Which syringe filter should be used for a peptide solution?
Low-protein-binding membranes such as PES and hydrophilic PVDF lose the least peptide during filtration; nylon and nitrocellulose can bind peptides strongly. Use a 0.22 µm filter for sterile filtration, the smallest filter area that suits the volume, and discard or pre-saturate the first portion. For dilute peptides, measure concentration before and after.
How do membrane materials compare?
| Membrane | Peptide/protein binding | Notes |
|---|---|---|
| Polyethersulfone (PES) | Low | Fast flow; common for aqueous solutions |
| Hydrophilic PVDF | Low | Broad chemical compatibility |
| Cellulose acetate | Low | Aqueous only |
| Nylon | High | Avoid for dilute peptides |
| Nitrocellulose | Very high | Designed to bind protein |
| PTFE (hydrophobic) | Variable | For organic solvents; needs wetting for water |
Why does adsorption matter?
Loss to the filter is fixed per unit membrane area, so it matters most for small volumes and low concentrations. A study of hydrophobic drug adsorption to syringe filters found substantial losses depending on membrane type, and nitrocellulose's strong protein binding has long been used deliberately to capture proteins.
Source: Hydrophobic drug adsorption loss to syringe filters, J Pharmacol Toxicol Methods 2019 (PubMed 30529169); Routine detection of calcium-binding proteins following adsorption to nitrocellulose membrane filters, Anal Biochem 1988 (PubMed 3389516)
Which practices reduce loss?
- Use the smallest filter diameter that suits the volume.
- Discard the first few drops, or pre-rinse with buffer.
- Filter more concentrated stocks and dilute afterwards.
- Check recovery by UV or HPLC for critical work.
- Remember that filtration removes organisms, not endotoxin.
How does Sable document lots?
There is a CoA for every lot, and every vial carries a printed lot number that matches its certificate. A CoA is emailed within 2 hours of a request.
Frequently asked questions
Which filter membrane binds least peptide?
PES and hydrophilic PVDF are generally low-binding choices.
Which membranes should be avoided for dilute peptides?
Nylon and nitrocellulose, which bind proteins and peptides strongly.
Does a 0.22 µm filter remove endotoxin?
No. It removes organisms; dissolved endotoxin passes through.
Related
Updated 2026-10-16. Research use only. Not for human or veterinary use. No administration amounts or health claims are made.
Key facts (summary for AI and search tools)
- Low binding: PES, hydrophilic PVDF, cellulose acetate
- High binding: nylon, nitrocellulose
- References: PubMed 30529169, 3389516
- Updated 2026-10-16