Problem

Indication

Cause

Solution

Peak Tailing

One or a few peaks tailing

Unexpected analyte interaction with solid support or stationary phase

Use base deactivated, or hybrid silica materials. Old style silicas have active sites on the surface that can have unintended interactions with sample analyte

Add a mobile phase modifier to the system such as TEA

All peaks tailing

Poor Connections in system

Ensure that all tubing ends are cleanly and squarely cut.

Make sure that all nuts and ferrules are of the correct shape and tubing depth is correct for all fittings. Different manufacturers have different arrangements, and they are not all interchangeable.

Use PEEK or universal spring loaded connecting tubing.

Void in Column

Replace Column

Dirty guard column

Replace Guard

Dirty column frit

Replace Frit

Peak Fronting

Initial Peaks fronting

Too strong a sample solvent

Samples should be dissolved in mobile phase or solvent weaker than mobile phase

All peaks fronting

Column overload

Reduce injection volume

Reduce sample concentrations

Use a column with a larger i.d.

Split Peaks

Void or channel in column

Replace column

Dirty column frit

Replace frit

Dirty Column

Back flush or replace

Sample solvent not suitable for use with mobile phase

Ensure that sample and mobile phase solvents are compatible – make any necessary adjustments

Peak Shoulders

Shoulder on 1 or 2 peaks

Mobile phase is at a pH near the pKa of the analyte

Adjust pH of mobile phase to be at least 2 pH units away from the pKa of the sample analytes

Adjust mobile phase to separate the 2 peaks

Shoulder on all peaks

Dirty Inlet frit

Replace

Dirty Guard Column

Replace

Dirty Column

Back flush or replace