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Adsorption / desorption

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Description of key information

The calculated adsorption coefficient (Koc) from MCI method was 5.21 x 105 L/kg (log Koc = 5.72).

Key value for chemical safety assessment

Koc at 20 °C:
521 000

Additional information

The adsorption coefficient of the test substance was calculated using EPI Suite’s KOCWIN software. Estimation of Koc by using reverse phase HPLC method is only applicable to the test substances with log Koc value ranging from 1.5 to 5.0 (OECD Guidelines No. 121, page 3, paragraph 9). Under the reverse phase HPLC conditions used for the study, a compound with a log Koc value of 5 should elute out around 24.5 minutes. However, the test substance did not elute out within 60 minutes. Therefore, its Koc value cannot be determined by using reverse phase HPLC. Instead, the adsorption coefficient of the test substance was calculated using EPI Suite’s KOCWIN software. The KOCWIN estimates Koc using two methods: the molecular connectivity index (MCI) and a log Kow based method. The MCI method is more robust and been in use longer. Fragment corrections are applied in this method. The calculated adsorption coefficient (Koc) from MCI method was 5.21 x 105 L/kg (log Koc= 5.72) (Rivera C, 2014).

[LogKoc: 5.72]