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Environmental fate & pathways

Adsorption / desorption

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Administrative data

Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2016-03-04 to 2016-04-05
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2016
Report date:
2016

Materials and methods

Test guidelineopen allclose all
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))
Qualifier:
equivalent or similar to guideline
Guideline:
EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))
GLP compliance:
yes (incl. QA statement)
Type of method:
HPLC estimation method

Test material

Constituent 1
Chemical structure
Reference substance name:
-
EC Number:
469-070-1
EC Name:
-
Cas Number:
17861-60-8
Molecular formula:
C9H26O2Si3
IUPAC Name:
4-ethyl-2,2,4,6,6-pentamethyl-3,5-dioxa-2,4,6-trisilaheptane
Test material form:
liquid
Details on test material:
Appearance: clear colorless liquid
Storage conditions: Room temperature, in the dark
Radiolabelling:
no

Study design

HPLC method

Details on study design: HPLC method:
EQUIPMENT
- Apparatus: Agilent Technologies 1100 series, incorporating autosampler and workstation
- Type, material and dimension of analytical (guard) column: Phenomenex Luna CN 5 µm 100 Å (150 x 4.6 mm)
- Detection system: diode array detector (DAD) for dead time, mass spectroscopy detector (MSD) for the test item
- Column temperature: 30 ºC

MOBILE PHASES
- Type: 55:45 (v/v) methanol:purified water
- Experiments with additives carried out on separate columns: no
- pH: 6.81
- Flow rate: 1.0 mL/min
- Injection volume: 10 µL for dead time and reference items, 50 µL for test item

DETERMINATION OF DEAD TIME
- Method: The dead time was determined by measuring the retention time of formamide (purity 99.94%, 635 mg/L solution in 55:45 (v/v) methanol:purified water).

REFERENCE SUBSTANCES
- Identity: Solutions of reference items (see table 1) were prepared in methanol.

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 1.4796 g of the test item was diluted to 10 mL with methanol to give a concentration of 1.48 x 10^5 mg/L
- Quantity of reference substances: see table 1

REPETITIONS
- Number of determinations: 2 injections

EVALUATION
- Calculation of capacity factors k': k' = (tr - t0) / (t0)
k' = capacity factor
tr = retention time (min)
t0 = dead time (min)

- Determination of the log Koc value: log10 Koc = (log10 k' - A) / (B)
Koc = adsorption coefficient
k' = capacity factor
A = intercept of the calibration curve
B = slope of the calibration curve

Results and discussion

Adsorption coefficientopen allclose all
Type:
Koc
Value:
> 427 000 dimensionless
pH:
7
Temp.:
30 °C
Type:
log Koc
Value:
> 5.63 dimensionless
pH:
7
Temp.:
30 °C

Results: HPLC method

Details on results (HPLC method):
- Retention times of reference substances used for calibration: see Table 2
- Details of fitted regression line (log k' vs. log Koc): log10 k' = -1.22 + 0.396 × log10 Koc (r = 0.991)
- Average retention data for test substance: 1.985 min

Any other information on results incl. tables

Table 2: results of Reference Items

Reference Item Retention Time (min) Mean Retention Time (min) Capacity Factor (k') Log10 k' Log10 Koc
Injection 1 Injection 1
Acetanilide 2.319 2.318 2.319 0.168 -0.774 1.25
Phenol 2.272 2.272 2.272 0.145 -0.839 1.32
Atrazine 2.642 2.642 2.642 0.331 -0.48 1.81
Isoproturon 2.778 2.777 2.778 0.4 -0.398 1.86
Triadimenol 3.121 3.124 3.123 0.573 -0.242 2.4
Linuron 3.284 3.286 3.285 0.655 -0.184 2.59
Naphthalene 3.866 3.869 3.868 0.95 -2.28 x 10-2 2.75
Endosulfan-diol 3.62 3.618 3.619 0.824 -8.43 x 10-2 3.02
Fenthion 4.798 4.8 4.799 1.42 0.152 3.31
Phenanthrene 6.409 6.408 6.409 2.23 0.348 4.09
a-Endosulfan 7.24 7.241 7.241 2.65 0.423 4.09
Diclofop-methyl 7.059 7.069 7.064 2.56 0.408 4.2
DDT 20.543 20.542 20.543 9.35 0.971 5.63

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The adsorption coefficient (Koc) of the test item has been determined to be greater than 4.27 x 10^5, log10 Koc greater than 5.63.