ABSTRACT
Fluorescence is a specific type of luminescence. When molecules are excited by electromagnetic radiation to produce luminescence, the phenomena is termed photoluminescence. If the release of electro magnetic energy is immediate, or stops on the removal of the excitation radiation, the substance is said to be fluorescent. If, however, the release of energy is delayed, or persists after the removal of the exciting radiation, then the substance is said to be phosphorescent. Due to its persistence (even with a short but significant lifetime), phosphorescence is of little use for LC detection. This is because the persistence of the signal will cause unacceptable apparent peak broadening with the consequent loss of resolution and the loss of quantitative accuracy. In contrast, fluorescence has been shown to be extremely useful and detectors based on fluorescent measurement have provided some of the highest sensitivities available in LC.
