The development of optimized high performance liquid chromatography systems for the analysis of improvised explosives

Existing instrumental techniques must be adaptable to the analysis of novel explosives if science is to keep up with the practices of terrorists and criminals. The focus of this work has been the development of analytical techniques for the analysis of two types of novel explosives: ascorbic acid-based propellants, and improvised mixtures of concentrated hydrogen peroxide/fuel. In recent years, the use of these explosives in improvised explosive devices (IEDs) has increased. It is therefore important to develop methods which permit the identification of the nature of the original explosive from post-blast residues. Ascorbic acid-based propellants are low explosives which employ an ascorbic acid fuel source with a nitrate/perchlorate oxidizer. A method which utilized ion chromatography with indirect photometric detection was optimized for the analysis of intact propellants. Post-burn and post-blast residues if these propellants were analyzed. It was determined that the ascorbic acid fuel and nitrate oxidizer could be detected in intact propellants, as well as in the post-burn and post-blast residues. Degradation products of the nitrate and perchlorate oxidizers were also detected. With a quadrupole time-of-flight mass spectrometer (QToFMS), exact mass measurements are possible. When an HPLC instrument is coupled to a QToFMS, the combination of retention time with accurate mass measurements, mass spectral fragmentation information, and isotopic abundance patterns allows for the unequivocal identification of a target analyte. An optimized HPLC-ESI-QToFMS method was applied to the analysis of ascorbic acid-based propellants. Exact mass measurements were collected for the fuel and oxidizer anions, and their degradation products. Ascorbic acid was detected in the intact samples and half of the propellants subjected to open burning; the intact fuel molecule was not detected in any of the post-blast residue. Two methods were optimized for the analysis of trace levels of hydrogen peroxide: HPLC with fluorescence detection (HPLC-FD), and HPLC with electrochemical detection (HPLC-ED). Both techniques were extremely selective for hydrogen peroxide. Both methods were applied to the analysis of post-blast debris from improvised mixtures of concentrated hydrogen peroxide/fuel; hydrogen peroxide was detected on variety of substrates. Hydrogen peroxide was detected in the post-blast residues of the improvised explosives TATP and HMTD.

The Development of High Performance Liquid Chromatography Systems for the Analysis of Improvised Explosives

Existing instrumental techniques must be adaptable to the analysis of novel explosives if science is to keep up with the practices of terrorists and criminals. The focus of this work has been the development of analytical techniques for the analysis of two types of novel explosives: ascorbic acid-based propellants, and improvised mixtures of concentrated hydrogen peroxide/fuel. In recent years, the use of these explosives in improvised explosive devices (IEDs) has increased. It is therefore important to develop methods which permit the identification of the nature of the original explosive from post-blast residues. Ascorbic acid-based propellants are low explosives which employ an ascorbic acid fuel source with a nitrate/perchlorate oxidizer. A method which utilized ion chromatography with indirect photometric detection was optimized for the analysis of intact propellants. Post-burn and post-blast residues if these propellants were analyzed. It was determined that the ascorbic acid fuel and nitrate oxidizer could be detected in intact propellants, as well as in the post-burn and post-blast residues. Degradation products of the nitrate and perchlorate oxidizers were also detected. With a quadrupole time-of-flight mass spectrometer (QToFMS), exact mass measurements are possible. When an HPLC instrument is coupled to a QToFMS, the combination of retention time with accurate mass measurements, mass spectral fragmentation information, and isotopic abundance patterns allows for the unequivocal identification of a target analyte. An optimized HPLC-ESI-QToFMS method was applied to the analysis of ascorbic acid-based propellants. Exact mass measurements were collected for the fuel and oxidizer anions, and their degradation products. Ascorbic acid was detected in the intact samples and half of the propellants subjected to open burning; the intact fuel molecule was not detected in any of the post-blast residue. Two methods were optimized for the analysis of trace levels of hydrogen peroxide: HPLC with fluorescence detection (HPLC-FD), and HPLC with electrochemical detection (HPLC-ED). Both techniques were extremely selective for hydrogen peroxide. Both methods were applied to the analysis of post-blast debris from improvised mixtures of concentrated hydrogen peroxide/fuel; hydrogen peroxide was detected on variety of substrates. Hydrogen peroxide was detected in the post-blast residues of the improvised explosives TATP and HMTD.

