Effect of autoclave on solution concentration? - Buffer, sugar, salt (Dec/04/2006 )

Dear all,

I need to sterilize my stock solution for my buffers becuase the volumes are too much to filter sterilize. But I am not sure that how the autoclave would affect the final concentration of my solutions? Because I observed that after autoclave, the volume of solutions are decreased. Should I compensate the lost volume because of volatilization?

Please help me with these question if you have any idea about that.
Thanks a lot for your time and help!

Minhhanh

i don't think that the volume decreased is significant...anyway, adding to compensate lost volume may contaminate your autoclaved samples once again

Better autoclave some water and reconstitute it to the original volume. Sugars can go bad after autoclave.

You should not have big problems with concentration if you just autoclave liquids only and for a short time of period. And this will sound stupid but it could happen check that the autoclave isn't in dry cycle and the end.

You should place your bottle containing liquid on a tray to catch any liquid come out from the bottle, in case wrong cycle was selected. Most likely, you will loss a significant part (1/2 to 2/3) of it if you picked "dry cycle". If no liquid was found outside the bottle, eveporation could happen if it was left inside the autoclave for too long. I assume it is due to evaporation that causes the content loss, otherwise do it all over again.

There will always a change in the concentration even if you keep it in the fridge.
When you autoclave a buffer first of all make sure that you need it sterile.
I know to many people that autoclave many things that don't need to be sterile,
for example TBE for a common electrophoresis. Second use a bottle
that can hold twice the volume that will put into it. third leave the cap just hal turn unscrew
(I don't know if I spell it right, sorry my english is not my native language).
just autoclave for the minimum time required if it say 15 min..is 15 min not 30
min( "just to make sure..")4th make sure that the pressure is release slowly
5th as soon as is cool enough take it out from autoclave...don't leave things overnight.
I have been using autoclave for the past 10 years and never have a problem with the
concentration. You just need to be careful. good luck and if anything more just ask

if you overfill the bottle, you'll lose a bit of the solution. try to only fill the bottle 2/3 full, that way, you're less likely to loose much.

V

Thanks a lot for all of your kind helps. Yes, I do autoclave the stock solution for my buffers to do protein extraction and isolation which need to be sterilzed, but ofcourse not protease inhibitors:-). I did autoclave in short time (15 min) and tried to put them out as soon as I can (at about 95°C). I weighted the solution in bottles before and after autolave and saw that the differences of about 2 - 3.6% of the original volumes. I also autocaved a bottle of bidest water just to prepared if I need it to compensate for the lost of evaparation. But I think these lost is not much and as Merlav said "There will always a change in the concentration even if you keep it in the fridge". Therefore I think perhaps it is not necessary to add sterilzed bidest water to original volume and I also wonder if I add more water I might get the diluter concentrations comepared to original ones. How do you think about that!?

Thank you all.
Cheers,
Minhhanh