Syringe filters for laboratories: a selection guide
Which syringe filters are available and where are the differences between the individual manufacturers? In many laboratories syringe filters are used on a daily basis. There are large differences between the individual syringe filters for example in terms of size and material. The choice of the right size, pore size, material and chemical resistance is crucial when deciding which syringe filter is best used.
Syringe filters are ideal for filtration of the sample solution before injection. These are usually membrane filters made of the appropriate materials. However, they are also available as glass fiber filters or as membrane filters with glass fiber prefilters. When selecting syringe prefilters, materials of the highest quality should be used as the sensitivity of the analytical method increases. These are specially tested for interfering substances. They also guarantee high batch consistency for consistent, reliable analytical results.
This is explained in the following video. It also shows how syringe filters are applied correctly:
Consider also the following aspects to select the appropriate syringe filter for your application:
1) Sample volume
The size of the filter depends on the volume to be filtered. You can use the following values as a general guideline:
Sample volume
< 1 ml
> 2 ml
1 - 5 ml
> 10 ml
< 100 ml
> 100 ml
Filter diameter
3 mm
4 mm
13 - 15 mm
17 mm
25 mm
30 mm
2) Size and amount of pariculates in the sample
Sample particle size
< 0.5 μm
< 2.0 μm
> 5 μm
HPLC column particle size
> 3.0 μm
> 3.0 μm
High particle load
Filter pore size
0.22 μm
0.45 μm
GMF
3) Membrane compatibility with sample type and technique
Sample type
Membrane
Standard HPLC samples/solvents
Nylon (PA)
Regenerated Cellulose (RC)
Polyvinylidene Fluoride (PVDF)
Standard GC samples/solvents
Polytetrafluoroethylene (PTFE)
UV spectrometry
PVDF
Capillary electrophoresis
Polyethersulfone (PES)
High particle load
Glass Microfiber (GF)
Protein analysis
PVDF
Protein removal
GF
Trace metals
PES
Aggressive and nonpolar solvent
PTFE
Biological sample preparation
Cellulose Acetate (CA)
Protein and peptide samples, general HPLC
Polypropylene (PP)
Highly particulated samples
GF
4) Characteristics and application areas of the membrane
Membrane
Characteristics
Applications
Nylon (PA)
Naturally hydrophilic with broad chemical resistance
Excellent flow rates and high-throughput loading
Chemical incompatibilities:
Acids > 1N
Analytics applications
HPLC and organic solvent sample preparation and clean up
Dissolution sample analysis
General sample preparation prior to analytical analysis
Low non-specific binding with exceptional chemical resistance
Hydrophilic membrane provides excellentf low rates and low binding coefficients
Well defined pore structure, giving effective retention of particles without excessive pore blockage
Compatible with aqueous and most organic solvents
Chemical incompatibilities:
DMF, DMSO, MEK, acetone and most caustic solutions > 6N
HPLC and organic solvent samplepreparation and clean up
Protein based samples with high non-specific binding
Environmental water samples
Polytetrafluoroethylene (PTFE) (Hydrophobic and Hydrophilic)
Excellent flow rates and high loading capacities
Exceptional temperature stability
Organic solvent recommended
Hydrophilic PTFE can be used for the same application but no pre-wetting of the membrane is required
PTFE hydrophobic membranes requires pre-treatment with alcohol before being suitable for aqueous or high aqueous/organic samples. Do not use directly with aqueous solutions.
Chemical incompatibilities:
Perchloric acid, methylene chloride (limited exposure), dioxane, DMF, formic acid > 50%, aqueous-based sample matrix (unless the filter is pre-wetted with an alcohol
HPLC and organic solvent sample preparation and clean up
Dissolution sample analysis
General sample preparation prior to analytical analysis
Elevated temperature samples, caustic or acidic solutions
Polyethersulfone (PES)
Precise results in sensitive analysis of ionic analytes
Certified for low-level IC interference by ICP analysis
Hydrophilic membrane provides excellent flow rates and low binding coefficients
Low affinity for binding drugs, ideal for dissolution testing procedures
This hydrophilic polymer has excellent cleanliness and is compatible with a wide range of solvents.
