<p>This dissertation presents several examples of diverse applications of mass spectrometry. For example, high-resolution mass spectrometry was utilized for qualitative and quantitative chemical characterization of ionized compounds in petrochemical samples, specifically, in condensate-like oil samples. Further, the ability to use tandem mass spectrometry to rapidly detect trace amounts of short-lived reaction intermediates in solution reactions is demonstrated. Finally, selective tandem mass spectrometry methods based on diagnostic gas-phase ion-molecule reactions were developed for the identification of carboxylic acid functionalities in protonated analytes.</p>

Natural nanominerals are abundant in Earth's critical zone and important in innumerable environmental processes that affect water quality. The chemical behavior of many natural nanominerals is related to their extreme small size (<10 nm) and high surface area. Atomic structural and chemical heterogeneity are also important factors affecting nanoparticle reactivity, and are a consequence of the mechanisms and complex (natural) conditions by which they form. The relationships between these factors remain poorly understood and limit our ability to predict the formation, transformation, and chemical behavior of natural nanominerals in the environment. We are using a poorly crystalline ferric hydroxysulfate nanomineral, schwertmannite, as a model system to understand the effect of formation conditions, specifically solution chemistry, on its physico-chemical characteristics. Previous studies indicate schwertmannite has highly variable bulk sulfate (Fe/S molar from 3-15) and water contents (Caraballo et al., 2013). In addition, both natural and synthetic schwertmannites have recently been described as "polyphasic" (i.e., consisting of sulfate-poor, goethite-like ordered domains embedded in a sulfate-rich, amorphous material) from observations using transmission electron microscopy (French et al., 2012). We hypothesize that solution chemistry at the time of schwertmannite formation directly affect its composition and structure. Using a factorial experiment design, we investigated the effects of increasing solution sulfate concentration ([SO4]/[Fe] at 1, 2, 3 and 5) and pH (2.4-5.6) on the crystallinity and composition of the products. Ferric hydroxide and hydroxysulfate solids were precipitated in batches by the rapid oxidation of Fe(II) by hydrogen peroxide, similar to what is seen in natural environmental systems. Sulfate and hydroxide concentrations were varied by addition of NaSO4 and NaOH, respectively. Solids were characterized using synchrotron X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), inductively coupled plasma-mass spectrometry (ICP-MS), scanning electron microscopy (SEM), and high resolution- transmission electron microscopy (HR-TEM). Our results show that schwertmannite is the only precipitate formed at low pH and that goethite rapidly becomes dominant at pH > 3.5. High-resolution TEM showed our synthetic schwertmannite samples consist of poorly crystalline goethite-like nanodomains within an amorphous solid, similarly seen in previous results. ICP-MS results reveal a narrow Fe/S molar ratio of 4.5 ±0.1 for our synthetic schwertmannite, which suggests that schwertmannite chemical composition does not depend strongly on pH or initial solution sulfate concentration. Increasing pH from 2.4 to 3.2 also has little effect on the crystallinity, bulk Fe/S ratio and water contents of schwertmannite. Increasing solution [SO4]/[Fe] also has little to no impact on crystallinity, water content or the amount of sulfate incorporated in schwertmannite. Thus, schwertmannite crystallinity and composition is not affected by initial solution sulfate and concentration under our experimental conditions. Thermal analysis allows us to independently measure OH and SO4 content in synthetic schwertmannite. In doing so, we propose a more accurate chemical formula (Fe8Oz(OH)24-2z-2x(SO4)x). The average stoichiometry based on thermal analysis of schwertmannite precipitated at [SO4]/[Fe] = 1 and pH ranging from ~2.4 2.9 is Fe8O6.51(OH)8.4(SO4)1.28. Interestingly, the calculated number of moles of oxygen is less than 8, which suggests that the standard formula Fe8O8(OH)8-2x(SO4)x is incorrect. These results for synthetic samples provide important constraints for future studies aimed at better understanding the formation, compositional variability and chemical behavior of natural schwertmannite. / Master of Science

