Equilibration Regeneration and Maintenance of HPLC Column

For a general reversed-phase HPLC column, it is washed and put into pure methanol (acetonitrile) or about 80% methanol (acetonitrile) water, and then both ends of the column are plugged tightly with plugs to avoid evaporation of the preservation solvent. There should be no special protection.

The maintenance of the liquid chromatographic column is divided into the balance of the chromatographic column, the regeneration of the chromatographic column, and finally the maintenance of the HPLC chromatographic column.

HPLC Column equilibration

Equilibration is the process of stabilizing the HPLC column by establishing a consistent mobile phase and temperature environment before sample analysis.

Steps:

  1. Initial Equilibration:
    • Before starting a new analysis or after installing a new column, perform an initial equilibration. Run the mobile phase through the column for a sufficient amount of time to ensure that the column is thoroughly wetted.
  2. Column Conditioning:
    • If the column has not been used for an extended period, consider running a few column volumes of mobile phase through it to condition the stationary phase and ensure consistent performance.
  3. Mobile Phase Compatibility:
    • Use the same mobile phase that will be used for the actual analysis during equilibration. This ensures that the column is exposed to the same conditions as during sample analysis.
  4. Stable Flow Rate:
    • Maintain a stable and constant flow rate during equilibration to ensure reproducibility in subsequent analyses.
  5. Equilibration Time:
    • Allow sufficient time for equilibration. This typically involves running the mobile phase through the column for 15-30 minutes.

The reversed-phase column is stored in acetonitrile/water after being tested by the factory. The new column should be flushed with 10-20 column volumes of methanol or acetonitrile. Please make sure that the mobile phase you use for analyzing the sample is miscible with acetonitrile/water. Spend enough time every day to equilibrate the column with the mobile phase, you will get the greatest “compensation” in dealing with the problem, and the life of your column will become longer!

High Purity HPLC Columns

Slowly increase the flow rate at the beginning of equilibrium, and equilibrate the HPLC chromatographic column with the mobile phase until a stable baseline is obtained (if the flow rate of buffer salt or ion pair reagent is low, it will take longer to equilibrate).

If the mobile phase used contains buffer salts, you should pay attention to the “transition” with pure water, that is, you must rinse with pure water for more than 30 minutes before starting the analysis every day, and then balance with the buffer salt mobile phase; after the analysis, you must rinse with pure water 30 After removing the buffer salt for more than minutes, rinse the column with methanol for 30 minutes to protect the column.

HPLC Column regeneration

Regeneration is the process of cleaning and rejuvenating the HPLC column when its performance deteriorates due to contamination or fouling.

Steps:

  1. Flush with Mobile Phase:
    • Flush the column with the mobile phase to remove any loosely bound impurities. Use the same mobile phase as used during equilibration.
  2. Solvent-Based Regeneration:
    • If the column is heavily contaminated, consider using a more aggressive solvent or a solvent mixture to remove impurities. This can be done by running a gradient or isocratic elution with a stronger solvent or a solvent blend.
  3. pH Adjustment (if applicable):
    • If the stationary phase is sensitive to pH changes, adjust the pH of the mobile phase accordingly to optimize column regeneration.
  4. Backflushing (if applicable):
    • Some columns can be backflushed to remove impurities from the column bed. Consult the column manufacturer’s guidelines to determine if backflushing is appropriate for your column.
  5. Extended Regeneration:
    • For severe cases of contamination, consider more aggressive regeneration techniques, such as flushing the column with organic solvents, or using specialized column cleaning solutions.

Chromatographic columns that are used for a long time tend to decrease their efficiency (the number of theoretical plates on the column decreases). The chromatographic column can be regenerated, and a cheap pump should be used to regenerate the column in a qualified laboratory.

When regenerating the NH2-modified chromatographic column, since NH2 may exist in the form of ammonium ion, it should be washed with 0.1M ammonia water after washing with water, and then use water washed until the alkali solution completely flows out.

When cleaning the contaminated column, 0.05M dilute sulfuric acid can be used. If the simple organic solvent/water treatment cannot completely remove the impurities adsorbed on the silica gel surface, it is very effective to add 0.05M dilute sulfuric acid after washing.

HPLC Column maintenance

Routine maintenance practices help extend the life and performance of the HPLC column.

Steps:

  1. Regular Checks:
    • Periodically check the column for signs of physical damage, such as cracks or leaks. Inspect fittings and connections for tightness.
  2. Guard Columns:
    • Consider using guard columns to protect the analytical column from contamination. Guard columns are disposable columns placed before the analytical column.
  3. Mobile Phase Filtration:
    • Filter the mobile phase to remove particulate matter that could potentially harm the column.
  4. Sample Filtration:
    • Filter samples before injection to prevent particulates and contaminants from entering the column.
  5. Avoid Extreme Conditions:
    • Avoid exposure to extreme pH, temperature, or pressure conditions that could damage the column.
  6. Regular Backflushing (if applicable):
    • If backflushing is recommended for your column, consider incorporating it into your routine maintenance schedule.
  7. Record Keeping:
    • Maintain a log of column usage, regeneration, and any unusual observations. This can help identify trends or issues that may require attention.

Use a pre-column to protect the analytical column, because silica gel has a certain solubility in the polar mobile phase/ionic mobile phase. Please try not to exceed the pH range of 2-7.5 for most reversed-phase columns. Avoid The composition and polarity of the mobile phase changing drastically.

Before use, it is necessary to degas and filter the mobile phase. If a polar or ionic buffer solution is used as the mobile phase, the column should be rinsed after the experiment and stored in a methanol or acetonitrile Medium. Chloride solvents are corrosive to a certain extent, so please pay attention to them when using them, and do not store such solvents in the column and connecting pipe for a long time to avoid corrosion.