[NHCOLL-L:4060] RE: use of picric acid

Fri Oct 31 05:34:38 EDT 2008

Bear in mind that Picric acid is a primary fixative but was considered
too dangerous to use on its own (due to the possibility of drying out
&c!) otherwise people tended to use it as a storage medium
(preservative) instead of alcohol, like your helminth collection.  It
also meant that much safety equipment and care had to be used in case of
splashes leading to (almost) permanent yellow staining.  I have had my
share of Maxwell House coffee jars and other (very) temporary containers
from the 60s being used as permanent.

Nowadays fixing agents tend to be the less hazardous ones - a retrograde
step in my view as nothing else as good has been discovered and
providing they were used by responsible adults (who understood the
possible hazards in their use) then there was no problem.  The
safety-conscious tendency to banish formalin as a fixative would be
disastrous!!  However, I musn't get on my soap box about this issue but
I would be interested in hearing the views of others!

With all good wishes, 
Simon Moore, MIScT, FLS, ACR, 
Senior Conservator of Natural Sciences. 
Hampshire County Council 
Recreation & Heritage Department, 
Museums & Archives Service, 
Chilcomb House, Chilcomb Lane, 
Winchester SO23 8RD. UK. 
Internal  8 327 6737 
01962 826737 
http://www.hants.gov.uk/museum/biology 

________________________________

From: owner-nhcoll-l at lists.yale.edu
[mailto:owner-nhcoll-l at lists.yale.edu] On Behalf Of Bryant, James
Sent: 30 October 2008 16:45
To: NHCOLL-L at lists.yale.edu
Subject: [NHCOLL-L:4053] RE: Fwd: [H&S] Fwd: Safe disposal of picric
acid

This prompted me to pull out an old slide-rule style chart from Turtox
on fixatives and preservatives. Sure enough, picric acid and Bouin's are
there (I'd heard of Bouin's before), and it suggests the formulation for
Bouin's, when used in fixing worms, was usually formalin, acetic acid
plus a saturate aqueous solution of picric. This Turtox chart also
suggests picric was popular in fixing protozoans, and it appears to
recommend alcohol as the preservative.

James M. Bryant

Curator of Natural History

Museum Department, City of Riverside

3580 Mission Inn Avenue

Riverside, CA 92501

(951) 826-5273

(951) 369-4970 FAX

jbryant at riversideca.gov

________________________________

From: Judith Price [mailto:JPRICE at mus-nature.ca] 
Sent: Thursday, October 30, 2008 9:00 AM
To: Bryant, James
Subject: RE: [NHCOLL-L:4050] RE: Fwd: [H&S] Fwd: Safe disposal of picric
acid

Picric acid is part of a fixative named Bouin's Fluid (Picric acid +
formalin + glacial acetic acid).  It works fine as a fixative, but lousy
as a preservative.  Too often preservative = fixative + neglect.  I was
told that specimens were often fixed in this prior to histological
sectioning, but that if left too long in the Bouin's became practically
useless, as well as dangerous.

Judith

-----Original Message-----
From: owner-nhcoll-l at lists.yale.edu
[mailto:owner-nhcoll-l at lists.yale.edu] On Behalf Of Bryant, James
Sent: October 30, 2008 11:36 AM
To: CAHawks at aol.com; NHCOLL-L at lists.yale.edu
Subject: [NHCOLL-L:4050] RE: Fwd: [H&S] Fwd: Safe disposal of picric
acid

Thank you all for the background on this preservative. I'm curious as to
why picric acid was ever used? It's new to me.

