Browsing by Subject "ICP-MS"
Now showing items 1-7 of 7
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(2023)A geopolymer waste form containing gasified ion exchange resin loaded with stable analogues of radionuclides (e.g., Sr, Co, Ni, Cr, Cs) was studied using semi-dynamic batch leaching experiments. The experiments were conducted for 180 days using an alkaline groundwater simulant in a glove box with controlled N2 atmosphere with < 10 ppm CO2 and O2. The experiments were conducted to investigate the leaching behavior of the geopolymer in conditions relevant to a low- and intermediate-level waste repository. The leaching results of the geopolymers showed leaching of cesium, sodium, aluminum, and silicon from the geopolymer, while potassium and calcium in the leachant sorbed to the geopolymer. The leaching and sorption rates were at their highest for the first 28 days of the experiment, before slowing down to a steady state which were maintained until the end of the experiment. This suggests that the geopolymers immobilized the waste analogues effectively with exception of cesium which had leached by 55 wt% of the initial fraction by day 180. The leaching indices of sodium, aluminum, silicon, and cesium were determined as: 9.9 ± 0.38, 10.1 ± 0.47, 10.5 ± 0.40, and 9.1 ± 0.30 respectively. The leaching indices are well above 6, which is considered a minimum value for WAC of cementitious waste forms by USNRC. The solid phase analysis of the geopolymer samples showed both presence of calcium rich secondary phases and increasing calcium concentration in the bulk matrix on the leachant contact surface of the geopolymer. It was concluded that the secondary phases consisted of CaCO3 minerals.
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(2020)Inductively coupled mass spectrometry (ICP-MS) is a state-of-the-art technique for elemental analysis. The technique allows fast and simultaneous analysis of multiple elements with a wide dynamic range and low detection limits. However, multiple adjustable parameters and the complex nature ICP-MS instruments can make the development of new analysis methods a tedious process. Design of experiments (DOE) or experimental design is a statistical approach for conducting multi- variate experiments in a way that gives maximal amount of information from each experiment. By using DOE the number of experiments needed for analytical method optimization can be minimized and information about interrelations of di↵erent experimental variables can be obtained. The aim of this thesis is to address the utilization of DOE for ICP-MS method developement as a more e cient mean to optimize analytical methods. The first part of this two part thesis gives an overview on the basics of ICP-MS and DOE. Then a literature review on applying experimental design for ICP-MS method optimization is given and the current state of the research is discussed. In the second part, two new ICP-MS methods for simultaneous determination of 28 elements from six middle distillate fuels, diluted with xylene or kerosine, are presented. The method developement involved optimization of the integration times and optimization of test sample dilution ratios and viscosities using univariate techniques. In addition, experimental designs were succesfully utilized together with desirability approach in multivariate optimizations of the plasma conditions and sample matrix compositions to achieve the best possible analyte recoveries from various matrices.
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(2022)In chemical forensics inorganic analysis is for example used to detect traces of explosives and drugs, to find residues of firearms, and as aid when searching for hidden burial sites. Forensic investigators also utilise inorganic information in chemical source attribution or fingerprinting, which seeks to identify chemical profiles of inorganic and/or organic compounds and elements that can provide information on the origin of the sample, how it has been produced and using which raw-materials. As the chemical profiles typically contain information for several compounds, comparison of profiles have to be analysed by multivariate statistical tools such as principal component analysis (PCA), hierarchical cluster analysis (HCA) and linear discriminant analysis (LDA). In this work the applicability of inorganic source fingerprinting on soil samples was investigated. For this an extraction procedure and an ion chromatographic (IC) method for the determination of F–, Cl–, Br–, NO3–, PO43–, SO42– and AsO43– in soil were developed and validated. Extraction of anions was done by microwave assisted solvent extraction, with good recoveries (86.15 % – 115.23 %) for nearly all recovery samples. The recovery of F– from soil was 174.77 %, due to enhanced extraction efficiency caused by the high extraction temperature. AsO43– could not be quantified due to low extractability and interfering matrix components. Development of a method for elemental analysis of soil samples by inductively coupled plasma mass spectrometry (ICP-MS) was also attempted. Complete dissolution was not achieved with microwave assisted acid digestion mainly because of the large particle size of the soils analysed. Samples were analysed for As, Co, Cr, Cu, Fe, Mn, Mo, Ni, V and Zn, but Ni could not be quantified from any of the samples because of the high detection limit caused by contamination of samples. Due to contamination and incomplete dissolution the variation in the results were large, leading to a large uncertainty for the results. Analysis of variance (ANOVA) revealed that there is a significant (α = 0.05) difference in the concentrations of all analytes but Mo and V between the samples. Two step PCA and LDA were performed on tha anion and elemental results separately. Better clustering of sample results were typically got with LDA than with PCA. LDA on the anion results was able to discriminate all samples while only four out of seven samples were identified by PCA. The large variation in the data meant that only the reference soil could be identified when all elemental concentrations were included. Removal of outliers from the data lead to identification of all samples by both PCA and LDA. This work showed that samples can be identified by their inorganic profiles, but large variations in the measured concentrations will make the discrimination by multivariate statistics difficult. Further work should focus on improving the separation of the IC method and on decreasing the variation in the data by decreasing sample heterogeneity and contamination during the sample preparation.
