Analcime crystallization and compositional profiles - Comparing approaches to detect post-depositional alterations in archaeological pottery

The approaches of comparative studies and profile measurements, often used in order to detect post-depositional alterations of ceramics, have been applied simultaneously to two sets of Roman pottery, both of which include altered individuals. As analytical techniques, Neutron Activation Analysis and X-Ray Diffraction have been used. Both approaches lead to substantially different results. This shows that they detect different levels of alteration and should complement each other rather than being used exclusively. For the special process of a glassy phase decomposition followed by a crystallization of the Na-zeolite analcime, the results suggest that it changes high-fired calcareous pottery rapidly, and so fundamentally that the results of various archaeometric techniques can be severely disturbed.

Effect of cocoa powder in the prevention of cardiovascular disease: biological, consumption and inflammatory biomarkers. A metabolomic approach

Numerous health benefits have been attributed to cocoa and its derived products in the last decade including antioxidant, anti-platelet and positive effects on lipid metabolism and vascular function. Inflammation plays a key role in the initiation and progression of atherosclerosis. However, cocoa feeding trials focused on inflammation are still rare and the results yielded are controversial. Health effects derived from cocoa consumption have been partly attributed to its polyphenol content, in particular of flavanols. Bioavailability is a key issue for cocoa polyphenols in order to be able to exert their biological activities. In the case of flavanols, bioavailability is strongly influenced by several factors, such as their degree of polymerization and the food matrix in which the polyphenols are delivered. Furthermore, gut has become an active site for the metabolism of procyanidins (oligomeric and polymeric flavanols). Estimation of polyphenol consumption or exposure is also a very challenging task in Food and Nutrition Science in order to correlate the intake of phytochemicals with in vivo health effects. In the area of nutrition, modern analytical techniques based on mass spectrometry are leading to considerable advances in targeted metabolite analysis and particularly in Metabolomics or global metabolite analysis. In this chapter we have summarized the most relevant results of our recent research on the bioavailability of cocoa polyphenols in humans and the effect of the matrix in which cocoa polyphenols are delivered considering both targeted analysis and a metabolomic approach. Furthermore, we have also summarized the effect of long-term consumption of cocoa powder in patients at high risk of cardiovascular disease (CVD) on the inflammatory biomarkers of atherosclerosis.

Problems of the randomization test for AB designs

N = 1 designs imply repeated registrations of the behaviour of the same experimental unit and the measurements obtained are often few due to time limitations, while they are also likely to be sequentially dependent. The analytical techniques needed to enhance statistical and clinical decision making have to deal with these problems. Different procedures for analysing data from single-case AB designs are discussed, presenting their main features and revising the results reported by previous studies. Randomization tests represent one of the statistical methods that seemed to perform well in terms of controlling false alarm rates. In the experimental part of the study a new simulation approach is used to test the performance of randomization tests and the results suggest that the technique is not always robust against the violation of the independence assumption. Moreover, sensitivity proved to be generally unacceptably low for series lengths equal to 30 and 40. Considering the evidence available, there does not seem to be an optimal technique for single-case data analysis

Etude de la composition initiale et du vieillissement des traces digitales: vers le développement d'une méthode de datation?

