Ionene-coated sulfonated silica as a packing material in the packed-capillary mode of electrochromatography

An aliphatic ionene (2–10-ionene) has been selected as a modifier to prepare a novel polymer-coated packing material for capillary electrochromatography. The packing material was produced by dynamical modification of a commercially available sulfonated silica Exsil-100 SCX. Strong ion-exchange interactions in the capillary packed with ionene-modified sulfonated silica have been demonstrated by the example of the retention of p-aminobenzoic acid. The total calculated anion-exchange capacity of the sorbent in the capillary was about 4·10−9 mol. A fast separation (about 15 min) of several aromatic acids was achieved with the packing material. The highest number of theoretical plates obtained was about 120 000. Limits of detection of the aromatic acids were 2–5 μg/ml. The advantages and lacks of the approach are discussed briefly.