Isotopic ratios and ion composition of massive ground ice on Herschel Island

Herschel Island in the southern Beaufort Sea is a push moraine at the northwestern-most limit of the Laurentide Ice Sheet. Stable water isotope (d18O, dD) and hydrochemical studies were applied to two tabular massive ground ice bodies to unravel their genetic origin. Buried glacier ice or basal regelation ice was encountered beneath an ice-rich diamicton with strong glaciotectonic deformation structures. The massive ice isotopic composition was highly depleted in heavy isotopes (mean d18O: -33 per mil; mean dD: -258 per mil), suggesting full-glacial conditions during ice formation. Other massive ice of unknown origin with a very large d18O range (from -39 to -21 per mil) was found adjacent to large, striated boulders. A clear freezing slope was present with progressive depletion in heavy isotopes towards the centre of the ice body. Fractionation must have taken place during closed-system freezing, possibly of a glacial meltwater pond. Both massive ground ice bodies exhibited a mixed ion composition suggestive of terrestrial waters with a marine influence. Hydrochemical signatures resemble the Herschel Island sediments that are derived from nearshore marine deposits upthrust by the Laurentide ice. A prolonged contact between water feeding the ice bodies and the surrounding sediment is therefore inferred.

Characterisation of soluble components and PAH in PM10 atmospheric particulate matter in Brisbane

Fours sets of PM10 samples were collected in three sites in SEQ from December 2002 to August 2004. Three of these sets of samples were collected by QLD EPA as a part of their regular air monitoring program at Woolloongabba, Rocklea and Eagle Farm. Half of the samples were used in this study for the analysis of water-soluble ions, which are Na+, K+, Mg2+, Ca2+, NH4 +, Cl-, NO3 -, SO4 2-, F-, Br-, NO2 -, PO4 -3 and the other half was retained by QLD EPA. The fourth set of samples was collected at Rocklea, specifically for this study. A quarter of the samples obtained from this set of samples were used to analyse water-soluble ions; a quarter of the sample was used to analyse Pb, Cu, Al, Fe, Mn and Zn; and the rests were used to analyse US EPA 16 priority PAHs. The water-soluble ions were extracted ultrasonically with water and the major watersoluble anions as well as NH4 + were analysed using IC. Na+, K+, Mg2+, Ca2+ Pb, Cu, Al, Fe, Mn and Zn were analysed using ICP-AES while PAHs were extracted by acetonitrile and analysed using HPLC. Of the analysed water-soluble ions, Cl-, NO3 -, SO4 2-, Na+, K+, Mg2+ and Ca2+ were high in concentration and determined in all the samples. F-, Br-, NO2 -, PO4 -3 and NH4 + ions were lower in concentration and determined only in some samples. Na+ and Cl- were high in all samples indicating the importance of a marine source. Principal Component Analysis (PCA) was used to examine the temporal variations of the water-soluble ions at the three sites. The results indicated that there was no major difference between the three sites. However, comparing the average concentrations of ions and Cl-/Na+ it was concluded that Woolloongabba had more marine influence than the other sites. Al, Fe and Zn were detected in all samples. Al and Fe were high in all samples indicating the significance of a source of crustal matter. Cu, Mn and Pb were in low concentrations and were determined only in some samples. The lower Pb concentrations observed in the study than in previous studies indicate that the phasing-out of leaded petrol had an appreciable impact on Pb levels in SEQ. This study reports for the first time, simultaneous data on the water-soluble, metal ion and PAH levels of PM10 aerosols in Brisbane, and provides information on the most likely sources of these chemical species. Such information can be used alongside those that already exist to formulate PM10 pollution reduction strategies for SEQ in order to protect the community from the adverse effects of PM pollution.

Preparation, characterization of surfactants modified clay minerals and nitrate adsorption

Organic surfactants modified clay minerals are usually used as adsorbents for hydrophobic organic contaminants remediation; this work however has shown organoclays can also work as adsorbents for hydrophilic anionic contaminant immobilization. Organoclays were prepared based on halloysite, kaolinite and bentonite and used for nitrate adsorption, which are significant for providing mechanism for the adsorption of anionic contaminants from waste water. XRD was used to characterize unmodified and surfactants modified clay minerals. Thermogravimetric analysis (TG) was used to determine the thermal stability and actual loading of surfactant molecules. Ion chromatography (IC) was used to determine changes of nitrate concentration before and after adsorption by these organoclays. These organoclays showed different removal capacities for anionic ions from water and adsorption mechanism was investigated.

