SDS PAGE electrophoresis - (Jun/22/2018 )

I'm a new lab coordinator and this is my first time preparing the material to run an SDS page electrophoresis analysis. 

I'm adding DTT to my Laemmli buffer two months before the lab and keeping it in the freezer, is this fine?

Does 256 mg of DTT for 30 ml of Laemmli buffer sound right?

Should I autoclave all the plastic microcentrifuge vials even if they are new? what about the pipette tips?

Thanks

yes, it is okay to freeze the buffer (with dtt or without). but, defrost once. you should prepare aliquots for single use prior to freezing (eg enough for 8 samples).

what concentration do you want in your sample buffer, final sample concentration? 256mg in 30ml is ~55mM

as long as they're clean, you shouldn't need to autoclave either. we never bother to autoclave tubes and tips used for sds-page. of course, if you want to ensure sterility, and didn't purchase sterile, then by all means autoclave them.