Understanding Chromatography

Modern technology has yielded many different methods to help process everyday compounds and mixtures in our lives. It starts out as a complicated process but often yields to very common applications that you use every day. Chromatography is a similar technological process, which in its various types finds its application in both industrial and household levels.

What is chromatography?

It is a technique used for separating or identifying (sometimes both) the various components that make up a mixture. The process uses a simple principle that each component of the mixture has various tendencies of absorption or dissolution in to various surfaces and solvents respectively. In the technique there is always a stationary phase (usually a thin layer of solid. Inert or otherwise) through which a component (mobile phase) is passed to separate the elements.

Different types of chromatography:

     1.  Ion exchange chromatography

This method is very similar to the process of partition chromatography and uses a coated solid as the stationary phase. The liquid that is passed through the layer is called the mobile phase and the process works on the principle of opposite ions attracting each other. Domestic water softeners and the water softeners attached with commercial dishwashers work on this principle.

     2.  Paper chromatography:

This is the most common form of chromatography used in everyday household to separate a mixture of substances. Different types of paper here form the solvent. Separating inks from fountain pens and balls pens, also separating food colorings or dyes are common examples of this type of process. Thin layer Chromatography is another variation on this process. However, the solvent used here is a thin layer of solid such as aluminum supported on a base (inert), which does not participate in the process. TLC finds industrial application in the determination of the progress of a reaction by identifying and studying the nature of each of the components.

     3.  Liquid Column Chromatography:

Liquid Column chromatography uses a liquid mobile phase where the liquid is passed through an inert solid (e.g. Silica gel, cellulose) supported in a column of glass. This acts as a stationary phase for the reaction. Flash chromatography is an alternative technique, which works on the same principle as the liquid chromatography. However, under the flash technique the solvent is forced to pass through the column at a much higher pace. To achieve this, an inert gas like Nitrogen is used to apply extra pressure on the solvent without reacting to it.

HPLC or High Performance Liquid Chromatography:

Today a much-evolved variation of liquid chromatography finds its application in our industries. This new technique is called HPLC or high performance liquid chromatography. In this case, the particles in the stationary phase are made much smaller to help react with the mobile phase much giving us much more accurate readings. This technique is used in a variety of niche industries such as pharmaceutical, environmental and forensics. The technique helps separate different trace components and then identify them against known traces in the records. It is a very definitive analytical tool for the pharmaceutical industries to understand the various concentrations of medicinal drugs and study their interactions at a testing level.