Development of analytical techniques for studies on dispersion of actinides in the environment and characterization of environmental radioactive particles

Radioactive particles from three locations were investigated for elemental composition, oxidation states of matrix elements, and origin. Instrumental techniques applied to the task were scanning electron microscopy, X-ray and gamma-ray spectrometry, secondary ion mass spectrometry, and synchrotron radiation based microanalytical techniques comprising X-ray fluorescence spectrometry, X-ray fluorescence tomography, and X-ray absorption near-edge structure spectroscopy. Uranium-containing low activity particles collected from Irish Sea sediments were characterized in terms of composition and distribution of matrix elements and the oxidation states of uranium. Indications of the origin were obtained from the intensity ratios and the presence of thorium, uranium, and plutonium. Uranium in the particles was found to exist mostly as U(IV). Studies on plutonium particles from Runit Island (Marshall Islands) soil indicated that the samples were weapon fuel fragments originating from two separate detonations: a safety test and a low-yield test. The plutonium in the particles was found to be of similar age. The distribution and oxidation states of uranium and plutonium in the matrix of weapon fuel particles from Thule (Greenland) sediments were investigated. The variations in intensity ratios observed with different techniques indicated more than one origin. Uranium in particle matrixes was mostly U(IV), but plutonium existed in some particles mainly as Pu(IV), and in others mainly as oxidized Pu(VI). The results demonstrated that the various techniques were effectively applied in the characterization of environmental radioactive particles. An on-line method was developed for separating americium from environmental samples. The procedure utilizes extraction chromatography to separate americium from light lanthanides, and cation exchange to concentrate americium before the final separation in an ion chromatography column. The separated radiochemically pure americium fraction is measured by alpha spectrometry. The method was tested with certified sediment and soil samples and found to be applicable for the analysis of environmental samples containing a wide range of Am-241 activity. Proceeding from the on-line method developed for americium, a method was also developed for separating plutonium and americium. Plutonium is reduced to Pu(III), and separated together with Am(III) throughout the procedure. Pu(III) and Am(III) are eluted from the ion chromatography column as anionic dipicolinate and oxalate complexes, respectively, and measured by alpha spectrometry.

Metal doped nanosized titania used for the photocatalytic degradation of rhodamine B dye under visible-light

Metal-doped anatase nanosized titania photocatalysts were successfully synthesized using a sal gel process. Different amounts of the dopants (0.2, 0.4, 0.6, 0.8 and 1.0%) of the metals (Ag, Ni, Co and Pd) were utilized. The UV-Vis spectra (solid state diffuse reflectance spectra) of the doped nanoparticles exhibited a red shift in the absorption edge as a result of metal doping. The metal-doped nanoparticles were investigated for their photocatalytic activity under visible-light irradiation using Rhodamine B (Rh B) as a control pollutant. The results obtained indicate that the metal-doped titania had the highest activity at 0.4% metal loading. The kinetic models revealed that the photodegradation of Rh B followed a pseudo first order reaction. From ion chromatography (IC) analysis the degradation by-products Rhodamine B fragments were found to be acetate, chloride, nitrite, carbonate and nitrate ions.

Estudo preliminar da determinação de amônio por cromatografia de íons e sua remoção em lixiviados de resíduos sólidos utilizando argilas

A quantidade de resíduos gerados tem crescido rapidamente, sendo maior que a taxa de crescimento populacional, indicando um aumento na geração per capita. Este fato torna preocupante a maneira como é realizada a disposição final de resíduos e o impacto ambiental gerado com isso. Dentre os impactos está a produção de chorume, um poluente de elevada carga orgânica com altas concentrações de amônio e forte coloração, produzido pela decomposição química e microbiológica dos resíduos sólidos depositados em um aterro. Em locais de destino como aterros sanitários, este chorume é drenado para tratamento a fim de não impactar o local onde foi implantado o aterro. Porém, no Brasil, em grande parte dos casos, este tratamento não acontece, deixando o ambiente mais suscetível à contaminação. Este trabalho teve como finalidade determinar a quantidade de amônio presente em amostras de chorume do aterro de Gramacho no Rio de Janeiro, utilizando a cromatografia de íons para a sua quantificação, além de estudar a remoção de amônio por processos de adsorção em materiais como argilominerais. As amostras de chorume in natura apresentaram valores de pH em torno de 8,0 e concentrações de amônio entre 1665,0 e 2788,8 mg.L-1. Nas amostras analisadas após a destilação do chorume foram encontrados valores de pH entre 8,6 e 9,7 e concentrações de amônio de até 6362,3 mg.L-1, verificando que a maior concentração deste íon é arrastada nos primeiros 50 mL da destilação. Os testes de adsorção obtiveram um potencial de remoção de até 47 % do total de amônio. A metodologia aplicada se mostrou eficiente para determinação de amônio, uma vez que o tratamento prévio minimiza a ação de interferentes. Os baixos valores de remoção de amônio reforçam a necessidade de maior aprofundamento deste estudo, o que seria uma alternativa interessante para minimizar a ação deste poluente no meio ambiente

