Oligomerisation products of 2,2'-[(1-methylethylidene)bis(4,1-phenyleneoxymethylene)]bisoxirane with acrylic acid and fatty acids, C18-unsatd., dimers and nonanoic acid

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption, other

Remarks:

Estimation of the Adsorption Coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From December 10, 2011 to March 28, 2012

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:

no

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))

Deviations:

no

Principles of method if other than guideline:

The principle of the test method is similar to that of the OECD guideline no. 117: "Partition coefficient (noctanol/water), high performance liquid chromatography (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.

GLP compliance:

yes

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Radiolabelling:

no

Test temperature:

35.0°C +/- 1.0°C

Details on study design: HPLC method:

The test substance is a polymeric compound with a Mn of 950 Da. Based on this information it was decided to perform the HPLC method at neutral pH for the determination of the Koc.

Key result

Type:

Koc

Value:

3 300 L/kg

pH:

7

Key result

Type:

log Koc

Value:

3.52 dimensionless

pH:

7

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. A linear regression program was used to calculate the calibration curve. 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.

Equations:

Capacity factor (k') = (tr - t0)/t0 (where: tr = retention time, and t0 = mean column dead time)

Calibration curve (logK') = a logKoc + b (where: a = slope, and b intercept)

The equation of the regression line was: log k' = 0.299 x log Poc – 1.11 (r = 0.97, n = 16).

Conclusions:

Under the study conditions, the adsorption coefficient (Koc) of the test substance was determined to be 3300 and the logKoc was 3.52, at neutral pH.

Executive summary:

A study was conducted to determine the adsorption coefficient of the test substance according to OECD Guideline 121 and EU Method C.19 (HPLC method). The substance is a polymeric compound with a MW of 950 Da. Based on this information, it was decided to perform the HPLC method at neutral pH for the determination of the Koc. 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. A linear regression program was used to calculate the calibration curve. 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. Under the study conditions, the adsorption coefficient (Koc) of the test substance was determined to be 3.3E03 and the log Koc was 3.52, at neutral pH (Oudhoff, 2012).

Description of key information

The adsorption coefficient (Koc) of the test substance was determined to be 3300 L/kg and the log Koc was 3.52, at neutral pH.

Key value for chemical safety assessment

Koc at 20 °C:

3 300

Additional information

A study was conducted to determine the adsorption coefficient of the test substance according to OECD Guideline 121 and EU Method C.19 (HPLC method). The substance is a polymeric compound with a MW of 950 Da. Based on this information, it was decided to perform the HPLC method at neutral pH for the determination of the Koc. 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. A linear regression program was used to calculate the calibration curve. 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. Under the study conditions, the adsorption coefficient (Koc) of the test substance was determined to be 3.3E03 L/kg and the log Koc was 3.52, at neutral pH (Oudhoff, 2012).

[LogKoc: 3.52]