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(2022)Ihmistoiminnan seurauksena luonnonvesiin päätyy haitallisia metalli-ioneja, joiden aiheuttamista ongelmista kärsivät nykyään eniten köyhät ja kehittyvät maat. Metalli-ionianalytiikalla on tärkeä rooli sekä luonnonvesien tarkkailussa että tutkimisessa kuin myös teollisten prosessien laadunvalvonnassa ja kehityksessä. Induktiivisesti kytketystä plasma-massaspektrometrista (ICP-MS) on tullut yksi yleisimmistä metallianalytiikassa käytettävistä analyysilaitteista. Useiden metalli-ionien pitoisuudet vesinäytteissä ovat kuitenkin laitteen määritysrajaa matalampia, jonka vuoksi analyytit täytyy esikonsentroida mittausta varten. Lisäksi suuri liuenneen kiintoaineen määrä saattaa vahingoittaa ICP-MS -laitetta. Edellä mainitut ongelmat ovat usein ratkaistavissa kiinteäfaasiuuton avulla, josta on kehittynyt erittäin monipuolinen ja helppo esikäsittelymenetelmä erilaisten vesinäytteiden analysointiin. Tutkielman kirjallisessa osiossa perehdytään metalli-ionianalytiikan merkitykseen sekä tutkituimpien metalli-ionien ominaisuuksiin ja terveysvaikutuksiin. Osiossa esitellään yleisimpiä ja uusimpia kiinteäfaasiuuttotekniikoita sekä vertaillaan off-line- ja on-line-sovellusten erityispiirteitä. Lisäksi perehdytään tekijöihin, jotka saattavat vaikeuttaa tai haitata kiinteäfaasiuuttoprosessia ja ICP-MS -mittausta. Kirjallisen osion loppupuolella käsitellään mielenkiintoisimpia, pääsääntöisesti vuosina 2010-2022, raportoituja kiinteäfaasiuuttosorbentteja, joita on käytetty tutkimuksissa, joissa mittaus on suoritettu ICP-MS:lla. Tutkielmassa käsitellään eräiden sorbenttien ja analyysiprosessien erityispiirteitä sekä tarkastellaan tärkeimpiä analyysiparametreja. Tutkielman kokeellisessa osiossa määritettiin hopea- ja koboltti-ionipitoisuuksia ICP-MS:lla Loviisan ydinvoimalaitoksen boorihappopitoisesta primääripiirin jäähdytteestä. Ydinreaktorissa aktivoituvat hopea- ja koboltti-ionit aiheuttavat merkittävän osan voimalaitostyöntekijöiden vuotuisesta säteilyannoksesta, jonka vuoksi kyseisten ionien tarkkailulla on suora vaikutus laitosturvallisuuteen. Määritystä varten boorihappo poistettiin aluksi selektiivisellä N-metyyliglukamiinipohjaisella ioninvaihtohartsilla. Tämän jälkeen hopea- ja koboltti-ionit esikonsentroitiin iminodiasetaattipohjaisella kiinteäfaasiuuttosorbentilla. Tulosten perusteella kehitettiin esikäsittelylaittoisto, joka koostui kahdesta päällekkäin asetetusta kolonnista. Metalli-ionipitoisuudet määritettiin ICP-MS:lle kehitetyn menetelmän avulla.
