Chapter 10.2, Problem 3P

Interpretation Introduction

Interpretation:

The most likely $m/z$ values for the base peak in the mass spectrum of 3-methylpentane has to be given.

Concept introduction:

Interpreting a mass spectrum:

1. 1. The each m/z values is the m/z value of one the fragments to the nearest whole number.
2. 2. The peak with the highest m/z value in the molecular ions (M⁺), the fragment that results when the molecules lose an electrons as result of being bombarding by the electron beam.
3. 3. The m/z value of the molecular ion gives the molecular mass of the compound.
4. 4. Peaks with smaller m/z values, fragment ion peak represent positively charged fragments of the molecular ion.

Base peak of mass spectrum: The base peak is the one of highest (or) tallest peak, it has great abundance. It has the greatest relative abundance because it is generally the most stable positively charged fragment.

Percentage of base peak: The base peak is assigned a relative abundance (RA) of 100% and the relative abundance of each other peaks is respective mass spectrum percentage of base peak. For example the weak bonds break in preference to strong bonds and bonds that break to form more stable fragments break in performance to those that form less stable fragments.