Short answer: Choose the syringe filter membrane by solvent first, sample second, pore size third. Hydrophilic PTFE and nylon cover most HPLC sample preparation in organic or mixed solvents. PES is the standard choice for aqueous biological samples and sterile filtration of buffers and media. Hydrophilic PVDF suits protein and peptide samples that also need solvent tolerance. Hydrophobic PTFE is the membrane for aggressive organic solvents, gases and venting. Browse our syringe filter range for PTFE, nylon, PES and PVDF options.
Cover example: nylon syringe filters. Distinct catalogue photos for PTFE, PES and PVDF appear in the sections below; Membrane Solutions PTFE/PES/PVDF listings still share a nylon placeholder image in PIM.
Why the membrane matters more than the housing
A syringe filter looks like a simple consumable, but the membrane decides whether your result is reliable. The wrong polymer can swell or dissolve in the solvent, release extractables that appear as ghost peaks, or adsorb part of the analyte before it reaches the vial. In a regulated laboratory, that is not a purchasing detail: it is part of the method. As a European distributor of laboratory supplies, we compare the four membranes in our syringe filter range the way we would advise a colleague at the bench.
The criteria we use to compare syringe filter membranes
- Chemical compatibility: the membrane and housing must resist the solvent, its pH and its concentration for the contact time of the filtration.
- Wettability: hydrophilic membranes wet with water; hydrophobic membranes repel it and need pre-wetting for aqueous samples.
- Binding and adsorption: some polymers bind proteins and certain small molecules, which lowers recovery.
- Extractables and flow: what the filter releases into the filtrate, and how quickly a sample passes before the membrane clogs.
- Pore size and diameter: retention and sterility on one side, hold-up volume and filtration area on the other.
Syringe filter membranes compared
The table summarises general properties of each polymer. Always confirm against the manufacturer’s compatibility data for the specific product, because housing material and membrane treatment differ between products.
On a phone, swipe the table sideways to see every column.
| Membrane | Wets with water | Chemical compatibility | Protein binding | Typical use | Avoid with |
|---|---|---|---|---|---|
| Hydrophobic PTFE | No, pre-wet with alcohol | Very broad: strong acids, bases, aggressive organic solvents | Low | Organic solvents, gases, venting | Aqueous samples without pre-wetting |
| Hydrophilic PTFE | Yes | Very broad, including mixed aqueous-organic solvents | Low | HPLC and LC-MS sample preparation | Little; check extractables for trace work |
| Nylon | Yes | Good for water and most organic solvents; poor with strong acids | High | General HPLC sample preparation, aqueous and organic samples | Protein samples, strong acids |
| PES | Yes | Good for aqueous solutions; limited with many organic solvents | Very low | Buffers, culture media, biological samples, sterile filtration | Ketones, esters, chlorinated solvents |
| Hydrophilic PVDF | Yes | Broad for common HPLC solvents; weak with strong bases and ketones | Very low | Protein and peptide samples, HPLC sample preparation | Strong bases, acetone |
The four alternatives in detail
PTFE: hydrophobic and hydrophilic
PTFE syringe filters from our catalogue (Minisart® SRP PTFE, 0.2 µm, 25 mm).
Polytetrafluoroethylene has the broadest chemical resistance of the four. Hydrophobic PTFE, such as the hydrophobic PTFE syringe filters, 0.22 µm, 25 mm, is the reference for aggressive organic solvents, strong acids and bases, and for filtering or venting air and gases. Hydrophilic PTFE, such as the hydrophilic PTFE syringe filters, 0.45 µm, 25 mm, keeps that chemical resistance but wets with water, which makes it a versatile membrane for HPLC and LC-MS samples in mixed solvents.
- Pros: very broad compatibility; low binding; suitable for nearly every HPLC mobile phase; hydrophilic version handles aqueous and organic samples.
- Cons: hydrophobic PTFE needs pre-wetting with an alcohol for aqueous samples; confirm which version you order, because the two are not interchangeable.
Nylon
Nylon syringe filters, 0.45 µm, 25 mm (Membrane Solutions nylon).
Nylon (polyamide) is naturally hydrophilic and tolerates water and most organic solvents used in chromatography. That makes the nylon syringe filters, 0.45 µm, 25 mm a common general-purpose choice for HPLC sample preparation.
- Pros: wets with water; good mechanical strength; suitable for aqueous and organic samples in routine chromatography.
- Cons: high protein binding, so not suitable for protein or peptide samples; poor resistance to strong acids; can adsorb some analytes, which you should check during method validation.
PES (polyethersulfone)
PES syringe filters from our catalogue (Minisart® High Flow PES, 0.22 µm, 28 mm).
PES is hydrophilic, has very low protein binding and gives a high flow rate for aqueous solutions. The sterile PES syringe filters, 0.22 µm, 25 mm are a typical choice for sterile filtration of buffers, additives and cell culture media.
- Pros: very low protein binding; fast flow and low clogging with aqueous samples; available sterile for aseptic work.
- Cons: limited resistance to many organic solvents, such as ketones, esters and chlorinated solvents; not the membrane for organic HPLC samples.
PVDF (polyvinylidene fluoride)
PVDF syringe filter units from our catalogue (Millex® PVDF, 0.22 µm, 33 mm).
