Light Minded: Instruments for chemiluminescence and fluorescence measurements

Date: May 10, 1999

Table of Fluorometers and Luminometers

In the decades since luminescence techniques were first introduced as a common analytical tool, advances in electronics, computing, and optics have spurred a rapid proliferation of new methods and applications. In the past few years, chemiluminescence assays have begun to diverge from the mainstream of fluorescence techniques, and specialized instrumentation fills the needs of laboratories using chemiluminescence applications. Differences in the fundamentals of fluorescence and chemiluminescence have a lot to do with this trend.

All luminescence occurs when molecules or atoms that have been excited to higher-than-normal energies lose the excess energy by emitting photons and return to their ground state. The difference between fluorescence and chemiluminescence lies in how the molecules are excited.

Fluorescence requires an outside source of electromagnetic radiation at a wavelength (and energy) the fluorescent molecules can absorb. By contrast, the energy source for chemiluminescence is a...