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(2021)The Paleoproterozoic (1.87 Ga, ɛNd -3.7) Suvasvesi granitoid intrusion in southeastern Finland is considered to be a part of the Heinävesi intrusive suite. Inner parts of the lithologically zoned Suvasvesi intrusion are variably alkali feldspar porphyritic biotite granitoid rock and the margins are composed of a more biotite-rich equigranular granitoid rock variety. The Paleoproterozoic metasedimentary rocks of the Viinijärvi suite adjacent to the Suvasvesi intrusion are intruded by leucocratic pegmatite dikes. Potential sources and possible contamination of the granitoid melt are considered with the help of structural and textural observations, petrography, whole-rock geochemistry, mineral chemistry, and petrophysical data. The data were acquired from 34 rock samples collected during a bedrock mapping campaign and combined with the pre-existing mapping, petrographic, and geochemical data from the Suvasvesi and surrounding areas. The Suvasvesi granitoid intrusion is compared to other members of the Heinävesi suite to verify the hypothesis of their petrogenetic connection. The compositions of both Suvasvesi intrusion and Heinävesi suite are also compared to the potential proximal sources, the adjacent Paleoproterozoic metasedimentary rocks and Archean units in the area. In addition, the compositions of the Suvasvesi intrusion and Heinävesi suite rocks are compared to other granitoids from Eastern and Northern Finland with suggested Archean sources, and to regional granitoids of same age. Based on the similarity of major and trace element compositions, it is suggested that the Suvasvesi granitoid is part of the Heinävesi suite. The granites and granodiorites of the Suvasvesi granitoid and the Heinävesi suite are ferroan, calc-alkalic, and peraluminous with average ASI value of 1.08 (n = 73). Although the Heinävesi suite is postkinematic, it shows very few similarities to other rocks of same age. The εNd values of the Heinävesi suite and the paragneiss enclaves within the Suvasvesi intrusion indicate metasedimentary source component or assimilation. Conversely, the I-type mineralogy and geochemistry suggest igneous/meta-igneous source component for the Heinävesi suite. Potential infracrustal sources for the granitoid magma are the Archean TTGs and amphibolites. The conclusion for the magma source is ambiguous. For further studying additional isotope analyses and thermodynamic modelling of the Suvasvesi and Heinävesi magmas are suggested.
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(2020)Naturally occurring radioactive material (NORM) is defined by the IAEA as “Radioactive material containing no significant amounts of radionuclides other than naturally occurring radionuclides”. In the EC directive 2013/58/Euratom several industry sectors are listed that are known to often deal with NORM, either in residues, wastes, by-products, or products, the mining industry is one of these. The risk posed by NORM is defined by exposure potential and concentration. In the wastes created by the mining industry these are tied to the management of wastes and concentration of radionuclides in the exploited mineral resource. Wastes created by the mining industry are often of environmental concern as they are in many cases piled on the mining site after closure. The tailings of a mine may contain pyrite, which when oxidized creates acid mine drainage. The acidic waters in such sites can enhance the mobility of radionuclides and other harmful elements. In this thesis two mine waste sites were selected for study, which were known to have had issues with natural radioactivity. These two sites were the old Zn, Pb, Cu mine of Vihanti and the Pb, REE mine of Korsnäs. The current state of these two sites was studied. Possible transport of radionuclides or other harmful elements and the dose to a member of the public on the sites was also studied. Soil, waste, sediment, and water samples were collected from both sites and analyzed. Solid samples were analyzed using gamma spectrometry and the radionuclides of interest were: 238U, 226Ra, 210Pb, 232Th, 228Th, 228Ra. Water samples were analyzed with ICP-MS and the elements measured with this method were: Al, Si, P, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Pb and U. In addition, some mine waste samples were studied further using XRF and SR-XRPD methods. The results of this thesis indicate that in Vihanti, the wastes have been adequately covered, reducing the external radiation dose to near background levels. The gamma spectrometry results showed no concerning activity concentrations in soil, sediment or waste samples. Two locations were found where the ICP-MS analyses yielded high concentrations of nearly all measured elements, the pH of these sites was low as well. Signs of acid mine drainage were found in these locations, but the effects seem to be localized and no evidence of large-scale transport of contaminants through waterways was found. In Korsnäs the wastes are split into two piles, one containing tailings, and the other enriched lanthanide that was never sold. The results indicate that the lanthanide pile has been adequately covered and the external radiation dose around the pile is near background levels. While the tailings have not been covered like the lanthanide pile has, the results showed that a member of the public is unlikely to receive a dose exceeding 0.1 mSv/a from spending time on the site. Activity concentrations exceeding 1 Bq/g were detected in samples collected from the lanthanide pile, with some evidence of uranium mobilization also seen. In addition, uranium concentrations in the waters of the old open pit mine were relatively high.
