4-(1-methoxy-1-methylethyl)-1-methylcyclohexene

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:

01 June 2015 to 12 June 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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:

no

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:

no

GLP compliance:

yes

Type of method:

HPLC estimation method

Media:

other: soil-adsorption reference data

Radiolabelling:

no

Test temperature:

35°C ± 1°C

Details on study design: HPLC method:

EQUIPMENT
- Instrument: Acquity UPLC system (Waters, Milford, MA, USA)
- Detector: Acquity UPLC TUV detector (Waters)
- Column: Acquity UPLC HSS Cyano, 100 mm x 2.1 mm i.d., dp = 1.8 μm (Waters)
- Flow: 0.4 mL/min
- Injection volume: 5 µL
- UV detection: 210 nm

MOBILE PHASE
- Type: 30/70 (v/v) methanol/water
- pH: neutral (no buffers used)
- Solutes for dissolving test and reference substances: stock solutions in methanol; end solutions in 30/70 (v/v) methanol/water

DETERMINATION OF DEAD TIME
- Method: by inert substance which is not retained by the column (formamide)

REFERENCE SUBSTANCES
- Identity: Acetanilide; Monuron; 2,5-Dichloroaniline; Naphthalene; Benzoic acid phenylester; Fenthion.
- Stock solutions of approximately 1 g/L in methanol were diluted to obtain an end solution of 30/70 (v/v) methanol/water.
- The blank solution for the mixture of reference substances was 30/70 (v/v) methanol/water.

PREPARATION OF TEST SOLUTIONS
- A 2000 mg/L test substance stock solution in methanol was diluted to obtain a solution of 100 mg/L in 30/70 (v/v) methanol/water.
- The test substance blank solution was 30/70 (v/v) methanol/water.

REPETITIONS
- Number of determinations: 2 (for reference substances and test solutions); 1 (for blank solution)

EVALUATION
- Calculation of capacity factors k': k'= (tr-t0)/t0 where tr = reterntion time, t0 = mean column dead time
- Determination of the log Koc value: via linear regression; log k' = 0.728 x log Koc - 0.924 (r = 0.942, n = 12)

Key result

Type:

log Koc

Value:

2.85 dimensionless

Temp.:

35 °C

Remarks on result:

other: unbuffered mobile phase; Koc = 700

Details on results (HPLC method):

In the HPLC chromatograms of the test substance solution, one major peak and several small test substance peaks were observed. The small peaks eluted before the major peak. Measurements and results are summarized in the table below.

The test was performed at 35°C (i.e. the temperature of the column), but the log Koc value(s) obtained can be considered to represent the value(s) at an unspecified, probably ambient temperature (ca. 20°C) since no mention is made in the guidelines of the temperature at which the reference substance’s log Koc values were determined. Adsorption coefficients of the test and reference substances are assumed to vary with temperature in the same way.

Substance	tr,1 [min]	tr,2 [min]	mean tr (n=2)	log Koc	Koc
Formamide (t0)	0.677	0.680	0.679
Acetanilide	1.512	1.575		1.26
Monuron	2.992	3.217		1.99
2,5-Dichloroaniline	3.692	3.940		2.55
Naphthalene	5.784	6.302		2.75
Benzoic acid phenylester	12.075	13.654		2.87
Fenthion	32.468	38.141		3.31
Test substance	10.231	10.233	10.232	2.85	700

Remark: Log Koc values based on soil adsorption data (according to OECD 121)

A typical chromatogram is presented in the 'attached background material'.

Validity criteria fulfilled:

yes

Conclusions:

Based on the HPLC estimation method at neutral pH using soil-adsorption reference data, the log Koc for Orange Flower Ether was determined to be 2.85 (Koc = 700).

Executive summary:

The HPLC estimation method using soil-adsorption reference data was applied for the determination of the adsorption coefficient (Koc) of Orange Flower Ether. The mobile phase was 30/70 (v/v) methanol/water. The column temperature was 35°C. In the HPLC chromatogram of the test substance solution, one major peak and several small peaks were observed. The small peaks eluted before the major peak. The log Koc value of the substance (based on major peak in chromatogram) was 2.85 (Koc= 700). The study was performed in accordance with EC C.19 and OECD 121 and according to the principles of GLP.

Description of key information

The potential for adsorption/desorption is determined in a screening study according to OECD TG 121 and the log Koc value determined at 2.85 (Koc = 700 L/kg).

Key value for chemical safety assessment

Koc at 20 °C:

700

Additional information

The adsorption behaviour of the substance was determined in a study according to OECD TG 121 (HPLC method) and in compliance with GLP criteria (WIL Research, 2015). In this study solutions of reference substances with known log Koc values based on soil adsorption data and the test substance were analysed by HPLC using a Acquity UPLC HSS Cyano column and 30/70 (v/v) methanol/water as mobile phase. The column temperature was 35°C. In the HPLC chromatogram of the test substance solution, one major peak and several small peaks were observed. The small peaks eluted before the major peak. The Koc value of the substance (based on major peak in chromatogram) was 700 L/kg (log Koc= 2.85).

[LogKoc: 2.85]