6,6-dimethoxy-2,5,5-trimethylhex-2-ene

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

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))

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))

Qualifier:

according to guideline

Guideline:

other: Technical Guidance document in support of Commission Directive

Version / remarks:

Technical Guidance document in support of Commission Directive 93/67/EEC on Risk Assessment for new notified substances and Commission Regulation (EC) 1488/94 on Risk Assessment for existing substances. Part III Use of (Quantitative) Structure Activity Relationships ((Q)SARs), pages 532 - 543.

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Specific details on test material used for the study:

Test Item: 205601/A
Identification: Methyl Pamplemousse
Description: Clear colourless liquid (determined at Charles River Den Bosch)
Batch: PE00084535
Purity/Composition: See Certificate of Analysis
Test substance storage: In refrigerator (2-8°C) protected from light
Stable under storage conditions until: 15 March 2015 (expiry date)

Details on study design: HPLC method:

The principle of the test method is similar to that of the OECD guideline no. 117: "Partition coefficient (n-octanol/water), high performance liquid chromatogr phy (HPLC) method". While passing through the column along with the mobile phase the test substance interacts with the stationary phase. As a result of partitioning between mobile and stationary phases, the test substance is retarded. The dual composition of a cyanopropyl stationary phase, having polar and non-polar sites allows for interaction of polar and non-polar groups of a molecule in a similar way as is the case for organic matter in soil or sewage sludge matrices. This enables the relationship between the retention time on the column and the Koc on organic matter to be established.
Based on the molecular structure of the test item, no appreciable acid or basic groups were observed. Therefore, the calculations on the pKa values using the Perrin calculation method were not performed. The UPLC analysis was therefore only performed at neutral pH.
Solutions of reference substances with known log Koc values based on soil adsorption data and the test substance were analysed. The capacity factor (k') of each compound was calculated from its retention time. The log k’ values of the references substances were plotted against the known log Koc values. Linear regression analysis was performed using the least squares method. The coefficient of correlation (r) was calculated. The log Koc value for the test substance was calculated by substituting its mean log k’ in the calibration curve. The value of log Koc obtained from duplicate measurements was within+/- 0.25 log units.

Type:

log Koc

Value:

3.06

pH:

7

Temp.:

35 °C

Type:

Koc

Value:

1 100

pH:

7

Temp.:

35 °C

Validity criteria fulfilled:

yes

Conclusions:

The HPLC method using soil-adsorption-reference data was applied for the determination of the adsorption coefficient (Koc) of Methyl Pamplemousse.
For the measurement of the Koc and log Koc values, just the major peak (peak 2), with an area of 99% of the total, was considered. The Koc and log Koc values of the test substance at neutral pH were 1.1 x 10^3 and 3.06, respectively.

Description of key information

The HPLC method using soil-adsorption-reference data was applied for the determination of the adsorption coefficient (Koc) of Methyl Pamplemousse. For the measurement of the Koc and log Koc values, just the major peak (peak 2), with an area of 99% of the total, was considered. The Koc and log Koc values of the test substance at neutral pH were 1.1 x 10^3 and 3.06, respectively.

Key value for chemical safety assessment

Koc at 20 °C:

1 100

Additional information

[LogKoc: 3.06]