How does luminescence detection work?
Unlike fluorescence, where a molecule emits light upon excitation by an external light source, luminescence is generated by a chemical or biological reaction, for example an enzyme and its substrate. The resulting light can be detected by a photomultiplier tube (PMT), in which photons are converted to electrons, with the resulting current proportional to the amount of light. Measurement of the signal is expressed as relative light units (RLU).