Concentrated inverse emulsion polymerization was used for making chromatography columns [based on crosslinked polystyrene divinylbenzene (PS-DVB)] with pore sizes less than 10 mum. For application of these columns in ion-exchange chromatography, the sulfonation process was performed by concentrated sulfuric acid. According to X-ray fluorescence analysis and ASTM D2187-94 standard test method, the total capacity of resins (sulfonated PS-DVB) increased with increasing time. To obtain high-capacity resins, the sulfonation process was carried out over two steps. The optimum sulfonation time for the first and second sulfonation steps was 24 and 48 h, respectively. By increasing the DVB content, the capacity of resins passed through a maximum; thus the optimum amount of DVB, as crosslinking agent in the sulfonation process, was 22.5%. The structure of columns was analyzed by scanning electron microscopy (SEM). SEM evaluations showed that the porous structure of PS-DVB resin was maintained intact after the sulfonation steps. According to DSC-thermal gravimetry thermograms, it was confirmed that the residual monomer concentration after polymerization process was negligible. Also, the PS-DVB resins exhibit thermal stability up to 300degreesC and this quantity would increase with increasing amount of DVB weight percentage. (C) 2004 Wiley Periodicals, Inc.