Registration Dossier

Administrative data

Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2017-09-20 to 2017-10-24
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report Date:
2017

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of method:
HPLC estimation method
Media:
soil/sewage sludge

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: solution of the substance in water
Radiolabelling:
no

Study design

Test temperature:
Temperature of Measurements: 19 - 21 °C

HPLC method

Details on study design: HPLC method:
Test Setup
Test System
Apparatus: A high performance liquid chromatograph with an UV-VIS detector was used. The detection wavelength depended on the characteristics of the test item and the reference items.
Stationary Phase: The stationary phase was a cyanopropyl phase.
Mobile Phase: The mobile phase was 55% methanol / 45% citrate puffer pH 6
Test Temperature: 19°C to 21°C
Reference Items: Chemicals for which log Koc has been reported were used to calibrate the elution time in units of log Koc. Structurally heterogeneous reference items were chosen:
Acetanilide
N,N Dimethylbenzamid
Methylbenzoat
Isoproturon
Linuron
1,2,3 Trichlorobenzene
Pyrazophos
Diclofop-methyl
Sodium nitrate

Application
Stock/Application Solutions
Stock Solution of the Test Item: A stock solution of the test item was prepared by dissolution in methanol. 49.91 mg of the test item were weighed, dissolved and made up to 50 mL using methanol.
Application Solution of the Test Item: For application the stock solution was diluted in mobile phase to obtain a solution at the concentration of 10 mg/L and 1 mg/L.
Stock Solution of the Reference Items: A stock solution of each reference item was prepared by dissolution of the reference item in methanol.
Application Solution of the Reference Item: Appropriate volumes of the stock solutions were diluted using mobile phase solvent to prepare standard solutions of these compounds at concentration of 100 mg/L. In addition, defined volumes of each of the stock solutions were diluted to prepare a reference item mixture at a concentration of 10 mg/L per compound.
Inert Reference Item: Sodium nitrate was used as inert substance (not retained by the column) to determine the dead time. A stock solution of the compound was prepared by dissolution in pure water (1000 mg/L). This stock solution was diluted with mobile phase (100 mg/L) and was injected to determine the dead time t0 (t0 = retention time of the unretarded component).
Test Strategy:
The log Koc of the test item was estimated using HPLC method. Based on calibration curves obtained by correlation of the retention time of heterogeneous reference items with their known adsorption coefficient, the log Koc of the test item was to be estimated. Methanol/citrate buffer pH 6 was used as mobile phase solvent. The pKa values of the test item were estimated to be 0.2, 3.2, 14.6 and 15.2. Thus the test substance is not present in ionized form at pH 6.
Test Procedure:
Each reference item was injected separately to the HPLC system to determine the individual retention time of the compounds under test conditions. Subsequently the inert compound and a mixed solution of the reference items were injected. Thereafter, the test item was injected in triplicate. After the analysis of the test item solution the mixed solution of the reference compounds and of the inert substance was injected two times. N,N-Dimethylbenzamid was used as reference item to verify the test procedure and was injected three times.
Analytical Methods
HPLC-Conditions:
Column: LiChrospher 100 CN (250*4 mm, 5 µm)
Eluent: 55% methanol / 45% citrate puffer pH 6
Flow: 1.0 mL/min
Injection Volume: 10 µL
Temperature: 20°C ± 1°C
UV-Vis Detector: 220 nm or 637 nm

Results and discussion

Adsorption coefficient
Key result
Type:
log Koc
Value:
2.9
pH:
6
Temp.:
20 °C

Results: HPLC method

Details on results (HPLC method):
Calibration:
A calibration curve correlated the retention time of 6 reference items with their adsorption coefficient. The calibration curve was obtained from data generated by HPLC-UV detection.
Calibration curve: y = 0.1584* x – 0.354; regression coefficient r = 0.9953
Linearity: The linearity of the method was proven in the log Koc-range from 1.25 to 4.2.
Adsorption Coefficient Koc of the Test Item:
Based on the retention times the system independent capacity factor was calculated for the test item. Based on the capacity factor and on the calibration curve obtained by HPLC analysis, the log Koc of the test item was calculated.
log Koc (estimated): 2.9
Estimated Adsorption Coefficient Koc of one Reference Item: Based on the retention times the system independent capacity factor was calculated for the reference item N,N-Dimethylbenzamid test item. The log Koc was calculated to be 1.2 which is in agreement with the literature value (log Koc 1.5).

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The present study estimated the log Koc of the test item using HPLC method. Based on calibration curves obtained by correlation of the retention time of structurally heterogeneous reference items with their known adsorption coefficient, the log Koc of the test was estimated to be 2.9.
Executive summary:

This study was designed to comply with the following methods:

OECD Guideline for Testing of Chemicals Guideline No.121: ”Estimation of the Adsorption Coefficient on Soil and on Sewage sludge using High Performance Liquid Chromatography (HPLC)”, adopted , 2001

Commission Regulation (EC) No.440/2008, Annex, C.19: “Estimation of the Adsorption Coefficient on Soil and on Sewage sludge using High Performance Liquid Chromatography (HPLC)”.

GLP: Yes (certified laboratory)

Purpose: The purpose of the study was to estimate the adsorption coefficient Koc of the test item using HPLC-method.

Test Setup: A HPLC with UV detection was used for estimation of the adsorption coefficient Koc.

 

Results:

The present study estimated the log Koc of the test item Sanolin Lave Blue A VP 5453 using HPLC method.

Based on calibration curves obtained by correlation of the retention time of structurally heterogeneous reference items with their known adsorption coefficient, the log Koc of the test was estimated to be 2.9.

This study is classified acceptable and satisfies the guideline requirements for adsorption/desorption studies.