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Administrative data

Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
May 29, 2002 - June 07, 2002
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study under GLP compliance with acceptable restrictions.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2002
Report date:
2002

Materials and methods

Test guideline
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))
GLP compliance:
yes (incl. QA statement)
Type of method:
HPLC estimation method
Media:
soil/sewage sludge

Test material

Constituent 1
Reference substance name:
MV31 Kaliumsalz
IUPAC Name:
MV31 Kaliumsalz
Details on test material:
- Name of test material (as cited in study report): MV31 Kaliumsalz
- Substance type: Single component
- Physical state: grey globular substance
- Storage condition of test material: dry and room temperature
Radiolabelling:
no

Study design

HPLC method

Details on study design: HPLC method:
The Koc of MV31 K salt was determined based on the correlation between the retention of a substance on a reversed phase column packed with a commercially available cyanopropyl solid phase containing lipophilic and polar moieties and the adsorption coefficient Koc.

EQUIPMENT:
- Apparatus: HPLC pump G1311 A, Autosampler G1313A, column oven G1316A,
- Type, material and dimension of analytical (guard) column: stationary phase: LiChrospher 100 CN 5 µm by Duratec (18904-02); material: stainless steel; dimension: 125 mm x 4.6 mm; Column temperature: 20°C;
- Detection system: UV/VIS detector G1314A by Agilent. Detection wavelength at 210 nm (dead time marker and test substance), 220 nm (calibration substances without Direct Red), 395 nm (direct Red).

MOBILE PHASES:
- Type: acetonitrile/buffer pH 8.0 25:75 (v/v), isocratic elution;
- Flow rate: 0.8 ml/min;
- Injection volume: 10 µl (dead time marker and calibration substances without Direct Red), 25 µl (test substance), 100 µl (direct Red).

DETERMINATION OF DEAD TIME: The dead time marker was Uracil dissolved in acetonitrile/distilled water (50:50) and injected twice. The mean dead time of the test system was 2.05 minutes.

Calibration Substances:
- Identity: Benzamide, Acetanilide, Aniline, Monuron; 3,5-Dinitrobenzamide, Triadimenol; Linuron; terbutryn, Naphthalene, Direct Red 81. The Calibration substances (without Direct Red) were dissolved in acetonitrile and diluted 0.1 to 1 in the mobile phase and injected as single standard twice. Direct Red was dissolved in distilled water and diluted 0.1 to 1 in the mobile phase and injected as single standard twice. It is notable that the calibration substances are aromatic compounds and/or pesticides. The calibration substances are approved for use in the method, but bear little or no structural similarity to the test substance. This is a limitation of the test guideline.

DETERMINATION OF RETENTION TIMES
- Quantity of dead time marker: 2.72 µg
- Quantity of test substance introduced in the column: 111.13 µg
- Quantity of calibration substances: 0.71 - 7.42 µg

REPETITIONS
- Number of determinations: Two (duplicate) injections

EVALUATION
- Calculation of capacity factors k': k' = (Tr - T0) / T0, where: Tr = retention time;
T0 = mean column dead time (Uracil peak);

- Calculation of retention times: The test substance was dissolved in distilled water and diluted 0.5 to 1 with acetonitrile/buffer pH 8.0 50:50 (v/v) and injected twice. Mean retention times were taken for the unretained and test substance retention times only. Retention times for the duplicated injections of the calibration substance peaks were used to generate the regression curve.

- Determination of the log Koc value: Linear regression according to calibration curve of the log k of the reference substances as function of log Koc
log Koc = a +b x logk

Results and discussion

Adsorption coefficient
Type:
log Koc
Value:
1.83
Temp.:
20 °C
Remarks on result:
other: RSD% = 1.4

Results: HPLC method

Details on results (HPLC method):
- Retention times of calibration substances used for calibration: 3.19 - 18.18 min (See table 1)
- Details of fitted regression line (log k' vs. log Koc):
1st measurement: a = 1.3591, b =1.5495, r² = 0.856,
2nd measurement: a = 1.3616, b = 1.549, , r² = 0.8547,

MV31 K salt had retention time of 5.45 minutes and 5.25 minutes for the duplicate measurements. The Log Koc were 1.85 and 1.81, respectively. Average Log Koc was 1.83, with RSD% = 1.4%

Any other information on results incl. tables

Table 1. Koc determination of MV 31 K Salt

Substance

Tr,1 [min]

Tr,2 [min]

mean Tr (n=2)

K

Log K

log Koc

Uracil (t0)

2.04

2.05

2.05

 

 

 

Measurement 1

 

Benzamide

3.19

 

 

0.56

-0.25

1

Acetanilide

4.09

 

 

1

0

1.25

Aniline

4.21

 

 

1.06

0.02

2.07

Monuron

6.71

 

 

2.28

0.36

2.21

3,5-Dinitrobenzamide

5.06(1)

 

 

1.47

0.17

2.31

Triadimenol

13.11

 

 

5.41

0.73

2.4

Linuron

15.84

 

 

6.74

0.83

2.59

Terbutryn

13.99

 

 

5.84

0.77

2.68

Naphthalene

18.18

 

 

7.88

0.9

2.75

Direct Red 81

3.91(1)

 

 

0.91

-0.04

3.43

 

Log Koc = 1.5495 + 1.3591 log K (r² = 0.856)  

MV 31 K salt

5.45

 

 

1.66

0.22

1.85

 

Measurement 2

 

Benzamide

 

3.19

 

0.56

-0.25

1

Acetanilide

 

4.09

 

1

0

1.25

Aniline

 

4.2

 

1.05

0.02

2.07

Monuron

 

6.71

 

2.28

0.36

2.21

3,5-Dinitrobenzamide

 

5.04

 

1.46

0.16

2.31

Triadimenol

 

13.1

 

5.4

0.73

2.4

Linuron

 

15.78

 

6.71

0.83

2.59

Terbutryn

 

13.96

 

5.82

0.77

2.68

Naphthalene

 

18.1

 

7.85

0.89

2.75

Direct Red 81

 

3.78

 

0.84

-0.07

3.43

 

Log Koc = 1.549 + 1.3616 log K (r² = 0.8547)  

MV 31 K salt

 

5.25

 

1.57

0.2

1.81

(1)Not used for calculation

Applicant's summary and conclusion

Conclusions:
Log Koc value of test substance was 1.83.
Executive summary:

Log Koc value of MV 31 K salt was assessed according to OECD Guideline TG121 "Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using HPLC". Under the analytical conditions used, the test substance had a log Koc value of 1.83 with RSD% of 1.4%.

The study was conducted according to internationally accepted test guidelines and under GLP compliance. The calibration substances are approved for use in the method, but bear little or no structural similarity to the test substance. Therefore, this study is considered as reliable with restrictions.