Chromatographic column plays a role of separation in chromatographic analysis system and is the core component of chromatographic analysis. It is very important to use and maintain chromatographic column correctly, improper use will reduce column efficiency, shorten service life and even damage. The following seven aspects of liquid chromatography column in the use of attention should be paid to the problem.
1.Avoid sharp changes in pressure and temperature
A sudden change in temperature or the column falling from the height will affect the filling condition of the column; The sudden increase or decrease of the column pressure will also impulse the column packing, so the flow rate should be adjusted slowly to maintain the stability of the column packing.
2. Avoid changing the composition of the solvent directly
In the need to change the composition of the test sample solution, the composition of the solvent should be gradually changed, especially in reverse phase chromatography, should not be directly changed from organic solvents to all water, and vice versa. When the column is rinsed with the eluent with high secondary elution capacity, the displacement of mobile phase in the flow path system should be gradually transited to miscible solvent, and the volume of each mobile phase should be about 20 times of the column volume, that is, 50~75ML is required for conventional analysis.
3. Avoid column recoil
Generally speaking, the column can not recoil, only the column can recoil to remove impurities left on the column head. Otherwise, the effect of recoil column is to rapidly reduce column efficiency.
4. Avoid damage to stationary phase due to improper use of mobile phase
Choose the appropriate mobile phase (especially PH) to avoid damage to the stationary phase. Sometimes a pre-column can be attached to the front of the sampler. If the analytical column is bonded to silica gel, the pre-column is silica gel to “saturate” the mobile phase prior to entering the analytical column, preventing the silica matrix from being dissolved in the analytical column.
5. It is forbidden for samples to enter the column directly without treatment
To avoid injecting complex matrix samples, especially biological samples, directly into the column, it is necessary to preprocess the sample or connect a guard column between the sampler and the column. The guard column is usually a short column filled with a similar stationary phase. Guard posts can and should be replaced frequently.
6. Do not store buffer solution in the column for a long time
The column should be filled with acetonitrile or methanol when preserving the column, and the column joint should be tightened to prevent solvent evaporation and drying. It is absolutely forbidden to leave the buffer solution in the column overnight or for longer periods.
7. It is forbidden to seal chromatographic column directly without treatment
Suitable solvent should be used to clean the column after completion of use, for example, ODS column should be washed with methanol to the baseline balance; When salt buffer solution is used as mobile phase, salt-free mobile phase flushing should be applied after use. Compounds containing halogen elements (fluorine, chlorine, bromine) may corrode stainless steel pipes, and should not be contacted for a long time; The chromatographic column installed in the liquid chromatograph should be flushed for 15 minutes every 4-5 days if it is not often used.
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