The advantage of one-bead-one-compound combinatorial libraries is that hundreds of thousands to millions of compounds can be rapidly synthesized and screened simultaneously. The beads supporting the compounds of interest are then isolated and analyzed to decipher the structure of the desired compound. Many methods are currently used to allow deconvolution of the compound on the individual beads. Herein is described a novel method to encode TentaGel beads using absorption of different ratios of lanthanide ions. The encoding process is completed in parallel with the synthesis of the library of compounds. Once the desired beads are identified, the lanthanide ions can be released from the bead and analyzed using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS).

Submitted by ANA MARTA CAVINATO MARCHINI ROLISOLA (anamartarolisola@hotmail.com) on 2018-06-21T22:43:46Z No. of bitstreams: 1 Ana Marta C M Rolisola_Tese de Doutorado.pdf: 4492180 bytes, checksum: d1fdb4a15ef3fdf8d398b1f8be14c005 (MD5) / Rejected by Ana Paula Santulo Custódio de Medeiros null (asantulo@rc.unesp.br), reason: - Falta o número do processo FAPESP nos agradecimentos: se você recebeu financiamento da FAPESP, ela exige que nos agradecimentos apareça o número do processo. on 2018-06-22T17:15:12Z (GMT) / Submitted by ANA MARTA CAVINATO MARCHINI ROLISOLA (anamartarolisola@hotmail.com) on 2018-06-23T14:11:42Z No. of bitstreams: 1 Ana Marta C M Rolisola_Tese de Doutorado.pdf: 4493139 bytes, checksum: 2980a550f843988e0a8bd31a8ee9ab8d (MD5) / Approved for entry into archive by Adriana Aparecida Puerta null (dripuerta@rc.unesp.br) on 2018-06-25T13:41:05Z (GMT) No. of bitstreams: 1 rolisola_amcm_dr_rcla.pdf: 4377095 bytes, checksum: da8491d59c9f3875c68e364b6648d0cf (MD5) / Made available in DSpace on 2018-06-25T13:41:05Z (GMT). No. of bitstreams: 1 rolisola_amcm_dr_rcla.pdf: 4377095 bytes, checksum: da8491d59c9f3875c68e364b6648d0cf (MD5) Previous issue date: 2018-05-02 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Atualmente, cerca de 18 compostos são utilizados como biocidas de reforço (metálicos) em tintas anti-incrustantes, como por exemplo Piritionato de Zinco (Zn(PT)2), Zineb e Ziram. É relevante o desenvolvimento de um método analítico para determinação das concentrações ambientais de biocidas metálicos. O presente estudo teve como objetivos i)desenvolver uma metodologia de extração em fase sólida (SPE) e cromatografia líquida de alta eficiência acoplada (HPLC) ao espectrômetro de massas com plasma acoplado indutivamente (ICP-MS) para determinação de Zn(PT)2, Zineb e Ziram e ii) quantificar, in lab, a fração lábil total do Piritionato de Zinco, Zineb e Ziram e in situ, a fração lábil total do zinco, utilizando a técnica de difusão em filmes finos por gradiente de concentração (DGT) em solução padrão e água estuarina, respectivamente. Na técnica de SPE foi utilizado o sorbente de sílica funcionalizado com fenil apresentando excelente retenção para Zn(PT)2, Zineb e Ziram (94 ± 0,1%, 85 ± 0,04% e 93 ± 0,1%, respectivamente) e recuperações entre 85% e 110%. Na determinação dos biocidas de zinco utilizando o acoplamento HPLC-VGroove-ICP-MS com diluição pós coluna cromatográfica, a fase móvel composta por metanol e 0,006 mol L-1 de acetato de amônio (50:50, v v-1) apresentou o melhor desempenho na separação do Zn(PT)2, Zineb, Ziram. A curva analítica obtida para o Zn(PT)2 apresentou coeficiente de correlação, LD e LQ satisfatórios para os isótopos 64Zn (0,98, 0,575 mg L-1, 1,916 mg L-1), 66Zn(0,99, 0,480 mg L-1 , 1,600 mg L-1), 68Zn(0,98, 0,602 mg L-1, 2,007 mg L-1). Na técnica DGT foi utilizado o agente ligante resina Chelex® 100 para avaliar a labilidade do Zn(PT)2, Zineb e Ziram em água estuarina. Os resultados demonstraram que a fração lábil total do Zn ficou em torno de 100% para o Zineb (111%) e Ziram (109%), ou seja, estes biocidas formaram espécies totalmente lábeis na amostra de água estuarina e para Zn(PT)2 foi de 75% indicando espécies parcialmente lábeis. Os resultados obtidos na técnica SPE, no acoplamento HPLC-VGroove-ICP-MS e DGT demonstraram que os