35S in PCR machines..

[Parke K. Flick]

MJ Research (a manufacturer of thermal cyclers) just issued a safety 
warning regarding the use of 35S in cyclers.  The problem is that,
during cycling, radioactive H2S is probably formed.  It works its way
through the walls of tubes, leading to contamination of the sample
block of the cycler and the laboratory air.  MJ recommends avoiding
35S altogether and substituting 33P.  If 35S must be used they suggest
putting a little mineral oil in the wells outside the tubes and using
only thick-walled 0.5ml tubes.  Perhaps the addition of a weak 
oxidizer, such as oxidized cysteine, to the reaction mixture may 
help.  
		
						P. Flick
-- 
Parke Flick, Ph.D.
U.S. Biochemical Corp.
Cleveland, OH  44128