Potential of ethylenediaminedi(o-hydroxyphenylacetic acid) and N,N '-bis(hydroxybenzyl)ethylenediamine-N,N '-diacetic acid for the determination of metal ions by capillary electrophoresis

Two aromatic polyaminocarboxylate ligands, ethylenediaminedi(o-hydroxypheny lacetic acid) (EDDHA) and N,N'-bis(hydroxybenzyl)ethylenediamine-N,N'-diace tic acid (HBED), were applied for the separation of transition and heavy me tal ions by the ion-exchange variant of electrokinetic chromatography. EDDH A structure contains two chiral carbon centers. It makes it impossible to u se the commercially available Ligand. All the studied metal ions showed two peaks, which correspond to meso and rac forms of the ligand. The separatio n of metal-HEED chelates was performed using poly(diallyldimethylammonium) polycations in mixed acetate-hydroxide form. Simultaneous separation of nin e single- and nine double-charged HEED chelates, including In(III), Ga(III) , Co(II)-(III) and Mn(II)-(III) pairs demonstrated the efficiency of 40 000 -400 000 theoretical plates. The separation of Co(III), Fe(LII) complexes w ith different arrangements of donor groups and oxidation of Co(II), Mn(II), Fe(II) ions in reaction with HEED have been discussed. (C) 2000 Elsevier S cience B.V. All rights reserved.