Prefabricated baby food is under strict EU legislation by Commission Regulation (EC) 1881/2006 Setting maximum levels for certain contaminants in foodstuffs regarding the maximum allowed content of potentially harmful elements. For potentially toxic trace elements the regulated maximum content is regulated for lead, cadmium, mercury, inorganic tin, inorganic arsenic, cesium, copper and manganese. The Swedish national food agency (Livsmedelsverket) conducts chemical analyses of the regulated elements by full microwave acid digestion followed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis. In this study a simple artificial in vitro digestion method was developed using a commercially available enzyme supplement and optimized to determine the bio-accessible amount of eight potentially harmful metal trace elements that are associated with modern electronics (lithium, vanadium, cobalt, nickel, arsenic, selenium, cadmium and lead) in five prefabricated baby meals from the Swedish market by well-established manufacturers. The results were compared to the total mass content as well as the regulated limits and toxicological literature data. The samples had analyte dry mass contents that were extractable by the developed in vitro method that ranged from 0.0314 μg g-1 to 0.0691 μg g-1 for lithium, 9.42*10-5 μg g-1 to 0.0152 μg g-1 for vanadium, 6.61*10-3 μg g-1 to 30.9*10-3 μg g-1 for cobalt, 0.0599 μg g-1 to 0.194 μg g-1 for nickel, 4.54*10-4 μg g-1 to 0.0431 μg g-1 for arsenic, 8.87*10-4 μg g-1 to 9.85*10-3 μg g-1 for cadmium and 1.24*10-3 μg g-1 to 0.0232 μg g-1 for lead. Selenium was not detected in any of the samples. None of the samples were found to contain toxic levels of any of the quantified elements. Comparisons and paired t-tests of recoveries between the in vitro digestion and control procedures consisting of digestion solutions that exclude either enzymes, pH adjustment or both suggested that lithium, cobalt and cadmium were protein bound and that the digestion enzymes used had a statistically significant effected on the recovery. With further optimization and more extensive comparison to reference data the method could potentially be established as a simple and affordable alternative to more elaborate methods for screening or small scale analysis of the bio-accessible fraction of metal trace elements in food.

El análisis elemental de muestras clínicas presenta grandes dificultades que superar como el bajo volumen de muestra, la baja concentración de analitos de interés y la compleja matriz de la muestra. El sistema hTISIS se plantea como una posible solución para llevar a cabo este tipo de análisis, debido a que se puede trabajar en modo de introducción de muestra segmentada, siendo el volumen de muestra necesario de unos cuántos µL y a que se consigue una eficacia de transporte cercana al 100%, al trabajar con dicho sistema a elevadas temperaturas, independientemente de la matriz. Esto hace que se pueda analizar este tipo de muestras mediante calibración externa con patrones acuosos, lo cual es una gran ventaja sobre todo para aquellas muestras en las que además no existen patrones de referencia.

En la presente Tesis Doctoral la técnica de ablación laser acoplada a ICP-OES/MS ha sido empleada para analizar muestras sólidas, como catalizadores usados en el refinado del petróleo y polímeros. Se han llevado a cabo dos tipos de análisis, un análisis global de las muestras que proporciona información general y un análisis localizado que permite obtener información acerca de la distribución espacial de los elementos de interés en las muestras. Las diferentes variables de la técnica ablación láser son estudiadas con el fin de seleccionar aquellas que conducen una señal alta y estable, así como a un menor grado de fraccionamiento. Este estudio se realiza para cada tipo de muestra, ya que los resultados dependen de la matriz estudiada. Además, en esta Tesis doctoral se desarrolla un método de calibración para llevar a cabo un análisis cuantitativo de las muestras sólidas, basado en la deposición de patrones líquidos sobre la muestra sólida. Este método es conocido como “dried droplet calibration approach” (DDCA), y permite cuantificar elementos presentes en muestras sólidas sin necesidad de usar materiales de referencia sólidos. Este nuevo método de calibración compensa el fraccionamiento elemental y los efectos de matriz, proporcionando resultados exactos y preciosos para muestras complejas tales como vidrios, catalizadores y polímeros.

The paper examines lead isotope and trace element analysis in the context of a battlefield and their role in determining the course of the battle and categorizing the bullets within and to each participating side. It uses a theoretical framework with papers from both the archaeological and the forensic field. It concludes that trace element analysis has its criticism, especially from the forensic field, but can act as a complement to lead isotope analysis as it can give different answers from other parts of the bullet’s life cycle and should have a place in archaeology. The focus is on lead isotopes but concludes ICP-MS as a tool for examining bullets and other ammunition from archaeological battlefields is preferable. This is because of ICP-MS’s capability to analyse both lead isotope and trace elements. The paper also studies the ethical problems of using these methods and the answers they may give as a vessel for a discussion about what actions we are measuring with these methods.

