Expiration of Standards & absorbtion of oil

[JHageman@swri.edu]

I have two questions, one from a coworker here at Sw Research Institute.

QUESTION 1:
	We are updating our SOP concerning how we assign expiration dates to 
chemicals and standards, but we're having trouble when it comes to 
radioactive materials and standards.  Do you know of any general guidelines 
for how long radioisotopes should be kept before they are no longer useful as 
standards, especially those with intermediate length half-lives (1 - 10 
years).  Would it make any difference if it is a sealed source?  What about 
dilutions from stock standards?  Any help would be appreciated.  

Thanks, Joe Patterson, Research Scientist, Chemical Analysis

QUESTION 2:

What is a recommended adsorbent for oil, one that will not let the oil 
squeeze out under pressure, as in a super-compactor? I tried a commercially 
available cellulose-adsorbent and it released the oil at a few PSI. 

Also, does anyone know the PSI of the super-compactor at Oak Ridge?

Thanks, John P. Hageman, RSO, SwRI. 
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