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The parameters and knowledge about membrane
Date: 2017-01-06

The importance of filtering
Because of the precision of the chromatographic system and the accuracy of the analysis of the results, it is very important to filter the sample.

Filtration can protect the chromatographic system and column, extend the service life of the column, and improve the accuracy of the data. Membrane Filter can eliminate the pressure fluctuations caused by the friction and the irregular impurities caused by the baseline fluctuations. It also can eliminate the interference of the detection system due to the existence of bubbles. Therefore, microporous filter membrane (Membrane) is usually used to filter the mobile phase, and the needle filter (Filter) is used to filter the sample.


Membrane parameters and knowledge
1. Absolute aperture: absolute aperture size class is defined by the 100% cut in very strict test conditions to leave a specific size of the challenge bacteria to distinguish the aperture. Conditions must be specified: test organism (or molecular) size and concentration, test pressure and test method.
2. Air flux: a method for measuring the air passing through the filter. The flow of air through the air flow under different pressure, different hole rate and different filter area.
3. Bubble point: in the microporous membrane industry, the use of specific membrane wetting liquid, and at a certain temperature, to be squeezed out of the minimum pressure liquid membrane hole in said.
4. Filter efficacy: the filter at its specific pressure, the total amount of its filter and the size of the particle size of the filter to define its filtration efficiency. Generally speaking, the lower the level of obstruction and the lower the pressure, the greater the effect of the filter.
5. Filter life: under certain operating conditions, the longest time filter. It depends on many factors, such as the nature of the filter, the operating temperature, the selection of filter material, etc..
6. Wettability: Hydrophilicity is defined as hydrophilic, hydrophilic membrane usually has a layer of special chemical layer makes the filter membrane can be water infiltration; Hydrophobiity is a reference to the repulsive force of water. Hydrophobic membrane is rarely completely water absorbent. In the observation, the surface of the membrane can be observed and the surface of the filter membrane can not be adsorbed on the surface of the membrane and can not be absorbed into the surface of the water. The hydrophobic properties of the filter depends on the size of the pore size and membrane material.
7. Flow rate: the flow rate is the total amount of the filtration membrane in the unit time under the specific temperature and pressure. The flow rate is closely related to the surface properties of the filter membrane. Flow rate and flux are two important parameters of filter design and performance. This performance depends on the following aspects:
1) Viscosity: viscosity determines the flow of liquid difficult. The higher the viscosity of the liquid (under a certain temperature and pressure) the lower the flow rate. The higher the pressure required to achieve the same flow rate.
2) Pressure difference: the filter inlet and outlet pressure difference, when the filter's full load, the filter pressure difference increases.

3) The ratio of the volume of all the pores on the membrane to the total volume of the membrane. The membrane has a 50-90% hole area, and the flow rate is directly related to the porosity of the membrane.

More membrane filter information please free to contact us at

Starlab Scientific Co., Ltd
Add:Room 1519, Building A1, No. 32 Jinye Road, Xi'an City, Shaanxi province, China 710077
Tel:+86 29 89284429
Fax:+86 29 89284425