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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
15 August 2017 to 16 August 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline 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:
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))
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of method:
HPLC estimation method
Media:
soil/sewage sludge
Radiolabelling:
not specified
Test temperature:
20 °C
Details on study design: HPLC method:
TEST DESCRIPTION
- The main test was performed by isocratic elution with acetonitrile/water in a ratio of 50 : 50 %.
- For the main test 19.2 mg of the dead time marker formamide were dissolved in 25 mL acetonitrile.
- Between 12.2 mg and 21.6 mg of the reference materials (Acetanilide, Atrazine, Triadimenol, Linuron, 1,2,3-Trichloro benzene, Diclofop-methyl and 4,4’-DDT) were dissolved in 25 mL acetonitrile.
- 7.2 mg of the test material were dissolved in 100 mL acetonitrile.
- The dead time marker (Formamide) was injected and measured twice before the reference materials and the test material. After that two series of measurements of the reference and test materials were performed, wherein the reference substances and the test material were injected separately into the mobile phase.

HPLC METHOD
- Parameters:
Apparatus: Agilent 1100/1200 System: degasser G1322A, quaternary pump G1311A, autosampler G1329A, ALS thermostat G1330B, COLCOM column oven G1316A, VWD UV-detector G1314A
Stationary phase: Nucleosil 100-5 CN, Macherey-Nagel
Column length: 150 mm
Column inner diameter: 4.6 mm
Pore size: 5 µm
Column temperature: 20 °C
Injection volume: 10 µL
Solvent flow: 1 mL/min
Wave length: Dead time marker: 210 nm, Reference materials: 254 nm and Test material: 386 nm
Mobile phase: Isocratic: acetonitrile / double distilled water 50:50 % (v/v)

- Quality criteria: The value of log Koc derived from repeated measurements made under identical conditions and using the same set of reference materials should fall within a range of ±0.25 log units.
Typically, the correlation coefficient r for the relationship between log k and log Koc for a set of test substances is around 0.95.
Key result
Type:
log Koc
Value:
3.98
Temp.:
20 °C
Remarks on result:
other: ± <0.01
Key result
Type:
Koc
Value:
9 640
Temp.:
20 °C
Remarks on result:
other: ± 70
Details on results (HPLC method):
MAIN TEST
- After the measurements of the retention times tR the log k values of the reference materials were plotted as a function of their log Koc values. The adsorption coefficient of the test material was obtained by interpolation of the calculated capacity factor on the calibration graph of the reference materials.
- Mean retention time of the dead time marker: 1.964 minutes
- Retention times of the reference materials (1st and 2nd measurements) can be seen in Tables 1 and 2, respectively. The first measurement and the linear regression of the calibration graph leads to an equation for the log Koc of:

log Koc = 5.495∙logk + 3.911 correlation coefficient r=0.9836.

The second measurement and the linear regression of the calibration graph leads to an equation for the log Koc of:

log Koc = 5.599∙logk + 3.924 correlation coefficient r=0.9834.

With the determined regression coefficients a and b, the log Koc of the test material can be calculated for both measurements.
- The retention times and calculation of log Koc for the test material can be seen in Table 3.
The test material has an adsorption coefficient at 20 °C of log Koc = 3.98 ± < 0.01, Koc = 9640 ± 70.

Table 1: Retention times of the reference materials (1st measurements)

Reference Material

tR

k

log k

log Koc[1]

Acetanilid

2.507

0.276

-0.558

1.25

Atrazin

2.823

0.437

-0.359

1.81

Triadimenol

3.059

0.558

-0.254

2.40

Linuron

3.214

0.636

-0.196

2.59

1.2.3-Trichlorobenzen

3.521

0.793

-0.101

3.16

Diclofop-methyl

4.264

1.171

0.069

4.20

4.4' DDT

5.426

1.763

0.246

5.63

Table 2: Retention times of the reference materials (2nd measurements)

Reference Material

tR

k

log k

log Koc1

Acetanilid

2.516

0.281

-0.551

1.25

Atrazin

2.835

0.443

-0.353

1.81

Triadimenol

3.064

0.560

-0.252

2.40

Linuron

3.219

0.639

-0.194

2.59

1.2.3-Trichlorobenzen

3.521

0.793

-0.101

3.16

Diclofop-methyl

4.240

1.159

0.064

4.20

4.4' DDT

5.372

1.735

0.239

5.63

[1]Literature values of log Koc from OECD Test Guideline 121 (2001)

Table 3: Retention times of the test material

Test Material

tR

k

log k

log Koc

Koc

1st measurement

3.987

1.030

0.013

3.982

9591

2nd measurement

3.979

1.026

0.011

3.986

9689

mean value

3.98

9640

standard deviation

<0.01

70

Validity criteria fulfilled:
yes
Conclusions:
Under the conditions of this study, the test material has an adsorption coefficient at 20 °C of log Koc = 3.98 ± < 0.01, Koc = 9640 ± 70.
Executive summary:

The adsorption coefficient of the test material was determined in accordance with the standardised guidelines OECD 121 and EU Method C.19, under GLP conditions.

The main test was performed by isocratic elution with acetonitrile/water in a ratio of 50 : 50 %. The samples were analysed using high performance liquid chromatography (HPLC). The dead time marker was injected and measured twice before the reference materials and the test material. After that two series of measurements of the reference and test materials were performed, wherein the reference substances and the test material were injected separately into the mobile phase.

After the measurements of the retention times tR the log k values of the reference materials were plotted as a function of their log Koc values, the partition coefficient of the test material was obtained by interpolation of the calculated capacity factor on the calibration graph of the reference materials.

Under the conditions of this study, the test material has an adsorption coefficient at 20 °C of log Koc = 3.98 ± < 0.01, Koc = 9640 ± 70.

Description of key information

Under the conditions of this study, the test material has an adsorption coefficient at 20 °C of log Koc = 3.98 ± < 0.01, Koc = 9640 ± 70.

Key value for chemical safety assessment

Koc at 20 °C:
9 640

Additional information

The adsorption coefficient of the test material was determined in accordance with the standardised guidelines OECD 121 and EU Method C.19, under GLP conditions. The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).

The main test was performed by isocratic elution with acetonitrile/water in a ratio of 50 : 50 %. The samples were analysed using high performance liquid chromatography (HPLC). The dead time marker was injected and measured twice before the reference materials and the test material. After that two series of measurements of the reference and test materials were performed, wherein the reference substances and the test material were injected separately into the mobile phase.

After the measurements of the retention times tR the log k values of the reference materials were plotted as a function of their log KOC values, the partition coefficient of the test material was obtained by interpolation of the calculated capacity factor on the calibration graph of the reference materials.

Under the conditions of this study, the test material has an adsorption coefficient at 20 °C of log Koc = 3.98 ± < 0.01, Koc = 9640 ± 70.