How to clean glass pipettes?

[NeoBrew]

I'm just getting started with yeast culturing and storage. I decided to get some glass pipettes as I was interested in being able to sterilize them in my pressure cooker. I am not a big fan of disposable equipment.

The tip of the pipettes are very tiny. Way too small for a tubing brush, a pin barely fits in there. What is the best practice for cleaning pipettes? I used one to put agar/wort in slants recently. The agar residue really stuck to the inside of that tip.

I swished water and PBW in it for a while then put it inverted in the pressure cooker. It is visually clean now, but I'm not certain this is best practice.

 

[ajdelange]

There is a variety of equipment sold for the express purpose of cleaning pipets but you probably wouldn't want to invest in any of that stuff beyond a rack to store them when not using.

The problem is, of course, getting rid of adhering organic material. A solution of potassium dichromate and sulfuric acid works nicely. But that solution is an environmental disaster and quite possibly a health/well being disaster too so while that may be what they did in the past don't do this today. An enzyme based cleaner such as Zymit is probably your best bet followed by lots of rinses (5) with RO and 1 rinse with DI water.

 

[NeoBrew]

Thanks ajdelange. It looks like some impressive stuff. It's $31 per liter at the one place that actually had a price quoted. That's one more bottle of stuff to keep on the shelf! I would think this would be good for cleaning all of the lab equipment, but it's not going to be very cheap if I start using it a lot.

I think I'm going to start off by hooking up a small pond pump and stretching a piece of silicone tubing over the large end of the pipette, then running it with PBW. If this doesn't work I'll step up to the Zymit.

Thank you for the response. You are a wealth of knowledge!

 

[ajdelange]

Yes, Zymit is rather dear but the good news is that that 1 L bottle will make 100L working solution and should last you a long time.

Another way to get protein is with lye but limit your exposure to that as it does dissolve glass (if slowly).

 

[matridium]

Thanks ajdelange. It looks like some impressive stuff. It's $31 per liter at the one place that actually had a price quoted. That's one more bottle of stuff to keep on the shelf! I would think this would be good for cleaning all of the lab equipment, but it's not going to be very cheap if I start using it a lot.

I think I'm going to start off by hooking up a small pond pump and stretching a piece of silicone tubing over the large end of the pipette, then running it with PBW. If this doesn't work I'll step up to the Zymit.

Thank you for the response. You are a wealth of knowledge!

Cleaning Pipettes is easy. Clean them as soon as you use them. When done using one place it in hot water with a detergent like alconox. https://alconox.com
Once soaked for a bit rinse multiple times with very hot water as hot as you can stand to handle. Wrap in foil and sterilize in an autoclave. The Alconox will dissolve all of the organics. The key is don’t let them sit after use, get them in detergent and soaking.
You can make a pipette syphon cleaner with 2 gallon bucket if you need to. In this case buy some alconox pipette cleaning tablets. I doubt you have the need for such a cleaning system since you won’t need to clean 50+ pipettes at one time.

 

[NeoBrew]

Cleaning Pipettes is easy. Clean them as soon as you use them. When done using one place it in hot water with a detergent like alconox. https://alconox.com

The good news, it's available at Amazon. The bad news...$36 for 4lb. The would probably last me just about forever though.