Reuse of 2-Mercaptoethanol added buffer - (Feb/19/2012 )

Hi,
I wonder can i re use a buffer in which i have added 5mM 2-mercaptoethanol (2-ME). I added 2-ME, 3 days ago,and i dont want to throw it away. Is it possible i add more 2-ME and re use it.

Thanks in advance

How did you store it? If at room temp, it is likely to have degraded, and you should throw it out. Remember the basic principle: If in doubt, throw it out. This rule stands because if you have something about which you are not sure (in your case the 2-ME), how will that uncertainty affect your results? At best, you would have to repeat the result completely with fresh buffer to be sure, and at worst, it would mean a complete failure of your experiment.