LC-MS method development and comparison of sampling materials for the analysis of organic gunshot residues

This study aimed at comparing the efficiency of various sampling materials for the collection and subsequent analysis of organic gunshot residues (OGSR). To the best of our knowledge, it is the first time that sampling devices were investigated in detail for further quantitation of OGSR by LC-MS. Seven sampling materials, namely two "swab"-type and five "stub"-type collection materials, were tested. The investigation started with the development of a simple and robust LC-MS method able to separate and quantify molecules typically found in gunpowders, such as diphenylamine or ethylcentralite. The evaluation of sampling materials was then systematically carried out by first analysing blank extracts of the materials to check for potential interferences and determining matrix effects. Based on these results, the best four materials, namely cotton buds, polyester swabs, a tape from 3M and PTFE were compared in terms of collection efficiency during shooting experiments using a set of 9 mm Luger ammunition. It was found that the tape was capable of recovering the highest amounts of OGSR. As tape-lifting is the technique currently used in routine for inorganic GSR, OGSR analysis might be implemented without modifying IGSR sampling and analysis procedure.

Modificação de um micro-extrator de vidro para pré-enriquecimento de traços de pesticidas organoclorados de água para análise por cromatografia gasosa

Two models of a glass micro-extractor were constructed after modification of a model proposed in the literature. The two models were used for the simultaneous extraction and enrichment of organochlorinated pesticides from aqueous matrixes to an organic solution appropriate for the gas chromatographic analysis of the pesticide. It was established that the performance of one of the modified micro-extractors permits the pre-concentration of the pesticides to a level that allow their quantitation at the trace level with electron capture detection. It is thus concluded that the glass micro-extractor is a suitable tool for the sample preparation step in the gas chromatographic analysis of environmental pollutants of the class of pesticides.

Caracterização química e física de vermicomposto e avaliação de sua capacidade em adsorver cobre e zinco

The physical and chemical characterization of vermicompost from bovine manure has been studied. It was examined the pH and cation exchangeable capacity (CEC), organic matter content, electric conductivity and elementary and XRD analyses, among other characteristics. The vermicompost was then applied to the retention and competition of metal micronutrients and pollutants (Cu and Zn) from metal nitrate solutions. The retention was affected by both the pH and adsorption time, while the competitive character of these metals for the substrate was relevant to each pH examined.

High voltage discharge for degradation of organic contaminants in water

The pulsed dielectric barrier discharge (PDBD) and pulsed corona discharge (PCD) were compared for their efficiency to degrade phenol in water solution. Results show that PCD has higher efficiency than PDBD to degrade phenol. When initial pH of water solution was elevated, phenol degradation in the PCD reactor was significantly enhanced, although no considerable effect was seen in the PDBD reactor. The PCD reactor was also able to degrade lignin significantly, both in synthetically prepared solution and in pulp and paper mill wastewater. Water temperature did not affect phenol degradation; however, lignin was better oxidized at lower temperature.

Computing the persistent homology of range images with alpha shapes

Laser scanning is becoming an increasingly popular method for measuring 3D objects in industrial design. Laser scanners produce a cloud of 3D points. For CAD software to be able to use such data, however, this point cloud needs to be turned into a vector format. A popular way to do this is to triangulate the assumed surface of the point cloud using alpha shapes. Alpha shapes start from the convex hull of the point cloud and gradually refine it towards the true surface of the object. Often it is nontrivial to decide when to stop this refinement. One criterion for this is to do so when the homology of the object stops changing. This is known as the persistent homology of the object. The goal of this thesis is to develop a way to compute the homology of a given point cloud when processed with alpha shapes, and to infer from it when the persistent homology has been achieved. Practically, the computation of such a characteristic of the target might be applied to power line tower span analysis.

One pot obtention of a tetrabutylammonium hydroxide solution for ironporphyrin-OH- interaction studies in organic solvents

In this work we report the obtention of a tetrabutylammonium hydroxide (TBAOH) solution in acetonitrile in a one pot process in order to study the interaction ironporphyrinOH- in non-aqueous systems. All the reactions were carried out under dry argon atmosphere to prevent the contamination of the solution with CO2, which leads to the formation of (TBA)2CO3.

