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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
18 March 2010 - 23 March 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
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))
Deviations:
no
GLP compliance:
yes
Type of method:
HPLC estimation method
Media:
soil/sewage sludge
Radiolabelling:
no
Test temperature:
25 °C (based on HPLC temperature)
Details on study design: HPLC method:
EQUIPMENT
The method uses HPLC for estimation of the adsorption coefficient, Koc.
The dual composition of the stationary phase having polar and non-polar sites allows for interaction of polar and non-polar groups of a molecule in a similar way, as in the case for organic matter in soil or sewage sludge matrices.

Apparatus

Stationary Phase: LiChrospher 100 CN 250 x 4 mm, 5µm HPLC Column No.: 841404

HPLC system:
Merck-Hitachi LaChrom HPLC system:
D-7000 Interface, No.: 1231-056
L-7100 HPLC Pump, No. : 1272-039
L-7200 Autosampler, No.: 1273-016
L-7400 UV Detector, No.: 1260-088
Jetstream Pluss Column Oven, No.: 160706

Ultrasonic bath: Elmasonic S300H, ELMA, No.: 010890105

Balances: BP221S Sartorius, No.: 11809117; L2200P Sartorius, No.: 38100037

Water purification system: MILLIPORE, DIRECT Q3, FOMNO 7334I

pH meter: METTLER TOLEDO DL 50 Graphix, No.: 5119033384

HPLC Conditions:

Detector: UV at 254 nm
Column: LiChrospher 100 CN 250 x 4 mm, 5µm No.: 841404
Mobil Phase: Methanol : 0.05 M K2HPO4 buffer solution pH=7 = 50 : 50
Flow: 1 ml/min.
Injection volume: 10 *l
Temperature: 25 °C

MOBILE PHASES
Reference substances were dissolved in methanol. Concentration of these stock solutions was about 1 mg/ml.
These stock solutions were diluted with the mobile phase resulting in about 10 g/ml solutions.
4,4-Diaminodiphenylether was also dissolved in methanol. The concentration of this solution was 0.5 mg/ml. This stock solution was diluted with mobile phase resulting in about 10 g/ml solutions.

DETERMINATION OF DEAD TIME
Dead time, t0 was determined by the injection of sodium nitrate solution.

REFERENCE SUBSTANCES
Seven chemicals for which log Koc has been reported were used to calibrate the elution time in units of log Koc. The reference substances utilised in the study are detailed below in Table 1.


DETERMINATION OF RETENTION TIMES
Three series of the above reference solutions and the test item solution were measured alternately, with two replicate injections.
For the determination of t0 (t0 = retention time of the unretarded component) sodium nitrate solution was injected.
The retention times were determined.

REPETITIONS
- Number of determinations: 3

EVALUATION
The capacity factors, k’ were calculated from the retention times (tR) of the selected reference substances and the dead time (t0):

k’ = tR-t0 / t0

A calibration plot of log k' versus log Koc was prepared. The calibration equation was determined by linear regression using the least squares method.
Repeatability is the difference of maximum and minimum values of log Koc derived from individual measurements.
Accuracy is the difference between the estimated log Koc and the log Koc value determined by the batch equilibrium method.
Details on sampling:
Not applicable
Details on matrix:
Not applicable
Details on test conditions:
Not applicable
Computational methods:
Not applicable
Key result
Sample No.:
#1
Type:
log Koc
Value:
ca. 1.66 dimensionless
Temp.:
25 °C
Key result
Sample No.:
#1
Type:
Koc
Value:
ca. 45 L/kg
Temp.:
25 °C
Details on results (HPLC method):
The three calibration series and three test item series were measured alternately. The adsorption coefficient Koc was determined based on a calibration curve using 7 reference items.
The capacity factors k’ were calculated from the dead time and retention times of the reference substances. The log k’ data of the reference substances were plotted against their log Koc values. The resulting calibration curve and the respective data are provided below. The equation of the curve fitted to the calibration points is as follows:
log k' = 0.419 * log Koc - 0.856 (Rsq = 0.976)

- Retention times of reference substances used for calibration: These are detailed in Table 2.

- Details of fitted regression line (log k' vs. log Koc): The calibration plot is attached in “Attached Background Material” below.

