Nylon vs PTFE vs Cellulose Acetate: Which 47mm Membrane Filter Do You Actually Need?

You've got a sample to filter and five membrane options staring at you. Pick wrong and you'll dissolve your filter into your sample, lose analyte to adsorption, or block your HPLC column anyway. Here's how to choose in 30 seconds. 

Start with your solvent, not your application

The number one mistake: choosing by application name ("I'm doing HPLC, so I'll grab whatever") instead of by what's actually in the solution. Your solvent compatibility determines which membranes survive contact, full stop.

Nylon (Polyamide) 0.22µm: the chromatographer's workhorse

Nylon is naturally hydrophilic, meaning it wets with both aqueous and organic solvents without pre-treatment. That makes it ideal for:

• HPLC mobile phase filtration (water/acetonitrile and water/methanol blends)
• Sample prep for LC and GC
• General laboratory filtration of mixed aqueous-organic solutions

The 0.22µm pore size removes particles and microorganisms that would otherwise foul your column or damage your detector. If your lab runs chromatography daily, nylon membranes should be your stock item.

One caveat: nylon has moderate protein binding. If you're filtering protein-containing samples for bioanalysis, reach for cellulose acetate instead.

Cellulose Acetate (CA) 0.45µm and 0.22µm: the low-binding specialist

CA membranes have the lowest protein adsorption of any common membrane material. That makes them the default for:

• Filtering sera and plasma
• Tissue culture media preparation
• Protein-containing buffers
• Any application where analyte loss to the membrane would skew results

The 0.45µm variant handles general clarification and particle removal. The 0.22µm provides sterilising-grade filtration for media and sensitive biologics.

The limitation: CA can't handle organic solvents. Methanol, acetonitrile, and DMSO will attack it. Keep it strictly aqueous.

PTFE Hydrophilic 0.45µm: the universal soldier

PTFE is chemically inert to virtually everything: strong acids, strong bases, aggressive organic solvents, oxidising agents. If your sample would destroy any other membrane, PTFE is your answer.

The "hydrophilic" treatment means it wets with water without pre-wetting in alcohol (untreated PTFE is naturally hydrophobic). This gives you universal compatibility: aqueous or organic, mild or aggressive.

Use it for:

• Concentrated acid or base filtration
• DMSO, DMF, and other aggressive solvents
• Samples where you're unsure of the exact chemistry
• Air and gas venting applications

PTFE is typically the most expensive membrane type, so don't default to it when nylon or CA would do the job perfectly well.

Quick decision matrix

Don't overpay for compatibility you don't need

PTFE costs more because it does more. But if 80% of your filtration is aqueous mobile phases, nylon at a fraction of the price does the job identically. Match the membrane to the actual chemistry, not the worst-case scenario you'll encounter once a year.

Our full 47mm membrane range (MCE, CA, Nylon, PTFE) is stocked at 100 discs per pack, priced to keep your lab running without blowing through your consumables budget.

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