Question: The mass spectrum of the following compound shows fragments at m/z = 127, 113, and 85. Propose structures for the ions that give rise to these peaks.

The ionization electron is removed from the vaporized organic molecule to produce a molecular ion in mass spectroscopy.

It is a radical cation that fragments into a radical and cation that moves into the spectroscopic instrument's detector.

The cation is detected by the instrument and produces a peak in the mass spectrum. The ion does not have any effect on the detector.

The mass spectrum is a plot of the fragments with their intensity in the y-axis and mass to charge ratio (m/z ratio) in the x-axis.

It is used to analyze the m/z ratio of the fragments to study the molecular structure of the original compound.

The peak with the highest intensity is called the base peak. It gives the most abundant ion, and the peak with the highest m/z value is the molecular ion peak which can be used to find the molecular mass of the original compound.

The given compound is 3-ethyl-3-methylheptane. The m/z value of the molecular ion is 142. The molecular ion is given by:

Molecular ion with m/z=142

This molecular ion fragments into cations and free radicals. The ions with given m/z values that are formed from the given molecular ion are:

Ion with m/z=85

Ion with m/z=113

Ion with m/z=127