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Adsorption / desorption

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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
05-Nov-2018 to 25-Feb-2019
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))
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of method:
HPLC estimation method
Media:
soil
Specific details on test material used for the study:
Identification: 5-Bromo-5-nitro-1,3-dioxane
Batch (Lot) Number: 201807021
Expiry date: 30 Jun 2020 (expiry date) (taken from label)
Physical Description: White crystal powder
Purity/Composition: See Certificate of Analysis
Storage Conditions: At room temperature
Stability at higher temperatures: Stable, maximum temperature: 50°C, maximum duration: 120 minutes
Radiolabelling:
not specified
Test temperature:
Analytical Method
Column temperature 35°C +/- 1°C
Details on study design: HPLC method:
Analytical Conditions
Instrument Acquity UPLC system (Waters, Milford, MA, USA)
Detector Acquity UPLC TUV detector (Waters)
Column Acquity UPLC HSS Cyano, 100 mm x 2.1 mm i.d., dp = 1.8 µm (Waters)
Column temperature 35°C +/- 1°C
Injection volume 5 µL
Mobile phase 55/45 (v/v) methanol/buffer pH 7
Flow 0.4 mL/min
UV detection 210 nm
Key result
Sample No.:
#1
Type:
Koc
Value:
ca. 1.9 L/kg
pH:
7
Temp.:
35 °C
Matrix:
cyanopropyl stationary phase
Sample No.:
#1
Type:
log Koc
Value:
ca. 1.28 dimensionless
pH:
7
Temp.:
25 °C
Matrix:
cyanopropyl stationary phase
Details on results (HPLC method):
pKa Values
No pKa values for acidic and basic groups in the molecular structure of the test item in the logarithm range of 1 – 14 were calculated.

Koc HPLC Method
In the chromatogram of the test solution, one major peak and two small test item peaks were observed. The equation of the regression line was: log k’ = 0.327 x log Koc – 0.803 (r = 0.98, n = 16).
Validity criteria fulfilled:
yes
Conclusions:
The HPLC method using soil-adsorption-reference data was applied for the determination of the adsorption coefficient (Koc) of 5-Bromo-5-nitro-1,3-dioxane. The Koc and log Koc values of the test item at pH 7 were:

Koc log Koc Peak Area %
Test item - peak 1 1.9 x 10 e1 1.28 96
Test item - peak 2 1.6 x 10 e4 4.21 1.8
Test item - peak 3 2.0 x 10 e4 4.30 1.8
Executive summary:

Information: Adsorption coefficient

Guideline: EC C.19 OECD 121

Result:     log Koc : 1.28 (area 96%)

log Koc : 4.21 (area 1.8%)

log Koc : 4.30 (area 1.8%)

HPLC method based on soil-adsorptionreference data

Description of key information

The HPLC method using soil-adsorption-reference data was applied for the determination of the adsorption coefficient (Koc) of the test substance. The Koc value of the main species identified in the test item (96% peak area) at pH 7 was 19.

Key value for chemical safety assessment

Koc at 20 °C:
19

Additional information