N1,N2-dimethyl-N1-{2-[methyl(propan-2-yl)amino]ethyl}-N2-(propan-2-yl)ethane-1,2-diamine

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:

November 30, 2020 - March 29, 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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))

Version / remarks:

2008

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

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source (i.e. manufacturer or supplier) and lot/batch number of test material: Source: Sponsor; Batch No. 10/16/2019
- Purity, including information on contaminants, isomers, etc.: 98.2%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: 18 – 25 °C, dark, in the tightly closed original container

Test temperature:

20 - 25 ± 1 °C (column Temperature)

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: Analytical HPLC-column packed with a cyanopropyl stationary phase and coupled to a diode array detector (DAD) and a mass spectrometer (MS). - Type: Cyanopropyl analytical column
- Type, material and dimension of analytical (guard) column: YMC-Pack Cyano, S-5 μm / 12nm / 250 x 4.0 mm, batch 13303, YMC EUROPE GMBH
- Detection system: DAD and MS/MS
- Injection volume 10 μL
- Flow rate 0.7 mL/min
MOBILE PHASES
- Type: Methanol: ultrapure water (55 : 45 v/v) containing 0.1 mol/L ammonium formate
- Experiments with additives carried out on separate columns: yes / no
- pH: PH values of 5.5 and 7.5, respectively, adjusted with formic acid and ammonia
- Reagents: Ammonium formate, for mass spectroscopy; Ammonium hydroxide, 25% (w/w) for analysis, Formic acid, ≥98%; Methanol, gradient grade; Purified water, ≤ 50 ppb TOC, ≥ 18.2 Mꭥ cm, in-house device
DETERMINATION OF DEAD TIME
- Method: reference substances: NaNO3, CAS 7631-99-4; Uracil, CAS 66-22-8
REFERENCE SUBSTANCES
System Suitability, Identity: 3-Nitrobenzamide, CAS 645-09-0; Endosulfan-diol (Endosulfan Alcohol), CAS 2157-19-9
Reference Items for Adsorption Coefficient on Soil and Sewage Sludge, Identity: Acetanilide, CAS 103-84-4; Atrazine; CAS 1912-24-9; Aniline; CAS 62-53-3; Linuron, CAS 330-55-2; Phenyl benzoate, CAS 93-99-2; Fenthion, CAS 55-38-9; Phenanthrene, CAS 85-01-8
DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 100 μg/L
- Quantity of reference substances: 20 mg/L for Endosulfan-diol, 10 mg/L for the others
- Intervals of calibration:
REPETITIONS
- Number of determinations: Single (three Injections)
EVALUATION
- Calculation of capacity factors k':
- Calculation of retention times:
- Determination of the log Koc value

Analytical monitoring:

yes

Key result

Sample No.:

#2

Type:

log Koc

Value:

3

pH:

5.5

Temp.:

21.5

Matrix:

sewage sludge

Key result

Sample No.:

#1

Type:

log Koc

Value:

2.8

pH:

5.5

Temp.:

21.5

Matrix:

soil

Details on results (HPLC method):

- Retention times of reference substances used for calibration: see background information
- Details of fitted regression line (log k' vs. log Koc): see background information
- Graph of regression line attached:see background information
- Average retention data for test substance: see background information

Adsorption and desorption constants:

Two individual log KOC values were derived under consideration of the first and second calibration
for the test item signal. Finally, a mean value was calculated from these individual log KOC value
for soil and for sewage sludge see Tab.1

Tab.1 Retentions times, Capacity Factors and Adsorption Coefficient of the Test Item, pH 5.5

	tR*[min]	k’	log k’	log KOC, soil ±  SD 95%CI 1st Calibration	log KOC, soil ± SD 95%CI 2nd Calibration	log KOC, sewage sludge ± SD 95%CI 1st Calibration	log KOC, sewage sludge ±  SD 95%CI 2nd Calibration
Test Item	5.259	0.776	-0.110	2.806 ± 0.1669 2.377 to 3.235	2.806 ± 0.1666 2.378 to 3.235	2.957 ± 0.1644 2.534 to 3.379	2.957 ± 0.1644 2.535 to 3.380
	5.340	0.803	-0.095
	5.340	0.803	-0.095
Mean	5.313	0.794	-0.100

*) = corrected tR = measured retention time – retention time shift

Conclusions:

The adsorption coefficient (KOC) for the test item on soil and on sewage sludge using high performance liquid chromatography (HPLC) was estimated at pH 5.5 according to OECD 121 (2001) and Council Regulation (EC) No. 440/2008, Method C.19 from 2020-12-09 to 2021-02-02.
Calibrations were performed using seven reference items with known log KOC values (given by the guidelines). The reference items were measured twice, once before and once after the measurement (double injection of one replicate) of the test item (three injections of one replicate) and were detected by DAD. The test item was detected by MS. Sodium nitrate was used for the determination of the void time of the HPLC system coupled to DAD. Uracil was detected by DAD as well as by MS to derive the retention time shift between DAD and MS.
The study was conducted at two different pH values, 5.5 and 7.5, as preliminary studies revealed a different retention behavior of the test item at neutral and slightly acidic conditions. At pH 7.5, the log KOC could not be determined because the test item is not eluted from the stationary phase (cyanopropyl analytical column). The test system is therefore considered as not suitable at this pH value.
The adsorption coefficients (log KOC) of the test item were determined at a mean value of 21.5 °C and pH 5.5 to be 2.8 for soil as well as 3.0 for sewage sludge

Description of key information

The adsorption coefficients (log KOC) of the test item were determined at a mean value of 21.5 °C and pH 5.5 to be 2.8 for soil as well as 3.0 for sewage sludge

Key value for chemical safety assessment

Koc at 20 °C:

631