It was found that there exist three major water environments when water is dissolved in nitrobenzene. 2H NMR has proved that these solvatomers exist irrespective of whether lithium salt is added to the system. 7Li NMR experiments suggested that the first solvatomer is majority nitrobenzene, the second a mixed solvation shell consisting of nitrobenzene and water and the third solvatomer is a large water aggregated at the glass surface. The mixed solvation state is short lived and is promoted by addition of water of by supersaturating the system upon cooling. This is a high energy state and decays either into the homogenous bulk NB state or to the surface of the glass wall, depending on if glass surface is present. In the 7Li NMR experiments, the hydrophobicity of the salt, determined by the anion, affects the relative intensity of the three 7Li resonances. Addition of lithium serves to promote hydrogen bonding in the majority nitrobenzene solvatomer, as confirmed by FTIR and neutron diffraction studies. There is no evidence that it has an effect on the size of the mixed solvatomer or the water aggregate immobilized on the glass surface. A reasonable hypothesis is that lithium exchanges between the water species which are formed independent of lithium involvement. The system is summarized as follows: Below critical water concentration (~200mM) nitrobenzene/water is a homogeneous distribution of water molecules in nitrobenzene. Addition of lithium salt to such a system has two main affects. First, the lithium promotes hydrogen bonding between the dissolved water molecules, as confirmed by FTIR and neutron scattering. Second, the hydrogen bonded water may precipitate causing microheterogeneity of the system, leading to a second resonance observed in both the 2H and 7Li NMR spectra (LiNB/W). In the presence of glass, a third solvation state can nucleate at the glass surface; this solvation state has character even closer to that of bulk water (LiW). These two supplementary solvation states can be artificially induced by either adding aliquots of water or cooling.

Thesis (doctoral)--Lund University, 1998. / Thesis statement inserted. Includes bibliographical references.

Thesis (doctoral)--Lund University, 1998. / Thesis statement inserted. Includes bibliographical references.

