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Physical & Chemical properties

Partition coefficient

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Description of key information

Worst case Log Dow of the most lipophilic constituent replaces the log Pow

Key value for chemical safety assessment

Log Kow (Log Pow):
3.45
at the temperature of:
30 °C

Additional information

The determination was carried according to EU Method A.8. As the test material was a mixture and showed surface-activity, the shake-flask method was not valid. Therefore, an HPLC estimation determination was performed, adjusting the mobile phase pH to eliminate ionization and therefore reduce surface activity. The Pow was determined to be >1.59E06, log Pow >6.20. However, computer estimations indicated possible overestimation of partition coefficient for a number of components possibly due to secondary interactions between the surface-active test material and the analytical column.

By definition log Pow is an intrinsic property of the neural molecule. The submission item constituents are subject to ionization. Therefore the log Pow is an inappropriate figure for the environmental behaviour and should be replaced by the highest Dow of the components within the environmentally relevant range (i.e. pH 5 to 9). These calculations are available from the section on Bioaccumulation. Log D data as computed by Marvin Sketch version 5.3.6 are generally increasing with pH. Accordingly the values at pH 9 are considered relevant, which are 1.22, 3.38 and 3.45 for constituents 1, 2 and 3, respectively.

In conclusion the value for worst case calculations of the environmental fate modelling is Log Dow (pH 9) 3.45. Is has to be mentioned that this level belongs not to the most important constituent, but a minor one.