What is a fragmentation pattern?
In mass spectrometry, fragmentation is the dissociation of energetically unstable molecular ions formed from passing the molecules in the ionization chamber of a mass spectrometer. The fragments of a molecule cause a unique pattern in the mass spectrum.
Why is the fragmentation pattern considered a fingerprint?
The energy added to the molecule can be controlled by the ionization energy setting, though in many instruments this is fixed at 70 eV. The fragmentation pattern which results is reproducible, allowing these patterns to be used as an identifying ‘fingerprint’.
What is the M+ peak?
The M+ peak is usually the highest intensity peak in the cluster of peaks at highest m/z.
Why is a vacuum used in mass spectrometry?
All mass spectrometers operate at very low pressure (high vacuum). This reduces the chance of ions colliding with other molecules in the mass analyzer. Any collision can cause the ions to react, neutralize, scatter, or fragment. All these processes will interfere with the mass spectrum.
What are fragment ions?
Fragment ions are produced by decomposition of a molecular ion (fragmentation) in the ion source. There exist many kinds of fragment ions, whose distribution reflects the chemical structure of a compound, according to various ways of fragmentation. The fragment ions have smaller masses than the molecular ion.
What is MZ in mass spectrometry?
m/z represents mass divided by charge number and the horizontal axis in a mass spectrum is expressed in units of m/z. Since z is almost always 1 with GCMS, the m/z value is often considered to be the mass.
What are the causes of Ridge destruction?
Ridge Destruction – destruction of the friction skin can either be temporary or permanent. Generally temporary destruction occurs when only the epidermis layer of the friction skin has been damage, while permanent damage can be injected to the friction skin due to damage to the dermis layer.
What factors affect fragmentation?
a) Energy of the molecular ion and the fragments formed from it.