métodos apresentam desempenho satisfatório para a determinação de Piritionato de Zinco, Zineb e Ziram. / About 18 compounds are used as booster biocides (metal) in antifouling paints such as Zinc Pyrithione (Zn(PT)2), Zineb and Ziram. It is important to develop an analytical method for determining of the environmental concentrations of zinc biocides. The present study had as objectives i) to develop a solid phase extraction (SPE) and high performance liquid chromatography (HPLC) coupled to the inductively coupled plasma mass spectrometer (ICP-MS) for the determination of Zn(PT)2, Zineb and Ziram and ii) quantify in lab the total labile fraction of Zn(PT)2, Zineb and Ziram and in situ the total labile fraction of zinc using the diffusive gradient in thin films (DGT) technique in standard solution and estuarine water, respectively. In the SPE technique, the silica sorbent functionalized with phenyl presented excellent retention for Zn(PT)2, Zineb and Ziram (94 ± 0.1%, 85 ± 0.04% and 93 ± 0.1%, respectively) and recoveries between 85% and 110%. In the determination of zinc using the HPLC-VGroove-ICP-MS coupling with post-column chromatographic dilution, the mobile phase composed of methanol and 0.006 mol L-1 of ammonium acetate (50:50, v v-1) of presented the best performance in the separation of Zn(PT)2, Zineb and Ziram. The analytical curve obtained for Zn(PT)2 presented satisfactory correlation coefficient, LD and LQ for the isotopes 64Zn (0.98, 0.575 mg L -1, 1.916 mg L-1), 66Zn (0.99, 0.480 mg L-1, 1.600 mg L-1), 68Zn (0.98, 0.602 mg L-1, 2.007 mg L-1). In the DGT technique, the Chelex® 100 resin binder was used to evaluate the lability of the zinc biocides Zn(PT)2, Zineb and Ziram in estuarine water. The results showed that the total labile fraction of Zn was around 100% for Zineb (111%) and Ziram (109%), that is, these biocides formed totally labile species in the estuarine water sample and for Zn(PT)2 was 75% indicating partially labile species. The results obtained in the SPE technique in the HPLC-VGroove-ICP-MS coupling and DGT demonstrated that the methods present satisfactory performance for the determination of Zn(PT)2, Zineb and Ziram. / CNPq: 164326/2015. / FAPESP: 2015/03397-4.

Chumbo (Pb) é um elemento tóxico ao qual estão associadas diversas doenças que afligem o ser humano. Dessa forma, o desenvolvimento de novas metodologias para a determinação de Pb no sangue traz uma importante contribuição na monitoração humana exposta a este metal. No presente estudo, é apresentado uma metodologia nova para determinação de Pb utilizando-se a técnica fingerstick com filtro de papel em conjunto com a espectrometria de massas de alta resolução em fonte de plasma indutivo (HR/ICP/MS). Os resultados encontrados mostraram-se robustos para uma digestão total de cerca de 0,1 g de sangue, em valores de referência, e níveis de chumbo inferiores a 5 μgdL-1. O presente método é pouco intrusivo permitindo a coleta e transporte das amostras à longa distância sem perda de integridade e/ou estabilidade. Dessa forma traz uma importante contribuição para o monitoramento da exposição do metal principalmente no atendimento às comunidades distantes. / Lead (Pb) is a toxic element to which several diseases affecting human beings are associated. Therefore, the development of new methodologies for the Pb determination in blood represents an important contribution to monitor human exposition to this metal. In the present study, a new methodology for Pb determination is presented using fingerstick techniques for sample collection and lead detection by using a high resolution inductively coupled plasma mass spectrometry technique. The results are robust for total digestion of 0.1 g of deposited blood and lead levels below to 5 μgdL-1. This method is less intrusive in comparison with the traditional ones. It allows the collection and transport of samples over long distances without loss of integrity and / or stability. Therefore, it brings an important contribution for monitoring the exposure of this metal mainly in the attendance to remote communities.

