Insect Trail Pheromone Sampling

Discussions about sample preparation: extraction, cleanup, derivatization, etc.

22 posts Page 2 of 2
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
Regards

Ralph
"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
Peter Apps
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
Hey Joe,

What kind of MS system are you using for this analysis?
Rndirk wrote:
Hey Joe,

What kind of MS system are you using for this analysis?


Hi Rndirk,

I am using an Agilent 7890B GC coupled to a 5977A MSD.

All the best,

Joe
Ento_Joe wrote:
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


If I still had the data you would be welcome to it - seeing as it hasn't been published after more than 20 years it would be glad to see the light of day.

Maybe the learned gentlemen of Chromforum should get together and publish a paper on a better word than volatiles for volatiles.

Have a good weekend.

Peter
Peter Apps
Now there's an idea Peter!

You too!

Cheers,

Joe
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