Spherical Carbon Packings Prepared from Spherical Cellulose Particles for High-Performance Liquid Chromatography

Packings of spherical carbon beads were prepared by graphitizing spherical particles of cellulose. The carbon bead obtained was a carbon microbead which was physically and chemically stable and which retained the spherical shape of the original material of cellulose particles. The diameter of the microbead was found to gradually become smaller as carbonization proceeded. The diameter of the resultant graphitized carbon microbead was <5 μm. This carbon bead was used as HPLC packing. Carbon microbead packing, unlike conventional carbon packings, was found not to show excessive retention or adsorption of electron-rich or hydrophobic compounds. It was also found that the peaks obtained using the carbon microbead packing became more symmetrical along with an increase 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 carbon packings. In addition, the carbon microbead packing, like conventional carbon packings, could separate positional isomers by the mechanism of a charge-transfer interaction.