No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

Analysis and identification of chemical warfare agent (CWA) degradation products presents notable challenges, primarily due to the extensive quantity of the compounds involved, surpassing millions. A majority CWA-related compounds are characterized by low volatility, making liquid chromatography high-resolution mass spectrometry (LC-HRMS) a suitable analysis method. Untargeted screening is promising technique for swift analysis of complex samples, without specific preselection of any compound. In this project, an LC-HRMS method was developed for separation and analysis of CWA-related compounds, using a Dionex 3000 UHPLC-system and a Bruker Impact qTOF mass spectrometer. The method was able to separate most compounds, including several isomers, from each other, and can be used for analysing samples with a large variety of unknown CWA-related compounds. Secondly, a MSspectra library was created for 115 CWA-related compounds. The spectra were obtained by alternating between full MS-scan and broad-band collision induced dissociation (bbCID). Four MS-spectra were added for each compound, one containing the precursor ion spectra (the full MS-scan) and three containing the product ion spectra when using the collision energies 10 eV, 20 eV and 30 eV. While not all compounds could be uniquely identified when screening towards the library, particularly when distinguishing certain isomers from one another, this resource can still be highly valuable for aiding characterization for a wide range of CWA-related compounds. Additionally, prior to adding the spectra to the library, an analysis of all fragment ions was performed and the most plausible structures were recorded in the database. Apart from the library serving as a useful screening tool, this knowledge can prove valuable for future identification of unknown CWA-related compounds. The third part of the project was to optimize the untargeted screening method for CWArelated compounds. A water sample containing 14 CWA-related compounds was analysed when varying the settings of the untargeted screening in the program Bruker Compass DataAnalysis. The new settings, almost exclusively, improved the screening and identification of the compounds. The usefulness and accuracy of the method was evaluated by analysing four different concentrations of a mixture, containing four alkylphosphonic acids, in four different matrices, one water and three soil matrices. The results showed that it was possible to identify several compounds when no visible peaks in the total ion chromatogram were present. This represents an important step for LC-MS analysis in general, since this technique can detect certain compounds that otherwise likely would have been missed when using manual integration.

Microalgae play a crucial role in the Earth’s ecosystem in addition to being utilized by various industries as a raw material for production of valuable goods. This prompts the question of how their growth conditions can be optimized. This work focuses on one of the crucial nutrients they need in order to grow and live - bioavailable iron. However, in natural open water most of the iron remains in a less soluble form, such as nanoparticulate ferrihydrite. The effects this specific iron oxide has on growth of Chlorella vulgaris, a freshwater unicellular green alga, have been compared to those of other forms of iron. The topic of bioavailability has further been tested using different organic agents, which have been shown to facilitate and improve uptake, the focal point being leonardite humic acid (LHA). Growth of C. vulgaris has been analyzed using spectrophotometry and cell count, however, the differences between various forms of iron and organic agents have mostly been determined statistically insignificant. Physical and chemical properties of ferrihydrite and LHA (such as iron content, surface charge and particle size) have been examined using XPS, DLS and FTIR. Zeta potential measurement by DLS has showed that ferrihydrite particles are positively charged at biological pH range, as opposed to the negative charge on the surface of microalgae. ICP-OES analysis has shown that the binding between ferrihydrite and microalgae or LHA occurred within several hours. These analytical methods have allowed a better understanding of the interactions between microalgae, ferrihydrite and LHA in a solution. These interactions require further investigation, especially in cold-adapted species.

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.