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.

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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.

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No description available.

The aim of this report was to investigate various chemical and enzymaticmethods/techniques of sulfation for polysaccharides. More specifically the focus wasmethods and techniques, both chemical and enzymatic, where the sulfation degree andpattern are controlled, the molecular weight of the polysaccharide is maintained. Lastly,we shine a light on how the bioactivity of polysaccharides can be modified withsulfation and the commons ways of analysis of the sulfation pattern and degree. Thiswas done by searching and reading research articles and journals with relevant keywords such as “Sulfated polysaccharides” and “glycosaminoglycan sulfation.” Theconclusion of this report is that complexes of SO3 with chemicals such astrimethylamine, pyridine or dimethylformamide (DMF) in polar aprotic solvents arepreferred to due to the maintenance of the polysaccharide backbone. More importantlyan 83% or 69% yield is achieved on high molecular weight hyaluronan with SO3-DMFand SO3-pyridine respectively. The degree of sulfation with these complexes wasreported to be 2.8 to 3.0 for the DMF complex and 1.0 to 1.5 for the pyridine complex.Regioselectivity can be achieved chemically using protecting groups such as benzoylfor the sulfation of positions C2 and C3. Another potential strategy is to de-sulfate theC6 position of highly sulfated hyaluronan to achieve high degree of sulfation on C2 andC3 positions. This can be achieved with silylating agents N-methyl-N-(trimethylsilyl)-trifluoroacetamide (MSTFA) or N,O-bis(trimethylsilyl)acetamide (BTSA). The use ofionic solvents or mixtures comprised polar aprotic solvents and ionic liquids haveshown efficacy as solvents for the dissolution of polysaccharides. Whether thesesolvents are viable substitutes for the current standard polar aprotic solvents remains tobe researched. As for the enzymatic methods of sulfation there is not much to say, thereare some enzymes such as sulfotransferases, human and squid cartilage chondroitinsulfate sulfotransferase that have potential in being used in industrial means of sulfationof polysaccharides. There is not enough available research on the scalability ofsulfotransferases for this purpose. A potential scalable enzymatic method is the totalbiosynthesis of sulfated polysaccharides in vitro.

<p>The behavior of block copolymer and protein films at interfaces is of central importance to their function in many application areas. Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) block copolymers function e.g. as emulsifiers and in coatings in oral, parenteral, and topical pharmaceutical formulations and are also widely used for cleaning purposes. The globular protein β-lactoglobulin is the most abundant whey protein and it is used within the food industry as a component of many common foods. To understand the interfacial behavior of block copolymers and proteins in such applications one has to study molecular processes like adsorption, the responses to shear and dilatational deformation of the interface (i.e. surface rheology), conformational changes of the molecules, and forces that are generated between interfacial layers. Such investigations form the focus of the work presented in this thesis. </p><p>Thin film measurements with a series of block copolymers composed of poly(ethylene oxide) and poly(butylene oxide) revealed that the thickness of foam films (air-aqueous solution-air) is determined by electrostatic and steric repulsion. The range of the steric repulsion is directly dependent on the size of the polymer, in particular the length of the poly(ethylene oxide) chains. Block copolymers attached to the air-water interface change their conformation with increasing surface concentration. The study of the dilatational modulus as a function of the surface pressure of spread and adsorbed block copolymer layers showed that the block copolymers pass from a two-dimensional conformation to a three-dimensional extended structure as the available area per molecule decreases. Relaxation processes occur mainly by a redistribution of segments within the surface layer. Mixing of the hydrophobic poly(propylene oxide) segments in a sublayer of poly(ethylene oxide) and water was proposed to occur at high surface concentration of the polymer. Conformational changes (partial denaturation) of globular proteins upon adsorption at the air-water interface leads to the formation of highly viscoelastic networks, which play an important role for the stabilization of foams and emulsions. Mixed layers, formed by competitive adsorption of β-lactoglobulin and block copolymers, were also investigated. On increasing the concentration of block copolymer, the viscoelasticity of the mixed protein/block copolymer layer gradually decreased. The polymer was able to displace the protein from the interface. The drainage rate of thin liquid films was also enhanced by the presence of block copolymer. Whether or not the incorporation of the polymer in the β-lactoglobulin layer has a detrimental effect on foam stability depends on the ability of the polymer to generate long-range steric repulsion across the foam films. For pure block copolymer systems, correlations between foam stability and the thickness of interfacial layers, in the steric regime, were found. The results obtained can be utilized for increasing the understanding of the mechanisms for foam stabilization in both model and industrial systems. </p>