Why is Gradient Chromatography Needed?

Why is Gradient Chromatography Needed?

Analytical samples are quite frequently made of complex analytes with varying physico-chemical properties, such as polarity. The analysis of these compounds using isocratic conditions could be impractical for a few reasons:

• There could be poor separation between the compounds, or
• Some analytes could be retained significantly with unrealistic run times and broad, inefficient peaks, or
• Some analytes could lack retentivity thus elute close to the void with limited interaction with the stationary phase.

The best option for compounds with a broad range of physico-chemical properties, such as hydrophobicities, is to use gradient chromatography.

Reversed phase gradient chromatography typically alters the composition of organic modifier throughout the analysis. The organic composition starts low to sufficiently retain polar compounds, and increases through the course of the gradient to elute the more hydrophobic compounds within a reasonable time frame.