The aim of this module is to introduce a variety of methods to speed up HPLC separations, and highlight the limitations of these methods. The fundamental approaches of speeding up HPLC will be explained. We will also investigate the balance between speed and resolution.

At the end of this unit, you will be able to understand the benefits and limitations of the various approaches to speeding up HPLC separations, and choose between them as appropriate. It will be easy to recognize some of the most important parameters which can be manipulated to reduce HPLC analysis time and the manner in which these might be used. You will be able to demonstrate an awareness of the limitations of each approach and appreciate the relative advantages and disadvantages. 

Topics include: 

• Separation efficiency
• Back pressure and particle size
• Superficially porous materials
• Increasing resolution via improved efficiency
• Speeding up HPLC separations
• HPLC method conversion - calculator
• Transferring methods - gradient elution considerations
• Transferring methods - calculating gradient conditions
• Transferring methods - quick method transfer tools
• Efficiency
• How to change efficiency
• Effects of efficiency on resolution
• Van Deemter plots
• Eddy diffusion (the A term)
• Longitudinal diffusion (the B term)
• Mass transfer (the C term)
• Packing material - particle size
• Packing material - particle size distribution
• Column internal diameter and linear velocity
• Packing material - morphology
• Reduced diameter/sub-2 µm particles
• Superficially porous particles
• Reduced diameter non-porous particles
• Temperature
• Kinetic plots
• Poppe plots - use and description
• Poppe plots - parameters
• Impedance plots - use and description
• Thermal considerations
• Imperdance plots - parameters
• Power plots