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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
16 January 2018 - 28 February 2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
Study was conducted in accordance with international guidelines and in accordance with GLP. All guideline validity criteria were met.
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:
Regulation (EC) 440/2008 of 30 May 2008
Deviations:
no
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:
22 Jan 2001
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of method:
HPLC estimation method
Media:
soil/sewage sludge
Radiolabelling:
no
Test temperature:
25 °C ± 1 °C
Details on study design: HPLC method:
EQUIPMENT
- Apparatus:
HPLC

- Type:
Agilent 1260 HPLC system

- Type, material and dimension of analytical (guard) column:
Column - EC 150/4.6 Nucleodur 100-5 CN-RP 150 x 4.6 mm; 5 µm. Guard column - None

- Detection system: PDA detector


MOBILE PHASES
- Type:
isocratic elution, 55 % methanol, 45 % ultra-pure water

- Experiments with additives carried out on separate columns:
not applicable

- pH:
Not measured.

- Solutes for dissolving test and reference substances:
Test item solute - Methanol was used as diluent for the reference item solution.
Reference mixture solute - Acetonitrile/ultra-pure water (50/50 [v/v]) was used as diluent for the test item solution.


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


REFERENCE SUBSTANCES
- Identity (dead time determination): Sodium Nitrate (EC: 231-554-3)
- Identity (reference substances, Koc determination): Phenol (EC: 203-632-7), Isoproturon (EC: 251-835-4), Naphthalene (EC: 202-049-5), 1,2,3-Trichlorobenzene (EC: 201-757-1), Phenanthrene (EC: 201-581-5), 4.4'-DDT (EC: 200-024-3)


DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 2 µL injections of 1011 mg/L of test item in acetonitrile/ultra-pure water (50/50 [v/v]) was introduced to the column

- Quantity of reference substances: Sodium Nitrate (71.68 mg/l), Phenol (19.85 mg/l), Isoproturon (61.20 mg/l), Naphthalene (3.55 mg/l), 1,2,3-Trichlorobenzene (44.16 mg/l), Phenanthrene (35.00 mg/l), 4.4'-DDT (246.96 mg/l)

- Intervals of calibration: Retention times of reference substances was determined over a 30 minute runtime duration. The following mean retention times were recorded arising from two calibration runs:
Calibration Run 1: Sodium nitrate (1.126 min), Phenol (2.608 min), Isoproturon (3.396 min), Naphthalene (4.950 min), 1,2,3-Trichlorobenzene (5.540 min), Phenanthrene (8.332 min), 4.4'-DDT (18.941 min)
Calibration Run 2: Sodium nitrate (1.830 min), Phenol (2.608 min), Isoproturon (3.393 min), Naphthalene (4.944 min), 1,2,3-Trichlorobenzene (5.534 min), Phenanthrene (8.319 min), 4.4'-DDT (18.884 min)


REPETITIONS
- Number of determinations: Eight repetitions in total, consisting of 4 injections per run over two runs.


EVALUATION
- Calculation of capacity factors k': The adsorption coefficient (KOC) is deduced from the capacity factor (k') using a calibration plot of log k' versus log KOC of the selected reference compounds. k' = (tR - t0)/t0. tR = HPLC retention time of test or reference item (minutes), t0 = HPLC dead time (minutes)

- Calculation of retention times: The reference mix was injected two times before and two times after the test item sample. The retention times were of these injections were measured directly.

- Determination of the log Koc value: The partition coefficient of the test item was obtained by interpolation from the calibration graph, using the calculated capacity factor.
Key result
Type:
log Koc
Remarks:
Mean value of Sample # 1 and # 2
Value:
< 1.32 dimensionless
Temp.:
25 °C
Remarks on result:
other: Mean value
Remarks:
Mean of two runs
Sample No.:
#1
Type:
log Koc
Value:
< 1.32 dimensionless
Temp.:
25 °C
Remarks on result:
other: Mean value
Remarks:
Mean value of four injections of test item.
Sample No.:
#2
Type:
log Koc
Value:
< 1.32 dimensionless
Temp.:
25 °C
Remarks on result:
other: Mean Value
Remarks:
Mean value of four injections of test item.
Details on results (HPLC method):
- Retention times of reference substances used for calibration:
See any other information on results incl. tables


- Details of fitted regression line (log k' vs. log Koc):
See any other information on results incl. tables


- Graph of regression line attached
See attached background material.


