In high-performance liquid chromatography, which elution technique may be used?

In high-performance liquid chromatography, which elution technique may be used?

• A. Amphoteric
• B. Isoelectric
• C. Gradient
• D. Ion exchange

Answer: (C)

In high-performance liquid chromatography, how the mobile phase changes during the run defines the elution technique. Gradient elution gradually increases the strength of the mobile phase, typically by raising the organic solvent content or adjusting salt/pH over time. This allows compounds with a wide range of affinities to be eluted efficiently, producing better resolution and shorter run times compared with a constant mobile phase. The other terms refer to properties of molecules or to a separation mode, not to the method of elution itself. Amphoteric and isoelectric describe chemical behavior of analytes, while ion exchange is a separation mechanism that can be run under various elution profiles, including gradient, but the broad, commonly used elution technique described here is gradient.

In high-performance liquid chromatography, how the mobile phase changes during the run defines the elution technique. Gradient elution gradually increases the strength of the mobile phase, typically by raising the organic solvent content or adjusting salt/pH over time. This allows compounds with a wide range of affinities to be eluted efficiently, producing better resolution and shorter run times compared with a constant mobile phase. The other terms refer to properties of molecules or to a separation mode, not to the method of elution itself. Amphoteric and isoelectric describe chemical behavior of analytes, while ion exchange is a separation mechanism that can be run under various elution profiles, including gradient, but the broad, commonly used elution technique described here is gradient.