«Quel est l'âge de cette trace digitale?» Cette question est relativement souvent soulevée au tribunal ou lors d'investigations, lorsque la personne suspectée admet avoir laissé ses empreintes digitales sur une scène de crime mais prétend l'avoir fait à un autre moment que celui du crime et pour une raison innocente. Toutefois, aucune réponse ne peut actuellement être donnée à cette question, puisqu'aucune méthodologie n'est pour l'heure validée et acceptée par l'ensemble de la communauté forensique. Néanmoins, l'inventaire de cas américains conduit dans cette recherche a montré que les experts fournissent tout de même des témoignages au tribunal concernant l'âge de traces digitales, même si ceux-­‐ci sont majoritairement basés sur des paramètres subjectifs et mal documentés. Il a été relativement aisé d'accéder à des cas américains détaillés, ce qui explique le choix de l'exemple. Toutefois, la problématique de la datation des traces digitales est rencontrée dans le monde entier, et le manque de consensus actuel dans les réponses données souligne la nécessité d'effectuer des études sur le sujet. Le but de la présente recherche est donc d'évaluer la possibilité de développer une méthode de datation objective des traces digitales. Comme les questions entourant la mise au point d'une telle procédure ne sont pas nouvelles, différentes tentatives ont déjà été décrites dans la littérature. Cette recherche les a étudiées de manière critique, et souligne que la plupart des méthodologies reportées souffrent de limitations prévenant leur utilisation pratique. Néanmoins, certaines approches basées sur l'évolution dans le temps de composés intrinsèques aux résidus papillaires se sont montrées prometteuses. Ainsi, un recensement détaillé de la littérature a été conduit afin d'identifier les composés présents dans les traces digitales et les techniques analytiques capables de les détecter. Le choix a été fait de se concentrer sur les composés sébacés détectés par chromatographie gazeuse couplée à la spectrométrie de masse (GC/MS) ou par spectroscopie infrarouge à transformée de Fourier. Des analyses GC/MS ont été menées afin de caractériser la variabilité initiale de lipides cibles au sein des traces digitales d'un même donneur (intra-­‐variabilité) et entre les traces digitales de donneurs différents (inter-­‐variabilité). Ainsi, plusieurs molécules ont été identifiées et quantifiées pour la première fois dans les résidus papillaires. De plus, il a été déterminé que l'intra-­‐variabilité des résidus était significativement plus basse que l'inter-­‐variabilité, mais que ces deux types de variabilité pouvaient être réduits en utilisant différents pré-­‐ traitements statistiques s'inspirant du domaine du profilage de produits stupéfiants. Il a également été possible de proposer un modèle objectif de classification des donneurs permettant de les regrouper dans deux classes principales en se basant sur la composition initiale de leurs traces digitales. Ces classes correspondent à ce qui est actuellement appelé de manière relativement subjective des « bons » ou « mauvais » donneurs. Le potentiel d'un tel modèle est élevé dans le domaine de la recherche en traces digitales, puisqu'il permet de sélectionner des donneurs représentatifs selon les composés d'intérêt. En utilisant la GC/MS et la FTIR, une étude détaillée a été conduite sur les effets de différents facteurs d'influence sur la composition initiale et le vieillissement de molécules lipidiques au sein des traces digitales. Il a ainsi été déterminé que des modèles univariés et multivariés pouvaient être construits pour décrire le vieillissement des composés cibles (transformés en paramètres de vieillissement par pré-­‐traitement), mais que certains facteurs d'influence affectaient ces modèles plus sérieusement que d'autres. En effet, le donneur, le substrat et l'application de techniques de révélation semblent empêcher la construction de modèles reproductibles. Les autres facteurs testés (moment de déposition, pression, température et illumination) influencent également les résidus et leur vieillissement, mais des modèles combinant différentes valeurs de ces facteurs ont tout de même prouvé leur robustesse dans des situations bien définies. De plus, des traces digitales-­‐tests ont été analysées par GC/MS afin d'être datées en utilisant certains des modèles construits. Il s'est avéré que des estimations correctes étaient obtenues pour plus de 60 % des traces-­‐tests datées, et jusqu'à 100% lorsque les conditions de stockage étaient connues. Ces résultats sont intéressants mais il est impératif de conduire des recherches supplémentaires afin d'évaluer les possibilités d'application de ces modèles dans des cas réels. Dans une perspective plus fondamentale, une étude pilote a également été effectuée sur l'utilisation de la spectroscopie infrarouge combinée à l'imagerie chimique (FTIR-­‐CI) afin d'obtenir des informations quant à la composition et au vieillissement des traces digitales. Plus précisément, la capacité de cette technique à mettre en évidence le vieillissement et l'effet de certains facteurs d'influence sur de larges zones de traces digitales a été investiguée. Cette information a ensuite été comparée avec celle obtenue par les spectres FTIR simples. Il en a ainsi résulté que la FTIR-­‐CI était un outil puissant, mais que son utilisation dans l'étude des résidus papillaires à des buts forensiques avait des limites. En effet, dans cette recherche, cette technique n'a pas permis d'obtenir des informations supplémentaires par rapport aux spectres FTIR traditionnels et a également montré des désavantages majeurs, à savoir de longs temps d'analyse et de traitement, particulièrement lorsque de larges zones de traces digitales doivent être couvertes. Finalement, les résultats obtenus dans ce travail ont permis la proposition et discussion d'une approche pragmatique afin d'aborder les questions de datation des traces