What does the process of chemiluminescence involve?

The process of chemiluminescence specifically involves the emission of light that occurs as a direct result of a chemical reaction. This phenomenon occurs when certain substances undergo a chemical change that releases energy in the form of photons, producing visible light. This principle is widely utilized in various laboratory techniques, particularly in immunoassays, where it can enhance the sensitivity of detection methods for biologically relevant molecules.

In contrast, measurement of optical density refers to quantifying how much light is absorbed by a sample, not the emission of light. Separation based on electrical charge pertains to electrophoresis, which is a different technique that involves moving molecules through a gel or solution in response to an electric field. Detection of proteins in a liquid sample can be accomplished by various methods, including enzyme-linked immunosorbent assays (ELISA) or Western blotting; however, these methods may use chemiluminescence as a detection strategy but do not describe the underlying phenomenon. Therefore, the correct option highlights the fundamental aspect of chemiluminescence itself, which is the light emitted specifically from a chemical reaction.