SPHERICAL CARBON PACKINGS PREPARED FROM SPHERICAL CELLULOSE PARTICLESFOR HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

Packings of spherical carbon beads were prepared by graphitizing spher ical particles of cellulose. The carbon bead obtained was a carbon mic robead which was physically and chemically stable and which retained t he spherical shape of the original material of cellulose particles. Th e diameter of the microbead was found to gradually become smaller as c arbonization proceeded. The diameter of the resultant graphitized carb on microbead was <5 mum. This carbon bead was used as HPLC packing. Ca rbon microbead packing, unlike conventional carbon packings, was found not to show excessive retention or adsorption of electron-rich or hyd rophobic compounds. It was also found that the peaks obtained using th e carbon microbead packing became more symmetrical along with an incre ase in the graphitization temperature. The capability of the obtained carbon packings in retaining hydrophobic compounds was similar to that of alkylated silica gels, rather than to that of the conventional car bon packings. In addition, the carbon microbead packing, like conventi onal carbon packings, could separate positional isomers by the mechani sm of a charge-transfer interaction.