digitales. Cette approche permet ainsi d'identifier quel type d'information le scientifique serait capable d'apporter aux enquêteurs et/ou au tribunal à l'heure actuelle. De plus, le canevas proposé décrit également les différentes étapes itératives de développement qui devraient être suivies par la recherche afin de parvenir à la validation d'une méthodologie de datation des traces digitales objective, dont les capacités et limites sont connues et documentées. -- "How old is this fingermark?" This question is relatively often raised in trials when suspects admit that they have left their fingermarks on a crime scene but allege that the contact occurred at a time different to that of the crime and for legitimate reasons. However, no answer can be given to this question so far, because no fingermark dating methodology has been validated and accepted by the whole forensic community. Nevertheless, the review of past American cases highlighted that experts actually gave/give testimonies in courts about the age of fingermarks, even if mostly based on subjective and badly documented parameters. It was relatively easy to access fully described American cases, thus explaining the origin of the given examples. However, fingermark dating issues are encountered worldwide, and the lack of consensus among the given answers highlights the necessity to conduct research on the subject. The present work thus aims at studying the possibility to develop an objective fingermark dating method. As the questions surrounding the development of dating procedures are not new, different attempts were already described in the literature. This research proposes a critical review of these attempts and highlights that most of the reported methodologies still suffer from limitations preventing their use in actual practice. Nevertheless, some approaches based on the evolution of intrinsic compounds detected in fingermark residue over time appear to be promising. Thus, an exhaustive review of the literature was conducted in order to identify the compounds available in the fingermark residue and the analytical techniques capable of analysing them. It was chosen to concentrate on sebaceous compounds analysed using gas chromatography coupled with mass spectrometry (GC/MS) or Fourier transform infrared spectroscopy (FTIR). GC/MS analyses were conducted in order to characterize the initial variability of target lipids among fresh fingermarks of the same donor (intra-­‐variability) and between fingermarks of different donors (inter-­‐variability). As a result, many molecules were identified and quantified for the first time in fingermark residue. Furthermore, it was determined that the intra-­‐variability of the fingermark residue was significantly lower than the inter-­‐variability, but that it was possible to reduce both kind of variability using different statistical pre-­‐ treatments inspired from the drug profiling area. It was also possible to propose an objective donor classification model allowing the grouping of donors in two main classes based on their initial lipid composition. These classes correspond to what is relatively subjectively called "good" or "bad" donors. The potential of such a model is high for the fingermark research field, as it allows the selection of representative donors based on compounds of interest. Using GC/MS and FTIR, an in-­‐depth study of the effects of different influence factors on the initial composition and aging of target lipid molecules found in fingermark residue was conducted. It was determined that univariate and multivariate models could be build to describe the aging of target compounds (transformed in aging parameters through pre-­‐ processing techniques), but that some influence factors were affecting these models more than others. In fact, the donor, the substrate and the application of enhancement techniques seemed to hinder the construction of reproducible models. The other tested factors (deposition moment, pressure, temperature and illumination) also affected the residue and their aging, but models combining different values of these factors still proved to be robust. Furthermore, test-­‐fingermarks were analysed with GC/MS in order to be dated using some of the generated models. It turned out that correct estimations were obtained for 60% of the dated test-­‐fingermarks and until 100% when the storage conditions were known. These results are interesting but further research should be conducted to evaluate if these models could be used in uncontrolled casework conditions. In a more fundamental perspective, a pilot study was also conducted on the use of infrared spectroscopy combined with chemical imaging in order to gain information about the fingermark composition and aging. More precisely, its ability to highlight influence factors and aging effects over large areas of fingermarks was investigated. This information was then compared with that given by individual FTIR spectra. It was concluded that while FTIR-­‐ CI is a powerful tool, its use to study natural fingermark residue for forensic purposes has to be carefully considered. In fact, in this study, this technique does not yield more information on residue distribution than traditional FTIR spectra and also suffers from major drawbacks, such as long analysis and processing time, particularly when large fingermark areas need to be covered. Finally, the results obtained in this research allowed the proposition and discussion of a formal and pragmatic framework to approach the fingermark dating questions. It allows identifying which type of information the scientist would be able to bring so far to investigators and/or Justice. Furthermore, this proposed framework also describes the different iterative development steps that the research should follow in order to achieve the validation of an objective fingermark dating methodology, whose capacities and limits are well known and properly documented.