- Average retention data for test substance:
See any other information on results incl. tables

Data Evaluation:

Calculation of log k’: The corresponding logarithms of the capacity factors, log k’, were calculated from the retention times and the dead time.

Calibration Graph: A correlation graph of log k’ versus log Koc was plotted.

Sample Results: As the log Koc was below determination limit of the method (log Koc = 1.5 according to OECD 121 and EC method C.19) and below the lowest used reference standard (log Koc of the lowest reference standard phenol is 1.32) the log Koc is stated as < 1.32.

 

 

Table 3:          Retention time and log Koc of t (mean of two runs)

 

Retention Time

[min]

Mean retention time

[min]

Mean retention time of two runs

[min]

Absolute deviation

[min]

Log Koc

Mean log Koc

Mean log Koc of two runs

Absolute deviation of log Koc

First run Injection 1

1.784

1.735

1.78

0.10

< 1.32*

< 1.32*

< 1.32*

not applicable

First run Injection 2

1.768

< 1.32*

First run Injection 3

1.694

< 1.32*

First run Injection 4

1.692

< 1.32*

Second run Injection 1

1.860

1.830

< 1.32*

< 1.32*

Second run Injection 2

1.832

< 1.32*

Second run Injection 3

1.815

< 1.32*

Second run Injection 4

1.811

< 1.32*

 

 

Table 4:          Calibration parameter obtained from first run

 

Slope

 

Intercept

Log k‘ =

0.243087

× log Koc

- 0.169869

R =

0.9980

 

 

Table 5:          Calibration parameter obtained from second run

 

Slope

 

Intercept

Log k‘ =

0.243656

× log Koc

- 0.17907

R =

0.9980

 

 

Table 6:          Values for determination of log Koc, dead time and calibration graph obtained from 1st run

Name

Log KOCnominal

Retention Time

[min]

Mean retention time

[min]

SD

[min]

log k’

Log KOC determined

Mean log KOC

SD log KOC

Comment

Test item

-

1.784

6.260

0.010

0.543

3.35

3.36

0.00

-

1.768

0.544

3.36

1.694

0.545

3.36

1.692

0.545

3.36

Sodium nitrate*

-

1.129

1.390

0.001

-

-

-

-

Dead time

1.123

1.121

1.131

Phenol

1.32

2.609

2.634

0.003

-0.049

1.11

1.12

0.01

Reference item

2.610

-0.049

1.11

2.607

-0.047

1.12

2.606

-0.047

1.12

Isoproturon

1.86

3.397

3.469

0.007

0.173

1.95

1.96

0.01

Reference item

3.400

0.174

1.96

3.396

0.176

1.96

3.389

0.176

1.96

Naphthalene

2.75

4.952

5.143

0.009

0.430

2.93

2.93

0.00

Reference item

4.957

0.431

2.93

4.947

0.432

2.93

4.942

0.432

2.93

1,2,3-Trichlorobenzene

3.16

5.544

5.778

0.010

0.498

3.18

3.19

0.00

Reference item

5.547

0.499

3.19

5.538

0.500

3.19

5.531

0.500

3.19

Phenanthrene

4.09

8.341

8.782

0.022

0.724

4.04

4.05

0.01

Reference item

8.348

0.725

4.04

8.326

0.727

4.05

8.314

0.727

4.05

4.4'-DDT

5.63

18.944

20.099

0.064

1.127

5.57

5.58

0.01

Reference item

18.985

1.128

5.57

18.936

1.130

5.58

18.897

1.130

5.58

* used for determination of the dead time; RT = retention time; SD = standard deviation

** *: below determination limit of the method (log Koc = 1.5 according to OECD 121 and EC method C.19) and below the lowest used reference standard (log Koc of the lowest reference standard phenol is 1.32)

 

 

 

Table 7:          Values for determination of log Koc, dead time and calibration graph obtained from 2nd run

Name

Log KOCnominal

Retention Time

[min]

Mean retention time

[min]

SD

[min]

log k’