Submitted by HENDRYK GEMEINER null (h.gemeiner@gmx.net) on 2016-11-11T17:05:34Z No. of bitstreams: 1 tese_mestrado_hendryk_gemeiner.pdf: 13978829 bytes, checksum: 08b385f98431fd9c29309e3aeb7cb1b2 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-11-11T17:52:30Z (GMT) No. of bitstreams: 1 gemeiner_h_me_rcla.pdf: 13978829 bytes, checksum: 08b385f98431fd9c29309e3aeb7cb1b2 (MD5) / Made available in DSpace on 2016-11-11T17:52:30Z (GMT). No. of bitstreams: 1 gemeiner_h_me_rcla.pdf: 13978829 bytes, checksum: 08b385f98431fd9c29309e3aeb7cb1b2 (MD5) Previous issue date: 2016-09-13 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação para o Desenvolvimento da UNESP (FUNDUNESP) / The toxic metal lead (Pb) can be harmful to human health in various manners, but is also considered as a distinguished tracer of environmental pollution, since the relative abundance of its four stable isotopes with the atomic masses of 204, 206, 207 and 208 varies with the emission source. This study is focused on the lead concentrations and isotope ratios in the particulate matter of the Brazilian cities of Goiânia (GO) and Rio Claro (SP), in order to determine the main Pb pollution sources. Particulate matter samples were collected on clean Teflon filters during the rainy and dry season between 2014 and 2016 on the campus of the State University of São Paulo (UNESP) in Rio Claro city and in the centre of Goiânia city near main roads with a high traffic volume. The Pb concentrations as well as the 206Pb/207Pb and 208Pb/207Pb stable isotope ratios of the particulate matter samples were analysed by Inductively-Coupled Plasma Mass Spectrometry. To apply this analytical technique successfully, it was necessary to optimize parameters in case of acquisition time, detector dead time and mass discrimination, which affect the measurement accuracy and precision. Results showed that lead concentrations in Goiânia were different between rainy and dry season. In Goiânia, Pb concentrations showed higher values in dry season than in rainy season, while Pb concentrations were more similar in both sampling periods in Rio Claro. Back trajectories were analysed with the HYSPLIT model to investigate associations between Pb concentration levels and the direction of incoming air masses. However, the comparison of the obtained 206Pb/207Pb and 208Pb/207Pb isotope ratios data with data of potential Pb sources from previous studies indicated that gasoline may be considered as main Pb sources in the particulate matter of Goiânia and Rio Claro. Pb isotope ratios in Goiania were slightly different between dry and rainy season, while in Rio Claro, 206Pb/207Pb isotope ratios showed markedly higher values in dry season than in rainy season. Hence, Pb in Rio Claro in dry season also seems to be influenced by industrial emissions. These assumptions were supported by the calculation of 208Pb/206Pb-207Pb/206Pb diagrams and the contribution factor of Pb coming from gasoline by applying binary mixing equations. / CNPq: 372125/2014-0 / FUNDUNESP: 0050.0092854.14.9

Submitted by Fernanda Rodrigues de Lima (fernanda.rlima@ufpe.br) on 2018-08-21T19:40:25Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) DISSERTAÇÃO Denilson Tenorio de Lyra.pdf: 3743839 bytes, checksum: eab771b5aee24f3e33428a1058314117 (MD5) / Approved for entry into archive by Alice Araujo (alice.caraujo@ufpe.br) on 2018-08-28T22:52:21Z (GMT) No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) DISSERTAÇÃO Denilson Tenorio de Lyra.pdf: 3743839 bytes, checksum: eab771b5aee24f3e33428a1058314117 (MD5) / Made available in DSpace on 2018-08-28T22:52:21Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) DISSERTAÇÃO