2-(4-methylphenoxy)-N-(1H-pyrazol-3-yl)-N-[(thiophen-2-yl)methyl]acetamide

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:

2017-07-04 to 2017-08-31

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study was performed according to OECD guideline 121 (2001) and Council Regulation (EC) No. 440/2008, Method C.19, with GLP compliance.

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

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

GLP certificate, inspection between June 7th and 10th 2016.

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Specific details on test material used for the study:

- Storage condition of test material: Storage in closed, preferably full containers, away from heat sources and protected from extreme variations in temperature.

Radiolabelling:

no

Test temperature:

23.1 °C (mean value)

Details on study design: HPLC method:

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
Prior to testing a stock solution of 2000 mg/L was prepared. The dilution was made with methanol and HPLC water to obtain 20 mg/L sample of the test substance.

Type and purpose of the study
Use of HPLC in combination with DAD (Photodiode array detection)for the estimation of the adsorption coefficient (Koc) of the test substance on soil and on sewage sludge. The decision for the HPLC method was made due to the results of a non GLP preliminary testing with log KOC values of 2.49 for sewage sludge and 2.49 for soil.

Test system
Analytical HPLC-column (based on silica matrix), coupled to DAD, packed with a cyanopropyl solid phase containing non-polar and polar moieties.

Reasons for the selection
The selection of the test system is based on the guidelines. HPLC coupled to DAD is a useful method for estimation of the adsorption coefficient KOC. The KOC indicates the binding capacity of the test item on soil or sewage sludge and allows comparing the adsorption behaviour of different chemicals. The test item and reference items will be detected by DAD. The study will be performed under neutral conditions, since the test item is not ionisable in the pH range of 4.5 to 7.5.

HPLC system
HPLC AGILENT 1100 consisting of:

Auto sampler G1329A
Auto sampler thermostat G1330B
Pump G1312A
Degasser G1322A
Column oven G1316A
Detector G1315B
Software Empower 2 (Build No: 2154), WATERS
Column YMC-Pack Cyano, S-5µm, 12 nm, 250 x 4.0 mm, YMC EUROPE GMBH
Mobile phase Methanol and HPLC water in a ratio of 55 : 45.
Column temperature 20 - 25 ± 1 °C
Flow rate 1.0 mL/min
Injection volume 20 µL
Temperature monitoring Data logger using 2 minutes interval
System suitability As a guidance, the following capacity factors k’ should be reached: log k’ > 0 for log KOC = 3.02 (Endosulfan-diol) and
log k’ > -0.4 for log KOC = 1.95 (3-Nitrobenzamide)
by using Methanol : HPLC water (55 : 45) as mobile phase.

REFERENCE SUBSTANCES
- Identity: Acetanilide, Atrazine, Aniline, 2,5-Dichloraniline, Linuron, Phenyl benzoate, Fenthion

EVALUATION
- Calculation of capacity factors k': Calibration of the method was done by determination of the capacity factor retention times tR of the reference items (minimum of six items). Each reference item was analysed separately once before and once after the test item. The retention time was described by the capacity factor k given by the expression: k' = (tR-t0)/t0
k’: capacity factor, tR: retention time, t0: dead time

- Determination of the log Koc value: By linear regression of the log k´ of the reference items against the log KOC of the reference items, the equation for the calibration graph was obtained. Two individual adsorption coefficients for the test item were calculated by experimentally determining its capacity factor k´ and inserting k´ into the following equation obtained from the first and second calibration graph: log Koc = a.log k + b
a: slope of the calibration graph, b: y-intercept of calibration graph. Finally, a mean value was calculated from these individual log KOC values.

Details on test conditions:

TEST CONDITIONS
- pH: The study was performed under neutral conditions, since the test item is not ionisable in the pH range of 4.5 to 7.5.

Key result

Type:

log Koc

Value:

2.45 dimensionless

pH:

7

Temp.:

23.1 °C

Remarks on result:

other: The log Koc was determined to be 2.45 for soil.

Key result

Type:

log Koc

Value:

2.5 dimensionless

pH:

7

Temp.:

23.1 °C

Remarks on result:

other: The Log Koc was determined to be 2.50 for sewage sludge.

