Capillary electrochromatography of tricyclic antidepressants on strong cation exchangers with different pore sizes

Four cation-exchange materials, possessing propanesulfonic acid ligands, fo r use in capillary electrochromatography were prepared from different comme rcially available 5-mum bare-silica particles ranging from 80 to 800 Angstr om in pore size. The performance of the materials was investigated at diffe rent compositions of the mobile phase (pH, ionic strength, and acetonitrile content) using tricyclic antidepressants and related quaternary ammonium a nalogues as test analytes. The wide-pore materials promoted pore flow, but this had no positive influence on the performance. The small-pore (highest surface area) particles gave, as could be expected, the best selectivity. ( C) 2001 Elsevier Science B.V. All rights reserved.