Forensic analysis of cigarette filter using non-destructive ATR-FTIR spectroscopy and chemometric methods

When a forensic investigator encounters a smoked cigarette butt at a crime scene, whether it's one involving dacoity, homicide, suicide, assault, or any other sort of violent conduct, the dominant thought that comes to mind is “DNA extraction.” However, environmental degradation of smoked cigarette butts can restrict the successful extraction of a DNA profile. Counterfeit cigarettes are also accessible on the market, and consumers involved in illegal trafficking can buy them for a fraction of the cost of legitimate cigarettes. A cigarette filter can be used as proof to identify legitimate brands and circumvent DNA profiling's limitations. When doing this research, there are two primary considerations to address. The first objective is to determine the origin of cigarette filter fibres and to isolate them from a range of fibre sources. The second objective is to use a similar approach to estimate the brands of different types of cigarette filters. The samples were all obtained in the nearby locality. The FTIR spectra of all the samples were taken in the mid-IR range, i.e., 4000–450 cm−1. Then, the normalised data is analysed using both unsupervised and supervised chemometric models. When the proposed technique is employed, both objectives provide outstanding results. As a result, this study offers a novel, non-destructive method of assessing cigarette filters. A repository of this type of evidence can be produced in the mid-IR range due to the lack of a similar library or database, which might be useful in a criminal investigation to pin down a suspect pool.