CHAPTER 8: FTIR and NIRS in Forensic Chemical Sensing

Vibrational methods include Raman, terahertz, NIR, and FTIR spectroscopy, having some potential applications in the forensic science field. However, the use of FTIR and NIR spectroscopy is thriving around the globe in the forensic context. This is due to the non-destructive, inexpensive method and the accurate prediction potential of the technique. This chapter summarizes the application of FTIR and NIR spectroscopy in the chemical sensing of the relevant forensic exhibits. A detailed idea on infrared spectroscopy is mandatory to understand its working principals and parameters which ultimately assist the forensic professionals and other researchers working on it. However, the history of IR radiations, their mathematical theories, different modes of vibrations and the major IR instrumentation have been thoroughly discussed. Some examples are also summarized from the published literature which will aid in facilitating the practical applications of infrared spectroscopy. A quick statistic about the utilizations of spectroscopy in forensics has also been reviewed. The validation of results can be confirmed by applying chemometrics methods on spectral data sets. To sum up, the infrared spectroscopy is a robust and reliable technique for the discrimination and classification of relevant forensic evidence to their respective groups. The statistical methods contribute more objectivity to the outcomes.