An eluent is the solvent or carrier substance used in chromatography to move analytes through the chromatographic system. In liquid chromatography, the eluent is a liquid solvent, while in gas chromatography, it is a carrier gas
. The eluent acts as the mobile phase, flowing through the stationary phase (such as an adsorbent in a column) and displacing the analytes so they can be separated and collected for analysis
. The process of elution involves the eluent washing the analytes off the stationary phase, allowing them to be carried out of the column. The mixture that comes out of the column, containing the analytes and other solutes, is called the eluate, which is distinct from the eluent itself
. Choosing the appropriate eluent is crucial for effective separation, as its properties-such as polarity-affect how well it can displace analytes from the stationary phase
. Eluents can be pure solvents or mixtures, and their strength in eluting analytes is often ranked in an eluotropic series
. In summary, the eluent is the mobile phase component in chromatography responsible for transporting substances through the chromatographic medium to achieve separation and analysis
