[No public or meaningful name is available]

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experiment start date - 22 March 2010; Experiment completion date - 23 March 2010; Study completion date - 08 June 2010.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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

Qualifier:

according to guideline

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. QA statement)

Type of method:

HPLC estimation method

Media:

soil

Specific details on test material used for the study:

Identification: FAT 40851/A TE
Batch Number: TZ 5891 / BOP 02-09
Purity: 69.9 % all coloured components
Appearance: Orange powder
Expiry Date: July 31, 2014
Storage Conditions: At room temperature at about 20 °C

Radiolabelling:

no

Test temperature:

At room temperature at about 20 °C

Details on study design: HPLC method:

EQUIPMENT
Apparatus: Varian autosampler 9095
Varian pump 9012
Varian UV/VIS detector 9050
Jones column oven 7990
Column: Luna CN, particle size 5 μm, 50 mm x 4.6 mm
HPLC Eluent: water and methanol (45:55; v/v); pH 6.15
Detection: Test item: 254 nm
Reference items: 210 nm
Sodium nitrate: 210 nm
Temperature: Room temperature
Injection Volume: 20 μL
Flow: 1.0 mL/min
Run Time: 15 minutes


STATIONARY/MOBILE PHASES
An analytical column packed with a commercially available, cyanopropyl solid phase containing lipophilic and polar moieties was used. A moderately polar stationary phase based on a silica matrix was used. While passing through the column along with the mobile phase, the test item interacts with the stationary phase. As a result of partitioning between mobile and stationary phases, the test item is retained. 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 is the case for organic matter in soil or sewage sludge matrices. This enables the relationship between the retention time on the column and the adsorption coefficient on organic matter to be established.

DETERMINATION OF DEAD TIME
Sodium nitrate (10.15 mg) was dissolved in 10 mL of methanol to obtain a stock solution. The stock solution (500 μL) was diluted to 5 mL with a solvent mixture of water and methanol (45:55; v/v). This sodium nitrate solution was injected four times for the determination of the dead time of the HPLC system

TEST SUBSTANCE
FAT 40851/A TE (28.34 mg) was dissolved in a solvent mixture of water and methanol (45:55; v/v) (25 mL) to prepare a stock solution of 1133.6 μg/mL. The stock solution (1 mL) was diluted with a solvent mixture of water and methanol (45:55; v/v) to 10 mL to obtain a test solution of 113.36 μg/mL. The pH value of the test item solution was determined to be 6.8.

REFERENCE SUBSTANCES
The reference items were chosen from the list given in the OECD Guideline No. 121, EC Directive C.19 and Council Regulation (EC) C.19.
Stock solutions of the reference items were prepared as described:
13.48 mg of acetanilide, 13.07 mg of isoproturon, 18.75 mg of linuron, 12.79 mg of pyrazophos, 11.71 mg of diclofop-methyl and 10.16 mg of 2,4-DDT were each dissolved in 10 mL of methanol. A combined reference solution was prepared by transferring 500 μL each stock solution into a 5 mL volumetric flask and filling up to the marking with a solvent mixture of water and methanol (45:55; v/v).


DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: Injected volume: 20 μL
- Quantity of reference substances: Injected volume: 20 μL

REPETITIONS
- Number of determinations:The test item solution was injected three times, the reference solution was injected six times

EVALUATION
- Calculation of capacity factors k':
the capacity factor (k’) is calculated from the retention time of the reference items, the test item (tR) and an un-retained item (t0):
k’ = (tR - t0) / t0
where
tR = Retention time of the test item or reference item
t0 = Time a non-sorbed chemical needs to pass the column (dead-time, sodium nitrate solution)

- Determination of the log Koc value:
The correlation of log k’ versus log KOC of the reference items is plotted using linear regression according to the following equation.
y = a + b • x ⇔ x = (y - a) / b

where
y = log k’ values
x = log KOC values
a = Y-axis intercept of the regression curve
b = Slope

Type:

log Koc

Value:

< 1.25

Temp.:

22 °C

Remarks on result:

other: pH not available

Type:

Koc

Value:

< 18

Temp.:

22 °C

Remarks on result:

other: pH not available

Details on results (HPLC method):

see "any other information on results incl. tables"

