1-Ethoxy-2,3-difluor-4-[4-(trans-4-propylcyclohexyl)-1-cyclohexen-1-yl]-benzene

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:

07.05.2018 - 01.10.2018

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))

Version / remarks:

2001

Deviations:

yes

Remarks:

According to the Guideline the water content in the mobile phase should be 45 % (v/v). As the solubility of the test item in water is very low the content of water had to be reduced to 10 % (v/v).

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))

Version / remarks:

2008

Deviations:

yes

Remarks:

According to the Guideline the water content in the mobile phase should be 45 % (v/v). As the solubility of the test item in water is very low the content of water had to be reduced to 10 % (v/v).

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Radiolabelling:

no

Test temperature:

25 °C

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: HPLC

MOBILE PHASES
- Type: Methanol/demineralized water
- Experiments with additives carried out on separate columns: no
- pH: 5.9
- Solutes for dissolving test and reference substances: methanol and diluted with the eluent

DETERMINATION OF DEAD TIME
- Method: by inert substances which are not retained by the column

REFERENCE SUBSTANCES
- Identity: Atrazin, Triadimenol, Linuron, Pyrazophos, Diclofop-methyl, 4,4' DDT

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 1.28 µg
- Quantity of reference substances: 0.86 - 1.28 µg

REPETITIONS
- Number of determinations: 2

EVALUATION
- Calculation of capacity factors k': k = (tr - t0)/t0 with tr: retention time of substances, t0: dead time

- Determination of the log Koc value: logKOC = a + b * log k

Analytical monitoring:

not required

Details on sampling:

N/A

Details on matrix:

N/A

Details on test conditions:

N/A

Key result

Sample No.:

#1

Type:

log Koc

Value:

6.3 dimensionless

pH:

5.9

Temp.:

20 °C

Key result

Sample No.:

#2

Type:

log Koc

Value:

6.3 dimensionless

pH:

5.9

Temp.:

20 °C

Details on results (HPLC method):

- Retention times of reference substances used for calibration: Atrazin (1.78 min), Triadimenol (1.82 min), Linuron (1.87 min), Pyrazophos (1.94 min), Diclofop-methyl (1.91 min), 4,4' DDT (2.02 min)
- Graph of regression line attached: Yes
- Average retention data for test substance: 2.48 min

Table 1: Determination of the dead time t₀ 

Dead time marker	tR/min  1^stinjection	tR/min  2^nd injection	tR/min  3^rd injection
Formamide	1.75	1.75	1.75

 

Table 2: Calibration data 1^st injection 

Calibration substance	tR/min	k	Log k	Log Koc
Atrazin	1.78	0.02	-1.77	1.81
Triadimenol	1.82	0.04	-1.44	2.40
Linuron	1.87	0.07	-1.17	2.59
Pyrazophos	1.94	0.11	-0.96	3.65
Diclofop-methyl	1.91	0.09	-1.05	4.20
4,4’-DDT	2.02	0.15	-0.82	5.63

Regression: log K_oc = a+ b · log k 

Parameters: a=7.652, b=3.559, r²=0.7742 

 

Table 3: Log P_ow of the test item 1^st injection 

	tR/min	k	Log k	Log Koc
Test item	2.48	0.41	-0.38	>5.6 ^1) (6.3) ^2)

¹⁾ above the highest log Koc value of calibration substances (DDT) 

²⁾ via extrapolation

 

Table 4: Calibration data 2^nd injection 

Calibration substance	tR/min	k	Log k	Log Koc
Atrazin	1.79	0.02	-1.71	1.81
Triadimenol	1.82	0.04	-1.39	2.40
Linuron	1.88	0.07	-1.14	2.59
Pyrazophos	1.95	0.12	-0.94	3.62
Diclofop-methyl	1.92	0.09	-1.03	4.20
4,4’-DDT	2.02	0.15	-0.81	5.63

Regression: log K_oc = a+ b · log k 

Parameters: a=7.733, b=3.718, r²=0.7650 

 

Table 5: Log P_ow of the test item 2^nd injection 

	tR/min	k	Log k	Log Koc
Test item	2.48	0.42	-0.38	>5.6 ^1) (6.3) ^2)

¹⁾ above the highest log Koc value of calibration substances (DDT) 

²⁾ via extrapolation

 

Within two injections, the adsorption coefficient K_oc of the test item was determined to be: 

Log K_oc  > 5.6 ¹⁾ (log K_oc  = 6.3) ²⁾

¹⁾ above the highest log Koc value of calibration substances (DDT) 

²⁾ via extrapolation

Validity criteria fulfilled:

yes

Conclusions:

The log Koc of the test substance was determined to be > 5.6.

Executive summary:

A study was conducted in accordance with OECD 121 to determine the adsorption coefficient of the test substance using the HPLC method. The adsorption coefficient of the test substance was derived from its retention time and the calibration graph. The retention time of the test item was above the retention time of the highest calibration standard (log Koc 5.63) and thus out of the calibration range. Therefore, the adsorption coefficient of the test substance was determined to be above 5.6 (log KOC = 6.3 via extrapolation).

Description of key information

The adsorption coefficient of the test item was found to be: log KOC > 5.6 (above the highest log Pow value of calibration substances) and log KOC = 6.3 (via extrapolation).  

The calculated log Koc is between 6.51 (MCI method) and 6.39 (Kow method).

Additional information

A study was conducted in accordance with OECD 121 to determine the adsorption coefficient of the test substance using the HPLC method. The adsorption coefficient of the test substance was derived from its retention time and the calibration graph. The retention time of the test item was above the retention time of the highest calibration standard (log Koc 5.63) and thus out of the calibration range. Therefore, the adsorption coefficient of the test substance was determined to be above 5.6 (log KOC = 6.3 via extrapolation).

 

The experimental result is supported by QSAR calculation. The calculated log Koc is between 6.51 (MCI method) and 6.39 (Kow method). Nevertheless, these values should be considered as the worst case for the substance, since the substance is poorly soluble in water and the level of substance released under standard environmental conditions is very low.