Les travaux de cette thèse intitulée « Associations supramoléculaires des Complexes de clusters métalliques avec les cyclodextrines : Des interactions en solution à la conception de systèmes mixtes Clusters-polyoxométallates » portent sur l’encapsulation de clusters octaédriques par des oligosaccharides cycliques appelés cyclodextrines. La première partie de ce travail concerne l’étude en solution aqueuse du comportement de clusters de rhénium cationiques [Re6Q8(H2O)6]2+ (avec Q = S ou Se) ou anioniques du type [Re6Q8(CN)6]4- (avec Q = S, Se ou Te) vis-à-vis de cyclodextrines de type α, β et γ. Les études menées en solution au moyen de la RMN de 1H montrent que les clusters aquo cationique [Re6Q8(CN)6]4- interagissent très faiblement avec la cyclodextrine γ (noté γ -CD) alors que la diffraction des rayons X révèle que ces systèmes cristallisés contiennent l’adduit supramoléculaire de type hôte-invité de stoichiométrie 1:1 {[Re6Q8(H2O)6]@g-CD}2+ sans que l’analyse structurale ne révèle d’intéractions attractives significatives entre le cluster et le macrocycle. L’étude des dérivés anioniques cyano [Re6Q8(CN)6]4- (Q = S, Se ou Te) a permis d’établir les critères favorisant les interactions de type hôte-invité. Les études en solution montrent que pour ces systèmes cluster-CD, les interactions supramoléculaires peuvent être classés selon l’ordre α-CD < β-CD < γ-CD. Cependant, la nature du ligand chalcogénure (Q = S, Se, Te) a aussi une influence déterminante dans le processus de reconnaissance supramoléculaire en suivant le classement suivant S < Se < Te. Les études RMN 1H, 77Se et 125Te complétées par la détermination par ITC des grandeurs thermodynamiques associées au processus de reconnaissance hôte-invité. Ces études révèlent dans tous les cas que le processus de reconnaissance est très largement favorisé d’un point de vue enthalpique alors que la contribution entropique est toujours défavorable. Cette signature thermodynamique peut être reliée au comportement chaotrope de ces ions en solution. Les études structurales menées par diffraction des rayons X ont dans tout les cas montrées des associations supramoléculaires qui peuvent différer subtilement selon la nature du cluster et le type de cyclodextrine. Enfin, des études électrochimiques confirment les résultats précédents et mettent davantage en lumière le rôle déterminant de la charge ionique sur la stabilité des agrégats supramoléculaires.Ces complexes de rhénium ont été engagés dans des associations inédites avec des polyoxométallates. L’idée sous jacente de cette étude repose sur la création de système « push-pull » inorganiques associant une unité riche en électrons (le cluster) avec unité pauvre en électrons (le POM). Plusieurs structures sont décrites avec l’ion de Dawson [P2W18O62]6- ou un POM géant dérivé des bleus de molybdène. Elles démontrent le rôle déterminant de la cyclodextrine dans le processus d’interaction qui permet d’associer des anions cluster-POM. Ces composés apparaissent comme de très bon candidats pour l’élaboration de phases nanostructurées à base d’oxychalcogénures métalliques.Dans une dernière partie, les travaux ont été étendus aux clusters {M6X8Cl6}2- ( avec M = Mo ou W et X = Br ou I). Bien que certains d’entre eux présentent des propriétés remarquables de luminescence, leur faible résistance à l’hydrolyse en milieu aqueux limite considérablement leur utilisation pour des applications biomédicales. Ce travail réalisé au moyen de la RMN de 35Cl et UV-vis montre que les associations supramoléculaires de type hôte-invité permet de stabiliser de façon spectaculaire ces clusters. Des études préliminaires de cytotoxicité et de photothérapie dynamique (PDT) menées sur certains de ces systèmes cluster-CD montrent des résultats encourageant qui augurent de belles perspectives pour l’avenir. / In this work, we report in first part the detailed study of the interaction of rhenium cluster complexes [{Re6Q8}(H2O)6]2+ and [{Re6Q8}(CN)6]4–/3– (Q = S, Se, Te) with cyclodextrins (α, β and γ). Upon dissolving the reagents in water and then evaporating the solution or diffusion of ethanol vapors into the solution, crystalline products were obtained which crystallized as fragments without the formation of host-guest compounds (α-CD and Q = Se, Te ) or inclusion compounds with weak interactions with the primary or secondary face of CD (β-CD and all complexes, γ-CD / α-CD and Q = S), or very tightly coupled inclusion compounds involving the secondary face of CD (γ- CD and Q = Se, Te), which was confirmed by XRD. Moreover, similar behavior was found in aqueous solutions using a wide range of methods such as NMR spectroscopy (both from the host and the guest side), ITC, mass spectrometry, etc. Also, it was demonstrated that the inclusion cyclodextrins strongly affects the properties of cluster complexes, especially redox and luminescent. All data obtained by solution methods lead to the identification of two main factors of interaction with the CD, namely: (1) size-matching of host and guest, (2) the chaotropic nature of the guest. The chaotropic effect (the water structure breaking) of the complexes makes a significant contribution to the formation of inclusion compounds, however, when size-matching is additionally observed, the interaction becomes even stronger. The chaotropic effect was also confirmed by studying two complexes with different charges. Thus, an increase in the chaotropic effect without changing the size of the complex led to an increase in the binding constants with γ-CD by approximately 1000 times.In the second part, we have demonstrated that the inclusion compounds of rhenium cluster complexes with cyclodextrin can be combined with other functional inorganic compounds - polyoxometalates. In such three-component systems, cyclodextrin plays the role of a binding agent. In the case of a logical combination of oppositely charged cationic cluster complexes and a Dawson-type anion, the system is mainly formed due to the strong bond between the POM and the CD, since cluster interacts very weakly with CD. On the other hand, ions of the same charge (anionic cluster and anionic POM) can also form three-component systems, which are mainly based on inclusion of cluster into CD. Moreover, inclusion compounds can participate in the formation of nanoscale supramolecular ensembles with a nano-wheel {Mo154}, which exist both in solid state and in aqueous solution.In the last part, it was demonstrated that, using the supramolecular approach, it is possible to stabilize molybdenum and tungsten cluster complexes with low hydrolytic stability in aqueous solutions. For the first time, water-soluble Na2[{M6X8}Cl6] complexes (M = Mo, W, X = Br, I) were obtained and the kinetics of substitution of terminal ligands in water was studied in detail. Adding γ-CD to the system leads to the formation of strong inclusion compounds in a 1:2 ratio with the participation of the secondary face of cyclodextrin. Moreover, inclusion in γ-CD significantly reduces the rate of substitution of terminal ligands and allows us to obtain solutions that are stable for at least several months. The obtained compounds possess the best photophysical characteristics of luminescence in aqueous solutions among molybdenum and tungsten cluster complexes. Also, inclusion in the CD allowed us to study for the first time the redox properties of complexes in water. In conclusion, it was demonstrated that such systems have the lowest cytotoxicity, which makes them promising for further studies for use in biology and medicine.

