SULFONATION AND PERFORMANCE OF SURFACE SULFONATED 5 AND 10 /μm DIAMETER,HIGHLY CROSSLINKED POROUS AND 15 μm DIAMETER, 10% CROSSLINKED GEL TYPE RESINS

Improved column efficiencies and decreased tailing of Eu³⁺ and Lu³⁺ elution peaks with 2-hydroxy isobutyric acid, HIBA, were obtained by partial sulfonation of experimental monodisperse 5 and 10 μm, highly (>40%) crosslinked porous beads. Blocking of micropores of such highly crosslinked porous gels with n-dodecane before sulfonation further reduces the extent of sulfonation and improves column efficiency. Simultaneous choice of a smaller particle size and less sulfonation improves the column performance. The normalized performance of a monodisperse 10 μm, highly crosslinked porous resin of 0.058 meq/ml capacity was similar to that of a monodisperse 15 μm, 10% crosslinked surface sulfonated gel type resin of 0.031 meq/ml capacity for Lu³⁺/HIBA.