):
- pH 2: in the HPLC chromatogram of the test substance solution, one peak with a retention time of 1.1 minutes was observed. Under the same analytical conditions, the retention time of Acetanilide was 1.6 minutes. Hence, it was concluded that the log Koc of the test substance is below the log Koc of Acetanilide (log Koc = 1.26).
- pH 7: in the HPLC chromatogram of the test substance solution, one peak with a retention time of 0.5 minutes was observed. Under the same analytical conditions, the retention time of Acetanilide was 1.5 minutes. Hence, it was concluded that the log Koc of the test substance is below the log Koc of Acetanilide (log Koc = 1.26).
- No test substance related peak was observed in the blanks.
Validity criteria fulfilled:
yes
Conclusions:
The HPLC method using soil-adsorption-reference data was applied for the determination of the adsorption coefficient (Koc) of FDCA. The Koc and log Koc values of the test substance at pH 2, as well as at pH 7, were < 18 and < 1.26, respectively.
Executive summary:

The HPLC method at pH 2 and at pH 7 using soil-adsorption-reference data was applied for the determination of the adsorption coefficient (Koc) of the substance, in accordance with EC C.9 and OECD 121 and according to the principles of GLP. At pH 2, most of the substance will be in its non-ionised form. At pH 7, the test substance will be fully ionised. The HPLC chromatogram of the test substance showed one peak at 1.1 minutes at pH 2 and one peak at 0.5 minutes at pH 7. Under the same analytical conditions, the retention time of the reference substance Acetanilide (log Koc = 1.26) was higher at both pH’s. Hence, it was concluded that the log Koc of the test substance at pH 2, as well as at pH 7, was < 1.26.

Description of key information

The HPLC method based on soil-adsorption-reference data (in accordance with EC C.19 and OECD 121) was applied for the determination of the adsorption coefficient (Koc) of the substance, resulting in a log Koc of < 1.26.

Key value for chemical safety assessment

Additional information

Key value for chemical safety assessment

Koc at 20 °C: < 18

Log Koc at 20 °C: < 1.26

The HPLC method at pH 2 and at pH 7 using soil-adsorption-reference data was applied for the determination of the adsorption coefficient (Koc) of the substance, in accordance with EC C.9 and OECD 121 and according to the principles of GLP. At pH 2, most of the substance will be in its non-ionised form. At pH 7, the test substance will be fully ionised. The HPLC chromatogram of the test substance showed one peak at 1.1 minutes at pH 2 and one peak at 0.5 minutes at pH 7. Under the same analytical conditions, the retention time of the reference substance Acetanilide (log Koc = 1.26) was higher at both pH’s. Hence, it was concluded that the log Koc of the test substance at pH 2, as well as at pH 7, was < 1.26.