Catalytic Wet Oxidation of Paper Mill Debarking Water

The objective of the research was to study the influence of temperature, oxygen pressure, catalysts loading and initial COD concentration of debarking wastewater on the pollutants during the catalytic oxidation. More importantly, how the addition of catalyst affects the wet oxidation process. The whole work was divided into two main sections, theoretical and experimental parts. The theoretical part reviews the pulp and paper industry from wood processing to paper production as well as operations that generate wastes. Treatment methods applicable for industrial pulp and paper mill effluents were also discussed. Wet oxidation and catalytic wet oxidation processes including mechanism, reactions, kinetics and industrial applications were previewed. In the experimental part, catalytic wet oxidation process were studied at 120-180°C, 0-10 bar oxygen pressure, 0-1 g/L catalyst concentration and 1000-3000 mg/L initial COD concentration. Responses, such as Chemical oxygen demand (COD), Total organic carbon (TOC), colour, lignin/tannin, Biochemical oxygen demand (BOD) and pH were measured. In the experiment, the best conditions occurred at 180°C, 10 bar, l g/L catalyst concentration and 3000mg/L initial COD. At these conditions; 74% COD, 97% lignin/tannin, 54% TOC, 90% colour were removed from the wastewater. pH was greatly reduced from 7 to 4.6. Lignin/tannin was removed most. Lignin/tannin showed linear dependency with colour during oxidation. Temperature made the most impact in reducing contaminants in debarked wastewater.

Suodatuskalvon puhdistaminen UV-valolla tai ultraäänellä aktivoidulla titaanidioksidilla

Kalvotekniikan suurin ongelma on edelleen kalvon likaantuminen, jonka tuloksena kalvon erotuskyky voi muuttua ja liuoksen vuo kalvon läpi pientyä huomattavasti. Kalvotekniikan teollisissa sovelluksissa kalvojen puhdistus on yksi tärkeimmistä pääkohdista, sillä se määrittää kalvon käyttöikää ja käyttötehokkuutta. Yleisimmin käytetyn kemiallisen pesun tuloksena muodostuu hävitettävä pesuliuos, joka sisältää sekä kemikaaleja, että kalvosta poistetun lian. Työssä on tutkittu kalvon puhdistusta ultravioletti-valo- tai ultraäänikäsittelyssä titaanidioksidin läsnäollessa. Menetelmien mahdollisina etuina ovat kalvosta poistetun lian hajotus harmittomiksi komponenteiksi ja mahdollisesti kalvon pienempi kuluminen pesussa. Työn kirjallisuusosassa on käsitelty orgaanisten ja epäorgaanisten aineiden hajottamista ultraviolettivalon tai ultraäänikäsittelyn avulla titaanidioksidin läsnäollessa sekä olosuhteiden vaikutusta menetelmien tehokkuuteen. Tämän lisäksi työssä on keskitytty polymeerikalvojen UV-valo- ja ultraäänikäsittelykestävyyteen. Kokeellisessa osassa on tutkittu UV-valo- ja ultraäänikäsittelyjen sopivuutta liatun PVDF-kalvon puhdistukseen titaanidioksidin läsnäollessa. Tavoitteena oli liatun kalvon permeabiliteetin palautus puhtaan kalvon tasolle käsittelyn avulla. Kalvon kestävyyttä on myös tutkittu. Tämän työn perusteella tutkittuja menetelmiä ei voida soveltaa tarkistettavan PVDF-kalvon puhdistukseen, ainakaan testeissä käytetyissä olosuhteissa, sillä kalvon ominaisuudet muuttuvat käsittelyissä.

