Syringe Filters

Whatman® Puradisc® syringe filters for removing impurities in sample preparation for HPLC and other analyses.

Syringe filters are used to remove particulate impurities from liquid and gas samples prior to analysis by methods such as HPLC, ion chromatography, gas chromatography, ICP, and dissolution testing. Proper filtration of samples improves the quality and consistency of analytical results and decreases instrument downtime. Syringe filters should be selected based on their physical characteristics.


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Article: Millex® Syringe Filters



Membrane Material

  • PES: fast flow rates, high filter capacity, low protein binding; recommended for cell culture and tissue culture applications
  • PVDF: recommended for filtering protein solutions as they are very low binding
  • Cellulose acetate: ideal for filtering biological samples and samples containing sera as they exhibit very low protein and macromolecule binding
  • Cellulose nitrate: recommended for general filtration applications including buffer filtration, and feature low extractable levels and a narrow pore size distribution
  • Hydrophilic PTFE: chemically resistant, flexible, thermally resistant, non-adherent, high strength; typically used in filtering aqueous solutions
  • Hydrophobic PTFE: chemically resistant and flexible; typically used for filtering organic solvents and gases, as well as particle monitoring
  • Regenerated cellulose (RC): hydrophilic with very good chemical resistance to solvents including DMSO; used in HPLC applications
  • Mixed cellulose esters (MCE): produced from biologically inert cellulose acetate and cellulose nitrate, mixed cellulose ester membranes are a versatile choice for biological, analytical, environmental monitoring, and research applications
  • Nylon (NY): naturally hydrophilic, surfactant-free, lowest extractables; commonly used in filtration of aqueous and organic solvents; nylon can bind proteins and isn't recommended for biological samples
  • Glass fiber: produced from borosilicate glass fibers; typically used to filter large particles or viscous solutions; many syringe filters feature glass fiber prefilters to extend the filter lifetime and prevent premature filter fouling
  • Aluminum oxide: feature very low levels of anion leaching for ion chromatography testing

Membrane Pore Size

Pore size provides an indication of the average pore diameter and can be related to the membrane’s ability to filter out particles of a certain size.

  • 0.1 µm: mycoplasma removal
  • 0.20 to 0.22 µm: filter sterilization and ultracleaning of aqueous solutions and organic solvents (e.g., HPLC, UHPLC)
  • 0.45 µm: clarification of aqueous solutions and organic solvents
  • 0.8 µm: coarse particulate removal and removal of bacteria
  • 100 µm: removal of sand, activated carbon, bead resins

Filter Diameter

Filter volume increases as filter diameter increases. To minimize sample loss and reduce the risk of membrane fouling, sample volume should be considered when selecting a filter diameter.

  • 4 mm: recommended for 0.05 mL - 1 mL volumes
  • 13-15 mm: recommended for 1 mL - 10 mL volumes
  • 25-28 mm: recommended for 10 mL - 50 mL volumes
  • 33 mm: recommended for 10 mL - 100 mL volumes
  • 50 mm: recommended for 100 mL - 500 mL volumes

Sterility

Sterile syringe filters are used to sterilize solutions or clarify sterile solutions, while nonsterile syringe filters are used for general filtration and sample purification. Filter housing: Filter housings provide structural support and create a seal around the membrane, preventing filtrate contamination. The housing material must be chemically compatible with the substance being filtered to avoid structural failure. Overmolded formats provide improved burst strength.

  • Polycarbonate: low to medium chemical compatibility; only recommended for filtering nonaggressive aqueous solutions and biological fluids
  • Polyvinyl chloride (PVC): low chemical compatibility; only recommended for filtering nonaggressive aqueous solutions and biological fluids
  • High-density polyethylene (HDPE): high chemical compatibility; resistant to many solvents
  • Polypropylene: high chemical compatibility; resistant to many solvents

Millex® syringe filters

Featuring reduced sample loss due to minimal hold-up volumes, Millex® syringe filters are ideal for use in a variety of applications including HPLC sample preparation, the filtration of antibiotics and tissue culture additives, and dissolution testing. Our controlled manufacturing process ensures reliable filter performance. Our sterile devices include a certificate of quality. Available with many different membrane and housing options, Millex® syringe filters are compatible with a variety of solvents and sample types.

  • Designed for sterile and nonsterile small-volume filtration (1-200 mL)
  • Produced with high-quality Millipore® membranes
  • Available in 4, 13, 25, 33, and 50 mm diameters
  • Minimal hold-up volume reduces sample loss
  • Low extractable and low binding membrane options

Whatman® syringe filters

  • Whatman® Puradisc® syringe filters combine premium quality and economy and are ideal for quick, efficient filtration of samples up to 100 mL volumes.
  • Whatman® Puradisc® Aqua syringe filters are specifically designed for filtration of environmental samples prior to COD and DOC analysis. The membranes used in these devices are prewashed prior to assembly to reduce the organic carbon level.
  • Whatman® Uniflo syringe filters are disposable filtration devices for removing solids from liquid samples prior to analyses such as HPLC and UV/Vis spectrophotometry. They are available in variety of membrane choices with 0.2 μm or 0.45 μm pore sizes, feature a polypropylene overmold housing, and include both sterile and non-sterile options.
  • Whatman® ReZist® syringe filters are specifically designed to be resistant to organic solvents. These filters are ideal for the clarification of aggressive organic solvents.
  • Whatman® Spartan® syringe filters provide reproducible filtration of organic and aqueous solutions for high performance and ultra-high performance liquid chromatography (HCLP and UHPLC) sample preparation. For batch-to-batch consistency, these filters are tested and certified for the absence of UV-absorbing substances at wavelengths of 210 and 254 nm with water, methanol, and acetonitrile.
  • Whatman® Roby syringe filters are designed specifically for automated filtration systems. The design of the polypropylene housing ensures smooth transport from the storage turntable to the filtration site.
  • Whatman® Anotop® syringe filters feature an inorganic Anopore® aluminum oxide membrane in a polypropylene housing and are specifically designed for the preparation of samples for subsequent ion chromatography and HPLC analysis. These devices ensure very low levels of anion leaching for ion chromatography testing.
  • Whatman® GD/X syringe filters are high-viscosity filters that incorporate a prefilter to enable filtration of viscous, dense or otherwise hard-to-filter material with high solids content as in environmental and food analysis samples.
  • Whatman® GD/XP disposable syringe filters, a modification of the GD/X line, use a polypropylene prefilter stack, making GD/XP suitable for samples that require inorganic ion analysis.

Corning® syringe filters

HPLC-certified non-sterile syringe filters are available with nylon, regenerated cellulose or polytetrafluorethylene (PTFE) membranes in polypropylene housing for extra chemical resistance. Sterile tissue culture-tested syringe filters are available in PES, regenerated cellulose, or surfactant-free cellulose acetate membranes in either polypropylene or acrylic copolymer housings. The larger 50 mm diameter disc filter has a PTFE membrane and polypropylene housing with hose barb connectors and is ideal for filtering aggressive solvents or gases and applications requiring sterile venting of gases. Because they have a hydrophobic membrane, they are also ideal for protecting vacuum lines and pumps.

Nalgene® syringe filters

Recommended for cell culture applications, the universal PES tissue culture membrane offers higher flow rates, lower protein binding, and lower extractables compared to cellulose membranes. These syringe filters are certified sterile, non-cytotoxic, and non-pyrogenic, are inherently hydrophilic, and contain no external wetting agents.


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