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Vantaanjoen Vanhankaupunginkosken padon yläpuolisten sedimenttien geokemiallinen koostumus ja määrä (2020)Helsingin kaupunki on pohtinut Vanhankaupunginkosken padon mahdollista purkamista, jotta Vanhankaupungin koski voitaisiin kunnostaa virkistäytymiskäyttöön. Padon purkamisella olisi positiivinen vaikutus alueen luonnolle sillä koskissa viihtyvät kalat saisivat suuremman lisääntymisalueen käyttöönsä. Vantaanjoki on vahvasti kuormittunut ihmistoiminnasta ja koko valuma-alueella on harjoitettu maataloutta ja teollisuutta. Tämän takia padon taakse kertyneet pohjasedimentit voivat sisältää pilaantuneen maan metalleja, jotka vapautuisivat Vanhankaupunginlahteen padon purkamisen myötä. Sedimenttinäytteitä kerättiin 14 kohteesta padon pohjoispuolelta Vantaanjoen yläjuoksulta. Seitsemässä sedimenttisarjassa pohjasedimentin paksuus vaihteli 70 ja 196 senttimetrin välillä. Kahdessa pohjoisimmassa sedimenttisarjassa oli nähtävissä jokisedimenttien vaihettuminen litoraalisiksi sedimenteiksi. Viikintien eteläpuolella patoaltaassa ei havaittu sedimentaatiota. Sedimenttinäytteet analysoitiin pilaantuneen maan metallien tutkimiseksi induktiivisesti kytketyllä massaspektrometrillä. Analyysi suoritettiin 113 näytteelle, jotka valmistettiin seitsemän sedimenttisarjan jokaisesta kerroksesta. ICP-MS-analyysissa mitattuja PIMA-pitoisuuksia verrattiin Suomen Valtioneuvoston PIMA-asetuksessa (214/2007) säädettyihin pitoisuuksiin. Asetuksessa jokaiselle PIMA-metallille on asetettu kynnysarvo sekä alempi ja ylempi ohjearvo. ICP-MS-analyysin tuloksista kynnysarvo ylittyi mitatuista 113 näytteestä arseenilla 93, kadmiumilla 14, koboltilla 4, kromilla 33, kuparilla 4, lyijyllä 38, nikkelillä 7 ja sinkillä 18 näytteellä. Alempi ohjearvo ylittyi kromilla kuudessa, lyijyllä kahdeksassa ja sinkillä 20 näytteessä. Ylemmän ohjearvon ylityksiä ei havaittu millään metallilla. Kohonneet pitoisuudet sijaitsivat pienellä alueella lähellä kohtaa, jossa Vantaanjoki haarautuu itäiseen ja läntiseen uomaan. Pilaantuneen maan metallien pitoisuudet ylittivät kynnysarvon monilla metalleilla ja alempi ohjearvo ylittyi kromilla, lyijyllä ja sinkillä. Vanhankaupunginkosken patoaltaasta mitatut metallipitoisuudet eivät kuitenkaan eroa Töölönlahdesta ja Laajalahdesta mitatuista metallipitoisuuksista. Hieman kohonneiden pitoisuuksien takia alueen pilaantuneisuutta ja puhdistuksen tarvetta tulisi kuitenkin arvioida.
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