Tetradecafluorohexane

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

October 2018 - March 2019

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Test guideline 1

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:

yes

Remarks:

High volatility of the test item made HPLC impossible to perform. QSAR calculation performed.

Test guideline 2

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))

Deviations:

yes

Remarks:

High volatility of the test item made HPLC impossible to perform. QSAR calculation performed.

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: • EC Technical Guidance Document on Risk Assessment Part III Chapter 4.3: Use of (Quantitative) Structure Activity Relationships ((Q)SARs) - Soil and Sediment Sorption. 2003.

Deviations:

not specified

GLP compliance:

yes (incl. QA statement)

Type of method:

other: QSAR

Media:

other: Not specified

Test material

Test material information

Constituent 1

Reference substance name:

Tetradecafluorohexane

EC Number:

206-585-0

EC Name:

Tetradecafluorohexane

Cas Number:

355-42-0

Molecular formula:

C6F14

IUPAC Name:

tetradecafluorohexane

Test material form:

liquid

Radiolabelling:

no

Study design

HPLC method

Details on study design: HPLC method:

8.2. Performance of the Study
The principle of the test method is similar to that of the OECD guideline no. 117: "Partition coefficient (n-octanol/water), high performance liquid chromatography (HPLC) method". While passing through the column along with the mobile phase the test item interacts with the stationary phase. As a result of partitioning between mobile and stationary phases, the test item is retarded. The dual composition of a cyanopropyl stationary phase, having polar and non-polar sites allows for interaction of polar and non-polar groups of a molecule in a similar way as is the case for organic matter in soil or sewage sludge matrices. This enables the relationship between the retention time on the column and the Koc on organic matter to be established.
According to the guidelines, the determination of the Koc for test items that are ionized for at least 10% within pH 5.5 to 7.5 should be performed with both the ionized and non-ionized form. Therefore, the pKa values of the test item were calculated using the Perrin calculation method (pKalc 5.0, module in Pallas 3.0, CompuDrug International San Francisco, CA, USA). Based on the calculations, the HPLC method was performed at neutral pH.
8.3. Analytical Method
8.3.1. Analytical Conditions
Instrument Acquity UPLC system
(Waters, Milford, MA, USA)
Detector Acquity UPLC PDA detector (Waters)
Detector Acquity Refractive Index detector (Waters)
Column temperature 35°C  1°C
Injection volume 5 µL
Mobile phase 55/45 (v/v) methanol/water
Flow 0.4 mL/min
UV detection 210 nm
RI detection
Temperature 30°C
Sensitivity 4
Time constant 1.0 seconds
8.3.2. Preparation of Solutions
Test Solution I
A 16 g/L stock solution of the test item prepared in methanol proved not possible.
Test Solution II
A 7.7 g/L stock solution of the test item was prepared in tetrahydrofuran. The stock solution was diluted to obtain an end solution of 55/45 (v/v) tetrahydrofuran/water. The final concentration of the test item solution was 768 mg/L.
The test item blank solution was 55/45 (v/v) tetrahydrofuran/water.
Test Solution III
A 14.9 g/L stock solution of the test item was prepared in tetrahydrofuran. The stock solution was diluted to obtain an end solution of 55/45 (v/v) tetrahydrofuran/water. The final concentration of the test item solution was 745 mg/L.
The test item blank solution was 55/45 (v/v) tetrahydrofuran/water.
8.3.3. Sample Injections
Test item solutions and blank solutions were analyzed by single injection.

Batch equilibrium or other method

Analytical monitoring:

yes

Computational methods:

The adsorption coefficient was calculated using a QSAR for hydrophobic substances. The following correlation was used:

Log Koc =0.81 * log Kow + 0.10

Results and discussion

Adsorption coefficient

Key result

Type:

log Koc

Value:

>= 3.7 dimensionless

pH:

7

Temp.:

20 °C

Remarks on result:

not determinable because of methodological limitations

Remarks:

Koc extrapolated from the Kow which was estimated based on a result estimated for water solubility. low reliability

Results: HPLC method

Details on results (HPLC method):

8.4.2. Koc HPLC Method
Using analytical method with PDA detector (set at 210 nm), no test substance peak was observed in the chromatogram of the test substance solution (Test Solution II). Therefore, analytical method with Refractive Index detector was tested. Again, no test substance peak was observed in the chromatogram of the test substance solution (Test Solution III).
From this, it was concluded that the HPLC method cannot be used for the determination of the Koc of Tétradécafluorohexane.

Any other information on results incl. tables

1.1.1.                pK_aValues

No pK_avalues for acidic and basic groups in the molecular structure of the test item in the logarithm range of 1 - 14 were calculated.

As an alternative, the adsorption coefficient was calculated using a QSAR for hydrophobic substances. The following correlation was used:

 

Log K_oc=0.81 * log K_ow+ 0.10

 

Using log P_owvalues of ≥ 4.5 for Tétradécafluorohexane (calculated during project 20150521), this resulted in log K_ocvalue of ≥ 3.7(K_oc≥5.0 x 10³).

Based on this, it was concluded that the log K_ocof Tétradécafluorohexane is ≥ 3.7 and that a more accurate determination of the adsorption coefficient is not possible.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

Koc extrapolated from the Kow which was estimated based on a result estimated for water solubility. low reliability.

Conclusions:

The log Koc value of the test substance is ≥ 3.7 (Koc ≥ 5.0 x 103).

Executive summary:

The objective of this study was to determine physico-chemical properties for Tétradécafluorohexane.

The summary of the results is listed below:

Information	Guideline(s)	Result	Comment
Adsorption coefficient	EC C.19 OECD 121	log Koc: ≥ 3.7	Based on QSAR calculation