Denilson Tenorio de Lyra.pdf: 3743839 bytes, checksum: eab771b5aee24f3e33428a1058314117 (MD5) Previous issue date: 2016-08-04 / FACEPE / A industrialização e a expansão urbana aumentam os problemas de contaminação ambiental devido à liberação descontrolada de efluentes industriais e domésticos. Como os solos de mangues são provenientes de sedimentos fluviais e marinhos sob a influência constante das marés, esse compartimento ecológico merece esforços quanto à determinação de sua composição química. Por outro lado, ainda não está claro o papel dos sedimentos em suspensão dada sua capacidade de transporte de uma grande gama de substâncias químicas para a formação desses solos. Por essa razão, o objetivo deste trabalho foi determinar Al, Br, Ca, Cd, Cu, Fe, K, Mn, Mo, Ni, Pb, Sb, Si, Sr, Th, Ti, U e Zn pela combinação das técnicas de Fluorescência de Raios-X por Dispersão de Energia – EDXRF, de Espectrometria de Absorção Atômica com Chama – FAAS e de Espectrometria de Massas com Plasma Acoplado Indutivamente – ICP-MS nos solos do manguezal urbano do Rio Beberibe, Pernambuco, Brasil. Os elementos químicos Al, Br, Ca, Fe, K, Mn, Ni, Pb, Si, Sr e Zn também foram quantificados por EDXRF nos sedimentos em suspensão do Rio Beberibe, em local próximo à sua foz. Foram coletadas 30 amostras de solo na profundidade de 0-20 cm no manguezal. Já para os sedimentos em suspensão, oito amostras compostas de aproximadamente 20 litros de água no Rio Beberibe foram coletadas ao longo de 105 minutos (15 minutos cada) em um evento de chuva. A preparação das amostras de solos envolveu a secagem, moagem e homogeneização. Após seis meses de sedimentação espontânea, o particulado em suspensão foi extraído a partir de sucção do sobrenadante e centrifugação, seguida por secagem a frio e homogeneização para a obtenção das amostras. Porções analíticas (0,5 g) das amostras de solos, de sedimentos em suspensão e de materiais de referência certificados foram transferidas para tubos de polietileno vedados com polipropileno especificamente desenvolvido para a análise por EDXRF. Porções-teste (0,1 g) das amostras de solos, materiais de referência e brancos analíticos foram submetidas a tratamento químico para possibilitar a análise por FAAS e ICP-MS. De acordo com os valores do número En obtidos a partir da análise dos materiais de referência SRM 2709 San Joaquin Soil, SRM 2711 Montana Soil e IAEA Soil 7, as técnicas foram adequadas para a quantificação dos elementos químicos nas amostras de solos e de sedimentos em suspensão. Os resultados da composição mostraram variabilidade considerável nas frações de massa de elementos terrígenos Al, Fe, Si e Ti nos solos do manguezal urbano. As concentrações máximas de elementos químicos relevantes do ponto de vista de impacto ambiental atingiram 0,49 mg kg⁻¹ para Cd, 48 mg kg-⁻¹ para Cu, 185 mg kg⁻¹ para Mn, 14,5 mg kg⁻¹ para Mo, 31 mg kg⁻¹ para Ni, 71 mg kg⁻¹ para Pb, 1,6 mg kg⁻¹ para Sb e 192 mg kg⁻¹ para Zn. De acordo com a legislação vigente para o Estado de Pernambuco, as concentrações de Cu, Ni, Pb e Zn estão acima dos valores normativos para solos. Contudo, ao se considerar as recomendações internacionais para a garantia da qualidade ambiental de ecossistemas aquáticos, apenas Zn ultrapassou a faixa de concentração em que efeitos adversos para a biota ocasionalmente ocorrem. Para os sedimentos em suspensão, diferentes fontes de elementos químicos foram cogitadas para a área estudada baseados nos resultados da Análise por Componentes Principais. Ainda, os elementos químicos Al, Ti e Zn determinados nos sedimentos em suspensão do Rio Beberibe apresentaram frações de massa superiores às médias mundiais, alcançando 