Eluate
Definition and meaning of Eluate in chemistry.
Eluate is the liquid or gas that emerges from a chromatography column or solid-phase extraction cartridge after passing through the stationary phase, carrying with it the separated components of the original sample.
In more detail
As the eluent (the mobile-phase solvent or carrier gas) is pumped or flows through the stationary phase, dissolved analytes migrate at different rates depending on how strongly each interacts with the stationary versus mobile phase. The eluate exiting the column therefore contains the sample components spread out in time, and it is collected as sequential fractions or passed directly into a detector. Tracking the eluate is central to techniques such as column chromatography, HPLC, gas chromatography, and ion-exchange purification, since collecting the correct fraction is how a target compound is isolated or a mixture is analyzed.
Key facts
| Field | Analytical Chemistry |
|---|---|
| Contains | Mobile phase plus separated sample components |
| Related term | Eluent (the mobile phase before entering the column) |
| Typical handling | Collected as timed fractions or fed directly into a detector |
During size-exclusion chromatography of a protein mixture, buffer is continuously pumped through the column; the eluate collected in each timed fraction is analyzed by UV absorbance, and the fractions showing a strong 280 nm signal correspond to the purified protein.
Frequently asked questions
What is the difference between eluent and eluate?
Eluent is the solvent or carrier gas as it enters and flows through the column; eluate is that same fluid after it exits the column, now carrying the separated sample components.
Is the eluate always liquid?
No. In liquid chromatography the eluate is a liquid, but in gas chromatography the eluate is the carrier gas stream exiting the column along with the vaporized analytes.