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what would happen if I autoclave ethanol? - (Apr/18/2007 )

i mean this is a stupid question of course, but I really cant figure out what to do. when i do large prep i throw all the waste into the E-coli bin which has to be autoclaved after the experiment. however I also throw there 75% ethanol after washings. so what happens if I put them into autoclave? and should I autoclave after all if I added ethanol on them? wont they be disinfected? sorry for such strange question. blush.gif

-Kathy-

QUOTE (Kathy @ Apr 19 2007, 05:00 AM)
i mean this is a stupid question of course, but I really cant figure out what to do. when i do large prep i throw all the waste into the E-coli bin which has to be autoclaved after the experiment. however I also throw there 75% ethanol after washings. so what happens if I put them into autoclave? and should I autoclave after all if I added ethanol on them? wont they be disinfected? sorry for such strange question. blush.gif


Urgh, nice question, taxing my brain....

In my opinion you shouldn´t autoclave! The flashpoint is 12°C and the lower explosion limit is 3.5%... In an autoclav with 400l volume and 2bar (~29psi) you "need" 1-2 mol ethanol for 3.5%, so 90 g or 120 ml would be enough...

Ad more ethanol to you waste, at a concentration of 70% there shouldn´t be one more living ecolis.....

Mh, maybe some more good ideas...

-ms-olli-

Hi,

Try separating liquid waste with solid waste when you autoclave. For liquid waste, you can opt for Ethanol or Chlorine to sterilise, then discard. If you need to autoclave liquid waste, just make sure there's not too much ethanol in it as it might be very dangerous. Also make sure to separate the autoclaving of liquid and solid waste as pipette tips might poke around the plastic bags and causes leakage of molten gel or broth into the autoclave.

-I love MSGs!-

A very good question. I personally usually just throw everything into a bag (A bad practise i guess after all). But if the amount of ethanol subjected for autoclaving, I don't think it will make any effect isnt it? Not too sure though.

But I love "I love MSGs" suggestion even though it is tedious, i am sure it serves a better solution.

-timjim-

Unless the bag is autoclaved the day of your prep (that is, if it gets sterilised several days later) most of the ethanol will have evaporated.

-swanny-

QUOTE (swanny @ Apr 19 2007, 05:20 PM)
Unless the bag is autoclaved the day of your prep (that is, if it gets sterilised several days later) most of the ethanol will have evaporated.


haha that is what i have been doing excatly. just out of fear I would let the bottle stand there for some days until i guess most of it have evaporated and then autoclave. yesterddays bottle is still sitting near autoclave until either me or someone couragous puts it into the autoclave ph34r.gif blink.gif anyway i guess i should seperate of course. thanx for the suggestions!

-Kathy-

QUOTE (swanny @ Apr 20 2007, 12:20 AM)
Unless the bag is autoclaved the day of your prep (that is, if it gets sterilised several days later) most of the ethanol will have evaporated.


That implicates the complete evaporation of water and ethanol, both forms an azeotropic mixture where the ethanol woudln´t evaporate seperately....

-ms-olli-

we always through used 70% ethanol in sink

-T. reesei-

My previous boss told me that when he was a PhD student, he put a small amount of ethanol to autoclave and ...... ph34r.gif

-Minnie Mouse-