129.000 mg kg⁻¹, 6.600 mg kg⁻¹ e 248 mg kg⁻¹, respectivamente. Os resultados enfatizam a necessidade de contínua monitoração dos ecossistemas aquáticos, principalmente em ambiente urbano. / Environmental contamination problems have increased with the industrialization and urban expansion due to uncontrolled release of industrial and domestic wastewater. As mangrove soils are formed by fluvial and marine sediments under constant tidal influence, this ecological compartment is of utmost relevance for the determination its chemical element composition. Otherwise, it is still not clear the contribution of suspended sediments due to its capability of transportation of a wide range of chemical substances for the development of these soils. For this reason, the objective of this work was to determine Al, Br, Ca, Cd, Cu, Fe, K, Mn, Mo, Ni, Pb, Sb, Si, Sr, Th, Ti, U and Zn by the combination of the analytical techniques Energy Dispersion X-Ray Fluorescence – EDXRF, Flame Atomic Absorption Spectrometry – FAAS and Inductively Coupled Plasma Mass Spectrometry – ICP-MS in the urban mangrove soils from Beberibe River, Pernambuco, Brasil. The chemical elements Al, Br, Ca, Fe, K, Mn, Ni, Pb, Si, Sr and Zn were also quantified by EDXRF in the Beberibe’s suspended sediments from a local near the estuary. For soil, 30 samples were collected at the 0-20 cm depth in the mangrove. Considering the suspended sediments, eight composite water samples of 20 L were sampled along 105 minutes (15 minute each) in the Beberibe River during a rain event. Soil sample preparation involved drying, milling and homogenizing. After six months of spontaneously sedimentation, the suspended matter was extracted by means of suction and centrifugation, followed by freeze-drying and homogenizing to obtain suspended sediment samples. Analytical portions (0.5 g) of soil and suspended sediment samples and certified reference materials were transferred for polyethylene vials sealed with polypropylene film specifically developed for EDXRF analysis. Test portions (0.1 g) of soil samples, reference materials and analytical blanks were chemically treated for FAAS and ICP-MS analyses. According to the Number En values obtained through the analysis of the reference material SRM 2709 San Joaquin Soil, SRM 2711 Montana Soil and IAEA Soil 7, the analytical techniques were adequate for quantifying chemical elements in the soil and suspended sediment samples. The results showed a considerable variability for the terrigenous chemical elements Al, Fe, Si and Ti in the urban mangrove soils. The maximum concentrations of chemical elements of relevance for environmental impacts achieved 0.49 mg kg⁻¹ for Cd, 48 mg kg⁻¹ for Cu, 185 mg kg⁻¹ for Mn, 14.5 mg kg⁻¹ for Mo, 31 mg kg⁻¹ for Ni, 71 mg kg⁻¹ for Pb, 1.6 mg kg⁻¹ for Sb and 192 mg kg⁻¹ for Zn. In accordance with the Pernambuco State’s legislation, the concentrations of Cu, Ni, Pb and Zn were above the normative values for soils. Although, considering the international recommendations for environmental quality assurance for aquatic ecosystems, only Zn surpassed the concentration range in which the possible adverse effects on the biota occasionally occur. For suspended sediments, different sources of chemical elements were realized for the studied area based on the Principal Component Analysis results. Besides, the chemical elements Al, Ti and Zn determined in the Beberibe River suspended sediments showed mass fractions higher than the world mean values, achieving 129.000 mg kg⁻¹, 6.600 mg kg⁻¹ and 248 mg kg⁻¹, respectively. The results emphasized the needs of continuous monitoring of aquatic ecosystems mainly in urban environment.

