Vibrational spectroscopy is a technique that involves the interaction of light with matter through absorption, reflection, or inelastic scattering, which helps determine the specific energies associated with molecular vibrations. Techniques such as infrared (IR) and Raman spectroscopy are essential tools in forensic chemistry, enabling the detection and analysis of physical evidence. These methods allow for rapid and accurate identification of various substances and materials encountered during criminal investigations. Although they are complementary tools that enhance the forensic toolkit, both provide valuable insights into the chemical and biochemical composition of evidence. Additionally, vibrational spectroscopy is highly effective for analyzing trace evidence in a non-destructive manner with minimal sample preparation. It has proven particularly useful in the analysis of gunshot residues, illicit substances, bodily fluids, toxicology samples, paints, and many other forensic materials.

The central challenge in forensic chemistry is the rapid, accurate, and non-destructive identification of evidence such as biological materials, drugs, toxins, and trace residues often at crime scenes where contamination and the time elapsed since deposition pose significant difficulties. Samples collected at different times may undergo chemical or physical changes, complicating both identification and quantification. Traditional screening tests can consume samples and sometimes produce false positives or negatives. Conventional laboratory-based methods are often time-consuming and may risk sample degradation or loss, causing delays in investigations. Recent advances focus on portable vibrational spectroscopy devices, such as handheld IR and Raman spectrometers, which enable forensic scientists to perform immediate, in situ analysis directly at crime scenes. These portable tools facilitate quick detection of drugs and toxins without extensive sample preparation or transportation, thereby accelerating decision-making. Additionally, the use of chemometric methods, including multivariate analysis, machine learning algorithms, and predictive modeling enhances the interpretation of complex or ambiguous spectral data. These techniques help develop models that account for factors such as the time since deposition, environmental conditions, and sample variability, resulting in more reliable and accurate identification. Combining portable spectroscopy with advanced chemometric analysis significantly improves the speed, precision, and robustness of forensic evidence analysis in real-time investigative scenarios.

We welcome original research, review, mini review, and perspective articles based on the use of vibrational spectroscopy on themes including, but not limited to:

• Portability of vibrational spectroscopy devices
• Analysis/detection of bodily fluid (from humans and animals) and fingermark
• Detection of gunshot residue
• Identification of illicit substances
• Examination of questioned documents
• Analysis of paint
• Determining of time since deposition of evidence
• Chemometrics techniques and data analysis

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Vibrational Spectroscopy Trends in Forensic Chemistry