A novel bonded stationary phase, octadecanamido imine bonded stationary phase(ODAI), for reversed phase HPLC was prepared by bonding stearyl chloride to YWG 80 silica gel through 3 (2 aminoethylamino)propyltrimethoxysilane. Hydrophobicity, selectivity and silanophilic activity of ODAI phase were evaluated by using aromatic compounds as analytes and methanol water as binary mobile phase. The organic components including acidic, basic, neutral aromatic analytes could be separated satisfactorily with an excellent selectivity and chromatographic peak shape. The asymmetry factors of basic aniline, o toluidine and N,N dimethylaniline were found to be 1 14, 1 06 and 1 01, respectively, using methanol water(volume ratio is 55∶45) as mobile phase. Aniline is eluted before phenol due to the internal masking interaction to suppress ion exchange activity of residual silanols.
A reversed-phase High Performance Liquid Chromatography method is developed for the determination of fenfluramine in slimming drug using precolumn derivatization.After eluted with chloroform,the samples were derivatized in solution of acetonitrile with water by 2,4-dinitrofluorobenzene at 40℃ for 60min in presence of Na2CO3 catalyst.The derivative obtained was determined on a Kromasil C18 column by using methanol-water （78:22,v/v） as mobile phase,and detection at 365 nm.The calibration curve is well linear in the range from 1.71～85.6 μg/mL with 0.9987 of correlation coefficient.The recoveries of the method range from 90.6 to 98.0% with a relative standard deviation less than 4% and the limit of detection 1.02 ng （S/N=3）.
