Re: Use of fume hood for S35?

[Quang Le <quangle@SLAC.Stanford.EDU>]

Dear Jennifer,
You  would definitely want to use a fume hood for the S-35 compound, P-32
compounds are not very volatile but most S-35s are. At my previous job,
S-35 was readily detectable in our stacks. Of course, we were using a lot
more, from hundreds of millicuries to curies amounts. As to your specific
questions:

1 - What form of S-35 will be airborne from the heating block inside the hood?
Ask your researcher to answer this question s/he should know or should be
able to figure out, hopefully :-)
I am not a chemist so I can't help you much here other than warning you
about Hydrogen Sulfide. HS did give us some headache because it can react
with TLD elements to give false doses. We had some lab personnel working
with both P-32 (thus requiring extremity TLDs) and S-35. After
investigating and being able to convince our regulators, we required that
those personnel not wear extremity TLDs when working with S-35.


2 - Do I need to filter/trap this in some way?
Depending on your license conditions and assuming you are talking about
environmental releases, most likely not. We did not have to, even though we
worked with a lot more than 250 uCi. 

3 - If I need to filter/trap the radioactivity, what do you recommend?
Activated charcoal comes to mind. We used "hockey puck" type charcoal
cartridges to monitor our releases.

Hope this helps. Contact me if you'd like further info.



<<<I am the RSO for a very small radiation program, so radiation is just one
of the safety areas that I cover.  There is currently one isotope lab that
is set up for use with P32, and the researcher would also like to use S35.
I am in need of guidance for S-35 usage as follows:

Compound:  S35-dATP
Source:  Amersham, Pharmacia Biotech
Amount per order:  250 uCi
Form:  Redivue stabilized and colored aqueous solution containing 5 mM
2-mercaptoethanol
Used for DNA sequencing:  Manual double-stranded DNA sequencing (Sanger
ddNTP method) will be performed using the Sequenase 2.0 kit for Amersham
Pharmacia.  Briefly, (1) DNA and primer will be denatured and neutralized,
(2) DNA will be precipitated and resuspended in reaction buffer and
single-stranded binding protein, (3) DTT, dNTPs, S35-dATP, and polymerase
will be added and incubated on a heat block at 37 C for 5 minutes, (4)
termination mix will be added to each tube or well and incubated another 10
minutes at 37 C, (5) stop solution will be added and the reactions will be
loaded and run on polyacrylamide sequencing gels (or stored at -20 C until
needed), (6) gels will be transferred to filter paper, covered with palstic
wrap, and autoradiographed.  The heated incubations will be done in a
chemical fume hood.

My questions are as follows:
1 - What form of S35 will be airborne from the heating block inside the hood?
2 - Do I need to filter/trap this in some way?
3 - If I need to filter/trap the radioactivity, what do you recommend?

Thanks in advance for your consideration!
Jennifer Ehlert
Safety Coordinator, College of Science and Technology
Central Michigan University
236 IET
Mount Pleasant, MI  48859
phone (517)774-4189
fax (517)774-1874
pager (517)612-1255
Jennifer.A.Ehlert@cmich.edu>>>
_____________________________________________________________________ 
Quang Le 
SLAC/OHP 
(650) 926-2610 
<quangle@slac.stanford.edu> 
Note: The above is my own opinion only!  
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