4,4',4''-(ethan-1,1,1-triyl)triphenol

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:

comparable to guideline study

Qualifier:

equivalent or similar 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:

The study was conducted according to the method described in OECD Draft Document TGP/94.75 (April 1994).

Deviations:

no

Remarks:

The study was conducted according to the test guidelines in effect at the time of study conduct.

GLP compliance:

yes

Type of method:

HPLC estimation method

Media:

soil

Radiolabelling:

no

Test temperature:

20 ºC

Details on study design: HPLC method:

EQUIPMENT
- Apparatus:
- Type: Autosampler: Model ISS200, Perkin Elmer
Pump: Model 1020, PE Nelson
Data handling system: Model 1020, PE Nelson
Printer: Model SQ850, Epson
- Type, material and dimension of analytical (guard) column: Cyano Apex, 5 µm, 25 cm x 4.6 mm id
- Detection system: Model UV 481, Waters Associates; detection wavelength 228 nm

MOBILE PHASES
- Type: methanol/0.01 M citrate buffer (aq) pH 6, 55/45 v/v
- Experiments with additives carried out on separate columns: no
- pH: 6
- Solutes for dissolving test and reference substances: methanol

DETERMINATION OF DEAD TIME
- Method: by inert substances which are not retained by the column (thiourea)

REFERENCE SUBSTANCES
- Identity: azinphos-methyl, fenthion, monuron, triadimefon, triapenthenol, and trifluralin

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 0.32 µg per injection
- Quantity of reference substances: azinphos-methyl: 0.25 µg; fenthion: 1.72 µg; monuron: 0.33 µg; triadimefon: 1.27 µg; triapenthenol: 1.06 µg; trifluralin: 1.32 µg
- Intervals of calibration: mean retention times of reference compounds ranged from 4.548 to 13.922 minutes

REPETITIONS
- Number of determinations: 2

EVALUATION
The adsorption coefficient is deduced from the capacity factor (k) using a calibration plot of log k versus log Koc of the selected reference compounds. The capacity factor is calculated from the equation:

K = (tR – to)/to

where:
tR = retention time of the test substance
to = column dead time (retention time of an inert substance)

Details on matrix:

COLLECTION AND STORAGE
-Geographic location: not reported
- Collection procedures: not reported
- Sampling depth (cm): not reported
- Storage conditions: not reported
- Storage length: not reported
- Soil preparation (e.g.: 2 mm sieved; air dried etc.): not reported

PROPERTIES
- Soil texture
- % sand: not reported
- % silt: not reported
- % clay: not reported
- Horizon: not reported
- Soil taxonomic classification: not reported
- Soil classification system: not reported
- Soil series: not reported
- Soil order: not reported
- pH: not reported
- Organic carbon (%): not reported
- CEC (meq/100 g): not reported
- Carbonate as CaCO3: not reported
- Insoluble carbonates (%): not reported
- Extractable Cations (Ca, Mg, Na, K, H) (MEQ/100 g): not reported
- Special chemical/mineralogical features: not reported
- Clay fraction mineralogy: not reported
- Moisture at 1/3 atm (%): not reported
- Bulk density (g/cm3): not reported
- Biomass (e.g. in mg microbial C/100 mg, CFU or other): not reported

Type:

Koc

Value:

174

Type:

log Koc

Value:

2.24

Details on results (HPLC method):

- Retention times of reference substances used for calibration (minutes):
Monuron: 4.548
Triapenthenol 5.655
Triadimefon 6.227
Azinphos-methyl 6.875
Fenthion 9.474
Trifluralin 13.922
- Details of fitted regression line (log k' vs. log Koc): Linear regression analysis of log k' versus log Koc for the reference compounds yielded a slope of 0.44977, an intercept of -1.2307, and a correlation coefficient of 0.99105.
- Average retention data for test substance: 5.159 minutes

Validity criteria fulfilled:

yes

Conclusions:

The soil adsorption coefficient of the test substance was determined as Koc = 174 at 20ºC. The result indicates that the test substance is likely to have medium mobility in soils.

Executive summary:

A study was performed to determine the soil adsorption coefficient (Koc) of the test substance by the high performance liquid chromatography (HPLC) method as described in the OECD Draft Document TGP/94.75 (April 1994). The Koc is 174 at 20ºC. The result indicates that the test substance is likely to have medium mobility in soils.

Description of key information

Koc = 174 L/Kg (logKoc 2.24) at 20-25°C

Key value for chemical safety assessment

Koc at 20 °C:

174