The Chemistry Behind Forensics

Chemistry Connections

Episode #2

Welcome to Chemistry Connections, my name is EMILY GREENBERG and I am your host for episode #2 called The chemistry behind forensics. Today I will be discussing the chemistry behind forensic science and crime scene investigation.

Segment 1: Introduction to forensics

Forensic science is the tests and techniques used in the detection of crime. Forensic scientists use the scientific method to solve crimes.

They collect data and evidence from crime scenes and analyze it to try to figure out the manner and the perpetrator of a crime.

Analysis of blood or fingerprints left at a crime scene are very important in identifying a victim or a suspect. Clothing fibers, ink, ash, and much more can also be used in forensics to detect and solve crimes.

Forensic science is one of the most critical aspects of the criminal justice system because it involves hard evidence and can be proven.

Forensics are so important because they can help rule out manners of death and can find suspects for different crimes.

Segment 2: The Chemistry Behind forensics

Chemistry is one of the most important aspects of forensics. The following methods are the most important chemical experiments that are used in forensics.

Chromatography: This is a process where chemists use heat to separate mixtures into different contents so they can determine the individual components of a mixture. There are many different types of chromatography which will be described in this episode.

TLC (thin layer chromatography) is a less complex type of chromatography.

Used to analyze inks and dyes of fibers left at a crime scene and can help a forensic scientist match a fiber to a specific company if differences between fibers are very small

Gas Chromatography is used for volatile liquids

Often used to separate and analyze blood left at a crime scene. This can determine if the victim or suspect had alcohol or drugs in their system.
Can be used to investigate cases of arson and can detect if an accelerant is used. This can be used to see whether a fire was intentional or not
Mass spectrometry is used as a detector by detecting the concentration of the substance

HPLC (High performance liquid chromatography) extracts individual components from a solution

HPLC is used for nonvolatile mixtures
A common detector for this type of chromatography is called an ultraviolet visible spectrometer
This is used for drug analysis because most pharmaceuticals have UV absorbance
Alain Baxter Case

Spectroscopy: field of chemistry that investigates spectrums created when matter interacts with electromagnetic radiation.

Substances will have certain transmittance spectrums which allows the substances to be identified

Certain types of spectroscopy are nondestructive and will be used before other destructive methods

FTIR is one of the main types of spectroscopy

infrared radiation is used to examine skin or clothing of a suspect in order to find evidence like gunpowder residue.
When the spectra of the unknown substance is created, a database can match the unknown spectra to a known spectra

Atomic Absorption Spectroscopy

Involves heating the substance in order to break individual bonds
Radiation in the form of light is then passed through the sample forcing the atoms to jump to a higher energy state

When collecting fingerprints, investigators use an alternate light source to find latent (invisible) fingerprints

SWGDRUG (Scientific Working Group for the Analysis of Seized Drugs) has guidelines for forensic chemists regarding the identification of unknown substances

Segment 3: Personal Connections

This topic is so important because it helps solve crimes and brings justice to criminals and victims. Forensic sciences have come a long way, and we can discover so many things about a crime just by looking at small particles left at a crime scene. I got into forensic science because I listened to True Crime podcasts, which inspired me to research this topic to discover the science behind crime investigation. I hope to one day become a forensic scientist, which is why I enjoyed researching this topic so much.

Thank you for listening to this episode of Chemistry Connections. For more student-ran podcasts and digital content, make sure that you visit www.hvspn.com.