The necessity of elemental analysis techniques to solve forensic problems continues to expand as the samples collected from crime scenes grow in complexity. Laser ablation ICP-MS (LA-ICP-MS) has been shown to provide a high degree of discrimination between samples that originate from different sources. In the first part of this research, two laser ablation ICP-MS systems were compared, one using a nanosecond laser and another a femtosecond laser source for the forensic analysis of glass. The results showed that femtosecond LA-ICP-MS did not provide significant improvements in terms of accuracy, precision and discrimination, however femtosecond LA-ICP-MS did provide lower detection limits. In addition, it was determined that even for femtosecond LA-ICP-MS an internal standard should be utilized to obtain accurate analytical results for glass analyses. In the second part, a method using laser induced breakdown spectroscopy (LIBS) for the forensic analysis of glass was shown to provide excellent discrimination for a glass set consisting of 41 automotive fragments. The discrimination power was compared to two of the leading elemental analysis techniques, µXRF and LA-ICP-MS, and the results were similar; all methods generated >99% discrimination and the pairs found indistinguishable were similar. An extensive data analysis approach for LIBS glass analyses was developed to minimize Type I and II errors en route to a recommendation of 10 ratios to be used for glass comparisons. Finally, a LA-ICP-MS method for the qualitative analysis and discrimination of gel ink sources was developed and tested for a set of ink samples. In the first discrimination study, qualitative analysis was used to obtain 95.6% discrimination for a blind study consisting of 45 black gel ink samples provided by the United States Secret Service. A 0.4% false exclusion (Type I) error rate and a 3.9% false inclusion (Type II) error rate was obtained for this discrimination study. In the second discrimination study, 99% discrimination power was achieved for a black gel ink pen set consisting of 24 self collected samples. The two pairs found to be indistinguishable came from the same source of origin (the same manufacturer and type of pen purchased in different locations). It was also found that gel ink from the same pen, regardless of the age, was indistinguishable as were gel ink pens (four pens) originating from the same pack.

As a consequence of the widespread use of computers coupled to high-quality printers and different types of papers, forgery, counterfeiting, change of wills, anonymous letter writing and felonious use of the documents have become serious problems. Forensic analysts are always seeking methods that can provide reliable information on whether a specimen collected at the crime scene is linked to the crime or to a source of known origin. Sensitive methods that can provide more detailed characterization of natural or man-made materials or even provide information not previously available to forensic examiners. Recent advances in rapid solid sampling of materials using laser ablation (LA) coupled to inductively coupled plasma mass spectroscopy (ICP-MS) have led to this analytical method to be regarded as the “gold standard” in the field of elemental analysis for trace level components in solids. Another, emerging, analytical technique that uses the same laser pulse to generate a plasma that can be interrogated with spectroscopy is laser induced break down spectroscopy (LIBS). The analysis of ink and paper is also possible because of the surface removal effect of laser interactions with the samples. In the present study, printing inks were analyzed using LIBS, LA-ICP-MS and both of them in tandem mode. In the tandem setup, the light generated during the relaxation of the excited species (LIBS) was used to create a spectral signature of the elements, and the mass-to-charge ratio of the ejected particles (ICP-MS) was used to create a mass spectrum. For a set of 319 printing ink samples, LA-ICP-MS alone provided discrimination greater than 99%. A subset of 43 printing inks, having a very similar elemental profile, was analyzed by tandem LIBS/LA-ICP-MS. The fusion of LIBS and LA-ICP-MS provided additional discrimination through the detection of elements like Ca, Si, Fe, and K by LIBS, that are difficult to detect and confirm using standalone ICP-MS because of the spectral interferences (isobaric and polyatomic) involved. The combination of these two sensors was found to minimize the individual limitations and provide a more complete and representative chemical characterization of printing inks.

Glass is a common form of trace evidence found at many scenes of crimes in the form of small fragments. These glass fragments can transfer to surrounding objects and/or persons and may provide forensic investigators valuable information to link a suspect to the scene of a crime. Since the elemental composition of different glass sources can be very similar, a highly discriminating technique is required to distinguish between fragments that have originated from different sources. The research presented here demonstrates that Laser Induced Breakdown Spectroscopy (LIBS) is a viable analytical technique for the association and discrimination of glass fragments. The first part of this research describes the optimization of the LIBS experiments including the use of different laser wavelengths to investigate laser-material interaction. The use of a 266 nm excitation laser provided the best analytical figures of merit with minimal damage to the sample. The resulting analytical figures of merit are presented. The second part of this research evaluated the sensitivity of LIBS to associate or discriminate float glass samples originating from the same manufacturing plants and produced at approximately the same time period. Two different sample sets were analyzed ranging in manufacturing dates from days to years apart. Eighteen (18) atomic emission lines corresponding to the elements Sr, K, Fe, Ca, Al, Ba, Na, Mg and Ti, were chosen because of their detection above the method detection limits and for presenting differences between the samples. Ten elemental ratios producing the most discrimination were selected for each set. When all the ratios are combined in a comparison, 99% of the possible pairs were discriminated using the optimized LIBS method generating typical analytical precisions of ~5% RSD. The final study consisted of the development of a new approach for the use of LIBS as a quantitative analysis of ultra-low volume solution analysis using aerosols and microdrops. Laser induced breakdown spectroscopy demonstrated to be an effective technique for the analysis of as low as 90 pL for microdrop LIBS with 1 pg absolute LOD and 20 µL for aerosol LIBS with an absolute LOD of ~100 fg.

