1-Ethoxy-2,3-difluoro-4-(trans-4-propylcyclohexyl)-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:

14.02.-17.02.2014

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:

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 40 % (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 40 % (v/v).

GLP compliance:

yes

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Radiolabelling:

no

Test temperature:

25 °C

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: HPLC

MOBILE PHASES
- Type: Methanol/distilled water 60:40% (v/v)
- Experiments with additives carried out on separate columns: no
- pH: 5.6
- 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: Acetanilide, Atrazin, Triadimenol, Linuron, Pyrazophos, Diclofop-methyl, 4,4' DDT

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 0.86 µg
- Quantity of reference substances: 0.78-1.16 µg
- Quantity of dead time marker: 18.1 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

Key result

Type:

log Koc

Value:

> 5.6

pH:

5.4

Temp.:

25 °C

Details on results (HPLC method):

Please refer to "Any other information on results".

Table 1: Determination of the dead time t₀ 

Dead time marker	tR/min  1^stinjection	tR/min  2^nd injection	tR/min  mean
Formamide	1.72	1.72	1.72

 

Table 2: Calibration data 1^st injection 

Calibration substance	tR/min	k	Log k	Log Koc
Acetanilide	2.02	0.18	-0.75	1.25
Atrazin	2.23	0.30	-0.53	1.81
Triadimenol	2.61	0.52	-0.28	2.40
Linuron	2.94	0.71	-0.15	2.59
Pyrazophos	3.97	1.31	0.12	3.65
Diclofop-methyl	4.35	1.53	0.19	4.20
4,4’-DDT	7.42	3.32	0.52	5.63

Regression: log K_oc = a+ b · log k 

Parameters: a=3.50, b=3.40, r²=0.9653

 

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

	tR/min	k	Log k	Log Koc
Test item	10.40	5.06	0.70	>5.6 ^1) (5.9) ^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
Acetanilide	2.02	0.18	-0.75	1.25
Atrazin	2.23	0.30	-.053	1.81
Triadimenol	2.61	0.52	-0.28	2.40
Linuron	2.94	0.71	-0.15	2.59
Pyrazophos	3.97	1.31	0.12	3.65
Diclofop-methyl	4.34	1.53	0.18	4.20
4,4’-DDT	7.40	3.31	0.52	5.63

Regression: log K_oc = a+ b · log k 

Parameters: a=3.50, b=3.41, r²=0.9650

 

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

	tR/min	k	Log k	Log Koc
Test item	10.38	5.05	0.70	>5.6 ^1) (5.9) ^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  = 5.9) 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 = 5.9 via extrapolation).

Description of key information

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

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 = 5.9 via extrapolation).