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Mass Spectrometry Unit

Mass Spectrometry Laboratory

Mass Spectrometry Laboratory Mass Spectrometry Laboratory

The possibilities of this technique embrace nearly all fields of chemistry, biology, biochemistry, medicine, etc… Mass Spectrometry is in many cases the most sensitive molecular analysis technique and provides information on the molecular mass and structure of the studied molecule and allows not only qualitative but quantitative studies as well

Basics of the technique

The technique is based upon the ionization of sample components; this process takes place in the ionization chamber. There are several techniques to produce ions from molecules and its suitability depends on the chemical nature of the compound; some of the commonest ones are Electronic Ionization (EI), Fast Atom Bombardment (FAB), Atmospheric Pressure Chemical Ionization (APcI), Matrix Assisted Laser Desorption/Ionization (MALDI) and Electrospray Ionization (ESI).
The gas phase ions produced in the ionization chamber, are accelerated towards the mass analyzer and separated according to their mass/charge ratio. This separation is achieved by means the application of complex electric, magnetic fields or recording the different times of flight of the ions. Finally the ions stoke the detector and these signals are amplified and converted into a mass spectrum which represents the ion intensities versus its mass/charge ratio.

Applications

• Structural characterization of organic compounds, organometallic and metabolites
• Analysis of polymers and dendrimers
• Determination of impurities and organic pollutants
• Analysis of mixtures of different origin (natural extracts, environmental, Characterization of products of synthesis, etc.)

Operation of the laboratory

 Available analysis:
• mass spectra over a standard limited mass range, applying Electronic Ionization (EI), Fast Atom Bombardment (FAB), Matrix Assisted Laser Desorption/Ionization (MALDI) or Electrospray Ionization (ESI)
• Exact mass measurements limited to a specific ion (FAB and MALDI) or over the full mass range (EI and Electrospray).
• Fragmentation studies (MS/MS) by selecting a precursor ion (MALDI and Electrospray).

General and specific sample requirements:
• The sample vial must be clearly and indelibly identified by a reference or code that would be the same as the one that appears in the application form.
• The sample should be submitted preferably in solid state (better than in solution).
• As the concentration is critical in some analysis, it’s advisable to weigh the sample and indicate the amount in the application form (1 mg is generally enough).
• To avoid interferences, the sample purity is a matter of concern especially in mass exact measurements.
• Generally, for sample preparation in Mass Spectrometry analysis is convenient to use volatile solvents, so it is recommended to choose the solvents taking in account this criterion.
• For insoluble samples only FAB and MALDI techniques can be applied as ionization methods.
• In cases of highly unstable samples it would be advisable to previously contact the laboratory to establish the better conditions for the analysis.

How to request an analysis:
• An application form should be fulfilled trough the @LIMS interface.
• In this application form it is possible to request analysis for more than one sample; nevertheless, it is advisable to fulfill one form for all the samples that require the same ionization technique.
• It is highly recommended to provide the maximum sample information, fulfilling all the fields in the form and using the additional space for comments if necessary.