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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
September 10, 2010 to October 20, 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. The study report was conclusive, done to a valid guideline and the study was conducted under GLP conditions.
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
Qualifier:
according to
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. certificate)
Remarks:
Date of Certificate: November 12, 2008
Type of method:
other: not applicable
Media:
other: EXAMPLE: Not applicable.
Radiolabelling:
no
Test temperature:
25 °C
Details on study design: HPLC method:
HPLC-Conditions
Apparatus: Varian autosampler ProStar 410
Varian pump ProStar 230
Varian UV/VIS detector 325
Jones column oven 7990
Column: LiChrosphere 100 CN, part. size 5 µm, 250 mm x 4 mm
HPLC Eluent: Water / acetonitrile (45:55; v/v); pH 6.78
Detection: Test item: 210 nm
Reference items: 210 nm
Sodium nitrate: 210 nm
Temperature: 25 °C
Injection Volume: 20 µL
Flow: 1.0 mL/min
Run Time: 20minutes
Retention Times: See Table 1
Analytical monitoring:
not required
Type:
Koc
Value:
133 377
Type:
log Koc
Value:
5.1
Transformation products:
not measured

The test item solution was injected three times and the combined reference solution was injected six times. The dead time solution was injected three times. In the present study the reference items covered the range of log KOC 1.25 to log KOC 5.63. The log KOC of the test item was calculated using a regression curve (log k' vs. log KOC) and was found to be 5.1, which is equal to a KOCvalue of 133377(see Table 3).

 

A typical HPLC chromatogram of the reference standard mixture is shown in the attached Figure 1. An HPLC chromatogram of the test item is shown in the attached Figure 2. A typical chromatogram of the determination of the dead-time is given in the attached Figure 3. The chromatography of the test item resulted in one peak with a reproducible retention time. The HPLC method was therefore considered to be suitable for the purpose of the study.

 

The retention times of the individual measurements of the reference items, test item and the dead time are given in Table 1. The capacity factor (k’) was calculated for each reference item using the retention times. Log k’ was plotted versus log KOCfor each component to obtain a regression curve (Table 2 and Figure 4).

 

The tabulated values of Table 2 and 3 represent rounded mean results, which were obtained by calculation using the exact raw data.

Table 1       Retention Times in Minutes of the Reference Items and the Test Item

 

1strun

2ndrun

3rdrun

4thrun

5thrun

6thrun

Sodium nitrate

(= dead time)

1.444

1.440

1.439

 

 

 

Reference Items:

Acetanilide

2.950

2.946

2.967

2.940

2.943

2.940

Isoproturon

3.342

3.339

3.370

3.325

3.333

3.328

Linuron

3.531

3.529

3.563

3.510

3.521

3.514

Pyrazophos

3.884

3.883

3.920

3.856

3.870

3.860

Diclofop-methyl

4.233

4.234

4.273

4.198

4.217

4.205

2,4-DDT

4.907

4.911

4.952

4.873

4.889

4.875

di-tert-butyl 3,3,5-trimethylcyclohexylidene diperoxide:

 

 

 

TestItemPeak

4.615

4.682

4.692

 

 

 

 

Table 2       Results of Linear Regression of Log k’ vs. Log KOC

 

Number
of
analysis

Mean retention time
[min]

k'

log k'

log KOC

Sodium nitrate (= dead time)

3

1.44

-

-

 

Reference Items:

Isoproturon

6

3.34

1.32

0.12

1.86

Linuron

6

3.53

1.45

0.16

2.59

Pyrazophos

6

3.88

1.69

0.23

3.65

Diclofop-methyl

6

4.23

1.93

0.29

4.20

2,4-DDT

6

4.90

2.40

0.38

5.63

 

slope =

 

 

 

0.078

Linear Regression:

y-axis intercept =

-0.050

 

Correlation coefficient (r) =

0.990

 

 

Table 3       Result of di-tert-butyl 3,3,5-trimethylcyclohexylidene diperoxide Analyses

Number
of
analyses

Retention time
[min]

k'

log k'

log KOC

Mean
log KOC

KOC

Mean
KOC

TestItemPeak

1

4.62

2.20

0.3429429

5.0

5.1

109145.1

133376.95

2

4.68

2.25

0.3520151

5.2

142623.1

3

4.69

2.26

0.353353

5.2

148362.7

 

Validity criteria fulfilled:
yes
Remarks:
EXAMPLE:
Conclusions:
The log of the adsorption coefficient (KOC) of di-tert-butyl 3,3,5-trimethylcyclohexylidene diperoxide was calculated to be log KOC = 5.1 which is equal to a KOC value of 133377 using the HPLC method. This value indicates that di-tert-butyl 3,3,5-trimethylcyclohexylidene diperoxide is immobile.
Executive summary:

The log of the adsorption coefficient (KOC) of di-tert-butyl 3,3,5-trimethylcyclohexylidene diperoxide was estimated to be

 

log KOC= 5.1 which is equal to a KOC value of 133377

 

using the HPLC method. This value indicates that di-tert-butyl 3,3,5-trimethylcyclohexylidene diperoxide will be adsorbed by organic carbon in soil. Di-tert-butyl 3,3,5-trimethylcyclohexylidene diperoxide can be classified to be immobile according these study results.

 

Description of key information

Koc determined using HPLC method

Key value for chemical safety assessment

Koc at 20 °C:
133 377

Additional information

The log of the adsorption coefficient (KOC) of di-tert-butyl 3,3,5-trimethylcyclohexylidene diperoxide was estimated to be

 

log KOC= 5.1 which is equal to a KOCvalue of 133377

 

using the HPLC method. This value indicates that di-tert-butyl 3,3,5-trimethylcyclohexylidene diperoxide will be adsorbed by organic carbon in soil. Di-tert-butyl 3,3,5-trimethylcyclohexylidene diperoxide can be classified to be immobile according these study results.

These results are supported by the QSAR.