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The Society for the study of flies (Diptera)

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#1 2017-11-07 15:09:30

Chrisbentley
DF Members
Name: Chris Bentley
From: Rye Harbour, East Sussex
Registered: 2008-03-11
Posts: 118
Website

Dehydration for slide mounting

I am hoping to have a go at mounting diptera specimens on slides (using euparal). The specimens are stored in 70% propanol so would it be sufficient to dehydrate in 99.9% propanol and then mount? And is 99.9% what is effectively meant by 'absolute'?

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#2 2017-11-07 16:51:54

brianh
DF Members
Name: Brian Harding
From: Kidlington, Oxfordshire
Registered: 2008-10-27
Posts: 323

Re: Dehydration for slide mounting

I checked with this link ( http://www.microbehunter.com/euparal-mounting-medium/ ).
It appears that you may be able to mount directly from 70% alcohol, but you may want to replace the original 70% alcohol or take it up to your 99.9% alcohol.
Best of luck in you trials.

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#3 2017-11-07 18:19:58

conopid
DF Members
Name: Nigel Jones
From: Shrewsbury
Registered: 2008-02-27
Posts: 630
Website

Re: Dehydration for slide mounting

I use euparal. I understand that it dissolves in alcohol, or was it water? (good), but I have not seen this written anywhere. Is either true?
Addendum:
I searched Google and found this which confirms that euparal can be dissolved in alcohol. Euparal seems to be the medium of choice too.
http://www.nhm.ac.uk/hosted-sites/acaro … mmary.html

Last edited by conopid (2017-11-07 18:30:54)


Nigel Jones
Shropshire

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#4 2017-11-07 18:51:57

Chrisbentley
DF Members
Name: Chris Bentley
From: Rye Harbour, East Sussex
Registered: 2008-03-11
Posts: 118
Website

Re: Dehydration for slide mounting

Thanks, a couple of useful links there. I've no doubt you will be seeing some of my half-a***d attempts in the future!

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#5 2017-11-07 19:16:30

Tony Irwin
DF Members
Name: Tony Irwin
From: Norwich
Registered: 2008-03-01
Posts: 643

Re: Dehydration for slide mounting

Suppliers of Euparal will also supply "Euparal Essence" with which stiff Euparal can be diluted. I don't know whether you can mount straight from iso-propanol straight into Euparal. Best thing is to try and see what happens. I would advise some dehydrating by soaking in 95% before transferring to Euparal. If there are problems, then transfer from iso-propanol to ethanol (70% DNA or IMS will do), then into 95% and then into Euparal. There's no need for complete dehydration, such as is required for Canada balsam.
For temporary mounts, Berlese Medium is easy and produces good material. The problem is the slides will deteriorate after a while, so if you have mounted something exciting, it's advised to remount using something like Euparal - a rather tricky business.

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#6 2017-11-07 23:37:28

Chrisbentley
DF Members
Name: Chris Bentley
From: Rye Harbour, East Sussex
Registered: 2008-03-11
Posts: 118
Website

Re: Dehydration for slide mounting

Thanks Tony, that's food for thought. I do have some Berlese mountant (I am primarily interested in slide mounting as a way to deal with the many phorids I get in pitfalls and the RES key suggests using Berlese) but then I did find reference to its impermanence and so got some euparal. The propanol/ethanol thing is a faff I hope I don't have to deal with. I take it DNA and IMS refer to denatured and methylated spirits?

Last edited by Chrisbentley (2017-11-07 23:40:27)

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#7 2017-11-08 01:47:24

Tony Irwin
DF Members
Name: Tony Irwin
From: Norwich
Registered: 2008-03-01
Posts: 643

Re: Dehydration for slide mounting

Sorry - yes, DNA is "denatured alcohol" and IMS is "Industrial methylated spirits". They are more or less the same thing - 95% ethyl alcohol topped up with a 5% methyl alcohol and stuff to make you sick if you drink it. NOT the same as the purple stuff for lighting primus stoves and Tilley lamps (or rubbing on soft feet) - that's methyl alcohol, and not good for preservation.
One of the other advantages of Berlese mountant is that it clears specimens as it sets, so no need for maceration in KOH or lactic acid beforehand. You will find that the darker phorids will need clearing in some way, otherwise the cuticle will be too thick for transmitted light, and the detail will not be visible.
It's possibly becoming obvious why syrphids and trypetids are more popular than phorids! wink

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#8 2017-11-08 10:59:09

Rainieria
Committee
Name: Darwyn Sumner
Registered: 2008-02-20
Posts: 307

Re: Dehydration for slide mounting

Can I add the obvious of good ventilation/safe storage and no naked flames/sparks please?
I worked in an histology laboratory before H&S was invented; open large Coplin jars of solvents such as Xylene and Toluene. Best to assume that many solvents are carcinogens and highly flammable.


Darwyn Sumner
DF Bulletin Editor, Scheme Organiser: Stilt & Stalk Flies

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#9 2017-11-09 12:45:08

Chrisbentley
DF Members
Name: Chris Bentley
From: Rye Harbour, East Sussex
Registered: 2008-03-11
Posts: 118
Website

Re: Dehydration for slide mounting

Thanks everyone for the helpful advice. I've sent off my form for the use of IMS just in case.

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#10 2017-11-13 15:17:17

Andy chick
DF Members
Name: Andy Chick
From: Nottingham
Registered: 2008-02-26
Posts: 96
Website

Re: Dehydration for slide mounting

if memory serves euparal essence is basically euparal with out the resin (Gum Sandarac) so a mix of Eucalyptus, parahyde and camsal. Eucalyptus oil is pretty unforgiving of imperfect dehydration (unlike clove oil) I would recommend a clearing step in euparal essence on a black tile, if the solution clouds there is water still in the specimen.

hope this helps

Andy

Edit: I have double checked my notes, my method is 10mins at 70% alcohol, 10mins at 100% alcohol, 10mins in a fresh change of 100% alcohol and finally mount in euparal. it is worth noting that "100% Alcohol" is very rarely "100%" as it rapidly absorbs water from the air.

Last edited by Andy chick (2017-11-13 15:32:22)

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#11 Today 14:58:19

Chrisbentley
DF Members
Name: Chris Bentley
From: Rye Harbour, East Sussex
Registered: 2008-03-11
Posts: 118
Website

Re: Dehydration for slide mounting

Sorry Andy, missed this one. Thanks for the info. Do you happen to know whether propyl alcohol is ok to use as to dehydrate?

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#12 Today 21:27:01

Andy chick
DF Members
Name: Andy Chick
From: Nottingham
Registered: 2008-02-26
Posts: 96
Website

Re: Dehydration for slide mounting

Chrisbentley wrote:

Sorry Andy, missed this one. Thanks for the info. Do you happen to know whether propyl alcohol is ok to use as to dehydrate?

IPA (Isopropanol) is fine for dehydration, it's only when we get to molecular work that EtOH (ethanol) is needed

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