Mass Spectrometry: Principles, Applications in Forensic Science

This report provides an overview of mass spectrometry and its applications in forensic science. Mass spectrometry is a scientific method used to analyze a sample of material to determine its molecular makeup in terms of content and chemical properties. The process involves bombarding organic molecules with energetic electrons, breaking them into cations and fragments, which are then accelerated through an electric field and sorted by their mass-to-charge ratio. The resulting mass spectrum identifies the presence of specific atoms or molecules. Applications include toxicological analysis, trace evidence investigation, arson analysis, and explosives residue analysis, as demonstrated in the 2004 Cameron Todd Willingham arson case. The report also details how to interpret a mass spectrum, including the identification of the base peak and molecular ions. Desklib offers a platform for students to access similar solved assignments and study resources.

Mass Spectroscopy
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-These cations molecular or parent ion) are formed due to loss of an electron
usually from n or π orbital from a molecule, which can further break up into
smaller ions
-All these ions are accelerated by an electric field, sorted out according to their
mass to charge ratio by deflection in variable magnetic field and recorded. The
output is known as mass spectrum.
-Each line upon the mass spectrum indicates the presence of atoms or molecules
of a particular mass.
-The most intense peak in the spectrum is taken as the base peak. Its intensity is
taken as 100 and other peaks are compared with it.
Mass spectrum is used in two general ways:
-To prove the identity of two compounds.
-To establish the structure of a new a compound
Introduction
-Scientific method that analyzes a sample of
material to determine its molecular makeup in
terms of content and chemical properties
Principle
-Organic molecules
are bombarded
with a beam of
energetic electrons
(70 eV) in
gaseousstate under
pressure between
10-7 to 10-5 mm of
Hg,using tungsten
or rhenium
filament. Molecules
are broken up into
cations and many
other fragments
Application
-Use in forensic science to carry out toxicological
analysis, trace evidence, investigate arson, analysis of
explosives residue
-For example, Mass spectroscopy was applied in the 2004
Cameron Todd Willingham arson case in Texas US.

References
Sturler, A. d. (2015, March 28). Case of the Month: Forensic arson detection.
Retrieved from Defrosting Cold Cases: https://defrostingcoldcases.com/case-of-the-
month-forensic-arson-detection/
What Is Mass Spectroscopy Used for in Forensic Science? (2018). Retrieved from
Seattle: https://education.seattlepi.com/mass-spectroscopy-used-forensic-science-
6611.html