Browsing by master's degree program "Kemian ja molekyylitieteiden maisteriohjelma"

Oxidized compounds in the atmosphere can occur as emitted primary compounds or as the products of secondary formation when volatile emitted precursors react with various oxidants. Due to the polar functional groups, their vapor pressures decrease and they condense onto growing small particles or forming new particles by the cloud condensation nuclei reaction. Small particles affect climate change by the formation of clouds and scattering solar radiation. The particles and oxidized compounds themselves could cause serious health problems when inhaled. Thereby, the study of oxidized compounds in the atmosphere is very important. Based on the literature review, the focus of the research is to discover new oxidized species, and to evaluate their sources and factors affecting their formation. Monitoring of biogenic and anthropogenic primary oxidized compounds or secondarily oxidized products in chamber experiments or field campaigns is common. New discoveries have been reported including various new oxidized compounds and a new group of compounds called highly oxidized organic molecules (HOMs). Analytics is mainly focused on chromatographic methods identifying and quantifying compounds in low concentrations. The analytics of HOMs are currently based on high-resolution mass spectrometry employing chemical ionization. Oxidized compounds could also be monitored by spectrophotometric methods in which the determinations of total amounts are based on functional groups. In the experimental part of this thesis, a liquid chromatography-tandem mass spectrometric method applying hydrophilic interaction chromatography was developed to analyze 18 organic acids. The developed method was sensitive to C4-C10 dicarboxylic acids and aromatic acids. In contrast, for smaller and multifunctional acids, the sensitivity decreased due to broader chromatographic peaks. Acids were determined from aerosol samples which were collected with conventional filter sampling and miniaturized filter sampling on a drone. The aim of the work was to compare samples collected with two different sampling techniques to assess if they provided comparable results. Concentration differences between daytime and night-time was assessed from samples taken with conventional filter sampling. C4-C9 dicarboxylic acids, cis-pinonic acid, benzoic acid, phthalic acid, and glycolic acid were detected in both sample types. Possible elimination of adsorption from gas phase to particle phase was demonstrated for cis-pinonic acid and succinic acid due to the lower sample volume in drone sampling. Other detected acids’ concentrations were comparable between two different sampling strategies, considering different sampling sites and extraction methods. Daytime and night-time comparison suggest that acids’ concentrations are higher in daytime when photo-oxidation reactions occur.

Optical frequency combs are broadband laser light sources that produce light consisting of equally separated narrow lines. The frequencies of these comb lines can be determined and stabilized accurately. A dual-comb spectrometer is based on two optical frequency combs, and it can measure spectra at high speed and with high spectral resolution and accuracy. This requires high mutual coherence between the two combs. In this thesis, a passively coherent dual-comb spectrometer was optimized for spectroscopic temperature measurements. Spectroscopic temperature measurements presented in this thesis are based on quantifying the temperature dependence of the molecular absorption lines. In the experimental part of this thesis, three different spectroscopic temperature measurement techniques were used to measure the temperature of acetylene gas and results were compared to the temperature value of a reference temperature sensor. The three methods that are demonstrated in this thesis are line-strength ratio thermometry (LRT), rotational-states distribution thermometry (RDT), and Doppler-broadening thermometry. The measured dual-comb spectra had high quality and the dual-comb figure of merit was determined to be 5.7×10^6 Hz^(-1/2), which is a typical value for a high-quality dual-comb spectrometer. All the temperature measurements were performed at room temperature (295 K). Line-strength ratio thermometry produced the most accurate temperature results, with an estimated uncertainty of approximately 1 K. Rotational-states distribution thermometry results had an estimated uncertainty of about 3 K. Doppler-broadening thermometry did not produce reliable results, most likely due to too high gas pressure. The possible future work should be performed with larger temperature and pressure ranges to assess the accuracy of the presented spectroscopic thermometry techniques more thoroughly.

