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Chapter 6 Inorganic analysis. Objective: You will be able to discuss the importance of inorganic analysis in forensics. Do Now: Read “What killed Napoleon”

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Presentation on theme: "Chapter 6 Inorganic analysis. Objective: You will be able to discuss the importance of inorganic analysis in forensics. Do Now: Read “What killed Napoleon”"— Presentation transcript:

1 Chapter 6 Inorganic analysis

2 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

3 Inorganics 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

4 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.

5 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”

6 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%

7 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

8 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

9 Figure 6–2 Parts of a simple emission spectrograph. II. The Emission Spectrum of Elements

10 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

11 Types of spectrums Sunlight and typical light bulbs emit the entire range of colors This is called a continuous spectrum

12 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

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


15 II. Continuous and lined spectrum

16 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


18 V. Neutron Activation Analysis

19 Quantitative & qualitative multi-element analysis of major, minor & trace elements Quantifies as low as parts per billion Requires a nuclear reactor

20 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

21 V. Neutron Activation Analysis

22 V. Neutron Activation Analysis Data

23 VI. X-Ray Diffraction

24 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

25 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

26 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

27 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

28 Antimony and Silver Concentrations in the Kennedy Bullets ID #SilverAntimony Found Q18.8 +0.5833 + 9 CONNALLY STRETCHER Q99.8 + 0.5797 + 7 CONNALLYS WRIST Q28.1 + 0.6602 + 4 LG frag from car Q4,Q57.9 + 0.3621+ 4 KENNEDY’S BRAIN Q148.2 + 0.4 642 + 6 Small FRAG IN CAR

29 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

30 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

31 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

32 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

33 Questions on p. 176-177 Complete the following #’s 4-8, 10, 12, 15, 19, 21-23, 31-33

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