Effect of cocoa powder in the prevention of cardiovascular disease: biological, consumption and inflammatory biomarkers. A metabolomic approach

Numerous health benefits have been attributed to cocoa and its derived products in the last decade including antioxidant, anti-platelet and positive effects on lipid metabolism and vascular function. Inflammation plays a key role in the initiation and progression of atherosclerosis. However, cocoa feeding trials focused on inflammation are still rare and the results yielded are controversial. Health effects derived from cocoa consumption have been partly attributed to its polyphenol content, in particular of flavanols. Bioavailability is a key issue for cocoa polyphenols in order to be able to exert their biological activities. In the case of flavanols, bioavailability is strongly influenced by several factors, such as their degree of polymerization and the food matrix in which the polyphenols are delivered. Furthermore, gut has become an active site for the metabolism of procyanidins (oligomeric and polymeric flavanols). Estimation of polyphenol consumption or exposure is also a very challenging task in Food and Nutrition Science in order to correlate the intake of phytochemicals with in vivo health effects. In the area of nutrition, modern analytical techniques based on mass spectrometry are leading to considerable advances in targeted metabolite analysis and particularly in Metabolomics or global metabolite analysis. In this chapter we have summarized the most relevant results of our recent research on the bioavailability of cocoa polyphenols in humans and the effect of the matrix in which cocoa polyphenols are delivered considering both targeted analysis and a metabolomic approach. Furthermore, we have also summarized the effect of long-term consumption of cocoa powder in patients at high risk of cardiovascular disease (CVD) on the inflammatory biomarkers of atherosclerosis.

Especiação de Arsênio - uma revisão

This paper provides a review on separation methods and analytical techniques for the determination of several species of organic and inorganic arsenic in different matrices. Arsenic is an element whose speciation is of particular interest due to the great variation of toxicity levels exhibited for its different chemical forms. Arsenic (III) and As (V) are the most toxic species while organic compounds such as arsenobetaine (AsB), produced by methylation of inorganics species (carcinogenics) are relatively less toxic, hence the great importance of arsenic speciation in the determination of the degree of contamination of an environmental or biological system.

Avaliação dos métodos analíticos para a determinação de metabólitos do benzeno como potenciais biomarcadores de exposição humana ao benzeno no ar

Increasing attention is being paid to the use of biomarkers for determining the exposure of humans to air toxics. Biomarkers include the nonreacted toxic substance, their metabolites, or the reaction products of these toxics with naturally substances in the body. Significant progress has been made in the measurement of biomarkers during the past several years. Much of this progress has been because of the development of advanced analytical techniques for identification and quantification of the chemical species in complex matrix, such as biological fluids. The assessment of the potential cancer risk associated with exposure to benzene at occupational and non-occupational ambient is necessary because of the toxicological implications of this air pollutant. Thus, in this review, the analytical methodologies used to determine the benzene metabolites, in special, urinary muconic acid and S-phenylmercapturic acid, are described and several problems affecting the precision of these procedures are discussed. Finally, in view of the difficulty pointed out for selecting the more adequate biomarker, further studies to evaluate the human exposure levels to benzene should be done.

Contaminação ambiental por compostos organoestânicos

The occurrence and the effects of organotin compounds (OTs) have been studied since a long time, due to their widespread use and deleterious effects. Some OTs are used as pesticides in crops, or as biocides in antifouling paints, applied in the ship hulls to avoid attachment and growth of tube worms, mussels and barnacles. However, "nontarget" organisms may be exposed, resulting in the poisoning of biological system, originating mutations and sentencing species to extinction. In this work we reported a revision study on the history of OTs and the techniques developed for its assessment and control.

