How to Select the Suitable Syringe Filters and the Commonly Used Filter Membranes?

Featuring small size, large filtering area, fast filtering speed, low blocking rate, acid and alkali corrosion resistance and long service life and so, the HPLC syringe filter are widely used in many industries. Adopting different filter membranes can remove various fine particles, colloids, metals, bacteria, residual chlorine and other impurities in water or air. Meanwhile, it can protect the chromatographic system.

For the syringe filter shell, it’s made of high-pressure polypropylene (PP), which is resistant to high temperature, does not leak, does not require membrane replacement and cleaning, and saves complicated and time-consuming preparations. Luer lock syringe filter is a product for filtering small samples of HPLC and GC. The commonly used are Φ13μm and Φ25μm, that is, Φ13μm for sample size 2-10ml, and Φ25μm for sample size 10-100ml.

How to select the suitable syringe filters?

1. Selection of filter membrane

The first thing to consider is chemical compatibility, that is, whether the filter membrane is resistant to acids, alkalis, organic solvents, etc.

2. Pore size of filter membrane

* 0.45μm pore size filter membrane: used for routine sample mobile phase filtration, which can meet general chromatographic requirements, such as: Chromatography system used for 3μm or larger particle size fillers.

* 0.22μm pore size filter membrane: used for removing very fine particles in the sample and mobile phase, such as: chromatographic system used for <3μm packing.

* 1-5μm pore size filter membrane: often used for difficult to handle turbid solutions, which can be pre-filtered with a 1-5μm filter membrane, and then filtered with the corresponding filter membrane.

If you cannot decide the pore size, please contact HAWACH directly and we will provide you the most suitable ones.

3. The characteristics of the filtered sample

A: Hydrophilic samples: Hydrophilic membranes are suitable for filtering water-based solutions, such as: tap water, surface water, and available filter membranes are: water-based membrane (mixed cellulose ester), nylon membrane (polyamide).

B: Nylon membrane (polyamide) is suitable for samples of organic and inorganic compounds (alcohols, esters, oils).

C: Protein solution sample: filter membrane suitable for low protein adsorption.

D: Hydrophobic PTFE (polytetrafluoroethylene membrane) is suitable for strong acid and alkali samples.

Sterile Hydrophilic PTFE Syringe FiltersSterile PVDF Syringe Filtersdisposable nylon Syringe Filters

7 commonly used filter membranes’ features and applications

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

Features: Uniform pore size, wide pore size selection, collection of retained granular cells, high porosity, no media shedding, no nitrate, thin texture, low resistance, low protein adhesion, fast filtration speed, low cost, natural hydrophilicity, but it is not resistant to organic solutions and strong acids and alkalis.

Application: Drinking water, surface water, well water, aqueous solution processing, groundwater filtration etc., sterilization filtration, analysis of particles and oil insolubles in solution, determination of water pollution index, particles and bacteria filtration. It is one of the filter membranes used in sample pretreatment filtration.

2. Nylon membrane (polyamide NYLON)

Features: Good temperature resistance, saturated steam autoclave sterilization for 30 minutes, maximum working temperature 60°C, good chemical stability, resistance to a variety of organic and inorganic compounds, solvents such as dilute acids and alkalis, natural hydrophilicity, no need to infiltrate before use, uniform aperture, good mechanical strength, threaded interface design.

Application: Suitable for water filtration in electronics, microelectronics and semiconductor industries, filtration of tissue culture media, liquid medicines, beverages, high-purity chemicals, water and organic solvent mobile phases.

3. PVDF membrane (polyvinylidene fluoride)

Features: The membrane has high mechanical strength, good tensile strength, good heat resistance and chemical stability, very low protein adsorption, and strong hydrophobicity, non-moisture absorption, resistant to chemical corrosion and oxidation and threaded interface design.

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

4. PTFE (Polytetrafluoroethylene)

Features: It has a wide range of chemical compatibility, good temperature resistance, resistance to strong acids and alkalis, solvents and oxidants with strong chemical corrosion and strong hydrophobicity. Both hydrophilic membrane and hydrophobic membrane can be provided to meet the needs of different liquid filtration.

Application: Used for chemical, pharmaceutical, environmental protection, electronics, food, energy and other fields. It can filter almost all organic solutions.

5. Mixed cellulose (MCE)

Features: High porosity, good interception effect, not resistant to strong acids, strong alkali solutions and most organic solvents, unique threaded interface design.

Application: Used for filtration of water solution in water machine; sterilization and particle removal in laboratories and small-scale test processes; sterilization and filtration of culture medium and culture solution; determination of flora in water.

In the pharmaceutical industry, autoclave water syringes, large infusions to filter out particles; for sterilization of heat-sensitive drugs (insulin ATP, coenzyme A and other biochemical preparations), use a 0.45μm filter (or 0.22); particles in the solution and analysis and determination of oil insoluble matter, and determination of water pollution index; also used in research departments such as somatic cell hybridization and mitochondrial complementation to predict hybrid vigor.

6. Polyethersulfone (PES)

Features: PES membrane has a series of excellent performance, ultra-high water flow rate and very low protein adsorption capacity, high strength and porosity, high flow rate, low dissolution, excellent chemical compatibility, low protein adsorption, excellent heat resistance Performance, particle retention rate: >99%.

Application: Sterilizing and filtering of beer, wine, beverages, etc.; ultra-pure water terminal filtering. It can be used for medical liquid filtration in precision infusion sets, conventional filtration of industrial wastewater treatment (water and organic matter), polar solvent filtration, sterile filtration in the biological field, sample preparation in HPLC, and wine filtration in modern society's winemaking process and so on.

7. Glass fiber (GF)

Features: Glass fiber has many characteristics, such as natural hydrophobicity, large flux, large amount of pollution, good mechanical strength, with low resistance and high filtration efficiency.

Application: It belongs to deep filtration, and its main purpose is to be used as a filter layer, directly added to the filter membrane for use. 2-3 layers of filter membranes with different pore diameters are stacked. A polyester separator layer is added between the filter membranes to facilitate liquid filtration. Add glass fiber pre-filter membrane to the uppermost layer.