Problems and solutions that are prone to problems when using columns
The most common problem with the column in use is the increase in column pressure. If the column pressure is slowly increased during prolonged use, it is normal. However, the column pressure suddenly rises during use (except for system blockage and pressure sensor failure). The possible causes are as follows:
(1) The filter screen of the column head is blocked or contaminated;
(2) The packing of the column head is contaminated by the sample;
(3) The salt in the buffer in the column encounters a high concentration of methanol or other organic solvent to form crystal precipitation;
(4) If the PH value of the mobile phase is too large or too small, the structure of the stationary phase is destroyed or dissolved.
The solution is as follows:
(1) If it is determined that the filter screen of the column head is contaminated, the column can be flushed to normal pressure in the opposite direction with methanol, or the column head is removed, and it is ultrasonically cleaned in 10% dilute nitric acid for 10 minutes. After that, it was sonicated with pure water for 10 minutes and reloaded into the column.
(2) If it is determined that the packing of the column head is contaminated, remove the stud screws, dig out the contaminated packing in the front part of the column, refill with the same column packing, and after careful repair, reinstall the stud screws.
(3) If it is determined to be salt crystal, rinse the column with 10% methanol/water to dissolve all the salt in the column, and then change the high concentration of methanol.
(4) If it is used improperly due to PH value, it is difficult to recover.