James M. Bryant

Curator of Natural History

Museum Department, City of Riverside

3580 Mission Inn Avenue

Riverside, CA 92501

(951) 826-5273

(951) 369-4970 FAX

jbryant at riversideca.gov

________________________________

From: owner-nhcoll-l at lists.yale.edu
[mailto:owner-nhcoll-l at lists.yale.edu] On Behalf Of CAHawks at aol.com
Sent: Wednesday, October 29, 2008 5:33 PM
To: NHCOLL-L at lists.yale.edu
Subject: [NHCOLL-L:4048] Fwd: [H&S] Fwd: Safe disposal of picric acid

Catharine Hawks
Conservator
2419 Barbour Road
Falls Church VA 22043-3026 USA
t/f 703.876.9272 

________________________________

	From: BallardM at si.edu
	Reply-to: aic-health at lists.stanford.edu
	To: aic-health at lists.stanford.edu
	Sent: 10/29/2008 9:58:15 A.M. Eastern Daylight Time
	Subj: Re: [H&S] Fwd: [NHCOLL-L:4037] Safe disposal of picric
acid

	Common name: Picric Acid

	Color Index Name Acid Yellow (no number)

	C.I. Constitution Number: 10305 

	Discovered by Woulfe, 1771.

	Solubility: sparingly soluble in water (yellow); readily soluble
in ethanol. 

	Toxicity information From NISax et al. Dangerous Properties of
Industrial Materials 6th ed. 1984 

	Can cause allergic irritation as well as dermatitis. Sympoms of
systematic poisoning are nausea, vomiting, diarrhea, yellow
discoloration of skin & convulsions, as well as stupor, skin eruptions,
anemia, abdominal pain and oligeria

	Explosion hazard: dangerous when shocked or exposed to heat.
Keep out of contact with metals. Forms unstable salts with concrete,
ammonia and bases. Picric acid is a more powerful explosive than TNT.

	Disaster hazard: highly dangerous, shock will explode it on
decomposition it emits highly toxic fumes and explodes. Can react
vigorously with reducing materials. 

	If you want to know what it looks like it's 2,4,6
trinitrophenol.

	Mary W. Ballard

	Senior Textiles Conservator,

	Museum Conservation Institute, Smithsonian Institution

	4210 Silver Hill Road, Suitland MD 20746 U.S.A.

	tel: 301-238-1210 fax: 301-238-3709 

	email ballardm at si.edu

________________________________

	From: aic-health-bounces at lists.stanford.edu
[mailto:aic-health-bounces at lists.stanford.edu] On Behalf Of
CAHawks at aol.com
	Sent: Tuesday, October 28, 2008 9:22 PM
	To: aic-health at lists.Stanford.edu
	Subject: [H&S] Fwd: [NHCOLL-L:4037] Safe disposal of picric acid

	Catharine Hawks
	Conservator
	2419 Barbour Road
	Falls Church VA 22043-3026 USA
	t/f 703.876.9272 

________________________________

		From: Morris.Robert at saugov.sa.gov.au
		To: NHCOLL-L at lists.yale.edu
		Sent: 10/28/2008 3:52:59 A.M. Eastern Daylight Time
		Subj: [NHCOLL-L:4037] Safe disposal of picric acid

		Dear All,

		We have a number of Helminth specimens housed in picric
acid solution that we would like to rebottle and store in a less
volatile medium. The specimens remain in solution but are housed in old
food jars with metal lids. This really is an OHS no no and one we need
to address before the safety auditors land on our doorsteps.  Although
reasonably stable if left alone, our fear is that by trying to unscrew
the metal lids we may ignite the crystalline form that may have formed
on the underside of the lids. 

		One thought would be to immerse the jars in a water tank
and allow them to slowly fill with water before attempting to unscrew
the lids. Has anyone encountered this problem and if so what methods did
you adopt to safely extract specimens from picric acid solution?

		Any advice would be appreciated

<file:///D:\My%20Documents\My%20Pictures\Email%20Logo.jpg> Robert Morris

		Head of Collections

		South Australian Museum

		North Terrace, Adelaide SA 5000

		Tel. +61 (0)8 82077455, Fax. +61 (0)8 82077222

		www.samuseum.sa.gov.au <http://www.samuseum.sa.gov.au/> 

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