Photocatalytic reactions utilize energy harnessed from light for the activation of a catalyst. In photoredox catalysis, an excited photocatalyst can take part in redox reactions with a substrate. The most common photocatalysts could be divided into three classes: metal catalysts, organic dyes, and heterogeneous semiconductors. These catalysts are often employed with a transition metal dual catalyst. The dual catalyst enables the cross-coupling of substrates, and the photocatalyst oxidizes or reduces the dual catalyst. Photocatalytic reactions can offer a milder alternative for the traditional C-N coupling reactions. In the literature review section, the photocatalytic N-arylation of pyrrolidines was examined. The review found that pyrrolidines were successfully N-arylated with all of the catalyst types, and multiple variations on the substituents on the aryl halide. In the majority of the research, electron withdrawing groups (EWG) as substituents enhanced product yields, but electron donating groups (EDG) decreased yields. In an organic dye catalysed reaction, the effects of the substituents were opposite. In addition, the photocatalytic reactions were compared with traditional C-N coupling reactions, such as the Buchwald-Hartwig reaction, Ullmann-type reactions nucleophilic aromatic substitution and the Chan-Lam reaction. These reactions often had harsh reaction conditions. The photocatalytic N-arylation of 3-substituted pyrrolidines was examined in the experimental part of this thesis. The objectives of this study were to investigate the use of photoredox methodologies for the C-N coupling of 3-substituted pyrrolidines to arenes and examine the scope and limitations of the reaction and the effects of substituents. In addition, the aim was to optimize the reaction conditions for multiple parameters and for each product separately, apply the reaction on a flow chemistry appliance, and execute scale-up reactions on both photoreactors. The study found 3-substituted pyrrolidines to be successfully coupled with aryl halides with great variation in the substituents of both starting materials. With optimization, the reactions with lower product yields were able to be improved significantly. The reaction was successfully upscaled, but the adaptation on the flow reactor requires further optimization. Photocatalytic C-N coupling reactions offer a promising alternative for traditional reactions.

Utilization of pesticides in the modern agriculture is often indispensable for gaining good crops. However, pesticides are abundantly being used in too hight quantities which leads to potential health risks for the consumers. Currently there are no pre-screening methods for monitoring the levels of pesticides in food, but only a negligible small percentage of all goods are being tested using the laborious standardized methods. This master’s thesis is an investigation, that was carried out in the wet laboratory of KARSA Oy Ltd, on 10 different pesticides: Glyphosate, Thiabendazole, 2-phenylphenol, Chlorpyrifos, Fludioxonil, Chlormequat, Bupirimate, Diflubenzuron, Fenpyrazamine and 2,4-dichlorophenoxyacetic acid. Pesticides were ionized using straight radiation chemical ionization (SRCI) in positive and negative modes without any added reagent and also using bromide, nitrate, acetonylacetone and acetone as reagents. Charged target molecules and adducts were detected using Thermo fisher Iontrap/Orbitrap (LTQ Orbitrap velos pro upgraded) mass spectrometer. After the initial method development and scoping measurements pesticides were studied both individually and as a mixture of all 10 pesticides. Sample solutions were first injected with syringe so that the solvent and targets evaporated at the same time inside the desorber heating block of SRCI inlet. In these syringe injection measurements, the desorber temperature was set at 150 °C. Mass range at 125–750 has been used for all the pesticides except for Chlormequat (100–750). After the syringe injection measurements, the mixture of 10 pesticides was analysed by TCM filters. Target solutions of 1 µl volume were placed on filters and after the solvents had evaporated the filters were heated from room temperature to 245°C using the same setup as with the syringe injections. In conclusion, with syringe injections 7 pesticides out of 10 were detected using positive and negative mode without any added reagent. The highest target intensities were recorded from TCM filters. Overall, applying the SRCI-Orbitrap setup for pesticide pre-screening from target solutions resulted in the detection of 9 pesticides out of 10.

