formalin

Many years ago, in another century, I used to use Formalin (you could still buy it then) for preserving minnows and Sprats in glass jars as baits for Fishing.
I remember I used to use a 10% solution but this only stopped them deteriorating for a few months as they were a bit 'high' when I opened them a year or so later.
John

I think 37% is how it's sold (it's quite volatile at high percentages, I think) have you tried goggling it?
John

Have you considered Alcohol, I have a friend who is an entomologist and he uses it for all his specimens. I think you can get that from the Chemist's?
John

platty252 wrote:

JohnH wrote:

I think 37% is how it's sold (it's quite volatile at high percentages, I think) have you tried goggling it?
John

The formalin i got came from a lab. for fish.

Sorry to 'keep on', but I think you use 10% solution (with remainder water) of the 37% solution you have been provided...does this make sense?
John

That's my interpretation, but I've emailed my entomologist friend in Scotland and am awaiting his response.
John

A couple of replies:

a] from my Entomologist friend:

"Yes it should be 9 parts water to 1 part of the formalin (37%)"



b] from Ian Millichip:

"Hi John,

Time is against me to give a full reply unfortunately,

but if Formalin is used then there are quite a few precautions that need to be followed:

-the Formalin has to be buffered (possibly slightly on the acidic side, and may depend upon tissue);
-unbuffered formalin is converted to formic acid and that may decalcify specimens (you'll get a mush)
-Formalin is not safe and workers need to consider the irritant effect
-Care needs to be taken with the storage jars....glass with polypropylene lids (and ideally polyethylene lining). Certain other materials will react with the formalin.
- the specimen to perservative ratio is important and the ideal varies from specimen size to specimen size and type.

The specimen would need to be 'fixed' and 'preserved'.

Now, alcohol (95%) is a good preservative but maybe not a great fixative.
Many people use, and it may even be the recommended method for holding specimens during a field trip.
The Herpetological Society of Ireland recommends to people to preserve their animals in alcohol if they are sending them for analysis, dissection or future preservation treatment.
There is little need to buffer the alcohol (so maybe more convenient to use)

Now, most of the notions of preservation to perfection are driven by the needs of museums.....but I would be sure that for 'single person' usage the alcohol preservation may do.

As I have to dash, then here is a link www.adfg.state.ak.us/pubs/afrb/vol3_n2/shiev3n2.pdf

ian"