Key Techniques Forensic Chemists Use in Case Analysis
Rapid advancement and growth in the medical field have led to tremendous improvement in the field of research and technology. Today, one can easily detect even minute differences between twins or parents and their children. Whether it is on-site detection of the culprit or real-time DNA analysis, all these have become just a matter of a few hours by the 'forensic chemistry'. It is gaining immense recognition and popularity with each passing day. It involves collecting the data and analysing the evidence from crime scenes and other locations to produce unbiased conclusions that can help with the investigation and conviction of criminals or exonerate an innocent person from suspicion.
Forensic Chemistry - Definition
The use of scientific procedures in criminal proceedings is known as forensic chemistry. Specialists in this field have a wide array of methods and instruments to help identify unknown substances. These include the use of high-performance liquid chromatography, gas chromatography-mass spectrometry, atomic absorption spectroscopy, infrared spectroscopy, and thin layer chromatography.
The spectrophotometer is used for determining the concentration, molecular weight, and composition of the compounds by measuring the absorbance capacity of the solution.
History of Forensic Chemistry
One of the very first significant advancements in forensic chemistry was made in 1836 by British scientist ‘James Marsh'. He developed the Marsh test for the detection of arsenic, which was then successfully applied in a murder prosecution. The "father of toxicology," Mathieu Orfila, also made significant contributions to the discipline in the early 19th century.
Role of Chemistry in Forensic Science
We wouldn't be able to determine the outcome of a crime without forensic chemistry. Examining evidence from a crime scene, as well as information about when and sometimes even the identity of the perpetrator, is the forensic chemist's job. In criminal cases, various reagents and procedures help examine elements like blood, DNA, and gunpowder residue to try and ascertain when and who committed the crime. It has reduced the time interval of the investigation process.
Advantages and Disadvantages of Forensic Chemistry
Advantages of Forensic Chemistry:
Chemists’ can detect gasoline or kerosene. This helps in determining whether the fire is set intentionally or not.
It also constricts the long suspicious list and makes investigation easier.
Identification of chemicals like RDX or C-4, which are both military-grade explosives, might suggest a connection to the military.
The identification of particular poisons during poisoning investigations might help detectives determine what to look for.
Disadvantages of Forensic Chemistry:
It can deteriorate the health conditions of an individual.
Long and cumbersome procedures involving consistent working hours in DNA analysis are found to be unethical processes. So a person might face serious problems.
The reagents and equipment used are expensive. Hence, it becomes difficult to set up research labs.
Job Prospects in Forensic Chemistry
A person can become a data analyst, crime scene investigator, research scientist, detective, professor, research writer, toxicologist, assistant researcher, or laboratory technician. Employment in this field is increasing with each passing day. Although competition is inevitable in every field, one can easily get a job on a pay scale of 3-4 lacs per annum which is incremented if one is acquainted with fine skills and proper subject knowledge and has acquired enough experience. Employment is generally found in the police sector, government or private research labs, federal bureaus and detective offices.
Methodologies Used in Forensic Chemistry
Different procedures are used to determine the actual cause of the event. The two most common methodologies used are spectroscopy and chromatography.
Spectrophotometry - It describes the collision energy of electrons, protons, and ions with other particles and with each other. Using it depends on whether the sample is pure or a common mixture. The two primary methods are FTIR and AA. FTIR is a non-destructive method of substance identification that makes use of infrared light. This process of analysing certain unidentified compounds is quick and simple. Atomic Absorption Spectroscopy(AA) is a destructive method that breaks the atomic bonds between atoms. This procedure is typically employed as a confirmatory technique of whether the damage has occurred or not.
Chromatography - It is a technique to separate a mixture's constituent parts. The mobile phase, a material, is used to first dissolve the mixture. The stationary phase is a subsequent substance that the mobile phase passes through. As a result, the mixture divides into two or more components. This method is used to dissect unknown combinations into their component parts so they can be investigated independently. This method is helpful in drug analysis, and fibres detection at the crime scene. Gas chromatography is a type of chromatography in which a gaseous substance is allowed to pass through the stationary phase. It is used to identify the poisoning and explosive items.