Psykotrooppiset lääkeaineet vaikuttavat potilaan psyykeeseen. Tällaisiä lääkeaineita ovat esimerkiksi antipsykoottiset ja antidepressiiviset lääkeaineet. Ne ovat tehokkaita tautien hoidossa, mutta vakavien haittavaikutusten välttämäiseksi lääkeaineenpitoisuuden tasoa tulee seurata. Terapeuttisessa lääkkeen monitoroinnissa on tärkeää toteuttaa seurantasuunnitelmaa, etenkin klotsapiiniä sekä norklotsapiini käyttävien potilaiden kohdalla. Tämän maisterin tutkielman kirjallisessa osassa tarkastastellaan psykotrooppisten lääkeaineiden luokituksia ja molekyylirakennetta. Lisäksi siinä esitellään neste- ja kaasukromatografisia erotusmenetelmiä eri detektoreilla, sekä nestekromatografinen laitteisto. Kromatografiset menetelmät ovat tärkeässä roolissa nykyaikana määritettäessä psykotrooppisia lääkeaineita. Massaspektrometrin käyttö detektorina on yleistynyt huomattavasti, mutta kliinisessä työssä suositaan myös UV-Vis- detektoreja tai diodirividetektoreja. Usein näytteen esikäsittelyssä käytetään aikaa vievää sekä kallista neste-neste uuttoa. Joskus käytetään myös kapillaarissa tapahtuvaa kiinteäfaasiuuttoa tai saostusta. Tutkielman kokeellisessa osassa validoitiin analyysimenetelmä, LC-MS/MS, joka oli lineaarinen, selektiivinen, tarkka ja yksityiskohtainen, sekä toistettava. Lyhyt retentioaika, tehokas ja helppo näytteenesikäsittely saostamalla ja Tecan nesteensiirtorobotilla tehtävä näytteensiirto rutiinianalysointia varten oli suuri etu verrattuna käytössä olleeseen HPLC-UV/Vis- menetelmään. Nykyisellä kuoppalevyllä voidaan tehdä 96- näytteen sarja kun aiemmin pystyttiin analysoimaan vain 50 näytteen sarja. Menetelmä paransi myös muiden analysoitavien näytteiden häiritsevyyttä tarkemmalla detektorilla. Lisäksi tarkoituksena oli vähentää orgaanisten liuottimien kulutusta muuttamalla neste-nesteuutto proteiinien saostukseksi.

Piperine represents the major plant alkaloid encountered in various Piperaceae species and has received in recent years considerable attention because of its broad range of favorable biological and pharmacological activities, including antioxidant, immunostimulant, bioavailability-enhancing and anti-carcinogenic properties. The literature part of this thesis gives a selective overview of advanced methods for the quantitative analysis of piperine in plant-base materials, and various approaches employed for instrumental analysis, including spectroscopic, chromatographic, and electrochemical techniques. An effort was made to evaluate the potential of the reported methods based on the analytical figures of merit, such as total sample throughput capacity, analytical range, precision, accuracy, limit of detection and limit of quantification. The objective of the experimental part of the thesis focused on the development of a convenient, robust, simple, efficient and reliable method to quantify piperine in pepper fruits. The analytical method established in this thesis involves liberation of piperine by continuous liquid extraction of ground pepper fruits with methanol, and cleanup of the crude extracts with reversed phase solid phase extraction. Analyte quantitation was accomplished using gradient reversed phase High Performance Liquid Chromatography with mass spectrometric detection, using Electrospray Ionization-Ion Trap Mass Spectrometry. To enable reliable internal standardization, deuterium labelled piperine surrogate (piperine-D10) was synthesized from piperine in three steps in a reasonable overall yield (65 %) and standard-level purity (99.7 %). It may be worth mentioning that the commercial market value of the amount of piperine-D10 synthesized in-house exceeds 167,400 euros. One of the major challenges encountered during the development and optimization of the analytical method was the extreme photosensitivity of piperine and piperine-D10, both suffering in solution extensive photoisomerization upon exposure to ambient light within matter of minutes. This issue was addressed by carrying out all tasks associated with synthesis, sample preparation and analytical measurements under dark conditions. For the preparation of calibrators, a fully automated procedure was developed, being controlled by custom-written injector programs and executed in the light-protected sample compartment of a conventional autosampler module. In terms of merits, the developed analytical method offers good sample throughput capacity (run time 20 min, retention time 8.2 min), excellent selectivity and high sensitivity (Limit of Detection= 0.012 ppm, Limit of Quantification= 0.2 ppm). The method is applicable over a linear range of 0.4 to 20 ng of injected mass (r2= 0.999). The stability of standards and fully processed samples was found to be excellent, with less than 5% of variations in concentrations occurring after a 3-week (calibrators) or 4-month (samples) storage at 4 °C and 23 °C respectively, under dark conditions. Intra-day repeatability were better than 2.95 %. Preliminary validation data also suggest satisfactory inter-operator reproducibility. To test the applicability of the developed LC-MS method, it was employed to quantify piperine in a set of 15 pepper fruit samples, including black, white, red and green varieties of round and long peppers, purchased from local markets and retailers. The piperine contents obtained were in the range of 17.28 to 56.25 mg/g (piperine/minced sample) and generally in good agreement with the values reported in the scientific literature. It is justified to assume that the developed analytical method may directly be applicable to the quantitation of related pepper alkaloids in herbal commodities, and after some modifications in the sample preparation strategy, also for the monitoring of piperine in biological fluids, such as serum and urine.

