Effects of Different Stationary Phases and Surfactant or Cyclodextrin Spray Reagents on the Fluorescence Densitometry of Polycyclic Aromatic Hydrocarbons and Dansylated Amino Acids

The detectable luminescence of twelve dansy1 amino acids and four polycyclic aromatic hydrocarbons (PAH's) spotted on five common TLC stationary phases was evaluated. The detectable luminescence varied appreciable for compounds associated with different stationary phases. The use of surfactant and cyclodextrin spray reagents caused luminescence enhancements on some stationary phases but not others. The reagents did not affect all compounds to the same degree indicating that qualitative information could be obtained in some cases. The largest luminescence increase for a compound spotted on silica gel was for pyrene (i.e., 47-fold) sprayed with sodium cholate. The degree to which the plates were dried also affected the luminescence intensity. Possible reasons for the observed effects are discussed.