What is gradient elution in liquid chromatography?

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What is chromatography? — chromatography Overview of the chemical technique of chromatography.

In liquid chromatography, the term "gradient elution" refers to a technique used to address the general elution problem, which occurs when a sample contains a mixture of both weakly and strongly retained solutes.1

While isocratic separations utilize a mobile phase of constant composition, gradient elution involves continuously changing the composition of the mobile phase throughout the separation process. By systematically altering the mobile phase's composition, its polarity is adjusted over time. This increase in the solvent's strength effectively elutes strongly retained solutes that would otherwise remain on the column for an impractical duration, ensuring a more efficient separation of all components in the sample. This method is functionally analogous to temperature programming in gas chromatography.1