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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:
EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))
Version / remarks:
August 21, 2001
Deviations:
yes
Remarks:
see "Principles of method if other than guideline"
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:
January 22, 2001
Deviations:
yes
Remarks:
see "Principles of method if other than guideline"
Principles of method if other than guideline:
According to guidelines, the determination of the Pow of the test substance should be performed in its non-ionised form. Therefore, the pKa values of the test substance were calculated using Perrin calculation method (pKalc 5.0, module in Pallas 3.0, CompuDrug International). These calculations show that there is not a pH at which all ionisable groups are in their non-ionised form. At pH 2, net charge of the test substance is zero and therfore it was descided to perform a test at this pH. However, this pH was not in the environmentally relevant range of pH 5.0-9.0. Thus, an additional test was performed at neutral pH. Under these conditions, the net charge will deviate from zero.
GLP compliance:
yes (incl. certificate)
Type of method:
HPLC estimation method
Media:
soil/sewage sludge
Radiolabelling:
no
Test temperature:
35±5°C
Details on study design: HPLC method:
EQUIPMENT
- Apparatus: Alliance Separation Module 2695, detector: Dual λ Absorbance Detector 2487 (Waters), column: 150 mm x 4.6 mm i.d. Hypersil BDS-CN; dp = 5 pm (Thermo, San Jose, CA, USA); column temp.: 35 ± 5.0°C; flow: 1 mL/min; Injection volume: 10 µL
- Detection system: UV detection (210nm)

MOBILE PHASES
Mobile phase pH 2.0: 55/45 (v/v) methanol/0.05 M phosphate buffer at pH 2.0
Mobile phase neutral pH: 55/45 (vlv) methanollMilli-Q water

DETERMINATION OF DEAD TIME
- Method: by inert substance which is not retained by the column (formamide)

REFERENCE SUBSTANCES
- Identity: Phenol, N, N-Dimethylbenzamide, Methylbenzoate, 3,5-Dinitrobenzamide, Naphthalene, Fenthion, Phenanthrene, 2,4-DDT

REPETITIONS
- Number of determinations: duplicates
Details on test conditions:
A 1294 mg/L or 1482 mg/L stock solution of the test substance was prepared in mobile phase pH 2.0 or mobile phase neutral pH. The test solutions were diluted with mobile phase pH 2.0 or mobile phase neutral pH, to a final concentration corrected for a purity of 50.60% of 253 mg/L. As test substance blank solution mobile phase pH 2.0 or mobile phase neutral pH was used.
Type:
log Koc
Value:
< 1.32 dimensionless
pH:
7
Temp.:
35 °C
Remarks on result:
other: component 1
Type:
log Koc
Value:
3.47 dimensionless
pH:
7
Temp.:
35 °C
Remarks on result:
other: component 2
Type:
log Koc
Value:
> 5.63 dimensionless
pH:
7
Temp.:
35 °C
Remarks on result:
other: component 3+4+5
Type:
log Koc
Value:
< 1.32 dimensionless
pH:
2
Temp.:
35 °C
Remarks on result:
other: component 1
Type:
log Koc
Value:
1.45 dimensionless
pH:
2
Temp.:
35 °C
Remarks on result:
other: component 2
Type:
log Koc
Value:
3.42 dimensionless
pH:
2
Temp.:
35 °C
Remarks on result:
other: component 6
Type:
log Koc
Value:
3.57 dimensionless
pH:
2
Temp.:
35 °C
Remarks on result:
other: component 7
Transformation products:
not measured

Koc at pH 2

log Koc at pH 2

area%

Koc at pH7

log Koc at pH 7

area%

component 1

<2.1E1

<1.32

26

<2.1E1

<1.32

24

component 2

2.80E+01

1.45

69

2.90E+03

3.47

1.7

component 3

2.00E+02

2.3

0.7

>4.3E05

>5.63

25

component 4

5.90E+02

2.77

0.1

>4.3E05

>5.63

3.8

component 5

1.60E+03

3.2

0.6

>4.3E05

>5.63

45

component 6

2.60E+03

3.42

1.4

component 7

3.70E+03

3.57

1.8

Validity criteria fulfilled:
yes
Conclusions:
The log Koc of Amphopropionate C8 is, for the different components, in the range of < 2.1 to 3.57 at pH 2.0 and < 2.1 to >5.63 at pH 7.0.
Executive summary:

In a screening study conducted according to OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)) the log Koc value of Amphopropionate C8 was determined at pH 2 and pH 7.

