Chapter 6Chapter 6Inorganic analysisInorganic 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

InorganicsInorganics Do not contain Carbon and Hydrogen

Includes metallic materials such as: Iron, steel, copper, aluminum

Can find inorganics in: 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 AnalysisInorganic 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 AnalysisInorganic 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 BrassCopper 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 BrassCopper 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 II. The Emission Spectrum of ElementsElements

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

Figure 6–2  Parts of a simple emission spectrograph.

II. The Emission Spectrum of II. The Emission Spectrum of ElementsElements

II. The Emission Spectrum of ElementsII. 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 II. The Emission Spectrum of Elements: Flame TestElements: Flame Test

             

     

            

    

             

     Elements can absorb and emit wavelengths of light

Tungsten=warm white light

Neon= glowing white

II. Continuous and lined spectrum

III. Atomic Absorption III. Atomic Absorption SpectrophotometrySpectrophotometry

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 AnalysisV. Neutron Activation Analysis

V. Neutron Activation AnalysisV. Neutron Activation Analysis

Quantitative & qualitative multi-elementanalysis 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 AnalysisV. Neutron Activation Analysis

V. Neutron Activation Analysis DataV. Neutron Activation Analysis Data

VI. X-Ray DiffractionVI. 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 I. Evidence in the Assassination of President Kennedyof 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 I. Evidence in the Assassination of President Kennedyof 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 throatchestConnally in

back chest rt wrist lodged in thigh, found later on stretcher

1 fatally killed president

I. Evidence in the Assassination I. Evidence in the Assassination of President Kennedyof 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 # Silver Antimony Found

Q1 8.8 +0.5 833 + 9CONNALLY

STRETCHER

Q9 9.8 + 0.5 797 + 7CONNALLYS WRIST

Q2 8.1 + 0.6 602 + 4 LG frag from car

Q4,Q5 7.9 + 0.3 621+ 4KENNEDY’S BRAIN

Q14 8.2 + 0.4642 + 6

Small FRAG IN CAR

Evidence

6.5 mm Mannlicher-Carcano rifle found inTexas School Book Depository Building

Oswald’s palm print •three spent 6.5 mm Western Cartridge Co/

Mannlicher-Carcano (WCC/MC) cartridgecases

•Bullets from victims

FBI Emission SpectroscopyConclusion 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