Reverse chromatography columns may encounter various malfunctions during use, and the following are solutions to address these issues:

1、 Abnormal increase in pressure

1. Blockage of sieve plate

-Performance: Significant increase or fluctuation in column pressure.

-Solution: Remove the sieve plate and place it in 10% dilute nitric acid for ultrasonic cleaning for 10 minutes. Rinse with pure water and reinstall. Strong solvents can also be used for reverse flushing. Be careful to avoid positive high-voltage impact.

2. Packing pollution

-Performance: The column head packing is covered by strongly retained substances, resulting in a decrease in column efficiency.

-Solution: Unscrew the column joint, excavate the surface contaminated filling material, replace it with new filling material, and compact it. This method can partially restore the column effect, but it is difficult to reach the new column level.

3. Salt crystallization precipitation

-Performance: When the mobile phase contains high concentrations of organic solvents, buffer salt crystals block the flow path.

-Solution: First dissolve the salts in low concentration methanol/water, then switch to high concentration organic phase for rinsing.

2、 Decreased separation efficiency

1. Abnormal peak shape

-Tail/fork: Due to column head collapse or increased dead volume, it is necessary to fill with the same type of filler and flatten it. If metal contamination occurs, use high-purity silica gel columns instead.

-Ghost Peak: Residual pollutants flow out at high temperatures and can be removed by increasing the final temperature and baking the chromatographic column.

2. Decreased column efficiency

-Reason: Loss of stationary phase or dissolution of silica gel.

-Solution: Optimize the pH of the mobile phase (recommended 2-9) to avoid alkaline conditions accelerating the hydrolysis of bonded phases.

3、 Retention time drift

1. Insufficient balance: After replacing the mobile phase, at least 10-20 times the volume of the column should be equilibrated.

2. Hydrophobic collapse: Long term operation of C18 column with water phase will cause pore shrinkage, requiring injection of 5% organic phase for recovery.

4、 Preventive maintenance strategy

1. Standardize the operation process

-To avoid sudden changes in pressure, the switch valve should be operated slowly.

-The switching of mobile phase requires gradient transition, and it is forbidden to directly switch from organic phase to pure water phase.

2. Regular deep cleaning

-Conventional flushing: Rinse sequentially with 95% water-5% methanol → pure methanol → isopropanol, with each solvent at least 10 times the column volume

-Stubborn pollutants: DMSO is used for protein residue, and starch is washed with water.

3. Optimization of storage conditions

-When not in use for a long time, the column should be filled with methanol or acetonitrile, and the joints should be tightened to prevent drying. Do not leave the buffer overnight.

The solution to reverse chromatography column failure requires a combination of physical flushing, chemical regeneration, and operating procedures. Prioritize eliminating non column related factors (such as instrument blockage), and then address issues with the chromatographic column itself. Establishing a complete maintenance log to record each flushing condition, pressure change, and test results can significantly extend the service life of the column.