What are the principles of chromatography?

Chromatography is based on the principle in which molecules in a mixture are applied onto the solid, stationary phase (or stable phase) and become separated from each other while moving with the assistance of a mobile phase. As their names imply, the stationary phase is immobile, while the mobile phase flows across, or through the solid phase. Typically, one phase is hydrophilic and the other phase is lipophilic. The components of the analyte undergo processes differently with these two phases. The higher the adsorption of the analyte to the stationary phase, the slower the molecule will disperse through the column. The polarity of the sample plays a crucial role in determining whether the analyte spends more or less time in the stationary phase and if they experience slower or faster movement through the column. Non-polar compounds are eluted first at a faster rate, and polar compounds disperse more slowly. The higher the solubility in the mobile phase, the faster the molecule will disperse through the column. Each sample elutes from the stationary phase at a specific time known as retention time. As the analytes pass through the detector, their signal is recorded and plotted on a chromatogram.