From: "CHANDRA, Tilak" <tchandra**At_Symbol_Here**FPM.WISC.EDU>
Subject: Re: [DCHAS-L] Conjugated picric acid hazards?
Date: January 27, 2012 3:28:33 PM EST
Reply-To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>
Message-ID: <6F431C2EE2F38D459F5DD28C5B9A10BC0A1776BC**At_Symbol_Here**>

Dear Ralph:

If the picric acid is conjugated with the proteins or lipopolysaccharides,
the nitro groups are stabilized with the hydrophobic groups either from
proteins or sugars and sometime water is also trapped in the matrix of the
conjugates. The ratio of picric acid in those conjugates will be very low,
and if the amount is less than 100 mg. it can be easily stored in a
desiccator. Even there is an explosion that will be very less intense. Use
chemical-resistant polypropylene desiccator where upper section is
shatterproof and transparent. You may also use secondary polypropylene vials
to store that conjugates, if the content is in glass vials. Picric acid must
never be permissible to dry out, particularly on metal or solid surfaces.

Good Luck.


Tilak Chandra, Ph.D.
Chemical Safety Specialist
Environment, Health and Safety
University of Wisconsin-Madison
30 East Campus Mall
Madison, WI 53715
Ph. 608-890-0255
FAX 608-262-6767

-----Original Message-----
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of
Ralph B Stuart
Sent: Friday, January 27, 2012 11:32 AM
Subject: [DCHAS-L] Conjugated picric acid hazards?

Our biosafety officer is reviewing work that includes the use of a couple of
forms of conjugated picric acid (TNP-AECM-FICOLL and TNP-Chicken Gamma
Gobulin). The MSDS's are pretty skimpy, but include the advice to store it in
a dessicated environment. This is counterintuitive to us and the MSDS's are
vague enough about the material's reactivity ("Risk of explosion by
mechanical impact: Not Available") that we'd like confirmation from people
with more experience in the use of this material that picric acid's
explosivity is not a concern in this application.

Does anyone on the list have more information about this concern?

Thanks for any help with this.

- Ralph

Ralph Stuart CIH
Laboratory Ventilation Specialist
Department of Environmental Health and Safety Cornell University


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