Diethyl sulphate, compound with 2-(heptadec-8-enyl)-4,5-dihydro-1H-imidazole-1-ethanol (1:1)

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:

2021-07-02 to 2022-01-05

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:

22nd January 2001

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- lot/batch number of test material: A35290Z2103
- Purity: 93 %

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: dry and dark at ambient room temperature (20 - 30 °C)
Manufactured Date: 23.04.2021
Expiry Date: 23.04.2023

Radiolabelling:

no

Test temperature:

25 ± 1 °C

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: Shimadzu - Model: Prominence-i LC-2030C 3D Plus
- Type: HPLC-PDA System
- Type, material and dimension of analytical (guard) column: ODS Hypersil (250 mm x 4.6 mm x 5.0 pm) ID: VIO/HC/025
- Detection system: Photodiode Array Detection (PDA)

MOBILE PHASES
- Type: Acetonitrile: Water = 75 : 25, v/v
- Experiments with additives carried out on separate columns: no
- pH: 6.57 at 25 °C

DETERMINATION OF DEAD TIME
- Method: using unretained organic substance (i.e. thiourea). The selected organic substance was dissolved in diluent and injected onto the selected HPLC-PDA parameters to determine the retention time of thiourea.
The obtained retentions time or dead time (t0) value was used to determine capacity factor (k') of the reference items and the test item.

REFERENCE SUBSTANCES
- Identity:
• Thiourea (CAS No. 62-56-6)
• Acetanilide(CAS No. 103-84-4)
• Naphthalene (CAS 91-20-3)
• Aniline (CAS 62-53-3)
• Methyl-Benzoate (CAS 93-58-3)
• Phenanthrene
• Diclofop — Methyl PESTANALTM (CAS 51338-27-3)

EVALUATION
- Calculation of capacity factors k':
k' = tR – t0 / t0

- Determination of the log Koc value:
Log Koc = a + (b x log k')

Where,
k' = capacity factor,
a = intercept,
b = slope

A correlation graph of log k' versus log Koc (values taken from OECD 121 guideline) for each reference item was generated and reported.
The linear regression of the reported Log Koc values and capacity factor (Log k) of the calibration of reference items was given a correlation coefficient of 0.9330 (as per OECD 121 guideline, correlation coefficient R for the relationship between log k' and log Koc for a set of selected reference items) and an equation obtained was

Log Koc = a + (b x log k')
= 3.2757 + (2.5319 x (-1.155)
= 0.35

Analytical monitoring:

no

Details on sampling:

- Concentrations:

Test item volume taken (mL) final volume (mL) Made up with concentration

EC 271-272-8 1.3 5 mobile phase 310.71
Acetanilide 1.2 5 mobile phase 308.37
Phenanthrene 1.2 5 mobile phase 305.19
Naphthalene 1.2 5 mobile phase 308.73
Thiourea 1.2 5 mobile phase 306.19
Diclofop-methyl 1.45 5 mobile phase 300.14
Methyl-benzoate 1.2 5 mobile phase 307.23
Aniline stock 1.2 5 mobile phase 309.09

The above mentioned working solutions of reference items and test item were injected in triplicate as sample diluent (Mobile Phase - in three replications), TI Dilute solution, reference item solutions [Acetanilide — (in three replications), Phenanthrene (in three replication), Naphthalene (in three replication), Thiourea (in three replication), Diclofop-Methyl (in three replication), Methyl-benzaote (in three replication), and Aniline (in three replication)] into the HPLC-PDA.

Details on test conditions:

TEST SYSTEM
Preparation of Mobile phase (Eluent):
Mobile Phase was prepared by mixing acetonitrile (HPLC grade) (750 mL) and deionised water (250 mL) in the ratio of Acetonitrile : Water — 75 : 25 % v/v as eluting solvent (Mobile Phase). The column was de-gassed before use. The pH of the eluent was measured using a calibrated pH meter and found to be 6.12 at 25.1 0 C. Isocratic elution method was employed.

Preparation of Sample Diluent:
Mobile Phase was used as a sample diluent and used to prepare the selected reference item and test item solutions.

Test condition:
The study was conducted at 25 ± 1 °C

Key result

Type:

log Koc

Value:

0.35

Temp.:

25 °C

Details on results (HPLC method):

- Retention times of reference substances used for calibration:

minutes

Acetanilide 3.939; 3.938; 3.936
Phenanthrene 9.197; 9.203; 9.208
Naphthalene 6.670; 6.669; 6.670
Diclofop-methyl 9.395; 9.384; 9.405
Methylbenzoate 4.998; 4.996; 4.996
Aniline 4.170; 4.170; 4.172
Thiourea 3.428; 3.430; 3.431

- Details of fitted regression line (log k' vs. log Koc):
The linear regression of the reported Log Koc values and capacity factor (Log k) of the calibration of reference items was given a correlation coefficient of 0.9330 (as per OECD 121 guideline, correlation coefficient

Validity criteria fulfilled:

yes

Conclusions:

The adsorption coefficient (Koc) of the test item diethyl sulphate, compound with 2-(heptadec-8-enyl)-4,5-dihydro-1H-imidazole-1-ethanol (1:1) was determined to be 2.24 ± 0.00 at 25 ± 1 °C using the HPLC-PDA method.

Executive summary:

The estimation of the adsorption coefficient (Koc) of diethyl sulphate, compound with 2-(heptadec-8-enyl)-4,5-dihydro-1H-imidazole-1-ethanol (1:1) on soil and on sewage sludge using HPLC has been perfomed in accordance with OECD 121. The adsorption coefficient (Koc) was determined under laboratory conditions (25 ± 1 °C) by High Performance Liquid Chromatography Photodiode Array Detection (HPLC-PDA). The analytical method was calibrated using seven known reference item solutions.

Under these conditons the adsorption coefficient (Koc) was determined to be 2.24 ± 0.00.

Description of key information

The adsorption coefficient (Koc) was determined under laboratory conditions (25 ± 1 °C) by High Performance Liquid Chromatography Photodiode Array Detection (HPLC-PDA). The analytical method was calibrated using seven known reference item solutions.
Under these conditons the adsorption coefficient (Koc) was determined to be 2.24.

Key value for chemical safety assessment

Koc at 20 °C:

2.24