According to guidelines, the determination of the Koc of the test substance should be performed in its non-ionised form. Therefore, the pKa values of the test substance were calculated using Perrin calculation method (pKalc 5.0, module in Pallas 3.0, CompuDrug International). These calculations show that there is not a pH at which all ionisable groups are in their non-ionised form. At pH 2, net charge of the test substance is zero and, thus, the test was performed at this pH. However, because this pH was not in the environmentally relevant range of pH 5.0-9.0, an additional test was performed at neutral pH. Under these conditions, the net charge will deviate from zero.

In the chromatograms of the test substance solutions, several test substance peaks were observed. Some peaks were broad indicating not pure reverse phase retention as required for accurate determination of Koc. Because a different method to determine Koc is not applicable, these values were reported as a range. The log Koc of Amphopropionate C8 is, for the different components, in the range of < 2.1 to 3.57 at pH 2.0 and < 2.1 to >5.63 at pH 7.0.

Description of key information

log Koc < 2.1 to 3.57 at pH 2.0 and < 2.1 to >5.63 at pH 7.0 (OECD TG 121; RL1; GLP)

Key value for chemical safety assessment

Koc at 20 °C:
38.9

Other adsorption coefficients

Type:
log Kp (solids-water in soil)
Value in L/kg:
-0.11
at the temperature of:
20 °C

Other adsorption coefficients

Type:
log Kp (solids-water in sediment)
Value in L/kg:
0.29
at the temperature of:
20 °C

Other adsorption coefficients

Type:
log Kp (solids-water in suspended matter)
Value in L/kg:
0.59
at the temperature of:
20 °C

Other adsorption coefficients

Type:
log Kp (solids-water in raw sewage sludge)
Value in L/kg:
1.07
at the temperature of:
20 °C

Other adsorption coefficients

Type:
log Kp (solids-water in settled sewage sludge)
Value in L/kg:
1.07
at the temperature of:
20 °C

Other adsorption coefficients

Type:
log Kp (solids-water in activated sewage sludge)
Value in L/kg:
1.16
at the temperature of:
20 °C

Other adsorption coefficients

Type:
log Kp (solids-water in effluent sewage sludge)
Value in L/kg:
1.16
at the temperature of:
20 °C

Additional information

In a screening study conducted according to OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)) the log Koc value of Amphopropionate C8 was determined at pH 2 and pH 7.

According to guidelines, the determination of the Koc of the test substance should be performed in its non-ionised form. Therefore, the pKa values of the test substance were calculated using Perrin calculation method (pKalc 5.0, module in Pallas 3.0, CompuDrug International). These calculations show that there is not a pH at which all ionisable groups are in their non-ionised form. At pH 2, net charge of the test substance is zero and, thus, the test was performed at this pH. However, because this pH was not in the environmentally relevant range of pH 5.0-9.0, an additional test was performed at neutral pH. Under these conditions, the net charge will deviate from zero.

In the chromatograms of the test substance solutions, several test substance peaks were observed. Some peaks were broad indicating not pure reverse phase retention as required for accurate determination of Koc. Because a different method to determine Koc is not applicable, these values were reported as a range. The log Koc of Amphopropionate C8 is, for the different components, in the range of < 2.1 to 3.57 at pH 2.0 and < 2.1 to >5.63 at pH 7.0.

The adsorption coefficients were calculated using EUSES based on log Kow.

[LogKoc: 1.59]

[LogKoc: 1.59]