Nickel-base superalloys have been emerged as materials for gas turbines used for jet propulsion and electricity generation. The strength of the superalloys depends mainly from an ordered precipitates of L12 structure, so called gamma prime (γ’) dispersed within the disorder γ matrix. The Ni-base alloys investigated in this dissertation comprise both model alloy systems based on Ni-Al-Cr and Ni-Al-Co as well as the commercial alloy Rene N5. Classical nucleation and growth mechanism dominates the γ’ precipitation process in slowed-cooled Ni-Al-Cr alloys. The effect of Al and Cr additions on γ’ precipitate size distribution as well as morphological and compositional development of γ’ precipitates were characterized by coupling transmission electron microscopy (TEM) and 3D atom probe (3DAP) techniques. Rapid quenching Ni-Al-Cr alloy experiences a non-classical precipitation mechanism. Structural evolution of the γ’ precipitates formed and subsequent isothermal annealing at 600 °C were investigated by coupling TEM and synchrotron-based high-energy x-ray diffraction (XRD). Compositional evolution of the non-classically formed γ’ precipitates was determined by 3DAP and Langer, Bar-on and Miller (LBM) method. Besides homogeneous nucleation, the mechanism of heterogeneous γ’ precipitation involving a discontinuous precipitation mechanism, as a function of temperature, was the primary focus of study in case of the Ni-Al-Co alloy. This investigation coupled SEM, SEM-EBSD, TEM and 3DAP techniques. Lastly, solute partitioning and enrichment of minor refractory elements across/at the γ/ γ’ interfaces in the commercially used single crystal Rene N5 superalloy was investigated by using an advantage of nano-scale composition investigation of 3DAP technique.

Yes / Cocrystals consist of two molecules bonded together in a single crystal lattice giving rise to wide applications including improving solubility of poorly soluble pharmaceuticals. Cocrystallization reaction occurs in the oily phase of liquid–liquid phase separation (LLPS) after it is mixed with coformers. Indomethacin–saccharin cocrystal formation was monitored in situ, and the kinetics of crystallization were determined. The crystallization rates show that the process can be proposed to prevent unwanted oily phase formation during LLPS. / Research Development Fund Publication Prize Award winner, Sep 2022.

