Mass Spectrometry - Analysis of biomolecules

Mass Spectrometry

It uses high energy electrons to break the molecule into fragments or ions either positively or negatively charged or commonly a cation and a radical. Bonds break to give the most stable cation. Stability of the radical is less important. Only cations are detected where as radicals are “invisible” in MS. These charged particles can be manipulated in an electric or magnetic field depending on their mass (m) and the charge (z) of the particle. It operates under high vacuum (keeps ions from bumping into gas molecules).Most cations formed have a charge of +1 so the amount of deflection observed is usually dependent on the mass of the ion. The resulting mass spectrum is a graph of the mass of each cation vs. its relative abundance.

Applications

·        Molecular mass, weights and molecular structure (fragmentation) determinations.

·        Discovery of isotopes and characterization of new elements

·        Qualitative and quantitative analyses

·        Identification of reaction products and industrial products for quality control

·        Identification of trace elements, pollutants in drinking and wastewater and drugs

·        Useful in the identification of a newly synthesized compound. The ion spectrum of unknown compound can be compared withthe absorption spectrum of several known compounds in the MS library and the unknown compound correlates or matches with the known compound then further confirmation of the compound cab be done by use of FTIR and NMR spectroscopy. The matching of the spectra with the standards of known compound in the MS library is called as spectral fingerprinting.