L'objectif de cette étude est d'étudier le potentiel d'Opuntia ficus-indica (Ofi) en tant que biomoniteur dans un environnement contaminé par des dépôts atmosphériques enrichis en métaux lourds. Trois sites d'étude pollués ont été sélectionnés: industriel, minier et routier. Le phénomène de bioaccumulation a été validé en analysant la concentration en métaux lourds par SAA et ICP-MS dans plusieurs raquettes d'âge différent, dans les fruits et les racines. L'identification de l'origine du Pb a été étudiée à partir de la signature isotopique du Pb (TIMS) dans les raquettes, les racines et les sols, avec une caractérisation microscopique (MEB-EDX) des particules déposées à la surface des raquettes. Le taux de bioaccumulation du Pb suite à une exposition racinaire ou foliaire à des particules de fluorapatite synthétisées et enrichies en Pb à permis de préciser les voies de transfert vers la plante. Ainsi, la distribution particulaire ou dispersée du Pb dans les raquettes contaminées a été identifiée au moyen de cartographies MEB-EDX et µXRF. Les résultats obtenus montrent qu'Ofi est un bioaccumulateur du Pb, Cd et Cr. Les signatures isotopiques dans les raquettes révèlent la nature des diverses sources polluantes tout en donnant une indication sur l'évolution de la pollution atmosphérique au cours du temps. Le taux le plus élevé de Pb a été mesuré dans les raquettes contaminées à leur surface par de la fluorapatite. Les analyses microscopiques ont démontré pour les deux approches suivies l'intégration des particules déposées à la surface des raquettes au niveau de la cuticule, des trichomes et des stomates. Cette obsevation est cohérente avec la cartographie obtenue en µXRF. Notre étude démontre le potentiel de cette plante cosmopolite qu'est Ofi en tant que biomoniteur. / This study reports the potential of Opuntia ficus-indica (Ofi) as a biomonitor of atmospheric pollution in three heavily polluted sites, i.e., industrial, mining and road sites. The bioaccumulation phenomenon by Ofi was investigated by studying the heavy metal concentrations in different cladodes of various ages, roots and fruits, using AAS and ICP-MS. To identify the origin of Pb in cladodes, two types of methods were used: TIMS analysis which provided the lead isotopes ratios in cladodes, roots and soil samples, and SEM-EDX analysis at the cladode surface which provided the elemental distribution of Pb and airborne particles and a characterization of their chemical structure at the microscopic scale. A second study was also carried out by testing Pb bioaccumulation after foliar and roots exposure to synthesized fluorapatite particles enriched with Pb. SEM-EDS and µXRF analyses were used to follow the Pb concentration from the contaminated surface to the internal tissues. The results show that Ofi is indeed a bioaccumulator of Pb, Cd and Cr. The Pb isotopic signatures indicate that Ofi is a sensitive species to local aerial pollution and their successive cladodes obviously identify the evolution of air pollution with time. In addition, Ofi cladodes were found more contaminated with lead after direct foliar contamination. SEM-EDS measurements underlined in the two studies the retention of deposited particles on specific zones of the cladode surface (cuticle, trichome and stomata), which were also identified by µXRF cartography. These results represent the first demonstration of the potential of using Ofi, a cosmopolitan plant, as a biomonitor.

Adhesive tapes are a common type of evidence involved in violent crimes and national security threats. This research evaluated the utility of LA-ICP-MS and LIBS for the characterization of the trace elemental signature in adhesive tapes for forensic comparisons. LA-ICP-MS and LIBS methods were developed, for the first time, for the qualitative and quantitative analysis of adhesive tapes. The backings of 90 black electrical tapes, previously characterized by conventional techniques (physical examination, IR, Py-GC-MS, and SEM-EDS), were analyzed by LA-ICP-MS to evaluate the ability of the technique to discriminate samples originating from different sources and to associate pieces of tapes originating from the same roll. The discrimination for the LA-ICP-MS analysis of the 90 samples was found to be 93.9%, greater than the discrimination found using SEM-EDS (87.3%). Moreover, 100% correct association resulted for the control samples evaluated in this study. The analysis of tapes by LIBS allowed to separate pairs of tapes that were not previously distinguished by LA-ICP-MS by detecting differences in lithium, calcium, and potassium. The potential of normalization strategies was evaluated for LIBS spectral and statistical comparisons. Two quantitative analysis methods were developed for the analysis of tapes and other polymers. These quantitative methods can help in creating and populating databases that can lead to the use of likelihood ratios and the development of standard methods of analysis and interpretation for tape evidence. Two interlaboratory trials including 7 operational and research laboratories were completed as part of this study. SEM-EDS resulted in 16.7% and 12.5% false positive rates for interlaboratory tests #1 and #2, respectively. Up to 7 and 8 elements were detected by SEM-EDS for interlaboratory test #1 and #2, respectively. LIBS and LA-ICP-MS resulted in no false positives or false negatives. In addition, increased characterization of the samples was obtained by detecting up to 17 elements by LIBS and 32 elements by LA-ICP-MS. The increased sensitivity and selectivity of LIBS and LA-ICP-MS methods has been shown to distinguish tapes originating from different sources, and to correctly associate tapes belonging to the same rolls in different laboratories and by different analysts.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18803号 / 理博第4061号 / 新制||理||1584(附属図書館) / 31754 / 京都大学大学院理学研究科地球惑星科学専攻 / (主査)教授 平田 岳史, 教授 田上 高広, 教授 土`山 明 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

No description available.

