![]() |
Welcome to Loot.co.za!
Sign in / Register |Wishlists & Gift Vouchers |Help | Advanced search
|
Your cart is empty |
||
|
Books > Science & Mathematics > Chemistry > Analytical chemistry > General
This book provides readers with in-depth insights into the changes in the Pantanal wetland from its formation to the actual and likely future states. It reveals that today's Pantanal is an evolutionary consequence of geological, ecological and, more recently, man-made events taking place at distinct space-time intervals. Topics include geotectonics and sun-earth interactions, which largely dictate the rate of drastic changes that eventually disrupt ecological stability and radically rebuild the regional landscape. Furthermore, the biota-climate system is discussed as a major driver reshaping the ecohydrology functioning of the landscape on an intermediate timescale. Also covered are major changes in the landscape ecohydrology and biodiversity due to recent land-use and climate changes induced by humankind in the Anthropocene. The ability to recognize how those temporal scales impact the Pantanal wetland provides the opportunity for wise management approaches and the sustainable development of the region.
by Professor D. E. Games, Mass Spectrometry Research Unit, University College of Swansea Sample preparation can be viewed as occupying a Cinderella role in analytical science. However, the quality of sample preparation plays a key role in high In the past decade, there has been quality analysis and deserves higher stature. considerable interest in the use of supercritical fluid extraction (SFE) as an alternative to conventional procedures for the preparation of samples for ana lysis. The driving force for this development is the need for automated, sim pler, faster, non-destructive and selective methods for extraction, preferably using non-toxic extraction media which are easily disposed of. Utilization of supercritical fluids for extraction fulfils these requirements because of their unique physical chemical properties and usually low toxicity. Selectivity can be achieved by suitable selection of pressure (density), temperature and modi fier conditions which enable solvating power to be varied. The high diffusivity of supercritical fluids provides rapid sample penetration and extraction. Use of fluids with low critical temperatures enables extraction to be conducted under mild thermal conditions ensuring that thermally labile compounds do not decompose. The technique can be used off-line, and the extracts analysed by appropriate techniques, or it can be used on-line, by coupling with a variety of chromatographic techniques. These can then, if necessary, be coupled fur ther with spectroscopic techniques, such as Fourier transform infrared, ultra violet or mass spectrometry, to provide specific identification or structural information."
Time-resolved fluorescence spectroscopy is widely used as a research tool in bioch- istry and biophysics. These uses of fluorescence have resulted in extensive knowledge of the structure and dynamics of biological macromolecules. This information has been gained by studies of phenomena that affect the excited state, such as the local environment, quenching processes, and energy transfer. Topics in Fluorescence Spectroscopy, Volume 4: Probe Design and Chemical Sensing reflects a new trend, which is the use of time-resolved fluorescence in analytical and clinical chemistry. These emerging applications of time-resolved fluorescence are the result of continued advances in laser detector and computer technology. For instance, pho- multiplier tubes (PMT) were previously bulky devices. Miniature PMTs are now available, and the performance of simpler detectors is continually improving. There is also considerable effort to develop fluorophores that can be excited with the red/ne- infrared (NIR) output of laser diodes. Using such probes, one can readily imagine small time-resolved fluorometers, even hand-held devices, being used fordoctor's office or home health care.
Over the last several years, the field of materials science has witnessed an explosion of new, advanced materials. They encompass many uses and include superconductors, alloys, glasses, and catalysts. Not only are there quite a number of new enhies into these generic classes of materials, but the materials themselves represent a wide array of physical forms as well. Bulk materials, for example, are being synthesized and applica tions found for them, while still other materials are being synthesized as thin films for yet still more new (and in some cases, as yet unknown) applications. The field continues to expand with (thankfully ) no end in sight as to the number of new possibilities. As work progresses in this area, there is an ever increasing demand for knowing not only what material is formed as an end product but also details of the route by which it is made. The knowledge of reaction mechanisms in their synthesis many times allows a researcher to tailor a preparative scheme to either arrive at the final product in a purer state or with a better yield. Also, a good fundamental experimental knowledge of impuri ties present in the final material helps the investigator get more insight into making it."
Bewitched is an odd word with which to begin a chemical textbook. Yet that is a fair description of how I reacted on first leaming of ion exchange and imagining what might be done with it. That initial fascination has not left me these many years later, and it has provided much ofthe motivation for writing this book. The perceived need for a text on the fundamentals of ion chromatography provided the rest. Many readers will have a general idea of what ion chromatography is and what it does. Briefly, for those who do not, it is an umbrella term for a variety of chromatographie methods for the rapid and sensitive analysis of mixtures of ionic species. It has become highly developed in the last decade, and while it is now routinely used for the determination of organic as weH as inorganic ions, its initial impact was greatest in the area of inorganic analysis. In the past the determination of inorganic ions, particularly anions, meant laborious, time-con suming, and often not very sensitive "wet chemieal" methods. In the last ten years that has changed radically as ion chromatography has supplanted these older methods."
This volume, written by a range of international experts, covers a wide range of topics involving organic fluorine compounds. Each chapter is preceded by a summary and includes extensive illustrations and references. The chapters cover atmospheric chemistry, application of 19F NMR, partition, degradation and transformation, naturally occurring organic fluorine compounds, toxicology of perfluoroalkanes and phosphorofluoridates, and application of aromatic compounds to the elucidation of the mechanism of cytochrome P450.