Avaliação do uso de métodos quimiométricos em análise de solos

One of the major interests in soil analysis is the evaluation of its chemical, physical and biological parameters, which are indicators of soil quality (the most important is the organic matter). Besides there is a great interest in the study of humic substances and on the assessment of pollutants, such as pesticides and heavy metals, in soils. Chemometrics is a powerful tool to deal with these problems and can help soil researchers to extract much more information from their data. In spite of this, the presence of these kinds of strategies in the literature has obtained projection only recently. The utilization of chemometric methods in soil analysis is evaluated in this article. The applications will be divided in four parts (with emphasis in the first two): (i) descriptive and exploratory methods based on Principal Component Analysis (PCA); (ii) multivariate calibration methods (MLR, PCR and PLS); (iii) methods such as Evolving Factor Analysis and SIMPLISMA; and (iv) artificial intelligence methods, such as Artificial Neural Networks.

A Headspace needle-trap method for the analysis of volatile organic compounds in whole blood

Needle trap devices (NTDs) are a relatively new and promising tool for headspace (HS) analysis. In this study, a dynamic HS sampling procedure is evaluated for the determination of volatile organic compounds (VOCs) in whole blood samples. A full factorial design was used to evaluate the influence of the number of cycles and incubation time and it is demonstrated that the controlling factor in the process is the number of cycles. A mathematical model can be used to determine the most appropriate number of cycles required to adsorb a prefixed amount of VOCs present in the HS phase whenever quantitative adsorption is reached in each cycle. Matrix effect is of great importance when complex biological samples, such as blood, are analyzed. The evaluation of the salting out effect showed a significant improvement in the volatilization of VOCs to the HS in this type of matrices. Moreover, a 1:4 (blood:water) dilution is required to obtain quantitative recoveries of the target analytes when external calibration is used. The method developed gives detection limits in the 0.020–0.080 μg L−1 range (0.1–0.4 μg L−1 range for undiluted blood samples) with appropriate repeatability values (RSD < 15% at high level and <23% at LOQ level). Figure of merits of the method can be improved by using a smaller phase ratio (i.e., an increase in the blood volume and a decrease in the HS volume), which lead to lower detection limits, better repeatability values and greater sensibility. Twenty-eight blood samples have been evaluated with the proposed method and the results agree with those indicated in other studies. Benzene was the only target compound that gave significant differences between blood levels detected in volunteer non-smokers and smokers

Redução de poluentes de efluentes das indústrias de papel e celulose pela floculação/coagulação e degradação fotoquímica

The abatement of recalcitrant lignin macromolecules from effluents of pulp and paper industry was investigated by combined process. Flocculation and coagulation with aluminum sulfate and natural polyelectrolytes extracted from cactus Cereus peruvianus were used in the first step. After separation of solid residues by filtration, the photochemical methods using TiO2 as catalyst were employed for photocatalytic degradation of lignin compounds from solution. The abatement of lignin compounds after flocculation and coagulation was 46%, and after the overall process, the pollutants reduction observed were 66%. The remaining organic compounds may be removed by any biological treatment.

Organometallic catalysis: some contributions to organic synthesis

In the present paper some general aspects of metal complex catalysis and its applications for oxyfunctionalization of various olefins, including naturally occurring ones, via selective oxidation, hydroformylation and alkoxycarbonylation are discussed.

Use of the EPR technique to determine thermal stability of some humified organic substances found in soil organic-mineral fractions

In this work, using the EPR spectroscopy, we analysed the thermal stability of some organic-mineral compounds found in a Gleysoil from Rio Janeiro. It was observed a complete disappearance of the EPR signal around 600 °C for the < 2 µm fraction and a residual EPR signal of semiquinone free radical for the 2-20 µm and 20-53 µm fractions at the same temperature. Also, the experiments showed that the 2-20 µm fraction had a larger concentration of semiquinone free radical per g of carbon and a smaller line width indicated a larger humification of this fraction. This is an evidence that the soil organic matter of this fraction (2-20 µm) is more stable than the other ones.

Analytical challenges in breath analysis and its application to exposure monitoring

There is an increasing interest in the use of breath analysis for monitoring human physiology and exposure to toxic substances or environmental pollutants. This review focuses on the current status of the sampling procedures, collection devices and sample-enrichment methodologies used for exhaled breath-vapor analysis. We discuss the different parameters affecting each of the above steps, taking into account the requirements for breath analysis in exposure assessments and the need to analyze target compounds at sub-ppbv levels. Finally, we summarize the practical applications of exposure analysis in the past two decades