Syringe Filter

What is the Syringe Filter?

A syringe filter is a small single-use device that attaches to a syringe to clean up small sample volumes. It removes particles before chromatography or analysis, with a choice of membrane and pore size.

Overview

The filter consists of a membrane disc, usually 13, 25 or 33 mm in diameter, held in a polypropylene housing with a luer lock or luer slip connection. Membranes are available in PTFE, PVDF, PES, nylon, cellulose acetate and regenerated cellulose, with pore sizes of 0.22 or 0.45 µm. Hold-up volume is small, roughly 20–100 µL depending on size, which matters when sample is limited, and some housings are designed to minimise it. The device is rated for a burst pressure, commonly 5–10 bar, above which the housing can fail. Syringe filters are used for sample clean-up, mobile phase preparation and small-volume sterilisation, and come gamma sterilised or non-sterile. They are single use and should be pre-rinsed for sensitive methods.

How does it work?

A laboratory filter separates particles from liquid by passing the liquid through a porous membrane with a defined pore size. Particles larger than the pore are retained on the surface or within the structure, while the filtrate passes through. Membrane material determines chemical compatibility and adsorption: PTFE is inert to most solvents and is used for organic mobile phases, PVDF suits aqueous and mixed phases, nylon binds proteins and is used where adsorption is not an issue, and cellulose acetate and PES are used for aqueous and biological solutions. Pore size of 0.45 µm removes most particulates, while 0.22 µm is used for sterilisation by filtration because it retains bacteria. The housing, whether polypropylene syringe filter, a bottle-top unit or a centrifugal device, provides the driving force and the connection. Extractables and hold-up volume are the main performance risks.

What are the key features?

• Membrane 13, 25 or 33 mm
• PP housing with luer connection
• Pore size 0.22 or 0.45 µm
• Hold-up volume 20–100 µL
• Burst pressure 5–10 bar
• Sterile and non-sterile options

What are the technical specifications?

A typical syringe filter configuration offers membrane diameter of 13, 25 or 33 mm, housing of Polypropylene, connection of Luer lock or slip, pore size of 0.22 or 0.45 µm, membrane of PTFE, PVDF, PES, nylon, CA and hold-up volume of 20–100 µL. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Syringe Filter is used in HPLC sample clean-up, small-volume sterilisation, mobile phase filtration and protein sample filtration. Across the wider Filters class, laboratories also deploy it for sample clean-up before HPLC, mobile phase filtration and sterilisation by filtration.

Which standards and certifications apply?

Relevant standards and methods include USP <788> (particulate matter in injections), USP <665> (plastic components and systems), ISO 13485 (medical device quality management), ISO 10993 (biological evaluation of medical devices), EN ISO 11607 (packaging for terminally sterilized devices) and USP <1664> (assessment of drug product leachables). Certification candidates for this model are CE and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Pre-rinse the filter with the solvent or mobile phase when the method is sensitive, because membranes contain extractables such as wetting agents or oligomers that can appear as peaks, especially with LC-MS. Use a filter with a larger pore or a glass fibre prefilter for dirty samples, since a clogged 0.22 µm filter is a common cause of lost samples. Do not use the same filter for different samples if carry-over matters, and never filter a sterile solution into a non-sterile container. Check the pressure rating of syringe filters, because high pressure can burst the housing and release particles. Store filters in their packaging and respect expiry, especially for sterile units. Record lot numbers, since extractables and adsorption can vary between lots.

How do I select the right Syringe Filter?

Choose the membrane for the solvent and the pore size for the purpose, and use the smallest housing that holds your volume to limit hold-up. RFQ: solvent, pore size, volume, sterility and membrane compatibility. Provide the solvent and sample volume.

How does it compare with other Filters variants?

Choose the membrane by the solvent, the analyte and the purpose. Use PTFE for organic solvents and aggressive chemicals, PVDF or PES for aqueous and mixed phases, and cellulose acetate for aqueous solutions where low protein binding is wanted. Choose 0.22 µm for sterilisation or where microbes must be removed, and 0.45 µm for general particulate removal before chromatography. Match the format to the volume: syringe filters for 1–100 mL, bottle-top units for 100 mL to several litres, disc filters for vacuum or pressure holders, and centrifugal units for small volumes and concentration. Confirm the housing is compatible with the solvent, check hold-up volume for small samples, and ask for extractables data when the method is sensitive. Do not use a filter that adsorbs the analyte, and verify recovery with your compounds.