Absorbance

Absorbance is a measure of how much light a substance absorbs as it passes through a solution. When light shines through a sample, some of it is absorbed by the molecules, reducing the amount that reaches the other side. The higher the absorbance, the more light is absorbed, indicating a greater concentration of the substance. This property is used in laboratory tests to determine how much of a particular compound is present in a sample. Absorbance is proportional to concentration and is often measured using a device called a spectrophotometer.