- Average retention data for test substance: 3.91 minutes.
Adsorption and desorption constants:
Not applicable.
Recovery of test material:
Not applicable.
Concentration of test substance at end of adsorption equilibration period:
Not applicable.
Concentration of test substance at end of desorption equilibration period:
Not applicable.
Transformation products:
not measured
Details on results (Batch equilibrium method):
Not applicable.
Statistics:
Not applicable.

Table 2:          Measured and calculated data of the reference substances and test item

Chemical name

log KOC

Retention time (min)

log k'

log Koc

Accuracy
log unit

Repeatability
DlogKOC, log unit

from OECD 121

Calculated

Calculated

Sodium nitrate

-

2.31

for determination of dead time

2.31

2.31

2.31

2.32

2.31

Mean

2.31

CV%

0

Acetanilide

1.25

3.38

-0.335

1.24

0.01

0.01

3.38

-0.335

1.24

3.38

-0.335

1.24

3.38

-0.335

1.24

3.38

-0.335

1.24

3.37

-0.339

1.23

Mean

3.38

-0.336

1.24

CV%

0.1

-

-

Methyl-benzoate

1.80

4.06

-0.121

1.75

0.05

0.00

4.06

-0.121

1.75

4.06

-0.121

1.75

4.06

-0.121

1.75

4.06

-0.121

1.75

4.06

-0.121

1.75

Mean

4.06

-0.121

1.75

CV%

0.0

-

-

Isoproturon

1.86

4.28

-0.070

1.88

0.01

0.01

4.28

-0.070

1.88

4.28

-0.070

1.88

4.28

-0.070

1.88

4.27

-0.072

1.87

4.28

-0.070

1.88

Mean

4.28

-0.070

1.87

CV%

0.1

-

-

Triazophos

2.55

7.04

0.311

2.78

0.23

0.01

7.05

0.312

2.79

7.03

0.310

2.78

7.03

0.310

2.78

7.02

0.309

2.78

7.02

0.309

2.78

Mean

7.03

0.310

2.78

CV%

0.2

-

-

Linuron

2.59

5.91

0.192

2.50

0.09

0.01

5.91

0.192

2.50

5.89

0.190

2.49

5.89

0.190

2.49

5.88

0.189

2.49

5.87

0.187

2.49

Mean

5.89

0.190

2.50

CV%

0.3

-

-

Naphthalene

2.75

6.62

0.270

2.69

0.07

0.01

6.61

0.269

2.68

6.60

0.268

2.68

6.60

0.268

2.68

6.58

0.266

2.68

6.57

0.265

2.68

Mean

6.60

0.268

2.68

CV%

0.3

-

-

Fenthion

3.31

10.01

0.522

3.29

0.03

0.01

10.01

0.522

3.29

9.97

0.520

3.28

9.97

0.520

3.28

9.93

0.518

3.28

9.93

0.518

3.28

Mean

9.97

0.520

3.28

CV%

0.0

-

-

4,4-Diamino-diphenylether

-

3.91

-0.160

1.66

-

0.01

3.91

-0.160

1.66

3.90

-0.163

1.65

3.90

-0.163

1.65

3.90

-0.163

1.65

3.91

-0.160

1.66

Mean

3.91

-0.162

1.66

CV%

0.1

-

-

 

Validity criteria fulfilled:
yes
Conclusions:
The capacity factors k’ and log Koc for 4,4-Diaminodiphenylether were calculated based on the calibration data obtained with the reference substances according to the OECD 121 guideline.
The estimated log Koc = 1.66.
The estimated Koc = 45.
Executive summary:

The capacity factors k’ and log Koc for 4,4-Diaminodiphenylether were calculated based on the calibration data obtained with the reference substances according to the OECD 121  guideline.

The estimated log Koc = 1.66.

The estimated Koc =  45.

Description of key information

The capacity factors k’ and log Koc for 4,4-Diaminodiphenylether were calculated based on the calibration data obtained with the reference substances according to the OECD 121  guideline.

The estimated log Koc = 1.66.

The estimated Koc =  45.

Key value for chemical safety assessment

Koc at 20 °C:
45

Additional information