Raman spectroscopy (RS) is a vibrational technique based on the Raman effect. The Raman effect arises due to the inelastic scattering of light. The scattered light is directly associated with the vibrational transitions within the molecule. Each molecule has its own vibrational signature which creates a unique Raman spectrum. During the past decades the analytical technique has undergone a rapid development and become popular in forensic science due its favorable properties. RS is a non-destructive technique well known for its short analysis time and its minimal sample preparation. RS and Fourier Infrared Spectroscopy (FTIR) are two complementary techniques which can be very powerful when applied together to obtain a more complete chemical profile of a sample. FTIR will also comprise a major of this research as well. This research was in collaboration with The National Forensic Centre (NFC). It is an organization within the Swedish Police Authority that performs laboratory analysis of different evidence material. In 2018, NFC installed an inVia Raman spectrometer coupled to a confocal microscope. The first aim of this research was to deepen the knowledge about the RS instrument. The spectral effect of the most significant instrumental parameters was investigated in order to understand the capacity of the instrument. Wavelength, laser power, exposure time, number of accumulations, objective lens and photobleaching were studied. It was found that all parameters should be modulated to optimal analytical conditions of each individual sample in order to obtain the most satisfactory spectrum. Moreover, the broad range of forensic applications of RS allowed investigations of different materials with specific objectives. Spray paints were the main focus followed by three smaller studies on fibers, explosive precursors, and E-cigarette liquids with the emphasis on the use of RS as a potential forensic tool for these types of materials. It was shown that RS is a promising technique with a great potential for these forensic purposes. This research highlights the importance of implementing the technique in forensic investigations at NFC due to its capability to provide valuable information about the chemical characteristics of spray paints, fibers, explosive precursors, and E-cigarette liquids.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:oru-114296 |
| Date | January 2024 |
| Creators | Nissmo, Felicia |
| Publisher | Örebro universitet, Institutionen för naturvetenskap och teknik |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
Page generated in 0.002 seconds