Per- and polyfluoroalkyl substances (PFASs) have drawn great attention recently, due to their environmental persistence, potential toxicity and global distribution. PFAS is a large family of substances, characterized by a perflourinated carbon chain and a functional group. All PFASs are synthetic and have been widely used since the 1950s due to their unique properties of being both hydrophobic and oleophobic, making them useful for many industries. To be able to predict the fate of PFASs in the environment and to obtain detailed understanding of the transport processes, their partitioning behavior between soil particles and water depending on a range of parameters must be investigated. The aims of this study was to investigate the effects of pH, cation composition, functional group and perfluorocarbon chain length on sorption of PFASs to soil particles, by batch sorption experiment in laboratory scale. The laboratory-scale experiments were combined with modelling of the net charge to evaluate if net charge is a good predictor for sorption of PFASs to soil particles. 14 PFASs of varying length and functional groups were studied (PFBA, PFPeA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnDA, PFDoDA, PFTeDA, PFBS, PFHxS, PFOS and FOSA). The effect on sorption of Na+, Ca2+ (two different concentrations) and Al3+ were investigated at pH-range 3-6. Modelling of net charge was carried out in the geochemical model Visual MINTEQ. The soil had 45% organic carbon content. The adsorption of PFASs was strongly correlated with perfluorocarbon chain length, showing a stronger adsorption to particles with increasing perfluorocarbon chain length (i.e. more hydrophobic). The relation between sorption (represented by the distribution coefficient log Kd) and perfluorocarbon chain length was linear for all PFSAs and C3 to C10 PFCAs. The PFSAs (sulfonate functional group) sorbed stronger to soil particles than the PFCAs (carboxylic functional group), and FOSA (sulfonamide functional group) sorbed the strongest. For most PFCAs, (C5-C13) there was a trend of decreasing log Kd (i.e. decreased sorption) with increasing pH, due to pH-dependent changes of the soil particle surfaces. For short and intermediate perfluorocarbon chain length PFCAs (C5-C8) and for PFHxS among the PFSAs, cations had a clear effect on sorption. Aluminium ions (trivalent, Al(NO3)3) had the largest effect, followed by calcium (divalent, Ca(NO3)2) where higher concentration resulted in stronger sorption. Sodium (univalent, NaNO3) had the least influence on sorption. The net charge modelled with Visual MINTEQ takes into account many parameters (including pH) that affect the surface charge and sorption of PFASs to soil particles. When comparing log Kd for the different PFASs with pH and net negative charge, net charge was a better predictor of sorption of PFASs to soil particles than solution pH alone. / Per- och polyfluoroalkylsubstanser (PFAS:er) har dragit stor uppmärksamhet till sig på senare tid, på grund av deras persistenta egenskaper, potentiella toxicitet och globala utbredning. PFAS är en stor grupp ämnen, kännetecknad av en perflourinerad kolkedja och en funktionell grupp. Alla PFAS är syntetiska och har använts i stor utsträckning sedan 1950-talet på grund av deras unika egenskaper av att vara både vatten- och fettavstötande, vilket gör dem användbara för många industriella tillämpningar. För att kunna förutsäga var dessa föroreningars hamnar i miljön och få mer detaljerad förstående för transportprocesserna, måste deras fördelningbeteende mellan jordpartiklar och vattenundersökas för en rad olika parametrar. Syftet med denna studie var att undersöka effekterna av förändrat pH, katjonsammansättning, funktionell grupp och perfluorkolkedjelängd på sorption av PFAS:er till jordpartiklar. Detta gjordes med sorptionsexperiment i laboratorieskala. Laboratorieexperimentet kompletterades med modellering av nettoladdning, för att se huruvida detta väl kunde förklara sorptionen till jordpartiklar. 14 PFAS:er av varierande längd och med tre olika funktionella grupper studerades (PFBA, PFPeA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnDA, PFDoDA, PFTeDA, PFBS, PFHxS, PFOS och FOSA). Effekten på sorption av Na+, Ca2+ (två olika koncentrationer) och Al3+ undersöktes vid pH-intervallet 3-6. Modellering av nettoladdning utfördes i den geokemiska modellen Visual MINTEQ. Jorden som användes hade en halt av organiskt kol på 45%. Adsorptionen av PFAS:er var starkt positivt korrelerad med kedjelängden på de perfluorinerade kolkedjan. Ju längre kolkedja (dvs. mer hydrofob), desto starkare adsorption till partiklar. Relationen mellan sorptionen (här uttryckt som partitioneringskofficienten log Kd) och kedjelängd var linjär för alla PFSA och för C3 till C10 för PFCA. PFSA (sulfonat) adsorberade starkare än PFCA (karboxyl), och FOSA (sulfonamid) adsorberades starkast. För de flesta PFCA, (C5-C13) fanns en allmän trend där log Kd (dvs. sorption) minskade med ökande pH, på grund av pH-beroende förändringar på jordpartiklarna. För korta och medellånga PFCA (C5-C8) och för PFHxS hade katjonsammansättningen en tydlig effekt på sorptionen. Aluminiumjoner (trevärd, Al(NO3)3) hade den största effekten, följt av kalcium (tvåvärd, Ca(NO3)2) där den högre koncentrationen resulterade i starkare sorption. Natrium (envärd, NaNO3) hade minst påverkan på sorptionen till jordpartiklar. Visual MINTEQ tar hänsyn till många parametrar (inklusive pH), när nettoladdningen på jordpartiklarnas yta räknas ut. När log Kd för olika PFAS:er jämfördes med endera pH eller negativ nettoladdning, drogs slutsatsen att nettoladdning korrelerade bättre med sorption än pH.

published_or_final_version / Education / Master / Master of Education