GOM wrote:Hi Joe
Reading the thread with interest - love it
Volatile/non volatile definition
For an insect a "non volatile"
at room temperature must surely be only sensed by direct touch taste
For an insect a "volatile" may be sensed by direct touch taste or an antenna
In terms of GC analysis the "non-volatile" at room temp may be actually "reasonably volatile" and may be detected if it falls in the usual < 800 MW range.
Anything above that would really require a different technique.
My instinct would be to follow your nose - or that of the insect
I won't make any further comment because I am now out completely out of my depth
Regards
Ralph
Hi Ralph,
I'm glad you're finding the thread interesting, I was concerned that people would think I am wasting their time with my queries as they're quite basic compared to some of the discussions I read on here!
For me, I refer to chemicals being volatile or non-volatile depending how they behave at room temperature. The beauty of chemicals that are volatile at temperatures of 300 C and less is that we can analyse the electrophysiological response of the insects to the them whilst also undertaking GC-FID analysis by using GC-EAG (electroantennography):
https://srs.fs.usda.gov/idip/spb_ii/gcead_what.html. The only problem I have is that I don't have a GC-FID that I can use, although I am begging Prof. John Pickett from Rothamsted to let me have a crack at his!
You are correct in that volatile chemicals are typically detected by the multi-porous sensilla on antennae of the insects and that the non-volatile chemicals are detected by sensilla on the mouth parts, which contain a single pore on their tips.
I suspect that the chemical I am looking for can be analysed by GC-MS. I left 10 weevils crawling around on some filter paper and some aluminium foil last night before solvent extracting today. Some observations:
1. Far more compounds found in the filter paper sample
2. I needed to leave the collecting material to soak for quite a while
3. Found lots of "cyclo" compounds e.g. methylcyclohexane
4. Also found: adipic acid, phytan, 1-decanamine, mesitylene. I need to ID some of the others, these were just some of the largest peaks
5. Both samples contain 250 + compounds
Cheers,
Joe
Peter Apps wrote:
"Volatile" and its shortcomings was actually the subject of a thread which got several forum members in touch with their inner Renaissance man; viewtopic.php?f=6&t=15700&hilit=volant
I did try it in a paper - the referees were obviously lacking in a classical education and told me to change it volatile. Which I did.
Peter
Hi Peter,
Thanks for your replies. I wouldn't ask for unpublished data, so no problem there. I Google Scholar-ed your name trying to find the paper and I have to say that you have come up with some nifty modifications to your systems over the years!
I agree that there also needs to be a better word than volatile!
Cheers,
Joe