How to Select and Use The Syringe Filter

General introduction of syringe filter

The syringe filter is composed of a graduated tube and a filter head. The filter head contains filter membranes with different characteristics. According to the experimental requirements, filter membranes with different performances can be selected. The syringe filter can be used for liquid sterilization and impurity removal, gas vapor dehumidification, dust removal and sterilization. It is used for sample pretreatment of liquid chromatography, which can avoid the blockage of the chromatographic column by particulate impurities in the sample, protect the pipeline system of the pump and the injection valve from being polluted, maintain the chromatographic system, and prolong the service life.

Because the syringe filter is disposable, it is fast and efficient. Disposable laboratory supplies are more afraid of contamination. Cross-contamination is difficult to solve.

Syringe Filter Selection Considerations

1. Consider the Effective Filtration Area (EFA)

Particles in the fluid can affect the life of the filter, and as the particles are removed by the filter, they also block the voids, reducing the usable portion of the filter. Fluids loaded with particulates are more likely to clog filters than “clean” fluids, and increasing the EFA (effective filter area) can extend filter life.

2. Consider the aperture size

Choose the appropriate pore size according to the analytical instrument. The filter material pore size will be decided by the minimum particle diameter due to volume, size of fillers and gaps. These particles will be effectively intercepted by filters of rated pore size.

3.Consider the filter membranes

HAWACH has summarized 5 frequently used membranes to discuss their features and applications:

Water-based membranes (mixed cellulose ester CN-CA)

Features: uniform pore size, high porosity, no media shedding, thin texture, low resistance, fast filtration, low cost, but not resistant to organic solutions and strong acids and alkalis.

Application: drinking water, surface water, well water, etc., sterilization filtration, analysis of particles and oil insolubles in solution, determination of water pollution index, filtration of particles and bacteria such as gas, oil, beverage, and wine. It is one of the most widely used filters in sample preparation filtration.

Nylon membrane (polyamide NYLON) syringe filter

Features: it has good temperature resistance, good chemical stability, and can withstand 121°C, saturated steam high pressure sterilization for 30 minutes, the maximum working temperature is 60°C, and can withstand a variety of organic and inorganic compounds and solvents such as dilute acid and alkali.

Application: It is suitable for water filtration in electronics, microelectronics, semiconductor industry, filtration of tissue culture medium, liquid medicine, beverage, high-purity chemicals, water and mobile phase of organic solution.

PVDF membrane (polyvinylidene fluoride) syringe filter

Features: The membrane has high mechanical strength, good tensile strength, good heat resistance and chemical stability, very low protein adsorption, and strong hydrophobicity.

Application: Gas and steam filtration, high temperature liquid filtration, sterilization filtration of tissue culture medium, additives, etc., solvent and chemical raw material purification filtration.

PTFE (polytetrafluoroethylene) syringe filter

Features: It has a wide range of chemical compatibility, good temperature resistance, strong acid and alkali resistance, strong chemical corrosive solvents and oxidants.

Application: It can filter almost all organic solutions in the fields of chemical industry, medicine, environmental protection, electronics, food, energy and so on.

PP(Polypropylene) syringe filter

Polypropylene microporous membrane is made of polypropylene ultrafine fibers by hot-melt bonding. Without any additives; stable physical and chemical properties, good compatibility; with a series of pore sizes, high porosity, large dirt holding capacity, recoil and high temperature disinfection; good pressure resistance.

1. The PP filter membrane has excellent chemical resistance, it is resistant to acid, alkali and solvent, including polar solvents (except benzene xylene, etc.).
2. The PP filter membrane is temperature-resistant and can be autoclaved at 121°C for 30 minutes, and the working temperature is below 100°C.
3. It can be used after soaking with 70% ethanol for a few minutes before use.
4. The PP filter membrane is a deep filtration, with low resistance and fast flow rate. It is especially suitable for the filtration of items with high viscosity and high suspended matter. The filtration time The longer it is, the higher the filtering precision is.
5. The PP filter membrane is hydrophilic, which is especially good for liquid filtration or gas filtration.

Use Instructions of Syringe Filter

1. Put the filter membrane flat in the clean container, soak it in distilled water of about 70 degrees to make it all wet, pour out the water after a few hours (about 4 hours or more), soak it overnight in the above method, and then use an appropriate amount of warm water before use. Soak in distilled water for cleaning.

2. Put the cleaned filter membrane (wet) into a suitable filter to prevent leakage around it, put the filtrate into the liquid inlet, and exhaust the air at the exhaust port, and then the filter can be carried out.

Matters needing attention of Syringe Filter

1. The water membrane is suitable for ph2-9 liquid, not suitable for strong acid and alkali or organic solvent including alcohol.
2. The microporous membrane can only be used as the final stage of filtration, and the filtrate must be pre-filtered by the plate frame or other filter materials to prevent the filter membrane from being blocked.
3. The above-mentioned methods are only applicable to the filtration of liquid medicines or other water solvents.

When using it, please note do not use too much force, so as not to break the filter membrane and lose the original filtering effect. To prevent emulsification or add a little sodium chloride to remove emulsification, how to make the sample solution clear and free of suspended solids is the goal of our research.