ABSTRACT
Fluorescence spectrophotometry is the measurement of “fluorescent” light emitted by certain molecules when excited by a radiation source of appropriate energy or wavelength. Since energy is lost in the transition, the fluorescent or secondary light is of lower energy, and consequently longer wavelength, than the exciting or primary light. For this reason, and because intense light sources are available in this region, the ultraviolet and lower visible wavelengths are most useful as a source of excitation. The exciting and fluorescing wavelengths for a given compound are characteristic and permit identification in many cases, particularly when the fluorimeter is of the scanning type.
