Since insect pheromones exhibit highly variable forms, as well as compositions, and can change based on various conditions, especially releaser pheromones, which are usually highly volatile, could someone provide information on how to prepare alive or preserved insect samples for specific pheromone analyses using mass spectrophotometry and chromatographic methods? Is there anyone who can offer insights on this topic?
Because of the volatility of these compounds, you could consider using a headspace sampling and concentration method such as SPME before GCMS measurement. I'm sure if you do an internet search you will find publications on this topic.
I used liquid nitrogen to contain the volatile alarm chemicals from ants. A single frozen head then released these on heating at the top of the gas-liquid chromatography column linked to a mass spectrometer. BTW the mass spec produced squiggles on light sensitive paper in those pre-pc days -what joy to interpret these in the semi-dark!
Ya, insect pheromones are very complex, and understanding difficult why because the pheromone is present in glands as acid form, and once released outside, it will convert into alcohol and aldehydes as gaseous form and reach their partner or offsprings for communication of sexual attraction and developmental aspects. Releaser pheromones are present in social insects like honeybees. We aim to catch the chemical composition between the releaser and the receiver. GCMS/MS or GC-FID with Electro antennogram (EAD) are suitable for finding the chemical composition in chromatography. Gland extraction with hexane is one option; here, we target exactly where pheromone attaches to hairs after immediate release. Sometimes tricky, very fast needed in gland extraction. In the case of GCMS/MS scan mode, it helps you find the peaks.
Modern Gas-liquid Chromatography with electronic processing is so wonderful, compared to what we did having to build these machines ourselves 60 years ago. GC "Standards" were essential at the beginning, so you could figure out what those thousands of "peaks" were, and thus begin to understand the incredible mixture or compounds in your beeswax! I remember well seeing my first Mass Spectrometer attached to a GC at U. California- Berkeley, California in a chem lab.
Yes David - I remember the glassblowing tutorials and questions over whar to fill your GC column with. Setting up an electroantennogram sounds simple - make your own sensors to fit the antenna, add a powerful amplifier for the signals.... then "they" move your lab and you realise you are now monitoring an electronically noisy fridge next door, not the ant antenna... I'm sure basic research is still just as exciting.
There is a huge amount of literature on insect pheromones and their analysis. You need to do a proper literature search with a focus on the classes of compounds and the taxa of insects that you are interested in.
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