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Normal-phase chromatography in HPLC typically encompasses adsorption chromatography on silica and partition chromatography on cyano and amino bonded phases. Unique separations are provided for saccharides, isomers, steroids, and class separations of lipids and polynuclear aromatic hydrocarbons.

Summary

No abstract

Chemiluminescence from thermal decomposition of dibenzal diperoxide in the presence of aromatic fluorescent compounds was studied. The emitting species was identified as the lowest excited singlet state of the aromatic fluorescer. The excitation step producing this species was shown to involve energy transfer from excited state species produced by the peroxide decomposition, i.e., triplet benzaldehyde and/or singlet oxygen monomers and collisional pairs. Energy transfer from the benzaldehyde triplet was shown to be due to a long-range dipoledipole interaction in solution. Energy transfer from singlet oxygen monomers, occurring through a two-step mechanism involving the fluorescer triplet as an intermediate, was shown to be more significant than transfer from singlet oxygen collisional pairs. Addition of dibenzal diperoxide to a paraffin oil solu-> tion of dibenzanthrone at 200°was observed by Kurtz to produce red chemiluminescence.28 Kurtz proposed a mechanism involving28 thermal decomposition of the peroxide, producing oxygen2b addition to dibenz-(1) (a) Paper presented at the