Nanjing Kejie Analytical Instrument Co., Ltd. is a professional research, development, manufacturing and sales chromatograph (gas chromatograph, Agilent gas chromatograph, liquid chromatograph, Agilent liquid chromatograph liquid chromatograph, Agilent liquid chromatograph), High-tech enterprise supporting gas chromatograph products (headspace sampler), high-purity gas analysis equipment, chromatography accessories, chromatography reagents and other analytical instruments. When we conduct liquid chromatography analysis, we sometimes encounter such a problem: there are bubbles in the flow path of the system. The presence of bubbles will cause sharp noise peaks on the chromatogram, which will cause a decrease in analysis sensitivity in severe cases. When the bubbles become larger and enter the flow path or column, the flow rate of the mobile phase will be slow or unstable, causing the baseline to fluctuate. There are three main reasons for the above phenomenon: one is that the mobile phase solution often forms bubbles due to the dissolved oxygen or mixed with air; the second is that the air in the flow path cannot be driven out when the system starts to work; the third is when the sample is injected When inadvertently mixed with air. In order to avoid such problems, the degassing of mobile phase must be emphasized during the actual analysis of liquid chromatography. The common degassing methods provided by Nanjing Kejie are as follows: 1. The helium blowing degassing method uses helium gas with a lower solubility than air in the liquid, and the flow is about 60ml / min under 0.1Mpa pressure. Phase 10-15min to drive off dissolved gases. This method is used for all solvents, and the degassing effect is better, but this method is used less because of the high price of helium in China; 2. The heating and reflux method has better degassing effect; 3. Vacuum degassing At this time, the micro vacuum pump can be used, and the dissolved gas can be removed by reducing the pressure to 0.05-0.07MPa. Obviously, using a water pump to connect the suction filter bottle and the G4 microporous glass funnel can complete the dual tasks of filtering mechanical impurities and degassing together. Since the vacuum will cause the composition of the mixed solvent to change, this method is suitable for degassing a single solvent system. The multi-solvent system should be degassed in advance and then mixed to ensure that the ratio after mixing remains unchanged. 4. Ultrasonic degassing method It is the most widely used degassing method in the laboratory at present. Place the prepared flow connection with the container into the ultrasonic water degassing for 10-20min. This method is easy to operate and can basically meet the requirements of daily analysis. 5. The online vacuum degassing method connects the vacuum degassing device to the liquid storage system in series and combines with the membrane filter to realize continuous vacuum degassing of the mobile phase before entering the infusion pump. The degassing effect of this method is significantly better than the above methods, and is suitable for multi-solvent systems. Second, before the liquid chromatography system starts to work, you can use a syringe to connect the drain valve of the constant flow pump, draw in the mobile phase, and drive the air in the flow path clean. Third, before injecting the sample, pay attention to exhaust the air in the sample syringe. console table modern,table console,hallway console table,console tables living room furniture Kumusi (Dongguan) Furniture Co., Ltd. , https://www.coombesfurniture.com