Analytické metody LIBS a LA-IPC-MS založené na Laserové Ablaci (LA) nabízejí možnost rychlé chemické analýzy přímo z povrchu vzorku. Nedávno bylo ukázáno, že interakce světla s nanočásticemi může být využita pro zlepšení analytických schopností těchto metod. Při interakci nanočástic s laserovým paprskem dochází k zesílení elektromagnetického pole v jejich blízkém okolí. Pokud jsou nanočástice přítomny na povrchu vzorku analyzovaném některou z metod založenou na LA, zesílené pole vytvořené interakcí laseru s částicemi může pozměnit průběh LA, a tak ovlivnit vlastnosti laserem indukovaného plazmatu. Bylo zjištěno, že použití nanočástic může snížit práh ablace, zesílit signál a změnit vlastnosti aerosolu. Nanočásticemi zesílená LIBS (NELIBS) našla své využití tam, kde použití konvenční LIBS je problematické, a to například při analýze vzorků, kdy je jejich poškození nežádoucí nebo u analýzy roztoků mikrolitrových objemů s limity detekce nižšími než ppm. Tato dizertační práce předkládá podrobný popis jevů doprovázejících nanočásticemi zesílenou LA, založený na rozsáhlé experimentální práci a fyzikální teorii. Na základě pochopení základních principů byly vyvinuty dvě nové aplikace. Nejprve, byla NELIBS použita pro detekci kovových iontů v řetězcích amyloidů, pokročilého bio-materiálu určeného pro čištění vody. Dále byla NELIBS využita jako nová metoda pro monitorování proteinové korony vytvořené kolem nanočástic, čímž tato aplikace rozšířila klasické použití NELIBS za hranice prvkové analýzy.

Inputs of the major element potassium into the ocean from rivers and on-axis high temperature hydrothermal systems have likely varied on geological timescales. Variable uptake of potassium into lavas altered in low-temperature, off-axis, hydrothermal systems could keep the potassium concentration in seawater within the narrow range (~9.5 to 11 mmol L-1) observed in the Phanerozoic. To test this hypothesis a better understanding of the timing of alteration, and of the role of changing environmental conditions on seawater/basalt reactions is required. The age of 69 samples of the secondary, potassium-rich, phyllosilicate mineral celadonite from lavas in the Troodos ophiolite were determined using Rb-Sr radiometric dating to test whether potassium uptake occurs within a specific time interval. Measurements used tandem quadrupole ICP-MS/MS. Combined with published radiometric ages the dataset revealed regional differences in the duration of celadonite formation in the Troodos ophiolite lavas. In one area, where significant hydrothermal sediments were deposited on the lavas, celadonite formed as much as ~40 Myr after the crust accreted, whereas in an area with rare hydrothermal sediments celadonite formation was largely limited to the first ~20 Myr after crustal accretion. These differences in duration of celadonite formation in the upper oceanic crust are interpreted as reflecting differences in distribution of hydrothermal sediments that act as a source of labile Fe that is needed for celadonite formation. To test if there are significant variations of duration and timing of celadonite formation on various scales in the upper oceanic crust I measured the first in-situ Rb-Sr ages of celadonite in lavas from DSDP and ODP drill cores. These ages show that ~80% of celadonite formed from pervasive fluid flow within the first ~20 Myr after the oceanic crust accreted. All celadonite ages roughly correlate with the cumulative heat flow removed from the oceanic lithosphere in the same time interval. In combination the >100 new celadonite ages presented here provide strong evidence that most celadonite forms in the first ~20 Myr after crustal accretion and environmental conditions could be significant in controlling potassium uptake. To determine whether the potassium sink from seawater into altered seafloor lavas varied over time I compile a dataset of the potassium content of lavas from DSDP and ODP drill cores (0 to 180 Myr age range). Estimates of the average potassium content of individual holes reveal that this varies with age. However, holes of similar age show a similar magnitude of variability to that which occurs over this time. To investigate the source of the variability of potassium in altered lavas I modelled the effects of bottom seawater temperature and pH using PHREEQC. The models indicate that if the fluid is in equilibrium with K-feldspar, Na-beidellite and calcite, an increase in bottom seawater temperature and/or decrease in pH would lead to the potassium concentration in the off-axis fluid to increase significantly. This emphasizes the need for future studies to investigate feedback mechanisms between low-temperature hydrothermal alteration in response to changing environmental conditions. / Graduate / 2022-07-12