Derivatisation Flashcards
Define Derivatisation
Technique used to transfer a compound into another with similar structure
Formula of Derivative
Compound + Derivasation Reagent -> Derivative
How derivatisation reaction are special compared to other chemical reaction?
Maintains the original compound structure
How can we change the functionality of the molecule without rearrangement?
another molecule is attached to a reactive functional group during derivatisation
Properties of Derivatisation
- Not volatile enough
- Heat sensitive
- Naturally unstable
- Show a very short lifetime
How to change the volatility of compounds?
Increase it by reducing adsorption in the system + analyse relatively non volatile compound
Mass Spectrometry applications: Improve analytical efficiency
- Full mass spectrum
- Abundance of small ions
- ^ the molecular weight of the target analyte by derivation -> bigger specific fragments
Mass Spectrometry:
(2) Increase detectability of very simple molecules
^ Mr, of very volatile compounds
- more complex mass spectrum
- ^s confidence for drug identification
List three other applications
- Liquid chromatography
- Markers
- Electron Capture Detector
Characteristic of a good derivatisation reagent
- Produces a reaction that is 95+% complete
- Does not induce rearrangement/internal structural alterations
- Produces a stable derivative (shelf life)
Example of Derivatisation Reagent
- Marijuana
- LSD
- Amphetamines
How to check if the reaction is complete?
- Inject aliquots of the mixture into the GC every x minutes
- Monitor the disappearance of the reagent peak and the increase of the derivative peak
Define Alkylation
The transfer of an alkyl group from one molecule to another
Properties of Alkylation
- To derivatise molecules presenting acidic hydrogen
- Can be used alone/couples with other types of derivatisation reagent
What is the process of Acylation?
Adding an acyl group to a compound
Highly polar molecules