The literature part of the thesis focused on reviewing published LC–MS/MS methods for cardiovascular drugs in biological matrices. Emphasis was given to the used sample preparation procedures and usability in different types of analyses, and their effects to the performances of the whole methods. Published methods for cardiovascular drugs in biological matrixes from the last decade were reviewed and presented. Insight into the challenges biological matrixes present was given, as well as a short overview of cardiovascular drugs. Plasma and urine were the most common sample matrixes, but some methods have also been published for serum and whole blood, and one even for fat tissue. Development and basic principles of liquid chromatography and mass spectrometry were presented, focusing on high and ultra-high performance liquid chromatography (HPLC and UHPLC) and triple quadrupole tandem mass spectrometry (QqQ–MS), as these seemed to be prevalent industry standard. Of sample preparation techniques, protein precipitation, direct dilution, liquid–liquid extraction (LLE), solid-phase extraction (SPE) and turbulent flow chromatography (TFC) were covered, with additions of some miniaturized versions. Some newer miniaturized online techniques have successfully been utilized for cardiovascular drug analysis, and their popularity will likely increase as the hardware in laboratories gets more and more modern. Advances in sample preparation techniques were relatively mild during the decade covered in this review, despite the significant proportion cardiovascular drugs hold in used medications. Newly published methods were either quantitative for a handful of analytes, or qualitative screenings for several analytes, some of which are cardiovascular drugs. Plasma and urine samples were used almost exclusively. In addition to the literary review, an experimental study was done at THL, where a LC–MS/MS method was successfully developed and validated during 2018–2019. The method has been used since 2019 as the primary qualitative method in cause–of–death investigations for 55 cardiovascular drugs analysed from post-mortem whole blood samples. In light of the done review, this method is exceptionally comprehensive regarding included analytes, and could potentially be at least partially automated with suitable instruments

Fluori-18 on hyvin suosittu nuklidi PET-kuvantamisessa ja yhä useampi merkkiaine halutaan leimata sillä. Kaikkia molekyylejä ei kuitenkaan pystytä 18F-fluoraamaan perinteisillä menetelmillä tai niiden radiokemialliset saannot ovat olleet huonoja. Varsinkin aromaattisten renkaiden suora, yhdenvaiheen 18F-fluoraus on ollut synteesimenetelmillä vaikeaa tai lähes mahdotonta. Siirtymämetallivälitteisellä 18F-fluorauksella voidaan välttää perinteisen fluorauksen heikkouksia. Uusilla menetelmillä voidaan syntetisoida [18F]fluoridilla merkkiaineita, joita on aiemmin pystytty tuottamaan vain elektrofiilisellä [18F]F2-kaasulla. Tähän mennessä aryylien siirtymämetallivälitteistä 18F-radiofluorausta on tutkittu esimerkiksi palladiumillä, nikkelillä, hopealla, kuparilla ja ruteniumilla. Pro Gradu-työn tarkoituksena oli optimoida siirtymämetallivälitteisiä radiofluorausmenetelmiä (kupari ja rutenium) ja tutkia niiden toimivuutta. Synteesit tehtiin Turku PET-keskuksessa lyijykaapissa puoliautomatisoidulla synteesilaitteella ja radiokemialliset saannot analysoitiin käyttäen radio-HPLC:tä. Kuparivälitteisissä radiosynteeseissä [18F]fluoridi irrotettiin kuparitriflaatin ja litiumtriflaatin avulla ja mallisynteesinä käytettiin tert-butyyli-(1R,3S,5S)-3-((6-([18F]fluori-pyridiini-2-yyli)oksi)-8-atsabisyklo[3.2.1]oktaani-8-karboksylaatin ([18F]7) synteesiä. Ruteniumvälitteisissä synteeseissä pyrittiin tuottamaan kahta aivokuvantamisen radiomerkkiainetta: 5-(3-[18F]fluorifenyyli)-3-(((R)-1-fenyylietyyli)amino)-1-(4-(trifluori-metyyli)fenyyli)pyrrolidiini-2-onia ([18F]4), sekä N,N-dietyyli-2-(2-(4-[18F]fluorifenyyli)-5,7-dimetyylipyratsoli[1,5-a]pyrimidiini-3-yyli)asetamidia ([18F]6). [18F]7 synteesitulos saatiin 7 mg:n anioninvaihtopatruunalla, jolloin irrotusprosentti oli 56 % ja tuotteen radiokemiallinen saanto 83 %. [18F]4 synteesi optimoitiin onnistuneesti ja sen radiokemiallinen saanto oli 86,2 %. Synteesin kriittisiä vaiheita olivat tarpeeksi korkea lämpötila (T= 160 ℃) ja 1,3-bis(2,6-diisopropyylifenyyli)-2-kloroimidatsoliumkloridin lisääminen kuumaan kompleksoituun lähtöaine-rutenium-kompleksi-seokseen, jolloin se pystyi muodostamaan sidoksen lähtöaine-kompleksin kanssa ja auttamaan [18F]fluoridin nukleofiilisessä substituutio reaktiossa. Toisella ruteniumvälitteisellä synteesimenetelmällä valmistetun [18F]6:n synteesin tulokset olivat heikkoja (8,3 %).

