Advance derivatization study of several amines with dansyl chloride has been carried out. The aim of this study was to determine influence of molecul structures compound toward dansylation. Derivatization was done by reacting 4000 ng drugs which contain primary or secondary amine group with 100 ng dansyl chloride at a temperature 450 C and pH 9 for a hour. Interference was separated using stationary phase silica G60 and mobile phase etyl acetat : methanol : ammonia (85:10:5), detection on spectrophotodensytometer ?eks 312 nm mode fluorescence with filter K400. Compounds that have a primary or secondary amine groups can be derivatized using dansyl chloride though that most affects of the reaction is rigidity of molecul structure. Differences fluorescence intensity between each derivatives influenced by the reactivity amine groups and steric hindrance of the compound.