Tall Oil Fatty Acids, compounds with 2-(2-aminoethoxy) ethanol

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:

05 June 2015 to 14 January 2015

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

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Media:

other: not applicable

Test temperature:

30 °C

Details on study design: HPLC method:

PREPARATION OF DEAD TIME SOLUTION
- The dead time was determined by measuring the retention time of formamide (99.94%) at 630 mg/L in methanol:water (55:45 v/v).

PREPARATION OF SAMPLE SOLUTION
- Test item (0.0067 g) was diluted to 100 mL with methanol.

DETERMINATION OF RETENTION TIME
- The sample, dead time and reference standard solutions were injected in duplicate using the high performance liquid chromatography (HPLC) parameters described below.
- HPLC system: Agilent Technologies 1200 incorporating workstation and autosampler
- Detector: Agilent variable wavelength detector (VWD) and Polymer Laboratories evaporative light scattering detector 2100 (ELSD).
- Column: Water XSelect CN 5 µm (150 x 4.6 mm id)
- Column temperature: 30 °C
- Flow-rate: 1.0 mL/min
- Mobile phase: methanol:purified water (55:45 v/v)
- pH of mobile phase: 6.3
- Injection volume: 10 µL
- UV detector wavelength (dead time and reference standards): 210 nm
ELSD parameters (sample): nebuliser temperature (40 °C); evaporator temperature (80 °C); gas flow (1.0 L/min)
- The mobile phase was ramped to 100% methanol shortly after elution of the last reference standard to elute the highly retained test item components. This was carried out for the sample and sample blank injections only.

CALCULATION
- Capacity factors were determined using Equation 3.1 (see attached document).
- A correlation of log10 k' versus Log10 Koc of the calibration standards was plotted using linear regression (see Figure 3.1, attached)
- The capacity factor (k') for the reference standards was calculated from the retention time data of the dead time and reference standard solutions using Equation 3.1 (see attached document).
- The capacity factor of the test item was calculated using Equation 3.1 (see attached document).
- The log10 Koc value was calculated for the test item using Equation 3.2 (see attached document) with reference to the calibration curve (see Figure 3.1, attached).

Key result

Type:

Koc

Value:

>= 57 100 - <= 427 000

Temp.:

30 °C

Remarks on result:

other: Log10 Koc 4.76 to > 5.63

Details on results (HPLC method):

- Typical chromatograms for dead time, reference standards and sample are attached.
- Retention times of the dead time and and retention times, capacity factors and log10 Koc values for the reference standards are shown in Table 3.2 and Table 3.3 (attached).
- The retention times, capacity factor and log10 Koc value determined for the sample are shown in Table 3.4 (attached).

DISCUSSION

The pH of the mobile phase was unadjusted as many of the components (amides) of the complex test item had no dissociation constant within the environmentally relevant pH range so were tested in their non-ionised form.

Some components of the test item (carboxylic acids) will have been ionised at the pH of the mobile phase. These probably account for the peak at 14.5 minutes because the peak is broad and irregular, which is a trait of ionic compounds. If the mobile phase had been acidified so these components were not ionised, their retention would have increased to indicate a higher adsorption coefficient. However, the test result being a range already considers the scenario of higher adsorption.

Other main components (cationic amines) are not covered by this method as the main mode of adsorption for cations is often cationic exchange. The amines will be ionised throughout the environmentally relevant pH range so cationic exchange will be a factor in most situations.

A number of smaller peaks were also integrated in the sample chromatography. These were considered less significant than the three largest peaks that are used in Table 3.4 (attached). However, this does not affect the overall result because it is a range encompassing the smaller peaks.

Validity criteria fulfilled:

not applicable

Conclusions:

The adsorption coefficient of the test item was assessed in accordance with EU Method C19. The adsorption coefficient of the test item was determined to be in the range 5.71 x 10E+04 to > 4.27 x 10E+05 with Log10 Koc 4.76 to > 5.63.

Executive summary:

GUIDELINE

Adsorption coefficient was determined using the HPLC screening method designed to be compatible with Method C.19 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.

METHOD

The test utilised a high performance liquid chromatograph. A commercially available cyanopropyl reverse phase HPLC column containing lipophilic and polar moieties was used.

RESULT

The adsorption coefficient of the test item was found to be in the range 5.71 x 10E+04 to > 4.27 x 10E+05 with Log10 Koc 4.76 to > 5.63.

Description of key information

 The adsorption coefficient of the test item was assessed in accordance with EU Method C19.  The adsorption coefficient of the test item was determined to be in the range 5.71 x 10E+04 to > 4.27 x 10E+05 with Log10 Koc 4.76 to > 5.63.

Key value for chemical safety assessment

Koc at 20 °C:

57 100

Additional information

No additional data.

[LogKoc: 5.63]