Analytical tool:

You have learnt about mass spectrometry which is an analytical tool with wide ranging applications. Within mass spectrometry a molecule in the vapour phase is bombarded with a beam of high energy electrons that knock off an electron from the molecule to give a positively charged molecular ion, M . The energetic molecular ions undergo fragmentation yielding smaller fragments. The molecular ion and the fragments obtained from it are then separated according to their m/ z ratio using magnetic and/or electrostatic fields. The record of m z values of these species against their relative amounts or intensities is known as mass spectrum of the sample. The most intense peak in the spectrum is called the base peak and the peaks at m/z values greater than that of the molecular ion are called isotopic peaks. These arise due to the natural abundance of the isotopes of different elements present in the molecule and are useful in the determination of molecular formula of the compound.