Avaliação da remoção do íon cádmio em solução aquosa utilizando processos de osmose inversa e nanofiltração

Os efluentes contendo cádmio podem ser gerados dos por várias indústrias. A aplicação de ambas as tecnologias osmose inversa (OI) e nanofiltração (NF) para o tratamento de efluentes contendo o íon cádmio para reduzir a degradação ambiental foram estudadas no presente trabalho. Amostras sintéticas contendo o íon cádmio em várias concentrações foram preparadas e submetidas aos tratamentos por OI e NF em escala laboratorial. Assim, dividiu-se o processo de remoção em três etapas: 1- analisou-se os processos de osmose inversa e nanofiltração em termos da rejeição do íon cádmio, onde se correlacionou e avaliou os principais parâmetros de processos (concentração da solução alimentação, fluxo de permeado e pressão) e comparou-se os sistemas entre si. Nas etapas 2 e 3 avaliou-se os efeitos da salinidade utilizando os contra-íons zinco e sódio respectivamente, sobre a rejeição do íon cádmio no sistema de osmose inversa em soluções aquosas contendo misturas de sulfato de cádmio e sulfato de zinco, e sulfato de cádmio e sulfato de sódio. Mediu-se as concentrações de cádmio e zinco por espectroscopia de absorção atômica e as concentrações de sulfato e sódio por cromatografia de íons. Os resultados obtidos na primeira etapa dos experimentos mostram que a osmose inversa e nanofiltração são eficientes na remoção de cádmio, onde se obteve as taxas médias de rejeição de 92,4% e 96,6% respectivamente, sendo esses valores iguais em magnitude, tendo em vista os valores da incerteza padrão relativa associada a esses resultados. Em ambos os sitemas, os fluxos de permeado e as rejeições não sofreram influência do aumento da concentração de cádmio na solução alimentação.Na etapa 2, os resultados mostraram a diminuição da rejeição de cádmio com o aumento da concentração de sulfato de zinco na alimentação, sendo esse fenômeno atribuído a semelhança existente entre os íons Cd2+ e Zn2+ associados aos seus raios iônicos de hidratação e as energias de hidratação. Foram observadas as quedas do fluxo de permeado e das rejeições com o aumento da concentração de alimentação provavelmente devido ao efeito da polarização. Na etapa 3, a rejeição do íon cádmio não foi afetada pelo aumento da concentração de sulfato de sódio na alimentação, assim como os fluxos de permeado. Outro aspecto relacionado à rejeição é que a difusão do sódio através da membrana é favorecida frente à difusão do cádmio, sendo atribuído ao menor raio de hidratação do sódio

Avaliação do tratamento de efluentes sintéticos com glifosato por osmose inversa

O presente trabalho avaliou a capacidade do sistema de osmose inversa de bancada na remoção de glifosato, em soluções de efluente aquoso sintético, empregando membrana de poliamida. Os parâmetros empregados para esta avaliação foram a pressão, o fluxo de alimentação, o tempo de operação, o pH e a concentração de glifosato na solução de alimentação em que os mesmos foram variados de modo a se ter um comparativo entre diferentes níveis. O sistema de osmose inversa teve em todos os experimentos uma boa resposta quanto a rejeição de glifosato em que a mesma variou entre 74,2% a 98,6 %, sendo a máxima atingida em condições de pressão em 30 bar, fluxo de alimentação 1 L.min-1 e pH 11 da solução de alimentação. A resposta do sistema foi avaliada quanto ao fluxo de permeado, de rejeição percentual e concentração de glifosato no permeado. O efeito da variação de concentração sobre a rejeição de glifosato foi pouco efetiva, mas apresentou grande influência quanto à variação de concentração deste no permeado. Ainda foi avaliada a remoção do ácido aminometilfosfônico (AMPA), pelo sistema de osmose inversa, obtendo-se uma boa resposta quanto à rejeição atingindo valores em torno de 95%. Uma solução combinada de AMPA e glifosato foi preparada e processada no sistema de osmose inversa, obtendo-se resposta similar quanto à concentração de permeado e rejeição para ambos os compostos. A quantificação de AMPA e glifosato se deu por cromatografia de íons, onde esta técnica se mostrou robusta e simples para quantificar ambos os compostos em meio aquoso, em baixas concentrações