Abstract A series of N, N, N-trialkyl-2-(hydroxyimino)-2-(pyridin-2-yl) ethan-1-aminium nitrates 3a-3h and N, N, N-trialkyl-4-(hydroxyimino)-4-(pyridin-2-yl) butan-1-aminium nitrates 3i-3l representing cationic surfactants with a powerful 1-(hydroxyimino)-1-(pyridin-2-yl) alkyl chelating subunit were prepared as potential selective metal ion extractants. Their extraction ability was tested in transport of Cu 2+, Ni 2+, Co 2+, and Pd 2+ through a bulk liquid ...