Laboratory measurements of primitive and differentiated meteorites have been made in order to understand the origin of isotopic anomalies. The element Zr is chosen for analysis, due to its potential for nuclear and astrophysical applications. Zirconium has five stable isotopes that are produced in different (neutron–capture) nucleosynthetic processes. By analysing the Zr isotope composition of meteorites, we are able to track the mixing of various neutron capture processes in the early Solar System. Measurements have been performed on carbonaceous, ordinary and enstatite chondrites, eucrites, the Moon and Earth. Samples are crushed, digested and passed through a two stage anion exchange separation to obtain a clean Zr fraction. All Zr measurements are made on a Nu Plasma multiple–collector inductively coupled plasma mass spectrometer (MC–ICPMS). The results indicate that the bulk of refractory Ca–Al rich inclusions of the Allende meteorite are characterised by uniform enrichments (around 2ε) of the neutron–rich isotope 96Zr, and potentially coupled with excesses reported for the neutron rich isotope 50Ti, indicating that both nuclides may have similar astrophysical origins. Analysis of bulk rock carbonaceous chondrites reveal 96Zr excesses (not exceeding 1ε) that scale with the abundance of CAIs. However, widespread 96Zr correlations are also seen, accompanied by minor depletions in 91Zr, which suggest the solar nebular had experienced thermal heating of some sort, altering the initial (possibly uniform) Zr isotope composition of the early Solar System from which planetary bodies formed.

Iron is ubiquitous in the environment, ranking fourth in abundance in the earth's crust. Iron is responsible for many environmental mechanisms including the distribution of plant nutrients and pollutants. Iron can exist in several minerals, including iron oxides. Arsenic is a naturally occurring metalloid which has been confirmed by the EPA as a carcinogen. Recently, an arsenic epidemic has unfurled in Bangladesh, poisoning an estimated 70 million people. Arsenic contamination does not exist only in the third world, but also in the United States, including Iowa. Due to the widespread distribution of arsenic and the potential for it to be leached into groundwater supplies, there has been a growing interest in establishing removal mechanisms. Atomic absorption (AA) spectroscopy and inductively coupled plasma optical emission spectrometry (ICP-OES) have been used. There has been a shift in arsenic analysis methods with the advent of more sensitive methods such as the inductively coupled plasma mass spectrometer (ICP-MS). The geology department recently acquired a Thermo Scientific XSERIES ICP-MS, so an arsenic analysis method was developed in preparation for the research conducted in this study. The ICP-MS, however, only measures total arsenic concentration. As this study focused on the oxidation state of arsenic, an alternative means for determining oxidation state was developed. As(V)-selective cartridges were used to adsorb arsenate, while letting arsenite run through. This method was checked for effectiveness and used to determine aqueous arsenic oxidation state. X-ray absorption spectroscopy (XAS) was used to determine the oxidation state of arsenic adsorbed onto the surface of iron oxide. Goethite (α-FeOOH) and magnetite (Fe3O4) are both known to strongly adsorb arsenic. In this work, the potential for As(III) oxidation and As(V) reduction by goethite was studied. As documented by Amstaetter et al., there was some evidence for adsorbed As(III) oxidation by an Fe(II)/goethite system. This study, however, also showed some evidence for oxidation of adsorbed arsenite in the presence of goethite alone. As(V) reduction by magnetite was also studied. Magnetite is capable of having different stoichiometries, or ratios of Fe(II) to Fe(III). Both an oxidized, x=0.27, and a near-stoichiometric, x=0.49, magnetite were studied for their ability to reduce arsenate. There was no evidence for As(V) reduction in the aqueous or adsorbed phase for either system.