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Glossary of Molecular Biology
What is OD260?
OD is a physical property of solutions defined as "Optical Density".
It can be described as "how much light is absorbed by a solution at a given concentration when the solution is is put in a cuvette of a given width."
The width of a cuvette is determining how many millimeters will the beam of light travel through the solution.
The higher the concentration of a solution - the higher is the optical density of the solution.
So, how to formularize the things said above?
Beer and Lambert derived an equation that is known as Beer-Lambert Law (or sometimes just Beer's Law).
Extinction coefficient is written as a small Greek letter epsilon (epsilon) or just e.
Absorbance is written as A, concentration as c and length of the cuvette (in cm) as l.
The formula for this law is:
A = e x c x l