Cellulose tribenzoate (CTB) and cellulose triphenylcarbamate (CTPC) were synthesized for the coating of high performance liquid chromatographic stationary phases. Elemental analysis and IR spectra indicated that most of the hydroxy groups of the microcrystalline cellulose had been converted into ester groups. The silanized gel was coated with CTB/CTPC by using tetrahydrofuran as solvent. The enantiomeric resolutions of phenylalanine (flow rate: 0.5 mL/min) and tryptophan were carried out with a hexane/2-propanol (9:1, v/v) mixture at 25 degrees C, when beta-cyclodextrin (beta-CD), dimethyl-beta-cyclodextrin (DM-beta-CD) and trimethyl-beta-cyclodextrin (TM-beta-CD) were used as mobile phase additives. The results showed that TM-beta-CD at the concentrations higher than 0.60 mmol/L had an explicit chiral two-phase synergistic effect with chiral stationary phase, but beta-CD and DM-beta-CD at any concentrations and TM-beta-CD at low concentrations had no effect.