Applications of Spectrophotometry In Forensic

Spectrophotometry is widely used in various applications that include food, agricultural science, pharmaceuticals, medicine, forensic science, and environmental science. Generally, in forensic science, a spectrophotometer is used to trace evidence. 

This process involves a micro-spectrophotometry that uses a microscopic light source analyzer to investigate tiny particles such as hair, textiles, and paints that are too small to analyze with the naked eye. 

As these particles are small enough to analyze, infrared and more commonly visible light radiation is used to determine transmission absorption and reflective properties of such tiny particles.

Forensic Science

Forensic science is the science that is used to find solutions to legal problems. Forensic experts analyze the particles that are collected in crime locations in a sophisticated science laboratory to identify the criminals. 

These analyses have proven to be useful evidence to produce judgment to protect innocent people and punish the criminals. The spectrophotometer is one such scientific piece of equipment that helps to detect the materials and allows to produce true evidence that is very much required for legal cases.

Process in Forensic Science 

Each organic and inorganic component has unique characteristics of absorption of light. The piece of particles collected from the crime location absorbs light emitted from the spectrophotometer. Spectrophotometry enhances the color visibility of the particle while determining its composition.


Forensic science is extremely important for any criminal investigation. Spectrophotometry is one of the important scientific tools in a criminal investigation that provides detailed information and the fundamental composition of the particles. This helps to understand the crime in detail and in numerous facets. This analysis allows providing the right judgment of the crime. Spectrophotometry provides detailed and conclusive reports for the products that are being analyzed.

These tiny particles should be handled with great care, spectrophotometry is an optimum analytical technique that helps in the analysis of various evidence ranging from biological fluids, drugs to trace materials found in the crime location. As this technique does not require any sample preparation, this technique is considered to be time-efficient compared to that of other analytical techniques.


There are two different types of UV/Vis spectrophotometer available and are classified in terms of optical pathways as single beam and double beam spectrophotometer. A double beam spectrophotometer splits the light into two equal intensities travelling in two different paths. One of the light beams is passed through the reference and the other light beam is passed through the sample. 

Single beam spectrophotometer is much simpler and compact which is usually dynamic and widely used. The UV visible spectrophotometer comes in various designs consisting of a monochromator with diffraction grating to analyze the different samples for accurate and reliable results.

SMACgig World linkedin


In forensic science, micro-spectrophotometry is used where the tiny particles collected from the crime location are inserted into the microscope, and then it is exposed to infrared and visible light radiation. 

The absorption, transmittance, and reflectance of light characteristics for the particular particle are detected and recorded. This acts as a fingerprint for that particle and it is recorded for future observation or use.

Spectroscopy – Forensic Applications

Spectroscopy for smokeless powder identification

Spectroscopy for smokeless powder identification

In the case of shooting crime, when no weapon is found, smokeless powder will be the crucial evidence for forensic. Smokeless powder is the propellant deposited from the cartridges. The information of smokeless powder is identified using a spectrophotometer and is compared with a database of different types of smokeless powder used in different cartridges. 

This identification will aid in a great way for the criminal investigation. Instrumental analyses such as FTIR and Gas Chromatography-Mass Spectroscopy are commonly used in the forensic laboratory to determine the chemical characteristics of the particles collected from the crime location.

FTIR analysis helps in the determination of the energetic ingredient, nitrocellulose, through identifying the functional groups that are present in the smokeless powder whereas GC-MS is used in the identification of other organic components.

UV/Vis Spectrophotometer for the analysis of fibers

UV/Vis Spectrophotometer for the analysis of fibers

Like hair, fiber is one of the class evidence in the crime scene. In forensic science, fibers as evidence have probative value as they draw connections or associations among suspect or victim.

The UV visible spectroscopy technique is one of the best techniques for the analyses of fiber as it is non-destructive on the sample. If any fiber is recovered in the crime location, can indicate the contact of a suspect or victim. The microscopic UV visible spectroscopy technique enables us to determine the comparison of textile fibers and find the similarity.

Generally, a Microscopic UV visible spectrophotometer is used in forensic laboratories. This technique is more advantageous on fiber analysis compared to that of Raman spectroscopy. The microscopic UV visible spectrophotometer technique is commonly used in the study of fibers.

FTIR spectroscopy technique is used to analyze fiber based on its type, structure, and measurement conditions. IR spectroscopy also allows identifying the difference in acrylic fibers based on the excitation wavelengths. This technique is effectively used in studying the matrix of textile fibers.

Spectroscopy technique to analyze automotive paints

In case of car accidents, vandalism, and burglaries paint bits in the crime location are useful forensic evidence. This evidence is helpful to determine crime to a potential suspect

Raman spectroscopy technique is an effective analytical technique to analyze the trace samples accurately. Furthermore, Raman and FTIR spectroscopy technique is effective in identifying automotive coatings consisting of both organic and inorganic chemical compounds. SEM/EDX and ICP-MS techniques are efficient in the analysis of determining additives on the automotive coating.

Spectroscopy for forensic toxicology

Forensic toxicology is the analysis of biological samples to determine the toxin or drugs. Toxicology provides the information what type of substance and the amount of substance used which is potential effect for the person illness or death.

Raman spectroscopy is a commonly used analytical tool in the field of forensic toxicology. As this technique is not influenced by the presence of water it is efficient in providing confirmatory testing for biological matrices.

This analytical tool allows detection of drugs even at a low level in the range of micrograms within a week of deposition. As these techniques are non-destructive in nature, the purity of the drug and the chain of custody that is crucial to be preserved in the forensic laboratory.


Forensic science requires analytical tools such as UV/Vis spectrophotometer, Raman spectroscopy, FTIR, GC-MS, SEM-EDX, ICP-OES, and ICP-MS to determine properties of different elements that are recovered in the crime location. The non-destructive nature of samples makes these methods efficient in determining different chemical characteristics of the particles. These techniques aid in the scientific evidence for crime investigation.

More Blogs

Principle of UV - Vis Spectroscopy

Principle of UV - Vis Spectroscopy

Read More
Selection of Cuvette in UV-Vis Spectroscopy

Selection of Cuvette in UV-Vis Spectroscopy

Read More
Factors Affecting UV-Vis Spectroscopy

Factors Affecting UV-Vis Spectroscopy

Read More