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Partition coefficient

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Reference
Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
June 2, 2006 to June 28, 2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
EPA OPPTS 830.7570 (Partition Coefficient, n-octanol / H2O, Estimation by Liquid Chromatography)
Version / remarks:
U.S. Environmental Protection Agency. 1996. Partiton Coeffcient (n- Octanol/Water), Estimation by Liquid Chromatography. Series 830 - Product Properties Test Gudelines, OPPTS 830.7570.
Deviations:
not specified
Qualifier:
according to
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
Version / remarks:
Organisation for Economic Cooperation and Development. 2001. Partiion Coeffcient (n-Octano/twater), High Performance LiquidChromatography (HPLC) Method OECD Guideline for
Testg of Chemicals, Proposal for Updatig Guideline 117. Adopted 13 April 2004.
Deviations:
not specified
Qualifier:
according to
Guideline:
EU Method A.8 (Partition Coefficient - HPLC Method)
Version / remarks:
Annex to Commission Directive 92/69/EEC. 1992. Partiton Coeffcient. Official Joural oF the European Communities No. L383. Method A.8.
Deviations:
not specified
GLP compliance:
yes
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
No further details specified in the study report.
Analytical method:
high-performance liquid chromatography
Key result
Type:
log Pow
Partition coefficient:
2.27
Temp.:
40 °C
Remarks on result:
other: Reported in study report of Log Kow
Details on results:
Along with analysis of reference standards, a standard of thiourea was injected in duplicate (once near the beginning and once near the end of the HPLC sequence) to determine the analytical column dead time (t0) for use in calculating capacity factors (k’) of the reference standards to the test substance. The mean retention time of the duplicate thiourea standard injection was 1.697 minutes.
Six additional standards were analyzed with the test substance. The reference standard series was injected at the beginning and at the end of the HPLC sequence. The capacity factors of each standard were calculated based upon their retention times. A reagent blank prepared and analyzed concurrently with the samples confirmed the reagents to be free of potentially interfering components.
The test substance was analyzed in triplicate and eluted as one peak. The corresponding mean peak retention time and standard deviation for the three injections were 2.484 ± 0.00231 minutes. The capacity factor (k’) for PHT4 was then calculated based on the above retention time. The corresponding mean partition coefficient (Log Kow) for the test substance was calculated as 2.27 ± 0.00491.

n-Octanol/Water Partition Coefficient (Log Kow) for PHT4

Sample Number (616C-108-)

Retention Time (min)

Mean (ẍ) Standard Deviation (SD)

Capacity Factor (k’)1

Log k’

Calculated Log Kow

Mean (ẍ) Standard Deviation (SD)

PHT4-1

PHT4-2

PHT4-3

2.481

2.485

2.485

ẍ = 2.484

SD = 0.00231

0.462

0.464

0.464

-0.3354

-0.3332

-0.3332

2.26

2.27

2.27

ẍ = 2.27

SD = 0.00491

1Capacity factor (k’) is the sample retention time minus the mean column dead time (1.697 minutes for thiourea) divided by the mean column dead time.

Results generated using Excel 2000 in full precision mode. Manual calculations with rounded values may differ slightly.

 

Conclusions:
Under the chromatographic conditions specified in the guidelines, the test substance eluted as one peak. The corresponding partition coefficient (Log Kow) for the test substance was calculated as 2.27 ± 0.00491.
Executive summary:

The n-octanol/water partitioning coefficient for PHT4 was determined using the high performance liquid chromatography method. Measurement of PHT4 retention times were obtained by high performance liquid chromatography with ultraviolet detection (HPLC/UV). Samples were prepared for HPLC/UV analysis by dilution of an aliquot from a 1000 mg PHT4/L stock solution of the test substance tetrahydrofuran (THF) in 75:25 (v/v) acetonitrile:reagent water. Reference materials of known Log Kow were analysed concurrently with samples of PHT4 prepared in triplicate. Dilution of reference standards and samples were performed in 75:25 (v/v) acetonitrile:reagent water. The Log Kow reference materals included acetanilide, 2-nitrophenol, toluene, naphthalene, phenanthrene and DDT. Thiourea was used as a non-retained reference material.

 

Under the chromatographic conditions specified in the guidelines, the test substance eluted as one peak. The corresponding partition coefficient (Log Kow) for the test substance was calculated as 2.27 ± 0.00491.

Description of key information

The corresponding partition coefficient (Log Kow) for the test substance was calculated as 2.27 ± 0.00491.

Key value for chemical safety assessment

Log Kow (Log Pow):
2.27
at the temperature of:
40 °C

Additional information

The n-octanol/water partitioning coefficient for PHT4 was determined using the high performance liquid chromatography method. Measurement of PHT4 retention times were obtained by high performance liquid chromatography with ultraviolet detection (HPLC/UV). Samples were prepared for HPLC/UV analysis by dilution of an aliquot from a 1000 mg PHT4/L stock solution of the test substance tetrahydrofuran (THF) in 75:25 (v/v) acetonitrile:reagent water. Reference materials of known Log Kow were analysed concurrently with samples of PHT4 prepared in triplicate.

 

Under the chromatographic conditions specified in the guidelines, the test substance eluted as one peak. The corresponding partition coefficient (Log Kow) for the test substance was calculated as 2.27 ± 0.00491.