Interesting Facts
Forensic chemistry analyses the physical and chemical properties of different materials in order to identify them correctly where one or more materials have similar properties.
Forensic science is crucial to law enforcement because it has improved the efficiency of crime solving drastically.
Key Features of Forensic Chemistry
The field of forensic chemistry requires keen observing skills and a stress-free enivironment to completely analyse and note the history of the case.
It constricts the investigation procedure by immediately determining the actual cause.
Accurate measurements are crucial in crimes like drunk driving because there are very few amounts that forensic chemists' instruments can detect.
Methodologies used are numerous, long and cumbersome. It can be changed according to the demand of the situation.
FAQs on Forensic Chemistry Explained: Role in Crime Investigation
1. What is Forensic Chemistry and what is its primary goal in a criminal investigation?
Forensic Chemistry is the application of chemical principles and analytical techniques to solve legal problems. Its primary goal is to analyse physical evidence collected from a crime scene. This analysis helps in identifying unknown substances, linking evidence to a suspect or victim, and reconstructing the events of a crime to provide objective, scientific information for the courts.
2. What are some common examples of evidence analysed using forensic chemistry?
Forensic chemists analyse a wide variety of evidence. Some common examples include:
- Drugs and Poisons: Identifying illegal substances or toxic materials in seized items or biological samples.
- Gunshot Residue: Determining if a firearm has been recently discharged by analysing residue on a suspect's hands or clothing.
- Accelerants: Detecting the presence of flammable liquids like petrol or kerosene in suspected arson cases.
- Paint and Fibres: Matching paint chips from a hit-and-run to a suspect's vehicle or linking fibres from clothing found at a scene.
- Explosives: Identifying the chemical components of a post-blast device.
3. What are the key analytical techniques used by a forensic chemist?
Forensic chemists employ several sophisticated techniques to analyse evidence. The most common methods include chromatography (like Gas Chromatography) to separate complex mixtures, spectroscopy (like Mass Spectrometry or Infrared Spectroscopy) to identify the specific chemical structure of substances, and microscopy to examine trace evidence like hair and fibres in detail.
4. How does forensic chemistry differ from standard analytical chemistry?
While both fields use similar instruments, their purpose and context are very different. Analytical chemistry typically focuses on quantifying and identifying substances in controlled, known samples for research or quality control. In contrast, forensic chemistry deals with samples that are often minute, degraded, and contaminated. The key difference lies in the interpretation; a forensic chemist must not only identify a substance but also explain its significance within the legal context of a crime.
5. What is the role of forensic chemistry within the broader field of criminology?
In criminology, which is the study of crime and criminal behaviour, forensic chemistry provides the crucial scientific backbone. While criminology explores the 'why' behind a crime (motive, social factors), forensic chemistry provides the 'what' and 'how' through physical evidence. It offers unbiased, data-driven facts that can corroborate or refute witness testimonies, establish timelines, and definitively link individuals to a crime scene, thereby transforming theoretical investigation into prosecutable fact.
6. Why is preventing evidence contamination so crucial in forensic chemistry?
Preventing contamination is paramount because forensic analysis often deals with trace amounts of material. Any foreign substance, such as DNA from an un-gloved hand or fibres from an officer's uniform, can lead to incorrect results. This could falsely implicate an innocent person or destroy the credibility of genuine evidence in court. Therefore, a strict chain of custody and sterile handling procedures are essential to ensure that the analytical results are valid and legally admissible.
7. Can forensic chemistry determine the exact time a crime was committed?
Forensic chemistry itself usually cannot pinpoint an exact time of death or crime. However, it provides crucial data that helps medical examiners and investigators estimate a timeframe. For instance, toxicology reports can show the rate of drug metabolism in a victim's body, and the analysis of degradation rates of certain chemicals at a crime scene can offer clues. While not providing a direct answer, its findings are a critical piece of the puzzle in establishing a probable timeline.
