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Administrative data

Endpoint:
adsorption / desorption: screening
Remarks:
adsorption
Type of information:
calculation (if not (Q)SAR)
Remarks:
estimated by calculation
Adequacy of study:
key study
Study period:
March 9, 2015 - March 23, 2015
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: calculation according to accepted formulas

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2015
Report date:
2015

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other:
Principles of method if other than guideline:
Calculation performed using the equation provided in the European Chemicals Bureau: Technical Guidance Document on Risk Assessment, Chapter 4 "Predominantly hydrophobobics".
GLP compliance:
no
Type of method:
other: QSAR
Media:
soil/sewage sludge

Test material

Constituent 1
Reference substance name:
HFP kinetic dimer
IUPAC Name:
HFP kinetic dimer
Details on test material:
- Name of test material (as cited in study report): MTDID 948
- Substance type: Single component substance
- Physical state: Clear, colorless liquid
- Test substance storage: At room temperature
Radiolabelling:
no

Study design

Test temperature:
Not Applicable

HPLC method

Details on study design: HPLC method:
The Koc of HFP kinetic dimer was attempted using OECD 121: "Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)” method.

Buffer solution: Buffer pH 7, 0.01 M solution of 0.01 M potassium dihydrogenphosphate adjusted to pH 7 using 1N sodium hydroxide. The buffer contains 0.0009% (w/v) sodium azide.

Analytical conditions:
-Analytical instrument:Acquity UPLC system (Waters, Milford, MA, USA);
- Detector Acquity UPLC PDA detector (Waters)
- Column: Acquity UPLC HSS Cyano, 100 mm × 2.1 mm i.d., dp = 1.8 μm (Waters)
- Column temperature: 22.5°C ± 1°C
- Mobile phase: 55/45 (v/v) methanol/0.01 M phosphate buffer at pH 7
- Flow rate: 0.4 ml/min
- Injection volume: 5 μl
- Detection system: UV detection 210 nm

DETERMINATION OF DEAD TIME: The dead time marker was Formamide. A 5.0 g/l stock solution of formamide in methanol was used. The stock solution was diluted in 55/45 (v/v) methanol/buffer pH 7. The dead time marker was injected twice. The mean dead time of the test system was 0.692 minutes.

Reference substance solutions:
- Identity : Acetanilide, Monuron; 2,5-Dichloroaniline, Naphthalene, Benzoic acid phenylester, Fenthion, Phenanthrene, and 4,4'DDT.
Stock solutions of the reference substances at concentrations of approximately 1 g/l in methanol were used. The stock solutions were diluted in 55/45 (v/v) methanol/buffer pH 7 and injected as single standard twice. It is notable that the calibration substances are aromatic compounds and/or pesticides. The calibration substances are approved for use in the method, but bear little or no structural similarity to the test substance. This is a limitation of the test guideline.

Test substance: An aliquot of 5 μl of the test substance was dissolved in 42 ml methanol. It was observed that the test substance was almost completely dissolved. The saturated solution was used for injection on the HPLC system.

The test system blank was methanol.

REPETITIONS: The reference substance and test substance solutions were injected in duplicate. Blank solutions were analysed by single injection.

EVALUATION
- Calculation of capacity factors k': k' = (Tr - T0) / T0, where: Tr = retention time;
T0 = mean column dead time (Formamide peak);

- Determination of the log Koc value: Linear regression according to calibration curve of the log k of the reference substances as function of log Koc
log k = a log Koc + b
where: a = slope, b = intercept
The equation of the regression line was: log k’ = 0.352 × log Koc – 0.779 (r = 0.98, n = 16).

Results and discussion

Adsorption coefficient
Key result
Type:
log Koc
Value:
3.4 dimensionless
Remarks on result:
other: Calculated using QSAR. Temperature not given.

Results: HPLC method

Details on results (HPLC method):
The adsorption coefficient (Koc) of the test substance was attempted using OECD 121: "Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)” method. The test substance had observed five peaks in the HPLC-UV chromatogram, with area% ranged from 6.8 - 28% peak area. The log Koc of these peaks ranged from 1.35 to 4.30 (see table 1). Since no dominating peaks were observed, data from HPLC determination was not be used.

Since the purity of the test substance is relatively high (99%), the Koc of the test substance was determined based on the molecular structure using a quantitative structure activity relationship (QSAR). The formula for calculating log Koc is based on the equation from European Chemicals Bureau: Technical Guidance Document on Risk Assessment, Chapter 4, 'Predominantly hydrophobics". For this chemical class, the log Koc is given as: log Koc = 0.81 log Pow +0.10.

From an experimentally determined log Kow value of 4.1, the Koc of the test substance is calculated to be 3.4, the Koc is 2.6 × 10³.

Any other information on results incl. tables

Table 1. Koc determination of HFP kinetic dimer

 

Substance

Tr,1 [min]

Tr,2 [min]

mean Tr (n=2)

Log Koc

Koc

Area%

Formamide (t0)

0.694

0.690

0.692

 

 

 

 

References substance:

Acetanilide

0.958

0.962

 

1.26

Monuron

1.238

1.243

 

1.99

2,5-Dichloroaniline

1.450

1.462

 

2.55

Naphthalene

1.759

1.775

 

2.75

Benzoic acid phenylester

2.200

2.210

 

2.87

Fenthion

3.197

3.242

 

3.31

Phenanthrene

3.501

3.526

 

4.09

4,4’-DDT

10.123

10.169

 

5.63

 

Log K = 0.352 log Koc -0.779 (r² = 0.98, n = 16)  

Test substance 

peak 1

 1.039

1.032

1.036

1.35

2.2E+01

28

peak 2

 1.671

1.654

1.663

2.63

4.3E+02

6.1

peak 3

 2.540

2.527

2.534

3.42

2.6E+03

22

peak 4

 3.702

3.664

3.686

4.02

1.1E+04

16

peak 5

 4.432

4.429

4.431

4.30

2.0E+04

27

QSAR: Log Koc = 0.81 log Pow +0.10

QSAR

Molecular structure

3.4

2.6E+03

 

Applicant's summary and conclusion

Conclusions:
The soil and sediment partition coefficient (log Koc) of HFP kinetic dimer was calculated to be 3.4 using the equation from European Chemicals Bureau: Technical Guidance Document on Risk Assessment, Chapter 4, 'Predominantly hydrophobics".
Executive summary:

The adsorption coefficient (Koc) of the HFP kinetic dimer was attempted using OECD 121: "Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)” method. The test substance had observed five peaks in the HPLC-UV chromatogram, with area % ranged from 6.8 - 28% peak area. The log Koc of these peaks ranged from 1.35 to 4.30. Since no dominating peak were observed, data from HPLC determination was not be used. Alternatively, the Koc and log Koc values were calculated using a quantitative structure activity relationship (QSAR).

The soil and sediment partition coefficient (log Koc) of HFP kinetic dimer was calculated using the equation from European Chemicals Bureau: Technical Guidance Document on Risk Assessment, Chapter 4, 'Predominantly hydrophobics". The log Koc is given as: Log Koc = 0.81 log Pow + 0.10. From the experimentally determined log Kow value of 4.0, the log Koc (soil and sediment partition coefficient) of HFP kinetic dimer is calculated to be 3.4, the Koc is 2.6 × 10³.

This data was calculated according to accepted Technical Guidance document, it is acceptable with restriction and a key study.