bis(2,2,6,6-tetramethyl-1-(phenylthio)piperidin-4-yl)carbonate

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:

2019-09-04 - 2019-11-06

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))

Version / remarks:

2001

Deviations:

yes

Remarks:

as reference Phenantrene was used instead of alpha-Endosulfan, mobile phase was methanol/water (80/20) instead of methanol/water (55/45)

Qualifier:

according to guideline

Guideline:

other: CEPA Test No. 121 Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge Using High Perfonnance Liquid Chromatography (HPLC)

Version / remarks:

2013

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Radiolabelling:

no

Test temperature:

30 °C

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: WATERS 2695
- Type: instrument No. C2019-003
- Type, material and dimension of analytical (guard) column: ECLIPSE XDB-CN (4.6x250 mm, 5μm)
- Oven: 30 °C
- Detection system: Detector Wavelength: 210 nm (Spectrophotometer)

MOBILE PHASES
- Type: Methanol/Water = 80/20
- Flow rate: 1.2 mL/min
- Experiments with additives carried out on separate columns: no
- pH: not specified
- Solutes for dissolving test and reference substances: Reference substance: methanol, Test item: acetone

DETERMINATION OF DEAD TIME
- Method: by inert substances which are not retained by the column
The NaNO3 solution was injected three times at the HPLC condition, and the average value of three retention times was considered to be the dead time t0.

REFERENCE SUBSTANCES
- Identity:
Sodium nitrate (CAS 7631-99-4)
N,N-dimethylbenzamide (CAS 611-74-5)
Atrazine (CAS 1912-24-9)
Naphtalene (CAS 91-20-3)
Triazophos (CAS 24017-47-8)
Phenantrene (CAS 959-98-8)
p,p'-DDT (CAS 50-29-3)

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 5.0 μL
- Quantity of reference substances: 5.0 μL
- Intervals of calibration: two times, at least one reference substance above and one below the retention time of the test item

The injection sequence was as below
1) reference substance individually for the first time, and record the tR1;
2) test item for one time, and record the tR;
3) reference substance individually for the second time, and record rR2
The average value of tR1 and tR2 was calculated to be the tR of the reference substance, which was employed in the k' calculation

REPETITIONS
- Number of determinations: 2

EVALUATION
If the method is not suitable, the results can only be given as > or < one certain log Koc value of the reference substance.
If the method is suitable, the data can be processed as below:
- Calculation of capacity factors k': k‘ = (tR- t0)/ t0
where k': capacity factor
tR: retention time of test and reference substance
t0: dead time
- Determination of the log Koc value: logKoc =α x Igk'+b

Sample No.:

#1

Type:

log Koc

Value:

> 5.63 dimensionless

Temp.:

30 °C

Sample No.:

#2

Type:

log Koc

Value:

> 5.63 dimensionless

Temp.:

30 °C

Details on results (HPLC method):

- Retention times of reference substances used for calibration: tR1: 1.56 min, tR2: 1.56 min, tR3: 1.558 min (tR mean. 1.559 min)
- Details of fitted regression line (log k' vs. log Koc): not available
- Graph of regression line attached: no
- Average retention data for test substance: not applicable, tR1: 4.489 min (first sequence), tR1: 4.484 min (second sequence)
ln the two injection sequences the retention times of test item were longer than that of the p,p'-DDT, which has the highest retention time and log Koc value.
So the HPLC estimation method was not suitable for the present test item, but the estimated logKoc can be deduced as >5.63, which was the logKoc of p,p-DDT.

Quality criteria

The RSD of three retention times of NaNO₃ was 0.1 %, which was much less than 3 % as described in the study plan. So the HPLC system was of enough suitability, the results are valid.

Validity criteria fulfilled:

yes

Conclusions:

ln the two injection sequences the retention times of test item were longer than that of the p,p'-DDT, which has the highest retention time and log Koc value.
So the HPLC estimation method was not suitable for the present test item, but the estimated logKoc can be deduced as >5.63, which was the logKoc of p,p-DDT.

Executive summary:

A HPLC estimation method with the registered substance was performed on the basis of OECD Test No 121 (adopted in 2001) and in compliance with GLP criteria.

Six reference points including N,N-dimethylbenzamide, atrazine, naphtalene, triazophos, phenantrene and p,p'-DDT were employed in the HPLC method. The retention time of the test item was longer than that of p,p'-DDT, so the estimated log Koc of the test item is > 5.63.

Description of key information

Adsorption / desorption

Key, OECD 121, GLP, HPLC method: log Koc > 5.63

Key value for chemical safety assessment

Koc at 20 °C:

426 579

Additional information

Adsorption / desorption

A HPLC estimation method with the registered substance was performed on the basis of OECD Test No 121 (adopted in 2001) and in compliance with GLP criteria.

Six reference points including N,N-dimethylbenzamide, atrazine, naphtalene, triazophos, phenantrene and p,p'-DDT were employed in the HPLC method. The retention time of the test item was longer than that of p,p'-DDT, so the estimated log Koc of the test item was > 5.63.