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Chapter 6 Inorganic analysis

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1 Chapter 6 Inorganic analysis

2 Inorganic Analysis ¾ of the weight of the earths crust is made of Oxygen and silicon. 10 elements make up approximately 99 % of the earth crust Oxygen 47.3% Silicon 27.7% Aluminum 7.9 % Iron 4.5% Calcium 3.5% Sodium 2.5% Potassium 2.5% Magnesium 2.2 % Titanium 0.5% Hydrogen 0.2 % Other elements 1.2%

3 Inorganic Analysis Looking back at the previous inorganics
Understand, at most the prevalence of metallic materials: Iron, steel, copper, aluminum Must recognize the possibilities of finding: Tools, coins, weapons, metal scrapings at a CS Other possible Inorganics to look for: Paints and dyes, explosives, and poisons like: Mercury, lead, arsenic

4 Inorganic Analysis Trace elements and their usefulness for the
forensic comparison of various types of physical evidence. Continuous and line emission spectra. Simple emission spectrograph. Simple atomic absorption spectrophotometer. Protons, neutrons, electrons, mass and charge relationship. Atomic number and atomic mass number.

5 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.

6 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”

7 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 % Manganese 1.06% Iron 0.90% Nickel 1.02% Tin 1.70% Lead 0.72% Silicon trace%

8 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

9 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

10 I. Evidence in the Assassination of President Kennedy
6.5 mm Manlicher-Carcano (Oswald Palm) 1977 Six bullet fragments analyzed: 6 Lead bullet Fragments Antimony [ ppm] (a metal not found alone") Copper Bismuth Silver [5 -15 ppm] Used Neutron Activation Analysis

11 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

12 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

13 Antimony and Silver Concentrations in the Kennedy Bullets
ID # Silver Antimony Found Q1 CONNALLY STRETCHER Q9 CONNALLYS WRIST Q2 LG frag from car Q4,Q5 621+ 4 KENNEDY’S BRAIN Q14 Small FRAG IN CAR

14 ID # Silver Antimony Found Q2 8.1 + 0.6 602 + 4 Q4,Q5 7.9 + 0.3 621+ 4
LG frag from car Q4,Q5 621+ 4 KENNEDY’S BRAIN Q14 Small FRAG IN CAR

15 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

16 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

17 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 Emission spec Atomic absorption spec

18 II. The Emission Spectrum of Elements

19 II. The Emission Spectrum of Elements
Heated matter in a solid or liquid state produces a continuous spectra, If it is Vaporized and “excited” by high temp, each element will emit a specific light and select frequency. The elemental “FINGERPRINT” We use an Emission spectrograph And known standards

20 II. The Emission Spectrum of Elements
Emission spectrum: light emitted from a source and is separated into its colors of frequencies If after being passed through a prism all colors seem to blend: Continuous Spectrum. (sunlight / Incandescent bulbs) Sodium, mercury or neon lights produce: non-continuous or lined spectrum. Each line represents a definite wavelength Continuous spectrum: a spec showing a continuous band of colors all bending into one another

21 II. Continuous and lined spectrum

22 II. The Emission Spectrum of Elements: Flame Test
                                    Elements can absorb and emit wavelengths of light Tungsten=warm white light Neon= glowing white

23 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

24 III. Atomic Absorption Spectrophotometry
Based on principle that attempts to explain the origin of EMISSION and ABSORPTION spectra must relate to the structure of the element Materials collected: SUBATOMIC particles Proton Neutron electron Lecture Notes

25 V. Neutron Activation Analysis

26 V. Neutron Activation Analysis
Quantitative & qualitative multi-element analysis of major, minor & trace elements Quantization in parts per billion Requires a nuclear reactor

27 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

28 V. Neutron Activation Analysis
Radioactive decay: Radioactivity: emission of radiation that accompanies the spontaneous disintegration of unstable nuclei. Type types Alpha: He losing an electron orbital Beta: “ electron” Gamma: similar to Xrays higher energy and frequency (neutron Utilized)

29 V. Neutron Activation Analysis
Neutron capture (n, gamma) reaction neutron collides non-elastically with nucleus compound nucleus formed in an excited state •binding energy –nucleus de-excites by emission of gamma rays

30 V. Neutron Activation Analysis

31 V. Neutron Activation Analysis Data

32 VI. X-Ray Diffraction

33 end

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