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Partition coefficient

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Description of key information

In an OECD 117 GLP study using HPLC, the overall weighted average log Kow of the test material was calculated to be 4.54 at 40 °C.

Key value for chemical safety assessment

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

Additional information

In the key GLP study conducted in accordance with OECD Guideline 117, EU Method A.8. and EPA Guideline OPPTS 830.7570, high performance liquid chromatography (HPLC) was used to estimate then-octanol/water partition coefficient (Log Pow) of the substance by comparison of its retention time(s) with those of calibration standards of known Log Pow values.

The substance, which contains a mixture of C14-, C16-, and C18- components, appeared to elute as four resolved peaks. The first peak appeared to elute at a retention time less than that of the lowest calibration standard, acetanilide, and was assigned a Log Pow of <1.0 and discounted from calculations of the weighted average Log Pow of the test material. The second peak had a broad elution profile and began to elute at a retention time less than that of acetanilide, however, the absorption maximum of peak 2 eluted within range of the calibration standards; the retention time of peak 2 absorption maximum was used in calculation of a weighted average Log Pow value. The third and fourth peak retention times were bracketed by those of the calibration standards and therefore considered reliable. From triplicate determinations, the mean Log Pow for the second, third and fourth test material peaks were determined to be 2.91, 5.13 and 6.08 respectively. The overall weighted average Log Pow of the test material was calculated to be 4.54 ± 0.11 log units at 40 °C (N = 3, CV = 2.4 %).

An earlier supporting study is provided, in which KOWWIN v1.35a chemical modelling software was used to calculate log Kow estimates of 9.2, 10.2 and 11.1 for the undissociated forms and 5.1, 6.1 and 7.0 for the more polar dissociated forms of the C14-, C16- and C18- components (which will predominate in the environment), respectively.