Analytical Techniques Flashcards
What is IR?
Infrared Spectroscopy.
What is the basis of Infrared Spectroscopy?
A covalent bond vibrates more when it absorbs infrared radiation
What does Infrared Spectroscopy allow us to identify?
The energy absorbed by a covalent bond is shown as an absorption peak on an infrared spectrum and allows us to identify particular bond and hence functional groups in a molecule.
What does an absorption peak allow?
It shows characteristics of a particular covalent bond.
What are applications of Infrared Spectroscopy?
-modern breathalysers measure ethanol the breath to provide evidence for law courts
-to monitor the gases causing air pollution
What is the molecular ion M+?
When an organic molecule is ionised and loses an electron to become the molecular ion, M+.
Where is the M+ peak located on the mass spectrum?
Produces a peak furthest to the right.
What is the m/z value?
mass/charge
What is the m/z value equal to?
The Mr of the molecule.
Why is the M+1 peak present?
Due to the presence of the C-13 isotope, which makes up 1.11% of all carbon atoms.
Where is the M+1 peak located?
A very small peak, one unit beyond the M+.
Can the molecular ion split into pieces?
Yes, by fragmentation.
What does fragmentation of the molecular ion always produce?
A +1 positive fragment ion and a neutral species.
What does the fragmentation pattern allow us to know?
The structure (hence the identity) of a molecule to be determined.
What are the applications of mass spectrometry?
-detecting drugs
-analysing molecules in space
