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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2010 (between 12 Octover 2010 and 6 November 2010)
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted using a documented method in accordance with REACH, and in compliance with GLP.
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
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))
Version / remarks:
HPLC method
Deviations:
no
GLP compliance:
yes
Type of method:
HPLC estimation method
Media:
other: soils, sludge, sediments
Radiolabelling:
no
Test temperature:
30 °C
Details on study design: HPLC method:
EQUIPMENT
- Apparatus: HPLC System
- Type: Agilent Technologies 1100, incorporating autosampler and workstation
- Type, material and dimension of analytical (guard) column: CN Optimal 5µ (150 x 4.6 mm id); Column temperature 30°C,
- Detection system: UV detector (wavelenght of dead time and reference standards. 210 nm; sample: 240 nm)

MOBILE PHASES
- Type: methanol:water (55:45 v/v)
- Experiments with additives carried out on separate columns: yes / no
- pH: approximately pH7
- Flow-rate: 1.0 mL/min
- Injection volume: 10 µL
- Solutes for dissolving test and reference substances: methanol
Test item (0.0521 g) was diluted to 100 mL with methanol.

DETERMINATION OF DEAD TIME
- Method: by means of homologous series / by inert substances which are not retained by the column
The dead time was determined by measuring the retention time of formamide (purity* 99.5%, 512 mg/L solution in mobile phase).

REFERENCE SUBSTANCES
- Identity:
Acetanilide (purity > 99 %; concentration: 100 mg/L), Phenol (purity = 98 %; concentration: 115 mg/L), Atrazine (purity = 97.4 %; concentration: 97 mg/L), Isoproturon (purity = 99.9 %; concentration: 109 mg/L), Triadimenol (purity = 98.4 %; concentration: 101 mg/L), Linuron (purity = 99.7 %; concentration: 102 mg/L), Naphthalene (purity = 98 %; concentration: 101 mg/L), Endosulfan-diol (purity = 99.8 %; concentration: 100 mg/L), Fenthion (purity = 98.3 %; concentration: 113 mg/L), alpha-Endosulfan (purity = 99.6 %; concentration: 100 mg/L), Phenanthrene (purity = 97 %; concentration: 104 mg/L), Diclofop-methyl (purity = 99.5 %; concentration: 104 mg/L), DDT (purity = 98 %; concentration: 106 mg/L)
Details: Solutions of reference standards were prepared in methanol.

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 10 µL
- Quantity of reference substances: 10 µL
- Intervals of calibration:
Construction of calibration curve: A calibration curve was constructed from the retention time data of the deadtime and reference standard solutions. The capacity factors (k) for the reference standards were calculated using Equation 10.1
Adsorption coefficient of sample: The capacity factor was calculated using Equation 10.1 and the log10Koc value determined using Equation 10.2 with reference to the calibration curve.

REPETITIONS
- Number of determinations:

EVALUATION
- Calculation of capacity factors k': the capacity factor was determiend using Equation 10.1: k = (tr- t0) / t0; where k = capacity factor, tr = retention time (min); t0 = dead time (min)
- Calculation of retention times:
- Determination of the log Koc value: The adsorption coefficient was calculated using Equation 10.2: Log10Koc = (Log10 k-A)/B, where Koc = adsorption coefficient; k = capacity factor; A = intercept of the calibration curve ; B = slope of the calibration curve
Type:
log Koc
Value:
>= 2.94 - <= 3.52 dimensionless
Temp.:
30 °C
Remarks on result:
other: Temp was temperature of column
Details on results (HPLC method):
- Retention times of reference substances used for calibration: see table below
- Details of fitted regression line (log k' vs. log Koc): see Graph attached
- Graph of regression line attached: yes
- Average retention data for test substance: see table below

The adsorption coefficeint results was taken from peak number 4 to 7 as these represented the main components of the test item and 94.7 % by percentage area normalisation.

Mean log10Koc range: 2.94 -3.52
Adsorption coefficient range: 872 to 3.28 x 10³

The determination was carried out using the HPLC screening method, desinged to be compatible with Method C19 Adsorption Coefficient of Commission regulation (EC) No 440/2008 of 30 May 2008 and Method 121 of the OECD Guideline for Testing of Chemicals, 22 January 2001.

The dead time was determined by measuring the retention time of formamide (Purity * 99.5%, 512 mg/L solution in mobile phase).

In the range 872 to 3.28 x 10³, lo0gKoc 2.94 to 3.52, using the HPLC screening method, designed to be compatible with Method C19 Adsorption Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 121 of the OECD Guidelines for Testing of Chemicals, 22 January 2001. This represented 94.7% if the test item by percentage area normalisation.

Validity criteria fulfilled:
yes
Conclusions:
Estimation of Koc value Koc = 2.94- 3.52 (at 30°C)
Executive summary:

The Adsorption and Desorption of the reaction mass of DEGDB and DPGDB has been determined according to EU Method C.19 (Estimation of the organic-normalized Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC)). The components represented by peak numbers 1 to 3 were considered to be minor components of the test item or impurities. Therefore, they were not used in the final result of the adsorption coefficient. The mobile phase pH was not adjusted as the test item had no modes of dissociation within in the environmentally relevant pH range, therefore a neutral pH was utilized.

The adsorption coefficient result was taken from peak numbers 4 to 7 as these represented the main components of the test item and 94.7 % by percentage area normalisation.

The adsorption coefficient of the test item has been determined to be as follows: log Koc = 2 .94 - 3.52 at 30°C and Adsorption coefficient range: 872 to 3.28 x 10³ at 30 °C.

Description of key information

Reaction Mass of DEGDB and DPGDB:

- Key study, reliability 1, EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Luquid Chromatography (HPLC)) - log Koc = 2 .94 - 3.52 at 30 °C and Adsorption coefficient range: 872 to 3.28 x 10³ at 30 °C.

Key value for chemical safety assessment

Koc at 20 °C:
3 280

Additional information

The Adsorption and Desorption of the reaction mass of DEGDB and DPGDB has been determined according to EU Method C.19 (Estimation of the organic-normalized Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC)). The components represented by peak numbers 1 to 3 were considered to be minor components of the test item or impurities. Therefore, they were not used in the final result of the adsorption coefficient. The mobile phase pH was not adjusted as the test item had no modes of dissociation within in the environmentally relevant pH range, therefore a neutral pH was utilized.

The adsorption coefficient result was taken from peak numbers 4 to 7 as these represented the main components of the test item and 94.7 % by percentage area normalisation.

The adsorption coefficient of the test item has been determined to be as follows: log Koc = 2 .94 - 3.52 at 30°C and Adsorption coefficient range: 872 to 3.28 x 10³ at 30 °C.