Colorimetry Principle: Colorimetry is the technique of determining the concentration of a chemical in a solution, if it has a color, is to measure the intensity of the color and relate the intensity of the color to the concentration of the solution. In colorimetry,
two fundamental laws are applied :
• firstly, a Lambert’s law. relates the amount of light absorbed and the distance it travels through an absorbing medium; and
• Secondly, Beer’s law relates light absorption and the concentration of the absorbing substance.
Application : It is used extensively for identification and determination of concentrations of substances that absorb light (any color solution). A simple application lies in comparing intensities of radiation transmitted through layers of different thicknesses of two solutions of the same absorbing substance, one with a known concentration, the other unknown.