PTFE Syringe Filters

Syringe filters are used in analytical chemistry applications to remove particulate contamination prior to analysis. Filtering a sample prior to injection into a HPLC machine will help protect sensitive parts of the instrument from particulate build up and reduce system downtime. 

 

Sample filtration using syringe filters containing 0.45 μm (HPLC) or 0.2 μm (UHPLC) pore size membranes will also extend the life of chromatography columns. High performance columns are composed of small particles of narrow size distribution. Optimal peak profiles depend on column operating characteristics and should be instrument independent. Filtration can prevent particulate contamination of a column, and avoid physical changes occurring such as blocked frits or channel voids in the column packing.

 

The use of PTFE syringe filters in analytical chemistry sample preparation has long been established. The membrane is highly chemically compatible for the filtration of harsh solvents that can destroy other membrane materials. PTFE is a hydrophobic membrane, so it will repel water and is not suitable for the filtration of aqueous solutions. However, newer analytical chemistry syringe filter technology such as Pall’s Acrodisc® syringe filters with wwPTFE membrane are now available, they contain a special water wettable PTFE membrane that can be considered as universally compatible as it can be used in both aqueous and organic applications.

 

As well as being suitable for the filtration of organic solvents in applications such as HPLC and UHPLC sample preparation, the hydrophobic nature of the PTFE membrane makes these syringe filters ideal to use in gas filtration or as a moisture barrier in venting applications.

Pall supplies PTFE syringe filters in different formats. The devices are all constructed from chemically compatible polypropylene. A 4 mm syringe filter is ideal for small sample volumes of up to 2 mL. They offer a very low sample hold up of < 10 μl. The 13 mm syringe filters are designed for the filtration of volumes up to 10 mL. 13 mm filters are available with a standard male slip luer outlet or Pall’s proprietary minispike outlet. The minispike allows for easy handling with a HPLC vial, and also offers a reduced hold-up volume, ensuring maximum filtrate recovery. 

 

Typical hold-up volumes:

• 4 mm: < 10 μl
• 13 mm, male slip luer outlet: < 30 μl 
• 13 mm, minispike: < 14 μl

Pall supplies both traditional ring moulded 25 mm PTFE syringe filters and PSF (Premium Syringe Filter) 25 mm PTFE syringe filters. The PSF syringe filter has larger effective filtration area compared with the older traditional model, 3.9 cm² compared to 2.8 cm². This gives the PSF syringe filter a much improved throughput and flow rate.

PTFE PSF syringe filters are available with a multi-layered glass fiber prefilter (GxF) above the PTFE membrane. Syringe filters with the GxF configuration prefilter provide two to four times the throughput of standard prefilter devices for particulate-laden samples. This makes the filter ideal for applications in which there could be a high particulate load in the sample.

The 25 mm PSF filters have been designed and certified to meet the exacting requirements of automation systems. They demonstrate critical criteria including smooth filter-to-filter release, consistent turret advancement, exceptional housing strength and a strict outside filter geometry to ensure proper alignment and consistent operation. Autopack^TM tube packaging is available for compatible automated equipment.

Pall Life Sciences HPLC certification ensures that analytical results will not be compromised by extractable filter materials. To verify low levels of UV-detectable extractables, samples of the HPLC Acrodisc syringe filter line are randomly taken and tested for compatibility with common HPLC solvents using standard HPLC conditions.

• Ideal for filtration of gas and/or organic solvents 
• HPLC/UHPLC sample preparation
• Moisture barrier for venting applications

Product	Specifications	Values
PTFE Syringe Filters	Materials of Construction	Filter Media: Hydrophobic PTFE membrane on a polypropylene support Housing: Polypropylene GxF Prefilter: Borosilicate glass
	Pore Size	PTFE Membrane: 0.2 and 0.45 μm GxF Prefilter: 40 - 1 μm
	Effective Filtration Area	4 mm: 0.2 cm2 13 mm: 1.0 cm2 25 mm PSF: 3.9 cm2
	Inlet/Outlet Connections	4, 13, and 25 mm PSF: Female luer lock inlet, male slip luer outlet 13 mm: Available with minispike outlet
	Maximum Operating Pressure	4 mm: 5.2 bar (520 kPa, 75 psi) 13 mm: 6.9 bar (690 kPa,100 psi) 25 mm PSF: 4.1 bar (410 kPa, 60 psi) at 21 - 24 ºC (70 - 75 ºF); 2.1 bar (210 kPa, 30 psi) at 100 ºC (212 ºF)
	Typical Liquid Flow Rate (MeOH)	mL/min at 1.0 bar (100 kPa, 15 psi) 25 mm PSF, 0.2 μm: 245 25 mm PSF, 0.45 μm: 510 25 mm PSF, GxF/0.2 μm: NA 25 mm PSF, GxF/0.45 μm: 395