Sínteses química e enzimática de peptídeos: princípios básicos e aplicações

This review begins with a brief discussion of the biological importance and chemical features of peptides. A description of the existing synthetic methods follows with emphasis on the basic aspects of the chemical and enzymatic syntheses. Techniques used to purify and characterize the synthesized peptides are also discussed. Finally, a few applications of the final products in chemistry, biochemistry, immunology and medicine are presented, such as identification and quantification of naturally occurring peptides, inspection of structure-activity relationships, therapeutics, development and/or improvement of analytical techniques and search for new vaccines.

Estratégias para aumento de sensibilidade em espectrofotometria UV-VIS

Spectrophotometry is one of the most widespread analytical techniques due to its simplicity, reliability, and low-cost instrumentation for both direct measurements and coupled to other techniques or processes such as chromatography, electrophoresis and flow analysis. However, the application is often limited by sensitivity. This article describes some advances that greatly improve the performance of spectrophotometric measurements, especially in order to increase sensitivity, including the employment of liquid-core waveguides and solid-phase spectrophotometry.

Bisfosfonatos: síntese, análises químicas e aplicações farmacológicas

Bisphosphonates are drugs that have been widely used in different bone diseases, and have recently been used successfully against many parasites. Various synthetic routes to prepare different types of bisphosphonates have been described, with distinct potency and pharmacological activity. A number of analytical techniques are currently being used to analyze these drugs; among these, the high performance liquid chromatography (HPLC), with different systems of detection, is worth highlighting. However, the development of more sensitive methods is still necessary, once they are essential for bioavailability and bioequivalence studies. This paper reports the major synthesis routes, chemical analysis methodologies and pharmacological applications of bisphosphonates.

Integração de técnicas analíticas e proposta de experimentos para cursos de graduação em análise instrumental: uso de espectrômetro de absorção atômica para medidas de absorção molecular

Simple experiments are proposed for measuring molecular absorption of chromate and dichromate ions using an atomic absorption spectrometer. The experiments can help undergraduate students in instrumental analysis courses understand important aspects involving conceptual and instrumental similarities and differences between frequently used analytical techniques. Hollow cathode lamps were selected with wavelengths in the region of molecular absorption of chromate and dichromate. Calibration curves were obtained and the linear dynamic range was evaluated. Results were compared with those obtained in a molecular absorption spectrometer. The molar absorptivities obtained were also compared.

Química Analítica de Processos

Process Analytical Chemistry (PAC) is an important and growing area in analytical chemistry, that has received little attention in academic centers devoted to the gathering of knowledge and to optimization of chemical processes. PAC is an area devoted to optimization and knowledge acquisition of chemical processes, to reducing costs and wastes and to making an important contribution to sustainable development. The main aim of this review is to present to the Brazilian community the development and state of the art of PAC, discussing concepts, analytical techniques currently employed in the industry and some applications.

Caracterização física, química e ecotoxicológica de efluente da indústria de fabricação de explosivos

The production and use of nitroaromatic explosives have resulted in their dissemination into the environment, where their presence in waterways and soil represents an ecological and health hazard. The hazardous characteristics of these compounds need to be carefully studied, so that the impact of their discharge on the environment can be better evaluated. This work presents the characterization of wastewater from Brazilian TNT industry using as analytical techniques mass spectroscopy, chromatography, toxicity assays and other physico-chemical analyses.

Determinação de paládio em amostras biológicas aplicando técnicas analíticas nucleares

This study presents Pd determinations in bovine tissue samples containing palladium prepared in the laboratory, and CCQM-P63 automotive catalyst materials of the Proficiency Test, using instrumental thermal and epithermal neutron activation analysis and energy dispersive X-ray fluorescence techniques. Solvent extraction and solid phase extraction procedures were also applied to separate Pd from interfering elements before the irradiation in the nuclear reactor. The results obtained by different techniques were compared against each other to examine sensitivity, precision and accuracy.