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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
May 5 - May 13, 2009
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The study was performed according to guideline. Restriction due to log Koc range of test material was outside the range of the calibration standards.
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)
Remarks:
Issued by: The Department of Health of the Government of the United Kingdom Inspection date: 19 August 2008 Signed by: Dr. Andrew J. Gray, Head, UK GLP Monitoring Authority
Type of method:
HPLC estimation method
Media:
soil/sewage sludge
Radiolabelling:
no
Test temperature:
30 C
Details on study design: HPLC method:
EQUIPMENT

- Apparatus: Agilent Technologies 1050

- Type: HPLC

- Type, material and dimension of analytical (guard) column: Zorbax SB-CN 5 μm (250 x 4.6 mm id)
- Detection system: UV 210 nm



MOBILE PHASES

- Type: methanol:reverse osmosis water (55:45 v/v), adjusted to pH 7.0 with 0.1M NaOH

- pH: 7.0

- Solutes for dissolving test and reference substances: methanol


DETERMINATION OF DEAD TIME

- Method: by inert substances which are not retained by the column

REFERENCE SUBSTANCES ( % purity and concentrations shown in Table 1)

- Identity: Acetanilide, Phenol, Atrazine, Isoproturon, Triadimenol, Linuron, Endosulfan-diol, Fention, a-Endosulfan, Phenanthrene, Diclofop-methyl, DDT

DETERMINATION OF RETENTION TIMES

- Quantity of test substance introduced in the column: 10μl of 0.106g/100 mL methanol

- Quantity of reference substances: 10μl of 1g/L solutions in methanol:RO water (55:45 v/v)


REPETITIONS

- Number of determinations: duplicate


EVALUATION

- Calculation of capacity factors k': calculated from the dead time and retention times of reference standards as described in guideline.

- Calculation of retention times: Dead time for formamide (shown in Table 2) and retention times for standards and test material (shown in Table 3 and Table 4).

- Determination of the log Koc value: determined from a calibration plot of log k' vs. log Koc as described in guideline. Log k1 and log Koc are shown in Table 4. Calibration graph is attached in Figure 1.
Type:
log Koc
Value:
< 1.25
Remarks on result:
other: 67.7 area %
Type:
log Koc
Value:
>= 1.36 - <= 5.09
Remarks on result:
other: 32.4 area %
Details on results (HPLC method):

The test substance is a mixture of several components with log Koc values ranging from < 1.25 to 5.09

- Retention times of reference substances used for calibration (shown in Table 3):

- Details of fitted regression line (log k' vs. log Koc): R2=0.968; slope = 0.357; intercept = -0.740

- Graph of regression line attached: Yes (Figure 1)

- Average retention data for test substance: multiple components resolved by HPLC with retention times ranging from 2.043 to 36.982 minutes. See table 5.

Table 2: Determination of Dead Time (formamide)

Substance

Retention Time (min)

Dead Time (min)

Injection 1

Injection 2

Formamide

2.864

2.861

2.8625

Table 3: Retention times, capacity factor and adsorption coefficients of Reference Standards

Reference Standard

Mean Retention Time (min.)

Capacity factor(k)

Log k

Log Koc

Acetanilide

3.913

0.367

-0.435

1.25

Phenol

3.716

0.298

-0.525

1.32

Atrazine

5.609

0.959

 -.00180

1.81

Isoproturon

5.928

1.7

.0297

1.86

Triadimenol

7.881

1.75

0.244

2.40

Linuron

8.331

1.91

0.281

2.59

Endosulfan-diol

9.828

2.43

0.386

3.02

Fenthion

13.182

3.61

0.557

3.31

a-Endosulfan

17.974

5.28

0.723

4.09

Phenanthrene

14.997

4.24

0.627

4.09

Diclofop-methyl

20.809

6.27

0.797

4.20

DDT

42.279

13.8

1.14

5.63

Regression line: slope = 0.357 intercept = -0.740 R2 = 0.968

Table 4. Retention times, capacity factors and adsorption coefficient (log Koc) for test material

Peak number

Injection

Retention time (min)

Capacity factor, k

log K

logKoc

Mean log Koc

% area

1

1

2.043

-0.286

-

< 1.25

< 1.25

55.6

2

2.046

-0.285

-

< 1.25

2

1

3.848

0.344

-0.463

< 1.25

< 1.25

12.1

2

3.833

0.339

-0.470

< 1.25

3

1

4.461

0.558

-0.253

1.37

1.36

10.5

2

4.437

0.550

-0.260

1.35

4

1

5.326

0.860

-0.065

1.89

1.92

8.00

2

5.419

0.893

-0.0493

1.94

5

1

6.962

1.43

0.156

2.51

2.51

0.423

2

6.943

1.43

0.154

2.51

6

1

7.269

1.54

0.187

2.60

2.60

0.63

2

7.249

1.53

0.185

2.60

7

1

7.832

1.74

0.239

2.75

2.75

1.12

2

7.799

1.72

0.237

2.74

8

1

10.534

2.68

0.428

3.28

3.28

1.89

2

10.534

2.68

0.428

3.28

9

1

11.43

2.99

0.476

3.41

3.41

3.13

2

11.337

2.96

0.471

3.40

10

1

12.019

3.20

0.505

3.49

3.49

1.14

2

11.903

3.16

0.499

3.48

11

1

36.982

11.92

1.08

5.09

5.09

5.54

2

36.557

11.77

1.07

5.08

Validity criteria fulfilled:
yes
Remarks:
A plot of log k vs log Koc for reference standards gave an R2 value of 0.968
Conclusions:
The log Koc determined for the test material ranged from <1.25 to 5.09
Executive summary:

The adsorption coefficient of the test material was determined by HPLC following the guidelines in EU Method C.19. The test substance is a mixture of components with log Koc values ranging from < 1.25 to 5.09.

Description of key information

The test substance is a mixture of components with log Koc values ranging from < 1.25 to 5.09 (EU Method C.19)

Key value for chemical safety assessment

Koc at 20 °C:
17.7

Additional information

The adsorption coefficient of the test material was determined by HPLC following the guidelines in EU Method C.19. The test substance is a mixture of components with log Koc values ranging from < 1.25 to 5.09.