How to Extend Column Life in HPLC

Column lifespan depends on analytical conditions and storage method. Here we introduce the causes of column damage and how to address them.

1. Contamination Buildup in the Column

Contamination in the column distorts peak shapes. In this case, please first try column washing. For example, follow the flow diagram on the right for reversed-phase columns. Methanol and acetonitrile are commonly used solvents in the washing process, but if contamination cannot be removed with these solvents, 2-propanol or organic solvents containing acid can eliminate it. If contamination buildup occurs frequently, the use of a guard column is recommended. Sometimes, eliminating the sample matrix through pre-treatment procedures such as solid phase extraction is effective. Remember that insufficiently end-capped columns tend to accumulate contamination more easily.  

2. Clogging of Column Filters

Filters are located at both ends of the column to prevent the packing material from leaking out. Insoluble compounds in the sample or mobile phase can clog these filters. In this case, the column pressure gradually increases and eventually becomes too high for the mobile phase to pass through. When this occurs, filter the sample or mobile phase before analysis. The analytical column can also be protected by installing a guard column in front of it. Generally, the larger the silica particles, the larger the filter mesh. This makes it easier for insoluble compounds to pass through the filters. For this reason, selecting a column filled with larger particles is one option to prevent filter clogging.

3. Degradation of Functional Groups

High concentrations of acids or bases sometimes shorten retention times. This is likely due to functional groups detaching from the surface of the packing material. Since re-attachment of detached functional groups is not possible, pH and temperature are kept within recommended values. For long-term storage, it is recommended to replace the solvent in the column with an organic solvent free of acid or base and to seal the column ends.

4. Deterioration of the Packing Material

Some solvents deteriorate the packing material. For example, basic solutions gradually dissolve silica through hydrolysis. Depending on the combination of material and solvent, polymers may swell. Generally, deterioration of the packing material increases column pressure and reduces the number of theoretical plates. Therefore, since deteriorated packing materials cannot be repaired, please maintain the working conditions shown in the instructions, such as pH range, to avoid damaging your column. Packing material with high hydrophobicity generally prevents silica hydrolysis. Under basic conditions, ODS columns are superior to C8 columns in this regard, and among ODS columns, the higher the carbon loading, the longer the column lifespan will be.

5. Changes in Packing Configuration

When column pressure exceeds maximum working pressure or fluctuates suddenly, particles in the column can change the packing configuration. Defects in packing configuration make the mobile phase flow irregular, which results in distorted peaks or lower theoretical plate counts. One preventive measure to avoid changes in packing configuration is to keep column pressure well below maximum working pressure. For example, even among ODS columns with the same column dimensions (i.e., I.D. and column length) and particle size, column pressure depends on the packing material. Selecting a column that produces as low pressure as possible can minimize the risk of accidentally exceeding maximum working pressure and damaging the column.  

Doğan Özdemir Sales Engineer GLSciences Product Manager Ant Teknik