1. Chem 4630
Forensic chemistry 1

2. What this class will provide:
- a toolbox of methods to analyze evidence
- a perspective on how to analyze data
- reinforcement of chemical and physical science methods

3. History of Forensic Science
Mathieu J. B. Orfila:
Many forensic science specialties can be traced back to the medicolegal institutes of Europe
One of the most renowned medicolegalist of the time was Mathieu Orfila ( )
Mathieu Orfila is best known for his involvement in the “Lafarge” arsenic poisoning case in France
He is often referred to as the “father of forensic toxicology”

4. History of Forensic Science
Hans Gross:
A magistrate and law professor in Austria
Known for his publications and for introducing the word “criminalistics”
In 1893, published a Handbook for Magistrates that greatly influenced the practice of criminal investigations

5. History of Forensic Science
Alphonse Bertillon:
Developed an anthropometric system for human identification in the 1890s
The limitations of this system was shown by its inability to distinguish between two Leavenworth, Kansas, penitentiary prisoners, Will West & William West
The Bertillon system was eventually replaced by the fingerprint system being developed by Francis Galton, William Hershel, Edward Henry & others in the late 1800s

6. Development of Forensic Science Laboratories
Professor R. A. Riess:
Established a forensic photography laboratory at the University of Lausanne, Switzerland in 1909
Edmond Locard:
Established one of the world’s first police crime laboratories in Lyon, France in 1910
Known for the Locard Exchange Principle

7. Development of Forensic Science Laboratories
August Vollmer:
Established a forensic laboratory at the Los Angeles Police Department in 1923
Colonel Calvin Goddard:
Established a crime detection laboratory at Chicago’s Northwestern University in 1929
Perfected the comparison microscope for bullet and cartridge case examinations

8. Development of Forensic Science Laboratories
J. Edgar Hoover:
Established the Federal Bureau of Investigation (FBI) forensic laboratory in 1932
New York City (NYC):
The NYC Police Department Crime laboratory was established in 1934

9. History of the Local Lab
Most Crime Labs were established within police agencies and performed
Firearms
Fingerprints
Photography
Missouri State Highway Patrol Lab
Established 1936
Full service lab system
No questioned document examiners in Missouri labs

10. History of the Local Lab
Formally known as SEMO Regional Crime Laboratory
served the southeast Missouri region since 1969
Under direction of chemistry department
First full time director in 1971
Prints, firearms, drug analysis
serving 20 counties, 90 agencies
Merged with MSHP in 2006

11. Forensic Science Specialties
Four major areas of examination:
Biological evidence
Forensic Chemistry
Pattern evidence
Other patterns (scene reconstruction)

12. Forensic Science Specialties
Forensic Pathology:
Pathology is a specialty area of medicine
Pathology is the study of diseases and the bodily changes caused by the diseases
Forensic pathologists determine the cause of death (the medical reason why a person died; e.g. asphyxiation)
Forensic pathologists determine the manner of death (the circum- stances causing death; e.g. homicide)

13. Forensic Science Specialties
Forensic anthropologists:
Can determine whether found remains are of human or animal origin
Reconstruct the skeleton from found remains
Provide an estimate of age, stature, and gender
Can sometimes determine racial origin
Detect skeletal abnormalities and any trauma
Can provide information about the cause of death

14. Forensic Science Specialties
Forensic Toxicology:
Forensic toxicology is the study of the effects of extraneous materials such as poisons and drugs in the body
Forensic toxicologists must determine both the presence and the amounts of extraneous materials in the body
Assist the medical examiners in determining the cause of death
May be involved in the determination of ethanol levels in blood and breath samples

15. Types of Uncertainty
Error - the difference between the true value and our estimation
Random
Systematic
Accuracy - the degree of agreement between the true value and the measured value
Precision - a measure of the agreement of replicate measurements

16. Significant Figures and Scientific Notation
Information-bearing digits or figures in a number are significant figures
The measuring devise used determines the number of significant figures a measurement has
The amount of uncertainty associated with a measurement is indicated by the number of digits or figures used to represent the information

17. Significant figures - all digits in a number representing data or results that are known with certainty plus one uncertain digit

18. Recognition of Significant Figures
All nonzero digits are significant
7.314 has four significant digits
The number of significant digits is independent of the position of the decimal point
73.14 also has four significant digits
Zeros located between nonzero digits are significant
has five significant digits

19. Use of Zeros in Significant Figures
Zeros at the end of a number (trailing zeros) are significant if the number contains a decimal point.
4.70 has three significant digits
Trailing zeros are insignificant if the number does not contain a decimal point.
100 has one significant digit; 100. has three
Zeros to the left of the first nonzero integer are not significant.
has two significant digits

20. Determining Significant
Figures
How many significant figures are in the following?
3.400
3004
300.

21. Scientific Notation
Used to express very large or very small numbers easily and with the correct number of significant figures
Represents a number as a power of ten
Example:
4,300 = 4.3 x 1,000 = 4.3 x 103

22. Rules for Rounding Off Numbers
When the number to be dropped is less than 5 the preceding number is not changed
When the number to be dropped is 5 or larger, the preceding number is increased by one unit
Round the following number to 3 significant figures: x 104
=3.35 x 104

23. How Many Significant Figures?
Round off each number to 3 significant figures:
61.40
6.171

26. Principles of modern forensic laboratories
Comparison of evidence with known standards
(Microtrace, DEA reference lib, FBI database)
Disproving a null hypothesis
Performing positive and negative controls on all tests