Butanedioic acid, 2-hydroxy-, 1,4-bis[5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)octyl] ester

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:

other: 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))

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Details on study design: HPLC method:

EQUIPMENT
- Apparatus:Merck-Hitachi autosampler L-7200; Merck-Hitachi pump L-6200
- Type:
- Type, material and dimension of analytical (guard) column: LiChrospher 100 CN, particle size 5 µm, 250 mm x 4 mm
- Detection system: Merck-Hitachi detector L-4000 / Sedex85, ELSD detector

MOBILE PHASES
- Type: Eluent A: water / methanol (45:55; v/v); Eluent B: tetrahydrofuran
- Experiments with additives carried out on separate columns: no
- pH: Eluent A: 6.6; Eluent B: -
- Solutes for dissolving test and reference substances: methanol

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

REFERENCE SUBSTANCES
- Identity: acetanilide, isoproturon, linuron, pyrazophos, diclofop-methyl, and 2,4-DDT

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 5.79 µg test item
- Quantity of reference substances: acetanilide (2.2 µg), isoproturon (2.2 µg), linuron (2.0 µg), pyrazophos (2.3 µg), diclofop-methyl (2.2 µg), and 2,4-DDT (2.1 µg)
- Intervals of calibration:

REPETITIONS
- Number of determinations: 2 runs test item; 6 runs reference items

EVALUATION
- Calculation of capacity factors k': k' = (tR-t0)/t0 ; tR: retention time of test item and reference substances; t0: time of sodium nitrate as non-sorbed chemical
- Calculation of retention times:
- Determination of the log Koc value: estimation based on reference substances

Key result

Type:

log Koc

Value:

> 5.63 dimensionless

pH:

6.6

Temp.:

20 °C

Key result

Type:

Koc

Value:

> 426 580 dimensionless

pH:

6.6

Temp.:

20 °C

Details on results (HPLC method):

- Retention times of reference substances used for calibration: sodium nitrate (1.35 min), acetanilide (3.24 min), isoproturon (3.95 min), linuron (4.97 min), pyrazophos (6.70 min), diclofop-methyl (7.97 min), 2,4-DDT (12.90 min)
- Details of fitted regression line (log k' vs. log Koc): Y = a+b*x (Y[log k']; x[log Koc]; a[-0.050];b[0.176]; r= 0.999)
- Average retention data for test substance: because elution was not possible with an aqueous eluent, the mobile phase was changed into 100 % tetrahydrofuran after 25 mins. Then the test item could be eluted (RT= 29.22 min, 29.23 min).

Validity criteria fulfilled:

yes

Conclusions:

The determination of the adsorption coefficient of the test item was performed according to the OECD standard testing guideline. The retention time of the test item was higher than the retention time of the reference substance 2,4-DDT with log Koc 5.63, which is equal to a Koc value of 426580. This value indicates that the test item will be adsorbed by organic carbon in soil. Thus, it can be classified to be immobile in soil.