Hexadecyl hydrogen maleate

Adsorption / desorption

Description of key information

LogKoc: 3.954 ± 0.049 (mean ± sd), at 25 °C

Key value for chemical safety assessment

Koc at 20 °C:

8 994

Additional information

The adsorption coefficient on soil and sewage sludge of the test item was evaluated by using the HPLC-method, accordimg to the OECD 121 and EU C.19. The study was performed using a HPLC with a cyanopropyl chemical bound resin on a silica base column. Six reference items with different retention times were used to produce a calibration curve, since retention time on cyanopropyl columns and KOC are correlated. One vial was filled with the reference item mix and one vial with the test item solution. The vials were analysed using the HPLC. First one injection from the solvent blank acetonitrile/water 55/45 (% v/v) was made. Then three injections were measured from the reference item mix, three injections from the test item and again three injections from the reference item mix. For each reference item, the capacity factor k’ was calculated from the retention time of sodium nitrate and the retention time of the respective reference item. A calibration function was set up using the literature values for Koc of the reference items and the mean capacity factor of the six determinations. In the graph log k’ versus log Koc, linear regression was performed, giving r2 = 0.9787 and r = 0.9893

The chromatogram of the test item gave one peak with a retention time of 4.524 min (mean).

With the calibration function log k’ versus log Koc, the corresponding log Koc could be calculated as: 3.954 ± 0.049 (mean ± sd).

Therefore, log Koc of the test item is stated as 4.0 (mean)