If anyone is looking for whatman syringe filters...

[ForeverSmall]

Whatman GD/X 25mm Sterile PVDF Syringe Filter, 0.2 um, Qty. 1

This is what I'm supposed to buy right?

 

[master.on]

Definitely read the filter specs from the manufacturer.
Some come in individual blister packs .i.e. Corning.

And nonsterile filters can be made sterile by running concentrated alcohol through them, then discarding the few ml of oil that come out when first filtering gear.

No

If you want to sterilize a syringe filter use an autoclave (read this is many places BUT I have never personally done this)

Makes sense - but bit above my price range atm... I'm guessing the Pressure cooker method ( the poor man's autoclave) is ok for metal or glass but could well damage the membranes inside a syringe filter? Best option clearly - just get sterile filters in the first place!

Many manufacturers use ethylene oxide
Ethylene oxide - Wikipedia
and NOT an autoclave to sterilize filters
Millex-GS Syringe Filter Unit, 0.22 µm, mixed cellulose esters, 33 mm, ethylene oxide sterilized | SLGS033SB

Some dentists have ethylene oxide sterilizing equipment.

At the end everything is as sterile as the weakest link in the chain:
usually the (reused) media bottle.
While not ideal, many people have reused their filters after storage (small, personal use brewers) with alcohol, some even used hydrogen peroxide. No horror stories so far.

 

[master.on]

Whatman GD/X 25mm Sterile PVDF Syringe Filter, 0.2 um, Qty. 1

This is what I'm supposed to buy right?

Definitely check the specs or ask the manufacturer to see if they are individually packaged.
At the end I agree with factory-sterile and individually-packed being preferable.
So far I got good results with Corning. They even come in individual blister packs for each filter.

 

[Naugahyde]

Many manufacturers use ethylene oxide
Ethylene oxide - Wikipedia
and NOT an autoclave to sterilize filters
Millex-GS Syringe Filter Unit, 0.22 µm, mixed cellulose esters, 33 mm, ethylene oxide sterilized | SLGS033SB

Some dentists have ethylene oxide sterilizing equipment.

At the end everything is as sterile as the weakest link in the chain:
usually the (reused) media bottle.
While not ideal, many people have reused their filters after storage (small, personal use brewers) with alcohol, some even used hydrogen peroxide. No horror stories so far.

I suppose as long as the alcohol is 'pushed through' the filter & FULLY dispersed before bottling - it could work, at a pinch. Not ideal though - I wouldn't like to think what injecting even residual hydrogen peroxide could do

 

[master.on]

I suppose as long as the alcohol is 'pushed through' the filter & FULLY dispersed before bottling - it could work, at a pinch. Not ideal though - I wouldn't like to think what injecting even residual hydrogen peroxide could do

Personally I've pushed a little alcohol through it and leave it "soaking" overnight as to kill all bacteria, not just a quick push.
Never ever had a problem.
I use real lab grade alcohol, BTW.

...and determined the contact times needed for complete destruction were 120–180 minutes, 45–60 minutes, and 5 minutes, respectively. ..
Chemical Disinfectants | Disinfection & Sterilization Guidelines | Guidelines Library | Infection Control | CDC
So overnight soaking allows for complete sterilization

Efficacy of Soaking in 70% Isopropyl Alcohol on Aerobic Bacterial Decontamination of Surgical Instruments and Gloves for Serial Mouse Laparotomies

 

[Naugahyde]

Went with these bad boys in the end - individually blister wrapped and 'gamma irradiated' for sterility.


Pall 4652 0.2 Μm 32 Mm Acrodisc Syringe Filters W Supor Membrane Sterile X50 | eBay