[3R-(3α,3aβ,6α,7β,8aα)]-octahydro-6-methoxy-3,6,8,8-tetramethyl-1H-3a,7-methanoazulene

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:

17 September 2015-16 December 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:

soil

Radiolabelling:

no

Details on study design: HPLC method:

PKA CALCULATION
- Perrin calculation method (pKalc 5.0, module in Pallas 3.0, CompuDrug International, USA)
- Calculated pKa values in the logarithm range of 1 - 14: pKa acidic groups: none, pKa basic groups: none
- Based on the results of the pKa calculations, the mobile phase was not buffered

HPLC CONDITIONS
- Instrument: Alliance Separation Module 2695 (Waters, USA)
- Detector: Refractive index detector 2414 (Waters)
- Column: Hypersil BDS-CN, 150 mm x 4.6 mm i.d., dp = 5 µm (Thermo Fisher Scientific, USA)
- Column temperature: 35°C ± 1°C
- Mobile phase: 40/60 (v/v) methanol/water
- Flow: 1 ml/min
- Injection volume: 10 µL
- RI detection
- Sensitivity: 4
- Time constant: 1.0 seconds
- Temperature: 30°C

UNRETAINED SUBSTANCE
- Formamide; dissolved in 40/60 (v/v) methanol/water

REFERENCE SUBSTANCES
- Reference substances: see the table in the result section .
- Stock solutions of the reference substances at concentrations of approximately 1 g/L in methanol were used. The stock solutions were diluted to obtain an end solution of 40/60 (v/v) methanol/water.

TEST SUBSTANCE
- A 1000 mg/L stock solution of the test substance was prepared in methanol. The stock solution was diluted to obtain an end solution of 40/60 (v/v) methanol/water. The final concentration of the test substance solution was 100 mg/L.

PERFORMANCE OF THE TEST
- Solutions of the unretained substance, the reference substances and the test substance were injected in duplicate.
- Blank solution (40/60 (v/v) methanol/water) was analysed by single injection.

DATA HANDLING
- Dead time (t0) was calculated as the mean retention time of the unretained substance.
- Using the retention time (tr) the capacity factor (k') was calculated for each reference substance: k'= (tr-t0)/t0
- Log k’ values of the references substances were plotted against the known log Koc values.
- Linear regression analysis (least squares method) was used to calculate the regression line.
- Regression line: log k’ = 0.404 x log Koc– 1.15 (r=0.97, n=16)
- Capacity factor (k') of the test substance was calculated from its retention time and the dead time.
- Log Koc of the test substance was calculated by substituting its mean log k’ in the regression line.
- The value of log Koc obtained from duplicate measurements was within ± 0.25 log units.

Key result

Type:

log Koc

Value:

4.48 dimensionless

Temp.:

20 °C

Key result

Type:

Koc

Value:

30 000 L/kg

Temp.:

20 °C

Details on results (HPLC method):

In the HPLC chromatogram of the test substance solution, one test substance peak was observed. The retention time was 12.1 minutes (see attachment).

Table: Results estimation method using HPLC:

Substance	tr,1 [min]	tr,2 [min]	mean tr(n=2)	log Koc	Koc
Formamide (t0)	2.193	2.191	2.192
Acetanilide	2.581	2.578		1.26
Monuron	3.112	3.109		1.99
2,5-Dichloroaniline	3.625	3.615		2.55
Naphthalene	4.271	4.260		2.75
Benzoic acid phenylester	5.004	4.991		2.87
Fenthion	7.933	7.912		3.31
Phenanthrene	7.912	7.855		4.09
4,4’-DDT	26.152	26.268		5.63
Cedramber	12.098	12.138	12.118	4.48	30000

 Remark: log Koc values of the reference substances are mentioned in OECD TG 121 and are based on soil adsorption data.

Conclusions:

Using the HPLC estimation method using soil-adsorption-reference data, the log Koc for Cedramber was determined to be 4.5 (Koc= 30000).

Executive summary:

The study was performed in accordance with EC C.9 and OECD 121 and in compliance with GLP. The HPLC estimation method based on soil-adsorption reference data was used for the determination of the adsorption coefficient (Koc) of Cedramber. The HPLC chromatogram of a 100 mg/L Cedramber solution showed one test substance peak. The log Koc value for the test substance has been determined as 4.5 (Koc= 30000). The column temperature was 35°C. 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.

Description of key information

Using the HPLC estimation method based on soil-adsorption-reference data, the log Koc for Cedramber has been determined as 4.5 (Koc= 30000). The study was performed in accordance with EC C.9 and OECD 121 and in compliance with GLP.

Key value for chemical safety assessment

Koc at 20 °C:

30 000

Additional information

[LogKoc: 4.5]