Chapter 6
Inorganic analysis
Objective: You will be able to discuss the
importance of inorganic analysis in forensics.
Do Now:
 Read “What killed Napoleon” at the
beginning of chapter 6
Inorganics

Do not contain Carbon and Hydrogen

Includes metallic materials such as:


Can find inorganics in:


Iron, steel, copper, aluminum
Tools, coins, weapons, metal scrapings at a CS
Other possible Inorganics to look for:

Paints and dyes, explosives, and poisons like:

Mercury, lead, arsenic
Inorganic Analysis

Typical requests of an unknown powder?

Explosive?



(look for base of Potassium chlorate KClO3 or Nitrogen bases )
Poison? Arsenic
Each analysis would need to be compared to a known
standard. One that has already been run.
Inorganic Analysis

Comparison of 2 or more objects

Brass pipe?
No edges for comparison
 No fittings align





Must compare through chemical analysis.
Both pipes will be alike: ie. Copper and zinc
Comparison of trace elements
Differences in earths crusts/impurities, <1%
differ

We are looking for “Invisible markers”
Elemental Analysis of Brass pipes
High-Tensile Brass
Copper 57%
Aluminum 2.8%
Zinc 35%
Manganese 2.13%
Iron 1.32%
Nickel 0.48%
Tin 0.64%
Lead 0.17%
Silicon 0.08%

Manganese Brass
Copper 58.6%
Aluminum 1.7%
Zinc 33.8%
Manganese 1.06%
Iron 0.90%
Nickel 1.02%
Tin 1.70%
Lead 0.72%
Silicon trace%

Objective: You will be able to compare and
contrast emission and absorption spectra.
Do Now:
 Begin reading “The Emission Spectrum of
Elements” on p. 164-167
 Define:



Emission spectrum
Continuous spectrum
Line spectrum
II. The Emission Spectrum of
Elements


Organic molecules can readily be characterized by
their selective absorption of UV, Visible or IR
Inorganic Molecules (Elements) will also selectively
absorb or emit light


Absorption spectrophotometry
Emission spectrophotometry
II. The Emission Spectrum of
Elements
Figure 6–2 Parts of a simple emission spectrograph.
II. The Emission Spectrum of Elements

Elements emit light



Ex. Typical tungsten light bulb
Ex. Neon light
The light given off by these elements can be
passed through a prism


This allows each wavelength of light to be
separated
This display is called an emission spectrum
OR
Types of spectrums

Sunlight and typical light bulbs emit the
entire range of colors

This is called a continuous spectrum
Types of spectrums cont…

Most types of elements produce several
individual color lines


This is called a line spectrum
Each line represents a specific wavelength
II. The Emission Spectrum of
Elements: Flame Test
Elements
can absorb and emit
wavelengths of light
Tungsten=warm
Neon=
white light
glowing white
II. Continuous and lined spectrum
III. Atomic Absorption
Spectrophotometry


Energy is a 2 way street, energy can be put into the
atom while at the same time energy is given off
The ABSORPTION of light by an atom causes an
electron to jump into a higher orbital
The EMISSION of light by an atom causes an
electron falling back to a lower orbital
 Heat and light is a result (energy absorption)
electrons are pushed into higher energy levels,
EXCITED STATE

Lecture Notes
V. Neutron Activation Analysis
V. Neutron Activation Analysis



Quantitative & qualitative multi-element
analysis of major, minor & trace elements
Quantifies as low as parts per billion
Requires a nuclear reactor
V. Neutron Activation Analysis Summary:



The neutron activation process requires the capture of a
neutron by the nucleus of an atom.
The “new Atom” ?? Is now radioactive and emits
gamma rays.
A detector permits the Identification of the radioactive
atoms present by measuring energizers and intensities of
the gamma rays emitted
V. Neutron Activation Analysis
V. Neutron Activation Analysis Data
VI. X-Ray Diffraction
X-ray Diffraction

X-ray diffraction is applied to the study of solid,
crystalline materials.

As the X-rays penetrate the crystal, a portion of the
beam is reflected by the substances

This creates a picture called a diffraction pattern.

Every compound is known to produce its own unique
diffraction pattern, thus giving analysts a means for
“fingerprinting” inorganic compounds.

The drawback is that it cannot identify substances found
in small concentrations
I. Evidence in the Assassination
of President Kennedy







Warren Commission
House Select Commission on Assassinations
Rockefeller Commission
FBI
Treasury Department
Department of Justice
Independents

Coroners, assassination researchers, forensic experts
I. Evidence in the Assassination
of President Kennedy


1963, Warren Commission
Oswald fired three shots from a posterior
position in the Texas school book depository.



1 missed the limousine
1 struck president in throatchestConnally in
back  chest  rt wrist  lodged in thigh, found
later on stretcher
1 fatally killed president
I. Evidence in the Assassination
of President Kennedy


16.5 mm Manlicher-Carcano (Oswald Palm)
1977 Six bullet fragments analyzed:

6 Lead bullet Fragments
Antimony [20 -1200 ppm] (a metal not found alone")
 Copper
 Bismuth
 Silver [5 -15 ppm]


Used Neutron Activation Analysis
Antimony and Silver Concentrations
in the Kennedy Bullets
ID #
Q1
Silver
8.8 +0.5
Antimony
Found
833 + 9
CONNALLY
STRETCHER
Q9
9.8 + 0.5
797 + 7
CONNALLYS
WRIST
Q2
8.1 + 0.6
602 + 4
LG frag from car
621+ 4
KENNEDY’S
BRAIN
Q4,Q5
Q14
7.9 + 0.3
8.2 + 0.4
642 + 6
Small FRAG IN
CAR
Evidence




6.5 mm Mannlicher-Carcano rifle found in
Texas School Book Depository Building
Oswald’s palm print
•three spent 6.5 mm Western Cartridge Co/
Mannlicher-Carcano (WCC/MC) cartridge
cases
•Bullets from victims
FBI Emission Spectroscopy
Conclusion based on Neutron Activation
Analysis

Compared the fragments from Connally’s
wrist to the bullet found on the stretcher

technique only semiquantitative for such tiny
Fragments “similar in composition”
 “no significant differences were found within the
sensitivity of the spectrographic method”


–those elements quantified had order of
magnitude uncertainties
Neutron Activation Analysis


Analyst Dr. Vincent P. Guinn
leading practitioner of forensic analysis of bullets &
fragments by NAA


had examined about 165 different brands & production
lots of bullets
Guinn’s studies had shown that quantities of
anitmony, silver & copper could be used to
distinguish bullets
The Analysis

Guinn analyzed five types of samples







the stretcher bullet
two metal fragments from Connally’s wrist
a fragment from the front seat of the limosine
two fragments from JFK’s head
three small fragments from the rear floorboard
carpet
•The same samples originally analyzed
Questions on p. 176-177

Complete the following #’s

4-8, 10, 12, 15, 19, 21-23, 31-33