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Administrative data

Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: OECD guideline, GLP study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2011
Report date:
2011

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))
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of method:
HPLC estimation method
Media:
soil/sewage sludge

Test material

Constituent 1
Reference substance name:
LCE08121
IUPAC Name:
LCE08121
Details on test material:
Identification LCE08121
Expiry date Not provided
Supplier SEPPIC
Appearance White pellets
Packaging 2 white plastic flasks with blue stopper
Quantity received 2 X 1 L
Date of the reception 03 November 2008
Storage In darkness at room temperature
Identification number for the study 08-132
Radiolabelling:
no

Study design

Test temperature:
around 20°C

HPLC method

Details on study design: HPLC method:
Analytical method for the adsorption/desorption coefficient determination
Reagents
Acetone for analysis
Methanol for HPLC
Water for HPLC
All the glassware was rinsed with acetone for analysis and air dried before use.

Apparatus
Autosampler Hitachi AS2000A
HPLC pump Hitachi L-6200A
UV visible detector Hitachi L-4250
Ultrasonic tank Transonic Type T425H
Magnetic stirrer Heidolph 94360
Balance: Accuracy  0.1 mg Mettler AE 100S
Usual laboratory apparatus

Safety instructions
The chemicals, solvents and equipment were used with caution. The safety rules defined within DEFITRACES were strictly followed.

Preparation of the mobile phase
A volume of 275 mL of water was transferred into a 500-mL graduated cylinder. A volume of 225 mL of methanol was added. The solution was treated with ultrasounds for
5 minutes and left to stand for 10 minutes before analysis.

Preparation of the thiourea solution
The thiourea solution was prepared at a concentration of about 800 mg/L and diluted 100 then 1.5 fold with methanol/eau 5/5 before analysis.
This diluted solution was used for the t0 determination.

Preparation of the analytical reference item solutions
Acetanilide, methylbenzoate, isoproturon, 1,2,3-trichlorobenzene, pyrazophos and 4,4’-DDT are the six reference items solutions chosen within the method recommended reference substances for the HPLC method.
For acetanilide, 1,2,3-trichlorobenzene, pyrazophos and 4,4’-DDT: A quantity of about 10 mg (to the nearest ± 0.1 mg) of reference item was weighed into a 100-mL volumetric flask. The volume was made up with methanol. The solution was treated with ultrasounds during 5 minutes.
For isoproturon: A quantity of about 5 mg (to the nearest ± 0.1 mg) of reference item was weighed into a 25-mL volumetric flask. The volume was made up with methanol. The solution was treated with ultrasounds during 5 minutes.
For methylbenzoate: A quantity of about 20 mg (to the nearest ± 0.1 mg) of reference item was weighed into a 25-mL volumetric flask. The volume was made up with methanol. The solution was treated with ultrasounds during 5 minutes.

Preparation of the diluted analytical reference item solutions
For acetanilide, methylbenzoate and isoproturon: A 20 times dilution was made up with a mixture of methanol/water 45/55 v/v. A vial was prepared for analysis.
For 1,2,3-trichlorobenzene, pyrazophos and 4,4’-DDT: A 5 times dilution was made up with a mixture of methanol/water 45/55 v/v. A vial was prepared for analysis.
These solutions were used as reference item solutions to obtain the calibration curve.

Preparation of the mixed analytical reference item solutions
Volumes of 1 mL of acetanilide, 1 mL of methylbenzoate, 1 mL of isoproturon, 4 mL of pyrazophos, 4 mL of 4,4’-DDT and 4 mL of 1,2,3-trichlorobenzene were transferred into a 20-mL volumetric flask. The volume was made up with the mixture of methanol/water 45/55 v/v.
A vial was prepared for analysis.

Preparation of the test item solution
A quantity of about 0.25 g of LCE08121 was accurately weighed into a 50-mL volumetric flask. The volume was made up with methanol. The solution was treated with ultrasounds for 5 minutes before analysis.

Instrumental analysis
The experimental conditions used for the determination of the retention times of the analytical reference items and of the test item by high pressure liquid chromatography equipped with an ultraviolet detector are as following:

Column
Column Supelco Length (cm) 25
Particle size (μm) 5.0 Internal diameter (mm) 4.6
Stationary phase Supelcosil LC-CN
Mobile phase Methanol / water 45/55 v/v
Flow rate (mL/min) 0.9
Injected volume (μL) 40 Wave length analysis (nm) 210

Injection sequence
Mixture of the analytical reference items, test item, mixture of the analytical reference items, test item, mixture of the analytical reference items, individual analytical reference items.

Results and discussion

Adsorption coefficient
Type:
log Koc
Value:
4.42
Temp.:
20 °C

Results: HPLC method

Details on results (HPLC method):
First run:

Products Mean Retention Time (min) Value of the Capacity factor k’ Value of log k’ Value of log koc
Acetanilide 4.68 0.27 -0.57 1.25
Methyl benzoate 5.80 0.58 -0.24 1.80
Isoproturon 6.74 0.83 -0.08 1.86
1,2,3-trichlorobenzene 12.41 2.37 0.37 3.16
Pyrazophos 20.25 4.50 0.65 3.65
4,4’ DDT 56.79 14.43 1.16 5.63
Test item 26.77 6.27 0.80 4.41

Mean t0 = 3.68 min (thiourea)

Using the Capacity factor and the adsorption coefficient of the reference items, the following calibration curve was obtained:
log k’ = 0.3855 log koc – 0.8998 r2 = 0.9652


Second run:
Products Mean Retention Time (min) Value of the Capacity factor k’ Value of log k’ Value of log koc
Acetanilide 4.69 0.27 -0.57 1.25
Methyl benzoate 5.81 0.58 -0.24 1.80
Isoproturon 6.74 0.83 -0.08 1.86
1,2,3-trichlorobenzene 12.34 2.35 0.37 3.16
Pyrazophos 19.97 4.43 0.65 3.65
4,4’ DDT 55.96 14.21 1.15 5.63
Test item 26.72 6.26 0.80 4.42

Mean t0 = 3.69 min (thiourea)

Using the Capacity factor and the adsorption coefficient of the reference items, the following calibration curve was obtained: log k’ = 0.3834 log koc – 0.8954 r2 = 0.9638


Discussion
Variation in the retention times of the reference items are very small. Therefore a stable configuration of the HPLC column can be assumed.
The correlation log k’/ log koc is accurate as calibration gave a coefficient of correlation near r2 = 0.965.
Under the normal chromatographic conditions, the test item peak showed a retention on the column around 26.75 min.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The adsorption / desorption coefficient of LCE08121 is equal to 4.42.
Executive summary:

Determination of the adsorption / desorption coefficient of LCE08121

In compliance withOECD Guideline No. 121 (2001)

 

 

The objective of this study was to estimate the adsorption/desorption coefficient on soil and on sewage sludge using (HPLC) High Performance Liquid Chromatographyfollowing the test method (OECD Guideline No. 121, 2001).

 

Using this procedure, it was shown that the adsorption / desorption coefficient of LCE08121 is equal to 4.42.