Chapter 14, Problem 78CP

(a)

Interpretation Introduction

Interpretation:

The structure of Pinolenic acid as well as the ionic structures consistent with the peaks listed has to be drawn.

Concept introduction:

Mass spectrometry:

• It is a technique used to find out the molecular weight of the compounds and thus providing the structure and chemical properties of different molecules.
• The sample ion is converted into gaseous ions with or without fragmentation and are characterized by their charge to mass ratios and relative abundances.
• Mass spectrum is a a plot of the relative abundance of the generated ions as a function of the charge to mass ratio.

  Molecular ion peak${\text{(M)}}^{\text{+}•}$: It is defined as the heaviest peak in the mass spectrum of the molecule which represents the largest molecular ion in the given molecule with greater m/z value.

  Base peak: It is the tallest peak in the spectrum.

  The ${\text{(M+1)}}^{\text{+}•}$ peak: It denotes the peak that arises next to molecular ion peak in the mass spectrum. The peak arises due to the presence of the isotope of carbon $\left({}^{\text{13}}\text{C}\right).$

(b)

Interpretation Introduction

Interpretation:

The $\text{m/z}$ values for four significant peaks in negative ion mode have to be predicted.

Concept introduction:

Mass spectrometry:

• It is a technique used to find out the molecular weight of the compounds and thus providing the structure and chemical properties of different molecules.
• The sample ion is converted into gaseous ions with or without fragmentation and are characterized by their charge to mass ratios and relative abundances.
• Mass spectrum is a a plot of the relative abundance of the generated ions as a function of the charge to mass ratio

  Molecular ion peak${\text{(M)}}^{\text{+}•}$: It is defined as the heaviest peak in the mass spectrum of the molecule which represents the largest molecular ion in the given molecule with greater m/z value.

  Base peak: It is the tallest peak in the spectrum.

  The ${\text{(M+1)}}^{\text{+}•}$ peak: It denotes the peak that arises next to molecular ion peak in the mass spectrum. The peak arises due to the presence of the isotope of carbon $\left({}^{\text{13}}\text{C}\right).$