Separation selectivity of some ethylenediaminetetraacetic acid and cyclohexane-1,2-diaminetetraacetic acid complexes in column and ion electrokineticchromatography

The complexes of Mn2+, Cd2+, Fe3+ Pb2+ Co2+, Zn2+ and Cu2+ with EDTA and cy clohexane-l,2-diaminetetraacetic acid (CDTA) were separated and detected in column and ion electrokinetic chromatography with suppressed conductivity and direct UV detection, respectively. In column ion chromatography (IC) th ese complexes were separated on an IonPac AS4A anion-exchange column (Dione x, USA). Parameters of carrier electrolyte, which were examined in the ion electrokinetic chromatography (IEKC) mode, include polymer acid sulfate con centrations. In IEKC separation selectivity of complexes with poly(diallyld imethylammonium) cation as modifier is similar as for an IonPac AS4A column both for EDTA and CDTA chelates, It was shown that the ion-exchange capaci ty of the electrokinetic system is more than 100-times lower than the capac ity of the IC column for the same peak resolution. In comparison with colum n main advantages of electrokinetic version are high separation efficiency (220 000-390 000 theoretical plates) and the absence of the analyte interac tion with the sorbent matrix. (C) 1999 Published by Elsevier Science B.V. A ll rights reserved.