Troubleshooting Problems with Peak Shape

Peak Tailing

Possible Cause	Prevention/Solution
Interaction with active silanols	Use ultra-high purity silica-based stationary phase Add basic mobile phase additive (eg. TEA) – not needed with ultra-high purity phases
Chelation with metal ions in stationary phase	Use ultra-high purity silica-based stationary phase Add basic mobile phase additive (eg. TEA) – not needed with ultra-high purity phases
Wrong mobile phase pH	Decrease mobile phase pH to suppress silanol ionization Increase buffer concentration.
Blocked frit	Reverse flush the column Use in-line filter
Column void	Reverse flush the column Replace the column
Unswept dead volume	Minimize the number of connections Use shorter connection tubing Check all fittings are tight

Split Peaks

Possible Cause	Prevention/Solution
Contamination on guard or analytical column inlet	Remove guard cartridge and carry out analysis – replace guard if necessary The reverse flush analytical column For strongly retained contaminants, try the regeneration procedure Replace column
Blocked frit	Reverse flush the column Use in-line filter
Sample solvent incompatible with the mobile phase	Inject sample in the mobile phase
Simultaneous elution of the second component	Use sample clean-up prior to injection Change selectivity by changing mobile phase or column phase
Column overloaded	Use higher capacity stationary phase Increase column diameter Decrease sample amount

Peak Fronting

Possible Cause	Prevention/Solution
Formation of channels in column	Replace the column Operate within recommended pH limits of the column
Column overloaded	Inject a smaller volume or more dilute sample solution Use higher capacity stationary phase
Sample solvent incompatible with the mobile phase	Inject sample in the mobile phase
Low temperature	Increase column temperature

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