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Administrative data

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
03 Sept - 29 Nov 2010
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: guideline study, non-GLP, analytical chemistry cannot be fully assessed.

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
2011
Report date:
2011
Reference Type:
other: reanalysis of data
Title:
Unnamed
Year:
2018
Report date:
2018

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 123 (Partition Coefficient (1-Octanol / Water), Slow-Stirring Method)
Deviations:
yes
Remarks:
equilibrium assumed after stirring rather than established analytically.
GLP compliance:
no
Type of method:
other: Slow stirring method
Partition coefficient type:
octanol-water

Test material

Constituent 1
Details on test material:
Name of test material (as cited in study report): TFEE-5
- Physical state: Colorless liquid
- Analytical purity: 97.21%
- Stability under test conditions: Test item stable
- Storage condition of test material: Ambient temperature, 10-30 °C

Study design

Analytical method:
gas chromatography

Results and discussion

Partition coefficientopen allclose all
Type:
log Pow
Partition coefficient:
2.6
Temp.:
25 °C
Remarks on result:
other: Value based on concentration ratios
Remarks:
water concentrations higher than solubility limit
Type:
log Pow
Partition coefficient:
3.1
Temp.:
25 °C
Remarks on result:
other: mass balance approach
Remarks:
value based on difference in octanol phase concentration before and after contact with water
Type:
log Pow
Partition coefficient:
3.2
Temp.:
25 °C
Remarks on result:
other: solubility ratio approach

Any other information on results incl. tables

TFEE-5 could not be quantified on direct injection after the equilibration step (Table), but the concentration in the aqueous phase was determined after a hexane extraction step which concentrated the analyte 18.2-fold.

Table, Results of analytical determinations for TFEE-5 partitioning

Variable

Trial 1

Trial 2

Trial 3

Initial concentration of TFEE-5 in n-octanol

327 ± 3 mg/L

Initial concentration of TFEE-5 in water

0 mg/L

Concentration of TFEE-5 in n-octanol after 3 weeks' equilibration (mg/L)

324 ± 5

318 ± 4

326 ± 6

Concentration of TFEE-5 in equilibrated aqueous phase based on hexane extraction (mg/L)

0.80

0.73

0.87

log Pow

2.607

2.639

2.574

mean log Pow ± st. dev.

2.60

It should be noted that the water concentration determined using a hexane extraction is higher than the water solubility value of 0.3 mg/L.

The mean of the final octanol concentrations after water contact was 322.5 mg/L. Assuming quantitative transfer of TFEE-5 to the dissolved phase, 50 mL of octanol, and 910 mL water, the estimated concentration of TFEE-5 in the water phase was 0.257 mg/L. The mass balance-based log Pow is 3.1.

As a preliminary step, the saturation limit of TFEE-5 in water-saturated n-octanol and octanol-saturated water were determined. The respective maximum concentrations are 476 ± 11 mg/L and 0.3 ± 0.01 mg/L. The ratio of the two solubility limits provides an estimated log Pow of 3.2.

Applicant's summary and conclusion

Conclusions:
The log n-octanol-water partition coefficient (log Pow) of TFEE-5 at 25 °C at highest slightly more than three.
Executive summary:

The log n-octanol-water partition partition coefficient (log Pow) of TFEE-5 was determined using a slow stirring method according to OECD TG123. TFEE-5 was equilibrated between water and octanol phases for 21 days before analysis by GC/MS. Analysis of the n-octanol phase was by direct injection, while analysis of the aqueous phase was by hexane extraction followed by direct injection of the hexane extract without further concentration. Water phase concentrations determined by this approach were somewhat above the water solubility limit, and therefore the resulting log Pow of 2.6 may be spuriously low. The log Pow estimated by a mass balance approach was 3.1, while the log Pow estimated by ratio of solubilities in the two solvents measured separately was 3.2. The log n-octanol-water partition coefficient (log Pow) of TFEE-5 at 25 °C is at highest slightly more than three.

The test followed internationally accepted guidelines with minor deviations. The analytical method cannot be fully assessed, but it is unlikely that the value of the log Kow is substantially different from approximately three. Therefore, this study is classified as reliable with restrictions.