Forensic Chemistry: Introduction, Advantages, Disadvantages, Jobs

The field of research and technology has greatly improved as a result of the medical sector’s rapid growth and development. In the present day, it has become increasingly feasible to discern even the most subtle distinctions between twins or the resemblances shared by parents and their offspring.

Forensic Chemistry
Forensic Chemistry [Image source: Chestnuthillcollege]

“Forensic chemistry” has made it possible to identify the offender on-site and to analyze DNA in real time. Its recognition and popularity are growing exponentially with each passing day. It entails gathering information and examining the evidence from crime scenes and other sites in order to draw unbiased conclusions that can aid in the investigation, lead to the conviction of criminals, or clear an innocent person of any wrongdoing.

Definition of Forensic Chemistry

  • The application of scientific methods within the context of the legal system is referred to as “forensic chemistry.” Experts in this particular domain possess a diverse range of methodologies and tools at their disposal to effectively discern unidentified substances.
  • The techniques employed encompass a range of sophisticated analytical methods, such as high-performance liquid chromatography, gas chromatography-mass spectrometry, atomic absorption spectroscopy, infrared spectroscopy, and thin-layer chromatography.
  • By measuring the absorbance capacity of the solution, the spectrophotometer can be used to figure out the concentration, molecular weight, and makeup of the substances.

Development of Forensic Chemistry

  • Throughout the annals of history, a myriad of toxic substances have been employed with nefarious intent, serving as lethal agents in the commission of heinous acts such as murder. Among these insidious compounds are the notorious arsenic, the deadly nightshade, the lethal hemlock, the potent strychnine, and the treacherous curare.
  • Prior to the arrival of the beginning of the nineteenth century, the absence of reliable techniques for ascertaining the presence of specific chemicals rendered it exceedingly challenging to identify their existence. Consequently, individuals who engaged in the malevolent act of poisoning were seldom held accountable for their transgressions.
  • One of the first significant advancements in forensic chemistry was accomplished by British scientist James Marsh in 1836. He developed the Marsh test, which was later used successfully in a murder prosecution, to identify the presence of arsenic.
  • Mathieu Orfila, widely regarded as an eminent figure in the realm of toxicology, spearheaded remarkable progressions within this discipline during the formative years of the 19th century. Orfila, a pioneer in the development of forensic microscopy, contributed to the advancement of this approach for the detection of blood and sperm. Orfila was also the first chemist to effectively categorize various substances into groups including corrosives, narcotics, and astringents.
  • In 1850, the chemist Jean Stas achieved a significant milestone in poison detection. He successfully developed a reliable method to detect vegetable alkaloids in human tissue.
  • The twentieth century saw significant technological advances that allowed chemists to detect tiny amounts of substances more accurately. A spectrometer that could quantify the signal produced by infrared (IR) light was created in the 1930s, marking the first significant development of this century.
  • Gas chromatography-mass spectrometry (GC-MS), developed by Fred McLafferty and Roland Gohlke in 1955, is one of the most significant developments in forensic chemistry.

Methods Used In Forensic Chemistry

A multitude of methodologies are utilized to determine the exact underlying factors that contribute to the occurrence. Spectroscopy and chromatography are widely recognized as the predominant methodologies utilized in scientific research and analysis.


  • Spectroscopy characterizes the kinetic energy released when electrons, protons, and ions collide with other particles or with one another. Whether the sample is pure or a typical combination will determine how to use it.
  • The two most common methods are FTIR and AA. The Fourier transform infrared (FTIR) technique uses infrared light for non-destructive material detection.
  • This method of analyzing hitherto unnamed chemicals is straightforward and fast. Atomic Absorption Spectroscopy (AA) is a destructive method that dissolves the bonds between atoms.
  • This method is often used as a confirmatory method to ascertain if any damage has occurred.


  • The process of separating the constituent parts of a mixture is commonly referred to as a technique. The mobile phase, which is a substance, is employed initially to dissolve the mixture.
  • The stationary phase refers to a substance that the mobile phase subsequently traverses. Consequently, the amalgamation undergoes a process of division, resulting in the formation of two or more distinct components.
  • This particular technique is employed to deconstruct unfamiliar amalgamations into their constituent elements, thereby enabling them to be examined and analyzed individually.
  • This technique aids in the examination of drugs and the discovery of fibers at crime scenes.
  • When a gaseous substance is permitted to pass through the stationary phase during chromatography, the process is known as Gas Chromatography.
  • This tool serves the purpose of identifying both poisonous substances and explosive materials.

