Isooctadecanoic acid, reaction products with tetraethylenepentamine

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:

2020

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

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Media:

other: Methanol (HPLC method)

Radiolabelling:

no

Test temperature:

HPLC Method

Details on study design: HPLC method:

* Preparation of dead time solution: The dead time was determined by measuring the retention time of a solution of formamide (purity* 99.6%) at 756 mg/L in mobile phase.

* Preparation of reference standard solutions: Solutions of reference standards were prepared in methanol.

* Preparation of sample solution: Test item (0.1006 g) was diluted to 10 mL with methanol to give a concentration of 1.01 x 10^4 mg/L.

* Determination of retention time: The sample, dead time and reference standard solutions were injected in duplicate using the following HPLC parameters:
HPLC System: Agilent Technologies 1200, incorporating workstation and autosampler
Detector types: variable wavelength (VW), evaporative light scattering (ELS)
Column: X-select HSS cyano 5 μ (150 x 4.6 mm id)
Column temperature: 30 °C
Mobile phase: methanol:purified water (55:45 v/v)
pH of mobile phase: 3.0 adjusted with trifluoroacetic acid
Flow-rate: 1.0 mL/min
Injection volume: 5 μL
VW detector wavelength: 210 nm (dead time and reference standards)
ELS detector parameters: nebuliser temperature: 40 °C; evaporator temperature: 80 °C (sample); gas flow: 1.0 L/min.

The mobile phase was ramped to 100% methanol shortly after the elution of the last reference standard in order to elute any highly retained test item components. This was carried out for the sample and sample blank injections only.

* Evaluation of Data:
The capacity factor for each reference standard was calculated using the following equation: k'=[t(r) - t(0)]/t(0), where: k' = capacity factor; t(r) = retention time (min) and t(0) = dead time (min).

Construction of the calibration curve: A correlation of log10 k' versus log10 Koc of the reference standards was plotted using linear regression. The capacity factors (k') for the reference standards were calculated using the previous equation. Log10 Koc values are those quoted in Method 121 of the OECD Guidelines for Testing of Chemicals, 22 January 2001.

Adsorption coefficient: Initially the capacity factor of the test item was calculated using the previous. The adsorption coefficient was then calculated using the following equation with reference to the calibration curve:
log10 Koc = (log10 k'-A)/B, where: Koc = adsorption coefficient; k' = capacity factor; A = intercept of the calibration curve; B = slope of the calibration curve.

Key result

Sample No.:

#2

Type:

log Koc

Value:

> 5.63 dimensionless

Matrix:

Methanol

Remarks on result:

other: no information for pH and temperature (HPLC method)

Key result

Sample No.:

#1

Type:

log Koc

Value:

> 5.63 dimensionless

Matrix:

Methanol

Remarks on result:

other: no information for pH and temperature (HPLC method)

Details on results (HPLC method):

Overall log10 Koc: >5.63
Adsorption coefficient: >4.27 x 10^5

Discussion: The mobile phase was adjusted to pH 3 to ensure any protonated nitrogen species (amines) in the test item would not have any significant secondary interaction with anionic silanol groups on the stationary phase of the column.

Validity criteria fulfilled:

yes

Conclusions:

The adsorption coefficient of the test item has been determined to be greater than 4.27 x 10^5, log10 Koc >5.63.

Executive summary:

The determination was carried out by the HPLC screening method, using a procedure designed to be compatible with Method C.19 Adsorption Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 121 of the OECD Guidelines for Testing of Chemicals, 22 January 2001. The test system utilized a high performance liquid chromatograph.

The adsorption coefficient of the test item has been determined to be greater than 4.27 x 10^5, log10 Koc >5.63.

 

Description of key information

Based on the physical chemical properties of EC 701 -204 -9, the registered substance would most likely partition to soil if exposed to the environment.

Key value for chemical safety assessment

Koc at 20 °C:

427 000

Additional information

EC 701-204-9 is non-polar and hydrophobic and will thus most likely partition to soil in the environment. While modelling is not optimized for UVCB substances, fugacity modelling (KOCWIN Kow method) confirms this assumption with 91.4% of a 455.78 MW fraction predicted to partition to soil. The adsorption coefficient of the test item has been determined to be greater than 4.27 x 10^5, log10 Koc >5.63 and thus immobile in the environment.