Hydrophilic PVDF combines low protein binding with good resistance to the solvents used in reversed-phase HPLC. The PVDF syringe filters, 0.45 µm, 25 mm therefore suit protein and peptide samples, and HPLC samples where recovery of the analyte is critical.
- Pros: very low protein binding; broad compatibility with common HPLC solvents; low extractables.
- Cons: weak with strong bases and with ketones such as acetone; hydrophobic PVDF also exists, so check the version before you order.
Our advice per use situation
- HPLC or LC-MS samples in organic or mixed solvents: hydrophilic PTFE as the most versatile option; nylon for routine small-molecule work; hydrophilic PVDF when recovery is critical. See also our HPLC and LC-MS grade solvents.
- Aqueous buffers, culture media and biological samples: PES, sterile and 0.22 µm when sterility is required.
- Protein and peptide samples: PES for aqueous solutions, hydrophilic PVDF when solvents are present; avoid nylon.
- Aggressive solvents, strong acids or bases: hydrophobic PTFE.
- Air, gas filtration and venting: hydrophobic PTFE.
- Hospital and clinical laboratories: choose the membrane that the validated examination procedure specifies and keep the same product for consistency; record any change of membrane as a change of method.
Pore size and diameter: 0.22 µm or 0.45 µm, 13 mm or 25 mm
A pore size of 0.22 µm (often written as 0.2 µm) is the usual choice for sterile filtration of solutions and for samples injected onto columns packed with very small particles, as in UHPLC. A pore size of 0.45 µm is common for general clarification and conventional HPLC; it filters faster and clogs less. A 13 mm filter suits the small volumes typical of autosampler vials and keeps the hold-up volume low. A 25 mm filter gives more filtration area for larger or more viscous samples. If you work with particle sizes and columns, our HPLC method transfer calculator and the wider scientific calculators can help with the calculations around the method.
Syringe filters in the European quality framework
Syringe filters for general laboratory use are normally not in vitro diagnostic medical devices: Regulation (EU) 2017/746 on in vitro diagnostic medical devices, Article 1(3)(a), excludes products for general laboratory use unless the manufacturer specifically intends them for in vitro diagnostic examination. Responsibility for fitness for purpose therefore sits with the laboratory method. Testing laboratories accredited to EN ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories, and medical laboratories accredited to EN ISO 15189, Medical laboratories – Requirements for quality and competence, validate or verify their methods, and the filtration step belongs in that work. A simple check is to compare the result of a filtered sample with an unfiltered or centrifuged one, and to discard the first portion of filtrate. For the solvents you filter, the safety data sheet required under Regulation (EC) No 1907/2006 (REACH) remains the reference for safe handling.
Frequently asked questions
Which syringe filter membrane is best for HPLC samples?
For most HPLC and LC-MS samples in organic or mixed aqueous-organic solvents, hydrophilic PTFE and nylon are the usual first choices. Choose hydrophilic PVDF when the sample contains proteins or peptides, and check every new method for analyte adsorption on the filter.
What is the difference between hydrophobic and hydrophilic PTFE?
Hydrophobic PTFE resists aggressive solvents, acids and bases, and is used for organic solvents, gases and venting, but must be pre-wetted with alcohol before aqueous samples. Hydrophilic PTFE keeps the same broad chemical resistance and wets with water, so it suits HPLC and LC-MS samples in aqueous or mixed solvents without pre-wetting.
Can I filter aqueous samples through a hydrophobic PTFE filter?
Not directly. Water does not wet hydrophobic PTFE, so the membrane must first be pre-wetted with a miscible solvent such as methanol or isopropanol. For routine aqueous work, choose hydrophilic PTFE, PES or hydrophilic PVDF instead.
Which membrane should I use for protein or peptide samples?
Use a low-binding membrane: PES for aqueous protein solutions and cell culture media, or hydrophilic PVDF when solvent tolerance is also needed. Avoid nylon for protein samples, because it binds proteins strongly.
Should I choose a 0.22 µm or a 0.45 µm pore size?
Choose 0.22 µm for sterile filtration of solutions and for samples injected onto columns with very small particles, as in UHPLC. Choose 0.45 µm for general clarification and conventional HPLC, where it gives a higher flow rate and less clogging.
Are syringe filters in vitro diagnostic medical devices under the IVDR?
Normally not. Article 1(3)(a) of Regulation (EU) 2017/746 excludes products for general laboratory use, unless the manufacturer specifically intends them for in vitro diagnostic examination. Your laboratory remains responsible for validating the filter within its own method.
How Luminix Health can help
Luminix Health is a European supplier and distributor of laboratory and hospital supplies with a catalogue of 150.000+ products, available in small or large quantities. Next to syringe filters we supply membrane filters, the full filtration range and HPLC columns. Products are delivered across Europe in two to five days when in stock. For unfamiliar terms, see our glossary and abbreviations; for the formulas behind daily lab work, see our article on scientific calculators and references. Not sure which membrane fits your method? Send your solvent, sample type and volume to sales@luminixhealth.com or use our quote request, and we will advise you.
Sources
- Regulation (EU) 2017/746 on in vitro diagnostic medical devices (EUR-Lex)
- Regulation (EC) No 1907/2006 (REACH) (EUR-Lex)
- EN ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories
- EN ISO 15189, Medical laboratories – Requirements for quality and competence
