Making solutions for RNA work - (Oct/09/2010 )

Hello, I am about to do a Northern blot but I am still hesitated to use the ph meter for making solutions since it is a shared equipment, it may have some RNase on it. I cannot simply add DEPC to the solution and autoclave because it contains Tris. Anyone has worked with RNA and made&pH solutions successfully? Thanks in advance for any suggestions!

Ideally what you would do is take a small volume out and pH it, after each addition of acid. The other option for pHing tris solutions is to make them up with tris base and tris HCl crystals in the required ratio to give a the final pH wanted.