PTFE (Polytetrafluoroethylene) Membrane Filters
The PTFE filters are:
- Strong and resistant to acids, bases, and solvents
- Hydrophobic
- Low background, interference-free chemical determinations
- Low tare mass for accurate gravimetric analysis
- Temperature resistant to 260°C (500°F) — autoclavable
- Ideal for aerosol sampling, especially in environments also containing water vapour
- 13 mm filter meets NIOSH Method 5517 specifications
PTFE filters are the versatile choice for size-selective samplers. The material’s unique properties make it ideal for gravimetric, chemical, and/or microscopic analysis of sample particulate. PTFE filters are used for aerosol sampling, air venting and gas filtration. Note that the back pressure on PTFE filters can vary within the same lot.
Specific applications include:
Sampling for Particulate Matter:
PTFE filters with a PMP support ring are the recommended filters for particulate matter samplers such as the SKC Personal Modular Impactor (PMI), the Sioutas Impactor, the IMPACT Sampler, the Personal Environmental Monitor (PEM), and the Button Sampler. These filters feature low back pressure which allows longer sampling periods at higher flow rates to enhance sensitivity. See PTFE filters Part No. 225-1709, 225-1747, and 225-1711.
Sampling for Lactic Acid:
The US pharmaceutical industry has designated lactic acid powder as the surrogate particulate to detect fugitive emissions from drug compounding and pill manufacturing. SKC developed a 25 mm conductive polypropylene cassette with 1.0 µm PTFE filter and polypropylene support pad to minimize wall losses and permit in-situ extraction for enhanced recovery of lactic acid at nanogram levels. See PTFE Filter 225-1725.
Sampling for Metalworking Fluids (NIOSH 5524):
PTFE filter Part No. 225-17-33 with a 2.0 µm pore size and laminated PTFE support may be used with the thoracic Personal Parallel Impactor (PPI) to sample thoracic particulate according to NIOSH Method 5524 for metalworking fluids.
| Diameter (mm) | Pore Size (µm) | Support Pad included † | Notes | Pack Size | Part Number |
| 25 | 0.5 | No | unlaminated | 100 | 225-17-21 |
| 25 | 1.0 | No | unlaminated | 100 | 225-17-22 |
| 25 | 2.0 | No | unlaminated | 250 | 225-3726 |
| 25 | 3.0 | No | with PMP support ring | 50 | 225-1711 ‡ |
| 25 | 5.0 | No | unlaminated | 100 | 225-1728A |
| 37 | 0.3 | No | For Anthrax/SARS, laminated spun-bound polyester. Also available in ready-to-use preloaded cassettes, see 225-1723. | 100 | 225-1722 |
| 37 | 0.45 | Yes | on polypropylene support | 100 | 225-17-04 |
| 37 | 1.0 | Yes | on polypropylene support | 100 | 225-17-01 |
| 37 | 1.0 | No | unlaminated | 100 | 225-17-32 |
| 37 | 2.0 | No | with PMP support ring | 50 | 225-1709 |
| 37 | 2.0 | No | unlaminated | 100 | 225-17-33 |
| 37 | 5.0 | Yes | unlaminated | 100 | 225-17P |
| 47 | 0.5 | No | unlaminated | 100 | 225-17-41 |
| 47 | 2.0 | No | with PMP support ring | 50 | 225-1747 |
| 47 | 2.0 | No | unlaminated | 100 | 225-17-43 |
| 47 | 5.0 | No | unlaminated | 100 | 225-1724 |
† Filter support pads available
‡ Recommended for use with the Button Sampler
All SKC preloaded filters include support pad and are in SureSeal leak-free cassettes that require a SureSeal Cassette Opener.
| Diameter (mm) | Filter and Cassette Specifications | Pack Size | Part Number | |
| 25 | PTFE, 1.0 µm with polyethylene support pad preloaded in 2-piece conductive cassette, black, goblet style | 50 | 225-1725 |  |
| 37 | PTFE, 0.3 µm, laminated with spun-bound polyester with cellulose support, unsterilized 3-piece clear styrene cassette, banded; for Anthrax/SARS | 50 | 225-1723 |  |
| 37 | PTFE, 1.0 µm with cellulose support, preloaded in a 3-piece, clear styrene (traditional style) cassette, banded | 50 | 225-1715 | |
| 37 | PTFE, 2.0 µm with cellulose ring, 2-piece plastic cassette, banded | 50 | 225-1713 |  |
| Cassette Opener, stainless steel, suitable for 25, 37, and 47-mm filter cassettes. Required for all SureSeal Cassettes. |
225-13-5B |  |
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