Chromatography, which means to write with color, is a common scientific procedure regularly used by chemists to identify biological compounds. Numerous industries implement this technique when separating mixtures, whether they be viruses or the chlorophyll found in plants. To learn how chromatography works, here is an overview of the process and the science behind it.

What Is Chromatography?

Chromatography is a technique used to separate the components of a mixture to identify the different chemicals contained within them. Separating mixtures in this manner allows scientists to determine what kinds of substances are present. As chromatography can separate numerous samples of different sizes, it is a highly versatile procedure that has found use in a variety of laboratory environments. Other reasons why chromatography has seen widespread use relate to its capability to utilize low concentrations of samples and its ability to separate the substances of a compound without knowing how many are present.

The Chromatography Process

Given how there are countless varieties of molecules that can be separated from one another, there are several different forms of chromatography. However, no matter what type is utilized, there will always be two substances known as the mobile and stationary phase. The mobile phase picks up the tested compounds and can be either a liquid or gas state, whereas the stationary phase, a liquid or solid, is an unmoving substance that the compound is carried through.

To explain how chromatography works, here is an overview of paper chromatography, one of the most commonly used varieties. A solvent containing the compound is placed on one end of filter paper, which acts as the stationary phase. After the solvent dries, the bottom of the paper is dipped in the mobile phase. As the liquid passes through the paper, it absorbs the molecules of the compound and will carry the mixture from the location it was placed upwards toward the top of the paper.

Once the substance is finished flowing through the stationary phase, the different molecules will be dispersed into separate layers along the distance traveled. Through this process, the scientist can see each molecule or component of the mixture individually, as different substances will be carried further than others.

How Chromatography Works

The reason why chromatography creates different layers on the paper is that the molecules in a complex mixture travel at varying speeds through the filter paper. Molecules come in numerous different shapes and sizes, meaning they come in a variety of weights. These differences are how chromatography works. 

The heaviness of a molecule determines how fast it is. Because a solution will have multiple molecules traveling at different rates from one another, they spread out and create distinct lines. Through this, chemists can deduce how soluble each component is based on how far or how little it traveled through the stationary phase.

Laboratories searching for a high-quality distillation apparatus to distill solvents of a mixture for chromatography can find them and other useful equipment at At-Mar Glass. We offer a wide supply of laboratory glassware and tools, such as inverted joints.