autoclaving
#16
Posted 01 September 2009 - 06:33 PM
I am not trying to make an enemy, nor get involved in a slinging match with anybody on this forum. The reason I visit is to learn, help when I can, and get help when I need it. It saddens me that there are people on this forum who use it as an outlet to insult and belittle others, all for what? To make themselves feel smarter?? Better?? Whatever. Your motivations for being that way are your deal. Good luck with that.
#17
Posted 01 September 2009 - 07:22 PM
1) to minimize the amount lost, use a vessel at least twice the volume of your solution. You're doing 250mL, so use a 500mL flask or bigger. Use aluminum foil to cover the opening, tie with a string to prevent the foil from falling off after autoclaving.
2) as someone already suggested, filter-sterilize. This is the best option if you want to be very precise.
#18
Posted 01 September 2009 - 10:50 PM
Back to the issue of autoclaving. When I usually autoclave something and require precise volumes I do as swanny mentioned - add the difference lost. Filter sterilize is also a good way if you are more confident of your reagent source and using a MUCH larger bottle than the volume autoclaved helps to reduce boil over as newbie99 said.
#19
Posted 02 September 2009 - 01:29 AM
- as said Leelee : us a bigger bottle (it means use a 2L bottle to autoclave 1L of liquid and not a 1L bottle. (I add this explanation because it doesn't seem obvious to every body than talking about a bigger bottle is not always vs a bottle smaller than the volume)), so that the liquid will not boil out of the bottle.
- don't open too early the autoclave, let it cool down close to room temperature.
About opening more or less the cap : it has no influence on losing liquid (if it's open even a little, the liquid will go out in any way.
#20
Posted 02 September 2009 - 02:20 AM
Edited by eberthella, 02 September 2009 - 02:21 AM.
#21
Posted 03 September 2009 - 03:39 AM
eberthella, on Sep 2 2009, 11:20 AM, said:
Is there no way to ban this clown?
Anyway on the topic of autoclaving... Does anyone do what we do and just place the top on the bottle and tape it down? I dont know if this is the best way but Ive never had any problems with it...
#22
Posted 03 September 2009 - 05:02 AM
Kami23, on Sep 3 2009, 01:39 PM, said:
eberthella, on Sep 2 2009, 11:20 AM, said:
Is there no way to ban this clown?
Anyway on the topic of autoclaving... Does anyone do what we do and just place the top on the bottle and tape it down? I dont know if this is the best way but Ive never had any problems with it...
What do you mean?
You close the bottle completely and then tape the top? Or you open the top 1/4 (orso) and then tape it down?
I cant imagine that the tape would stop the gas? Or even the boiling fluid?
Edited by pito, 03 September 2009 - 05:03 AM.
#23
Posted 03 September 2009 - 06:01 AM
pito, on Sep 3 2009, 02:02 PM, said:
Kami23, on Sep 3 2009, 01:39 PM, said:
eberthella, on Sep 2 2009, 11:20 AM, said:
Is there no way to ban this clown?
Anyway on the topic of autoclaving... Does anyone do what we do and just place the top on the bottle and tape it down? I dont know if this is the best way but Ive never had any problems with it...
What do you mean?
You close the bottle completely and then tape the top? Or you open the top 1/4 (orso) and then tape it down?
I cant imagine that the tape would stop the gas? Or even the boiling fluid?
nope i mean dont close the bottle at all with the screw fitting, just secure it with the tape... it lets the cap boing about a bit and theres no real risk of explosion (so long as you dont tape it down too tight)
#24
Posted 03 September 2009 - 07:09 AM
Kami23, on Sep 3 2009, 04:01 PM, said:
pito, on Sep 3 2009, 02:02 PM, said:
Kami23, on Sep 3 2009, 01:39 PM, said:
eberthella, on Sep 2 2009, 11:20 AM, said:
Is there no way to ban this clown?
Anyway on the topic of autoclaving... Does anyone do what we do and just place the top on the bottle and tape it down? I dont know if this is the best way but Ive never had any problems with it...
What do you mean?
You close the bottle completely and then tape the top? Or you open the top 1/4 (orso) and then tape it down?
I cant imagine that the tape would stop the gas? Or even the boiling fluid?
nope i mean dont close the bottle at all with the screw fitting, just secure it with the tape... it lets the cap boing about a bit and theres no real risk of explosion (so long as you dont tape it down too tight)
And you think that would help ?
It seems odd that if you let the top lose and tape it down you would lose less fluid, gas then when screwing the lid on and letting 1/4 turn open.
#25
Posted 07 September 2009 - 03:14 AM
#26
Posted 07 September 2009 - 05:18 AM
Astilius, on Sep 7 2009, 01:14 PM, said:
Honeslty, I do not know.
I simply have to press the "on" switch and that is it.
Its 15 minutes on 121°C ... So what kind of cycle is that?
#27
Posted 08 September 2009 - 01:31 AM
So, although the autoclaving conditions are different you can't tell from looking at them alone (if you follow me).
Do you have a lab tech that can explain the autoclave to you?
What might be happening is that the autoclave is venting at the end of the cycle and making the liquids inside boil over due to sudden pressure loss.
Rule of thumb: You can autoclave solids on a liquid cycle but you cannot autoclave liquids on a solid (gravity) cycle.
Not all autoclaves have solid cycles and you just need to wait until they equilibrate to atmospheric pressure. Check the instrument's manual as a first resort.
#28
Posted 25 September 2009 - 11:46 AM
I've autoclaved liquids a couple of different ways, always on the liquid cycle. During my undergrad, we had 2 autoclaves: a big honking thing that made horrible noises and a little one that looked like a rocket ship. A few times when I autoclaved solutions in the big one, the bottoms of the glass bottles blew out. I was certain that the caps were on loosely, at least a full turn. My PI told me to place the bottles in water to prevent them from blowing out. She thought that the metal rack the bottles were on was cooling at a different rate than the solution and the temperature difference was causing the glass to break. When I autoclaved the bottles in a water bath, they never broke and I noticed that it greatly reduced any solution loss. From that point on, whenever I autoclaved liquids in the large autoclave I placed them in a water bath. I never had a problem with massive solution loss or glass breakage in the little autoclave. I guess the type of autoclave can also affect solution loss.














