Who hasn't experienced the following?

Suddenly the chromatographic results have changed. For example, peak deformation such as splitting or tailing occur, retention time shifts  or nothing is detected at all.

Then it is time to find the cause of the anomaly and fix it. Because the final chromatogram is influenced by various factors, all the various components and variables should be examined in a systematically manner.

A systematic review of the following parameters is in order; each procedure will be described in more detail later in this document:

Accumulation of contaminants on the stationary phase are a common reason for adverse effects on column performance. This usually manifests itself in

• Higher back pressure,
• Shift in retention time or
• Deformed peaks.

To avoid accumulation on the column, the use of pre-columns and appropriate sample preparation such as filtration or extraction is advised.
Cleaning procedures are an effective measure for column regeneration in case of adsorption which has already occurred on the material of the stationary phase or to prevent  accumulation of contaminants in the first place. Because contaminants usually accumulate and remain at the column head, cleaning procedures should always flush the column in the opposite direction to he usual flow direction to remove the contaminants more easily and not spread them throughout the whole stationary phase. Sufficient cleaning can be  accomplished with a minimum of 20 column volumes of appropriate solvent.
When choosing the appropriate solvent, properties of the contaminants as well as stability of the column used should be considered. Examples for suitable solvents depending on the contamination present are listed in the following table. Higher efficiency of the cleaning procedure can be achieved by increasing the column temperature. Depending on the solvent and the stability of the stationary phase 40°C – 90°C is an appropriate temperature range for this. For further recommendations follow the instructions of the column manufacturer, usually found in the Care and Use Instructions.

General considerations:
• Frequent cleaning of system, column and injector
• Regular replacement of worn and damaged parts such as filters, frits and seals
to avoid contamination.

Additionally, troubleshooting can be simplified immensely by frequently recording a column journal. We recommend you record the identity of the column, number of injections, resulting backpressure, analytes and method used and regularly verify the quality of the column with the results of a standard test method. Switching of eluent bottles, error messages or other abnormalities should also be recorded.
A column journal can reduce the duration of troubleshooting from days to minutes and can additionally provide a way to track your productivity gain after the optimization of your method parameters.