1. All mobile phases (water phase, organic phase, salt solution, etc.) must be filtered with 0.45um filter membrane, otherwise, it may cause one-way valve blockage and wear of pump head piston rod and sealing device;

 

2. When using buffer solution and salt solution, use 10% isopropanol solution to flush the plunger online. After the analysis, flush the corresponding pipeline of degasser with water phase to prevent crystallization.

 

3. When the liquid chromatography is not used, the solvent filter head shall be taken out from the water phase or buffer liquid phase and soaked in the organic solvent, otherwise, the growth of mold and microorganism will be caused and the solvent filter head will be blocked. When the solvent filter head is blocked, it can be soaked in 35% nitric acid solution for 30 minutes, and then treated with pure water ultrasonic.

 

2、 Maintenance of injection system

 

1. The sample must be filtered with 0.45um filter membrane before injection to reduce the abrasion of particles on the injection valve

 

2. Do not rotate the valve core too slowly, or stay in the middle position, otherwise the flow phase will be blocked, which will cause the pressure in the pump to increase sharply, or even exceed the maximum pressure of the pump

 

3. In order to prevent buffer salt and sample remaining in the sample valve, flush the sample valve after each analysis. Generally, it can be washed with water, or first with solvent that can dissolve the sample, and then with water

 

4. Salt solution shall not be used for the washing solution of automatic injector, and degassing shall be carried out in advance before use

 

3、 Maintenance of inspection system

 

1. Do not switch the deuterium lamp of UV detector frequently

 

2. Pay attention to keep the outlet of the circulation pool unobstructed. Anyway, the back pressure should not be too large to prevent the circulation pool from cracking

 

3. Pay attention to the selection of mobile phase to avoid the pollution of circulation pool

 

4、 Maintenance of chromatographic column

 

1. Avoid sharp change of pressure and temperature and any mechanical vibration. The sudden change of temperature or the falling of chromatographic column will affect the filling condition in the column; the sudden increase or decrease of column pressure will also impulse the packing in the column, so it should be carried out slowly when adjusting the flow rate

 

2. The composition of solvents should be changed gradually, especially in reversed-phase chromatography. It should not be changed directly from organic solvents to all water, and vice versa

 

3. To avoid injecting complex matrix samples, especially biological samples directly into the column, it is necessary to pretreat the samples or connect a protective column between the injector and the chromatographic column. The protective column is usually a short column filled with similar fixed phase. The protection post can and should be replaced frequently

 

4. Choose suitable mobile phase (especially pH) to avoid the destruction of stationary phase

 

5. The following solvents can be selected to keep the chromatographic column unobstructed: hydrocarbon (heptane, octane) solvent for normal column; methanol or acetonitrile for reversed column; water for ion exchange column or methanol / water. 2. After the chromatographic column is polluted, appropriate solvent can be used for washing to regenerate the column efficiency