Log KOC determined

Mean log KOC

SD log KOC

Comment

Test item

-

6.250

6.247

0.002

0.545

3.35

3.35

0.00

-

6.247

0.545

3.35

6.247

0.545

3.35

6.244

0.545

3.35

Sodium nitrate*

-

1.387

1.386

0.001

-

-

-

-

Dead time

1.386

1.385

1.384

Phenol

1.32

2.637

2.636

0.001

-0.045

1.11

1.11

0.00

Reference item

2.636

-0.045

1.11

2.636

-0.045

1.11

2.634

-0.046

1.11

Isoproturon

1.86

3.475

3.474

0.001

0.178

1.96

1.96

0.00

Reference item

3.475

0.178

1.96

3.475

0.178

1.96

3.471

0.177

1.96

Naphthalene

2.75

5.147

5.142

0.006

0.434

2.93

2.93

0.00

Reference item

5.146

0.433

2.93

5.140

0.433

2.93

5.134

0.432

2.93

1,2,3-Trichlorobenzene

3.16

5.782

5.776

0.008

0.501

3.19

3.19

0.01

Reference item

5.781

0.501

3.19

5.773

0.500

3.18

5.766

0.500

3.18

Phenanthrene

4.09

8.794

8.780

0.015

0.728

4.05

4.05

0.00

Reference item

8.790

0.728

4.05

8.773

0.727

4.05

8.763

0.726

4.04

4.4'-DDT

5.63

20.125

20.079

0.043

1.131

5.58

5.58

0.01

Reference item

20.106

1.131

5.58

20.050

1.129

5.57

20.036

1.129

5.57

* used for determination of the dead time; RT = retention time; SD = standard deviation

Validity criteria fulfilled:
yes
Remarks:
Note that the log Koc of the test item was found to be below determination limit (log Koc = 1.5) of EU method C.19.
Conclusions:
The log Koc of the test item was found to be below determination limit (log Koc = 1.5) of EU method C.19 and below the log Koc of the lowest reference standard used in this study (phenol, nominal log Koc = 1.32).

Therefore, it can be concluded that the test item’s log Koc < 1.32.
Executive summary:

EU Method C.19. –  The estimated Adsorption Coefficient (Koc) of the test item was determined using a procedure designed to be compatible with Method C.19., Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC), of Commission Regulation (EC) No 440/2008 of 30 May 2008.

Analysis was performed using a HPLC equipped with an analytical column packed with a commercially available cyanopropyl solid phase containing lipophilic and polar moieties.  A moderately polar stationary phase based on a silica matrix was used (EC 150/4.6 Nucleodur 100-5 CN-RP 150 x 4.6 mm; 5 µm).  A mobile phase of 55 % methanol to 45 % ultra-pure water was used and the column temperature was 25 °C ± 1 °C.  The log Koc was measured in duplicate under identical conditions and using the same set of reference items.

The test item was shown to have a Log Koc below determination limit (log Koc = 1.5) of EU method C.19 and below the log Koc of the lowest reference standard used in this study (phenol, nominal log Koc = 1.32).  As such the estimated Adsorption Coefficient (Log Koc) of the test item was determined to be: < 1.32 at 25 °C ± 1 °C.  

Description of key information

Adsorption coefficient: log KOC <1.32 at 25 °C ± 1 °C; EU Method C.19.; C Bär (2018)

Key value for chemical safety assessment

Koc at 20 °C:
20.9

Additional information

EU Method C.19. –  The estimated Adsorption Coefficient (Koc) of the test item was determined using a procedure designed to be compatible with Method C.19., Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC), of Commission Regulation (EC) No 440/2008 of 30 May 2008.

Analysis was performed using a HPLC equipped with an analytical column packed with a commercially available cyanopropyl solid phase containing lipophilic and polar moieties.  A moderately polar stationary phase based on a silica matrix was used (EC 150/4.6 Nucleodur 100-5 CN-RP 150 x 4.6 mm; 5 µm).  A mobile phase of 55 % methanol to 45 % ultra-pure water was used and the column temperature was 25 °C ± 1 °C.  The log Koc was measured in duplicate under identical conditions and using the same set of reference items.

The test item was shown to have a Log Koc below determination limit (log Koc = 1.5) of EU method C.19 and below the log Koc of the lowest reference standard used in this study (phenol, nominal log Koc = 1.32).  As such the estimated Adsorption Coefficient (Log Koc) of the test item was determined to be: < 1.32 at 25 °C ± 1 °C.  

[LogKoc: 1.32]