HPLC Theory
Relative retention time
Selectivity
Efficiency
The Resolution Equation
The van Deemter equation
Peak Asymmetry
Effect of peak size ratio on overlap
Relationship between k' and resolution
Effect of changing k' on selectivity
Effect of changing solvent type
Optimising Efficiency
Thermodynamic properties
- Retention times
- Selectivity
Kinetic Properties
- Five processes contributing to band broadening
- Efficiency
Importance of particle size
Principles behind UPLC
Solvophobic Theory
Acid - Base Equilibria
Understanding Isocratic Elution
The usefulness of the void volume peak
Factors affecting peak retention time
- Solvent temperature
- Column temperature
- Eluent pH
- Buffer salt
- Buffer concentration
- Organic modifier in the eluent
- Eluent %B
- Column type or chemistry
- The distribution constant
The effect of changing column length
The effect of changing column width
Maintaining linear velocity when changing column diameter
Understanding Gradient Elution
The new Resolution equation for gradient elution
Gradient pre-elution
Gradient mixing volume
Gradient dwell volume
The Knox equation
Extra-column void volume
When to use a gradient
Which columns to use with gradient elution
The importance of gradient slope
The average k' parameter and how to change it.
The importance of the gradient composition range
What happens if we use the wrong gradient range?
- Initial %B too high
- Final %B too low
- Effect of changing flow rate
Optimising column dimensions, flow rate and particle size for resolution, run time or back pressure |