Long term nuclear waste disposal has arisen as an important field of study due to the increasing amounts of generated nuclear waste. A suggested approach to long term disposal is geological waste deposits. Selenium-79 is a relevant radionuclide in nuclear waste because it has a long half-life and its species can be very mobile. Sorption modeling is a way of studying the sorption behavior in a very detailed manner. This study focused on sorption behavior of selenium on kaolinite, which is a prevalent clay mineral. Sorption was studied with batch sorption experiments, which yielded distribution coefficients and a sorption isotherm that details low sorption of selenium on the surface of kaolinite. Mineral characterization of kaolinite along with titration experiments resulted in promising sorption data, that could be further used for sorption modeling in the future.

Surface charging behavior of commercial pure calcite and calcite samples from the Bukov underground research facility was studied by measuring the zeta potential of the samples after equilibration with CO2 gas and determining their cation exchange capacity. For zeta potential measurements, different calcite samples with grain sizes under 25 μm were submerged into five different electrolyte solutions: 0.01 M NaCl, 0.001 M CaCl2, 0.005 M NaCl + 0.0025 M MgCl2, 0.0025 M NaCl + 0.00375 M MgCl2, and a synthetic groundwater simulant (SGW2). A pH range of 6.5 – 11 was established and maintained across sample series for the duration of the experiments, and the samples were equilibrated with CO2 gas by regular bubbling of a 250 ppm CO2/N2 gas mixture into the solutions in 1-hour sessions. The length of the equilibration process varied from three days to one month, and after its conclusion the zeta potential of each sample was measured. The goal of the experiments was to evaluate the feasibility of equilibrating calcite samples with CO2 when studying their zeta potential. Additional goals included comparing different types of calcite in different solutions, as well as determining an optimal duration for equilibration. The results were compared with an earlier study where calcite zeta potential was determined under total CO2 exclusion. For the determination of cation exchange capacity, two cobalt hexamine trichloride solutions were used, one saturated with pure calcite and one saturated with Bukov calcite. Samples of both types of calcite were shaken for 1 hour in their respective solutions, and the ionic composition of the supernatant from each sample was determined using microwave plasma atomic emission spectrometry. Cation exchange capacity was calculated from the measurement results. According to the results obtained, long-term exposure and equilibration with CO2 may have a positive effect on the internal stability of calcite samples and lead to more reliable zeta potential measurements. Samples showed minimal fluctuation in the concentration of Ca in bulk solution after one week of equilibration, and no significant rise or decline in stability was noted to occur if equilibration was continued beyond one week. Compared to CO2 exclusion, equilibration produced more consistent trends in zeta potential values, though the results were heavily dependent on the electrolyte solution used in the experiment. Cation exchange capacity experiments also produced much larger values than the previous exclusion study despite using the same types of sample, hinting at a significant difference in the grain sizes used.