Identification of the Analyte, Single or in a Mixture:

Structure determination of an analyte from the mass spectrum is an elaborate job. As you have learnt above that it involves the identification of the molecular ion peak to determine the molar mass followed by determination of the molecular formula and thereafter interpretation of the characteristic fragments. After all these efforts an experienced mass spectrometrist can come close to a number of probable structures. The exact identification is then achieved by comparing the observed mass spectrum with the authentic spectra of the likely compounds. Many a times the analytical chemist is aware of the likelihood of the analyte; in such cases the identification is obtained simply by comparison spectra. This might sound quite simple therefore; it might not be so straight forward since the nature of spectrum depends a great deal on the instrumental parameters such as, ionisation method, pressure, temperature, etc. It may not always be possible to have reference spectra under the conditions of the sample being analysed.