Details on results (HPLC method):

- Retention times of reference substances used for calibration: See Table 3 in "Any other information on results including tables".
- Details of fitted regression line (log k' vs. log Koc):
soil replicate 1 : r² = 0.9424
soil replicate 2 : r² = 0.9430
sewage sludge replicate 1 : r² = 0.8768
sewage sludge replicate 2 : r² = 0.8755

- Graph of regression line attached

- Average retention data for test substance: See Table 4 in "Any other information on results including tables"

Transformation products:

not measured

Table 5.4.1/2 : Dead time of HPLC-System

Injection No.	t0 (min)
1	1.543
2	1.541
3	1.540
Mean +/- SD	1.541 +/- 0.002

Table 5.4.1/3 : Capacity factors (k') of the reference items for soil and sewage sludge

Reference item	Log Koc soil	Log Koc sewage sludge	1.			2.
			tR1 (min)	k’	Log k’	tR2 (min)	k’	Log k’
Acetanilide	1.26	1.52	3.437	1.23	0.0899	3.437	1.23	0.0899
Atrazine	1.81	1.66	4.002	1.60	0.203	4.011	1.60	0.205
Monuron	1.99	1.46	4.244	1.75	0.244	4.263	1.77	0.247
2,5-dichloroaniline	2.55	2.45	5.326	2.46	0.390	5.357	2.48	0.394
Linuron	2.59	2.43	6.539	3.24	0.511	6.597	3.28	0.516
Phenyl benzoate	2.87	3.26	6.434	3.17	0.502	6.485	3.21	0.506
Fenthion	3.31	3.75	10.728	5.96	0.775	10.843	6.03	0.781

Table 5.4.1/4 : Retention times, capacity factors (k') and adsorption coefficient (log Koc) of the test substance for soil and sewage sludge

	Test substance
	tR (min)	k’	Log k’	Log Koc soil		Log Koc sewage sludge
				1st calibration	2^ndcalibration	1st calibration	2^ndcalibration
	5.653	2.67	0.426	2.45 +/- 0.07 2.27 to 2.34 (95 % CI)	2.44 +/- 0.07 2.26 to 2.62 (95 % CI)	2.50 +/- 0.13 2.16 to 2.84 (95 % CI)	2.49 +/- 0.13 2.15 to 2.83 (95% CI)
	5.666	2.68	0.427
	5.673	2.68	0.428
Mean	5.664	2.67	0.427	2.45		2.50

Validity criteria fulfilled:

yes

Conclusions:

The adsorption coefficient log Koc of the test substance was determined to be 2.45 for soil and 2.50 for sewage sludge.

Executive summary:

This study was performed according to OECD Guideline 121 and EU Method C.19 with GLP statement to assess the adsorption coefficient of the test substance. The test utilized a high performance liquid chromatograph (HPLC).

The test was performed temperature controlled with a mobile phase consisting of 55% methanol and 45% HPLC water. A 20 mg/L sample of the test substance was analyzed threefold via HPLC on a cyanopropyl (CN-) column with DAD-detection.

Calibrations were performed using seven reference items for soil and for sewage sludge with known log Koc values. The reference items were measured twice, once before and once after the measurement (double injection of one replicate) of the test substance. Dead time of the HPLC-system was determined with sodium nitrate.

Two individual log Koc values for soil and for sewage sludge for the test substance were derived under consideration of the first and second calibration. Finally, a mean value for soil and for sewage sludge was calculated from these individual log Koc values.

The adsorption coefficient log Koc of the test substance was determined to be 2.45 for soil and 2.50 for sewage sludge.

Description of key information

OECD Guideline 121, EU Method C.19, GLP, key study, validity 1 :

log Koc (soil) = 2.45 ; log Koc (sewage sludge) = 2.50.

Moderately mobile in soils (according to P.J. McCall et al., 1981).

Key value for chemical safety assessment

Koc at 20 °C:

316

Additional information

One valid key study is available to assess the adsorption coefficient of the registered substance. This study was performed according to OECD guideline 121 and EU Method C.19 with GLP compliance. The adsorption coefficient log Koc of the test substance was determined, by HPLC, to be 2.45 for soil and 2.50 for sewage sludge. The result indicates that the substance is moderately mobile (according to P.J. McCall et al., 1981¹).

¹McCall P.J., Laskowski D.A., Swann R.L., and Dishburger H.J., (1981), “Measurement of sorption coefficients of organic chemicals and their use, in environmental fate analysis”, in Test Protocols for Environmental Fate and Movement of Toxicants. Proceedings of AOAC Symposium, AOAC,

Washington DC.