Who can provide a summary of LC training?

This training mainly focuses on the following six aspects: 1. Development of principles and methods of high performance liquid chromatography: 2. Principle, structure, use and maintenance of high performance liquid chromatography; 3. Sample preparation; 5. Principle, selection and maintenance of chromatographic column; 5. Data processing and qualitative and quantitative analysis of high-performance liquid chromatography: 6. Application of high-performance liquid chromatography in various fields Because high-performance liquid chromatography is suitable for analyzing unstable organic compounds, bioactive substances and various natural products with high boiling point and large relative molecular weight, these compounds account for about 80% of all organic compounds. Therefore, high performance liquid chromatography has a wide range of applications and is very important for organic monitoring. The maintenance of HPLC determines the working efficiency, so in order to complete the monitoring work better and faster, we must know how to maintain the instrument, and of course learn some basic maintenance skills of the instrument. The blockage problem often encountered is caused by the deposition of phosphate buffer in the pipeline. The solution is to wash it with pure water and then methanol after each experiment. Chromatographic column is the core part of high performance liquid chromatography instrument, and its quality directly affects the resolution of samples. In order to prolong the service life of HPLC liquid pump and maintain the stability of its infusion, the following matters must be paid attention to: 1. Prevent any solid particles from entering the HPLC liquid pump body, because dust or any other impurities will wear the HPLC liquid plunger, HPLC sealing ring, HPLC liquid cylinder and HPLC liquid check valve, so any solid particles in the mobile phase should be removed in advance. The mobile phase is best distilled in a glass container, and the common method is filtration. Filters such as microporous membrane (0.2um or 05um) can be used. 2. The mobile phase should not contain any corrosive substances, and the mobile phase containing buffer should not stay in the pump, especially if the HPLC pump stops overnight or longer. If the mobile phase containing buffer solution is left in the HPLC liquid pump, tiny salt crystals may precipitate due to evaporation or leakage, or even just because the solution is still, which will damage the HPLC sealing ring and HPLC plunger like the above solid particles. Therefore, it is necessary to pump pure water into HPLC for full cleaning, and then replace it with a solvent suitable for the storage of HPLC columns and beneficial to the maintenance of HPLC pumps (the reversed-phase bonded stationary phase is methanol or methanol and water).

3. When the HPLC pump is working, attention should be paid to prevent the mobile phase in the solvent bottle from flowing out, otherwise the HPLC plunger, HPLC sealing ring or HPLC cylinder will be worn when the HPLC empty pump is running, and the liquid will eventually leak. 4. The working pressure of 4.HPLC infusion pump should not exceed the specified maximum pressure, otherwise the high-pressure sealing ring will deform and leak. 5. The flow should be degassed first to avoid bubbles in the HPLC pump, which will affect the stability of the flow. If there are a lot of bubbles, the HPLC pump will not work. The causes and solutions of some common faults should also be mastered: 1, no mobile phase outflow and no pressure indication. The reason may be that there is a lot of gas in the HPLC pump. At this time, you can open the pressure reducing valve, make the HPLC pump run at a large flow rate (5ml/min) to discharge all bubbles, or use a 50ml syringe to help extract the gas at the pump outlet. Another reason may be that the HPLC sealing ring is worn and needs to be replaced. 2. The flow rate of 2.HPLC pressure is unstable. The reason may be that bubbles need to be removed, or there is a foreign body in the one-way valve. You can remove the HPLC check valve and immerse it in acetone for ultrasonic cleaning. Sometimes there may be bubbles in the sand filter rod or it may be partially blocked by tiny crystal particles of salt or propagated microorganisms. At this time, take out the sand filter rod, immerse it in the mobile phase to remove bubbles by ultrasound, or immerse the sand filter rod (piece) in dilute acid (such as 4mol/L nitric acid) to quickly remove microorganisms or dissolved salts, and then clean it immediately. 3. The reason of high 3.HPLC pressure is that the pipeline is blocked and needs to be cleaned or cleaned. The pressure drop may be caused by pipeline leakage. Check the blockage or leakage section by section. The existence of bubbles in the pipeline will cause sharp noise peaks on the chromatogram, which will reduce the analytical sensitivity in severe cases. When bubbles become larger and enter the flow path or chromatographic column, the flow rate of mobile phase will be slow or unstable, and the baseline will fluctuate. Therefore, the mobile phase must be degassed in advance, and attention should be paid to exhausting the air in the sample syringe before injecting the sample. The training also guided the selection of chromatographic columns. Only by choosing a suitable chromatographic column can we get a good chromatographic peak and achieve a good qualitative and quantitative analysis. If the chromatographic column is dented after a period of use, it can also be filled by itself, that is, the column head is opened and the dented part is filled with the same or similar packing. The column with serious pollution can be turned around for use, but the end connected to the detector must be disconnected to wash away the pollutants. If there is still a peak in the baseline, it can also be dug out and recovered frequently.