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

	1^strun	2^ndrun	3^rdrun	4^thrun	5^thrun	6^thrun
Sodium nitrate (= dead time)	0.426	0.429	0.430	0.435
Reference Items:
Acetanilide	0.816	0.808	0.808	0.808	0.808	0.808
Isoproturon	0.938	0.929	0.929	0.929	0.928	0.928
Linuron	1.192	1.179	1.179	1.177	1.184	1.174
Pyrazophos	1.504	1.485	1.484	1.481	1.497	1.474
Diclofop-methyl	1.864	1.839	1.837	1.832	1.855	1.821
2,4-DDT	3.171	3.124	3.125	3.111	3.145	3.123
FAT 40851/A TE:
1^stPeak	0.361	0.361	0.360

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)	4	0.43		-	-
Reference Items:
Acetanilide	6	0.81	0.88	-0.05	1.25
Isoproturon	6	0.93	1.16	0.07	1.86
Linuron	6	1.18	1.75	0.24	2.59
Pyrazophos	6	1.49	2.46	0.39	3.65
Diclofop-methyl	6	1.84	3.28	0.52	4.20
2,4-DDT	6	3.13	6.29	0.80	5.63
	slope =				0.192
Linear Regression:	y-axis intercept =				-0.287
	coefficient of regression (r) =				0.998

The tabulated values represent rounded results, which were obtained by calculation using the exact raw data.

The retention time of the test item peak in all runs is shorter than the retention time of acetanilide, the first reference item on the list of the guideline with a log KOC value of 1.25.

Validity criteria fulfilled:

yes

Remarks:

The chromatography of the test item resulted in one sharp main peak with a well-defined and reproducible retention time. The HPLC method was therefore considered to be suitable for the purpose of the study.

Conclusions:

The log of the adsorption coefficient (KOC) of FAT 40851/A was determined to be lower than that one of the lowest reference item acetanilide using the HPLC method: log KOC <1.25 which is equal to a KOC value of <18. This value indicates that FAT 40851/A will not be adsorbed by organic carbon in soil. FAT 40851/A is considered to be “very highly” mobile according to the scales of McCall et al (1981).

Executive summary:

The determination of the adsorption coefficient (KOC) of FAT 40851/A was performed according to the OECD Guideline for the Testing of Chemicals, No. 121, Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge using High Performance Liquid Chromatography (HPLC), January, 2001, the EC Directive 2001/59, C.19 (August 2001) and Council Regulation (EC) No. 440/2008, 30 May 2008, Part C, Methods for the determination of physico-chemical properties, C.19. The test item solution was injected three times and the combined reference solution was injected six times. In the present study the reference items covered the range of log KOC 1.25 to log KOC 5.63. Under the conditions of the test, the test item FAT 40851/A was found to elute as one peak at a retention time of about 0.36 minutes. Sodium nitrate that was used for the dead time determination was eluted at a retention time of about 0.43 minutes. The reference item with the lowest KOC was eluted at a retention time of about 0.81 minutes. FAT 40851/A was not retained under the chromatographic conditions of the test and was eluted at the dead time. The KOC of FAT 40851/A was therefore determined to be lower than that of the lowest reference item used (acetanilide). Therefore, the log KOC of the test item is <1.25, which is equal to a KOC value of <18. This value indicates that FAT 40851/A is very mobile.

Description of key information

The substance has a low organic carbon-water partitioning coefficient (log Koc <1.25).

Key value for chemical safety assessment

Koc at 20 °C:

18

Additional information

The determination of the adsorption coefficient (KOC) of FAT 40851/A was performed according to the OECD Guideline for the Testing of Chemicals, No. 121, Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge using High Performance Liquid Chromatography (HPLC), January, 2001, the EC Directive 2001/59, C.19 (August 2001) and Council Regulation (EC) No. 440/2008, 30 May 2008, Part C, Methods for the determination of physico-chemical properties, C.19. The test item solution was injected three times and the combined reference solution was injected six times. In the present study the reference items covered the range of log KOC 1.25 to log KOC 5.63. Under the conditions of the test, the test item FAT 40851/A was found to elute as one peak at a retention time of about 0.36 minutes. Sodium nitrate that was used for the dead time determination was eluted at a retention time of about 0.43 minutes. The reference item with the lowest KOC was eluted at a retention time of about 0.81 minutes. FAT 40851/A was not retained under the chromatographic conditions of the test and was eluted at the dead time. The KOC of FAT 40851/A  was therefore determined to be lower than that of the lowest reference item used (acetanilide). Therefore, the log KOC of the test item is <1.25, which is equal to a KOC value of <18. This value indicates that FAT 40851/A is very mobile.