Advantages of Forensic Chemistry

  • Chemists possess the ability to detect the presence of gasoline or kerosene. This aids in discerning whether the fire has been deliberately ignited or not.
  • Additionally, it serves to narrow down the extensive roster of potential suspects, thereby facilitating the process of conducting a thorough investigation.
  • The presence of chemicals such as RDX or C-4, known for their utilization as military-grade explosives, could potentially indicate a correlation with the military.
  • The process of identifying specific poisons during investigations related to intoxication incidents can prove invaluable for detectives, aiding them in determining the substances they should focus their attention on.

Disadvantages of Forensic Chemistry

  • Exposure to certain factors has the potential to adversely impact an individual’s state of health, leading to a decline in their overall well-being.
  • The ethical implications of protracted and laborious protocols entailing rigid working schedules in the realm of DNA analysis have come under scrutiny. Individuals may encounter significant challenges in their lives.
  • The utilization of reagents and equipment in this particular context entails a significant financial investment. Consequently, the establishment of a laboratory becomes a challenging endeavor.

Forensic Toxicology

  • Forensic toxicology encompasses the comprehensive examination of pharmacodynamics, which pertains to the effects of a substance on the human body, as well as pharmacokinetics, which focuses on the body’s interactions with said substance.
  • To correctly figure out how a drug affects the body, forensic toxicologists need to know about the different levels of drug tolerance a person can build up as well as the therapeutic index for different drugs.
  • Toxicologists must determine if any poison found in a person was the cause of or contributed to an incident, or whether it was present at too low a level to have an effect.
  • The identification of the precise toxin can be a time-intensive process owing to the multitude of substances that can induce harm or fatality. However, certain indicators can help to narrow down the range of potential options.

Forensic Chemist

  • A forensic chemist is an individual tasked with dedicating their time and expertise to the identification, quantification, and evaluation of unfamiliar substances encountered at a crime scene.
  • Dedicating their time within the confines of the laboratory, they meticulously scrutinize and dissect every piece of proof procured from the crime scene.
  • Subsequently, the gathered information is transferred to a seasoned detective who adeptly assimilates the various pieces of evidence from disparate departments, ultimately unraveling the intricacies of the crime at hand.
  • In order to excel in their field, a forensic chemist must possess a comprehensive understanding of both Physics and Organic Chemistry. With the help of Organic Chemistry, experts look at body samples to find the DNA or to find toxic substances.
  • Forensic chemists, equipped with their advanced understanding of physics, are also dispatched to crime scenes. They analyze the crime scene for things like blood patterns, injury or attack type, attack range, and so on.
  • Forensic chemists specializing in arson-related chemicals meticulously examine the sites of crimes for the presence of any explosive substances.

Job Profile of Forensic Chemist

  • The primary responsibility of a Forensic Chemist entails the meticulous collection of substances discovered at a crime scene, followed by a comprehensive analysis aimed at establishing their relevance to the criminal investigation at hand.
  • These chemists look for compounds that can aid in the investigation of crime using the principles of physics, chemistry, and biology. Their work entails tracing materials, narcotics, and several other substances; they also employ methods such as spectroscopy, chromatography, and the application of infrared or ultraviolet lamps to find evidence.
  • Typically, the samples discovered at crime scenes are meticulously preserved and subsequently subjected to testing, as deemed necessary.


  • Validation Guidelines for Laboratories Performing Forensic Analysis of Chemical Terrorism”. Forensic Science Communications7 (2). April 2005.
  • “Quality Assurance Guide for the Forensic Analysis of Ignitable Liquids”. Forensic Science Communications. 8 (2). April 2006.

About Author

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Jyoti Bashyal

Jyoti Bashyal, a graduate of the Central Department of Chemistry, is an avid explorer of the molecular realm. Fueled by her fascination with chemical reactions and natural compounds, she navigates her field's complexities with precision and passion. Outside the lab, Jyoti is dedicated to making science accessible to all. She aspires to deepen audiences' understanding of the wonders of various scientific subjects and their impact on the world by sharing them with a wide range of readers through her writing.

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