1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)pentane

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption

Remarks:

other: adsorption/desorption screening test

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2005-03-21 to 2005-03-30

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:

2005

Report date:

2005

Materials and methods

Test guideline

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))

Principles of method if other than guideline:

Organization for Economic Co-operation and Development
(OECD), OECD Guideline for Testing of Chemicals, Proposal
for a new guideline 121: "Estimation of the Adsorption
Coefficient (Koc) on Soil and on Sewage Sludge using High
Performance Liquid Chromatography (HPLC)~, January 2001.

GLP compliance:

yes

Type of method:

HPLC estimation method

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

459-520-5

EC Name:

-

Cas Number:

132182-92-4

Molecular formula:

Hill formula: C7H3F13O CAS formula: C7H3F13O

IUPAC Name:

1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)pentane

Specific details on test material used for the study:

Name of test material (as cited in study report): MTDID 665
- Physical state: Clear colorless liquid
- Analytical purity: 99.959%
- Storage condition of test material: At room temperature in the dark
- Expiration date of the lot/batch: 23 March 2006

Radiolabelling:

no

Study design

HPLC method

Details on study design: HPLC method:

EQUIPMENT
- Type: HPLC
- Column: Hypersil BDS-CN; 150 x 4.6 (I.D.) mm; 5 µm (Alltech, Deerfield, USA)
- Mobile phase: 55/45 (v/v) rnethanoVMilli-Q water
- Flow rate: 1 mL/min;
- Injection volume: 10 µl
- Detection system: Refractive index detector

DETERMINATION OF DEAD TIME T0 (retention time of the unretained component): A 5.1 g/l solution of formamide in methanol was diluted by a factor of 5 with mobile phase. This solution was used for the determination of T0. As formamide blank solution, 20/80 (v/v) methanol/mobile phase was used.

REFERENCE SUBSTANCES: The reference compounds used in this test were: Phenol, N,N-dimethylbenzamide, Methylbenzoate, 3,5-Dinitrobenzamide, Naphtalene, Mercaptodimethur, Fenthion, Phenantrene, 2,4-DDT. Solutions of the reference substances in methanol, at concentrations between 0.9 and 5.4 g/l, were used. From these solutions, two mixtures of reference substances were prepared. One mixture contained 5 reference substances and was prepared by adding 500 µl of each reference substance solution to a volumetric 5 ml flask. The other mixture contained 4 reference substances and was prepared by adding 500 µl of each reference substance solution and 500 µl methanol to a volumetric 5 ml flask. Subsequently, the flasks were filled up to the mark with mobile phase. As reference blank solution, 50/50 (v/v) methanol/mobile phase was used.

Preparation of blank solution: As blank solution, 10/90(v/v) methanol/mobile phase was used.

Preparation of test solution: The test substance did not dissolve in mobile phase. As an alternative a 4.2 g/l stock solution of MTDID 665 was prepared in methanol. The test solution was prepared by diluting the stock solution by a factor of 10 with mobile phase. As blank solution, 10/90(v/v)
methanol/mobile phase was used.

Based on the pK values calculated using a computer calculation program, no pKa values were calculable as this chemical does not contain ionisable groups, it was decided to perform the HPLC method at neutral pH.

REPETITIONS
- Number of determinations: 2

EVALUATION
- Calculation of capacity factors k': The capacity factor (k') is calculated from the retention of the substance concerned(Tr) and the unretained component (T0): k' = (Tr - T0)/T0

- Calculation of retention times:
- Determination of the log Koc value: Linear regression according to calibration curve of the log k of the reference substances as function of log Koc
log k' = a log Koc + b (a = slope derived from linear regression of reference compound; b = intercept derived from linear regression of reference compound).

Results and discussion

Adsorption coefficient

Adsorption coefficient 1

Type:

log Koc

Value:

3.8 dimensionless

Temp.:

35 °C

Adsorption coefficient 2

Key result

Type:

Koc

Value:

6 500 dimensionless

Temp.:

35 °C

Results: HPLC method

Details on results (HPLC method):

- Retention times of reference substances used for calibration: 2.595 - 7.820 (See table 1)
- Details of fitted regression line (log k' vs. log Koc): log k' = 0.252 log Koc - 0.870 (r2= 0.955. n=9)
- Graph of regression line attached, See Figure 1.
- Average retention data for test substance: 4.408

Any other information on results incl. tables

Table 1. Log Koc determination for MTDID 665

Substances	Retention time (min) #	k’	log k’	log Koc
Formamide	1.975
Phenol	2.595	0.314	-0.503	1.32
N,N-dimethylbenzamide	2.423	0.227	-0.644	1.52
Methylbenzoate	2.746	0.391	-0.408	1.80
3,5-Dinitrobenzamide	2.997	0.518	-0.286	2.31
Naphtalene	3.470	0.757	-0.121	2.75
Mercaptodimethur	3.284	0.663	-0.179	3.10
Fenthion	4.999	1.532	0.185	3.31
Phenantrene	4.804	1.433	0.156	4.09
2,4-DDT	7.820	2.960	0.471	5.63
MTDID 665	4.408	1.23	0.091	3.82

# Mean value of the retention times of two measurements

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The adsorption coefficient (Koc) of MTDID 665 was determined to be 6.5x10^3 at 35°C.

Executive summary:

Log Koc value of MTDID 665 was determined according to OECD 121 "Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using HPLC".  Under the analytical conditions used, the test substance had a log Koc value of 3.8. The Koc value was determined to be 6.5x10^3.

The study was conducted according to test guidelines and under GLP compliance. The reference substances are approved for use in the method, but bear little or no structural similarity to the test substance. Therefore, this study is considered as reliable with restrictions.