This volume provides a comprehensive overview of environmental aspects of the Sava River, which is the greatest tributary to the Danube River and the major drainage river system of South Eastern Europe. Hydroelectric power plants, river traffic, intensive agricultural activities, heavy industry and floods have considerable influence on the environment and biota in the basin. Summarizing the results that were gathered in the course of EU, bilateral and national projects, the book highlights the most important stressors and helps readers to better understand the impact of anthropogenic activities on the function of river basins. Topics include: transboundary water cooperation between the riparian countries; climate change projection, including its impact on flood hazards; evaluation of anthropogenic pollution sources; pollution of sediments, metal bioavailability and ecotoxicological and microbiological characterization of the river. The biological part also addresses quality aspects related to wildlife in river aquatic ecosystems (algae, macrophytes, zooplankton, macroinvertebrates and fish) and riparian ecosystems (amphibians, reptiles, birds and mammals). The general state of biodiversity and pressures caused by invasive aquatic species are also discussed.
Conference Overview and the Role of Chemistry in High-Temperature Materials Science and Technology LEO BREWER Department of ChemistIy, University of California, and Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 I don't want to compete with the fascinating historic account that John Drowart gave us, but I would like to go through the history of high don't get the reaction that I get from temperature symposia. I hope I some of my classes when I say, "Remember when such-and-such hap pened during the War?" And I get this blank look, and one of the students will say, "I wasn't born until after the Korean War. " Neverthe less, during World War II, many people in the high-temperature field had their first initiation. But there was one handicap. Owing to security measures, they were not able to interact with one another. Following the War, it was recognized that the high-temperature field was going to expand to meet the demands for materials with unique properties. To meet the demands for new fabrication techniques, it was important to establish better communications among various people. High-tempera ture symposia were established at that time and have continued very frequently, and I'd like to point out why they are especially important for this field. One problem is that it is not easy to work at high temperatures."
The book deals with various consequences of major nuclear accidents, such as in 1986 in Chernobyl and in 2011 in Fukushima. The public is extremely interested in learning more about the movements and risks posed by radiation in the environment related to food supply and food safety. Radionuclides are found in air, water, soil and even in us not only after nuclear accidents because they occur also in nature. Every day, we ingest and inhale radionuclides in our air and food and the water. This book provides a solid underpinning of the basic physical-chemistry and biogeochemistry of naturally occurring and anthrop radioactivity. The mechanisms of radioactive element transfer in the atmosphere, tropospheric and stratospheric diffusion of radioactivity, environmental contamination from accidents and the impact of atmospheric pollution on the food chain, soil and plants, are analyzed and the analytical methods are illustrated. The question of natural radioactivity concentration in building materials is addressed too. While the book contains many case studies and data for Greece, it is of general value. It contributes to the development of international environmentally safe standards and economically reasonable standard regulations based on justified radiological, social and economical legislation concepts.
The analysis of solid materials by introducing solid test sampies directly into the graphite furnace of an atomic absorption spectrometer must be regarded as a powerful analytical approach. Even if it is - of course - not the "ultimate method." After three decades of development, the instrumentation and the methodology are available to apply solid sampling successfully for the analysis of almost every material. Moreover, several tasks cannot be solved using other analytical methods as neatly as they can using direct solid sampling. The conventional methods work more or less satisfactorily, so why do we sug gest applying solid sampling much more extensively than it is today? To begin with, the features pointed out time and again should be named: Rapidity of the analytical procedure, low susceptibility to analyte loss or contamination, very smallquantities can be analyzed, and expenditure on instrumentation and per sonell is also low. These properties are examined and the necessary conditions are discussed (Chapter 1) as are the analytical tasks (Chapter 6) for which use of this method is advantageous. Other features that are often overlooked are just as important: The simplicity of the analytical procedures allows the analyst to main tain an intimate relationship with the original scientific task that has to be solved with the analysis. Furthermore, the considerable reduction of working place haz ards and pollution by avoiding the use of chemical reagents must nowadays be assessed as a feature as important as the others."
With their similarity to the organs of the most advanced creatures that inhabit the Earth, sensors are regarded as being the "senses of electronics": arti?cial eyes and ears that are capable of seeing and hearing beyond the range of - man perception; electronic noses and tongues that can recognise odours and ?avours without a lifetime training; touch that is able not only to feel the texture and temperature of the materials but even to discern their chemical compo- tion. Among the world of chemical sensors, optical devices (sometimes termed "optodes", from the Greek "the optical way") have reached a prominent place in those areas where the features of light and of the light-matter interaction show their advantage: contactless or long-distance interrogation, detection sensitivity, analyte selectivity, absence of electrical interference or risks, and lack of analyte consumption, to name just a few. The introduction of optical ?bres and integrated optics has added more value to such sensing since now light can be con?ned and readily carried to dif?cult-to-reach locations, higher information density can be transported, indicator dyes can be immobilised at the distal end or the evanescent ?eld for unique chemical and biochemical sensing (including multiplexed and distributed measurements), optical s- sors can now be subject to mass production and novel sensing schemes have been established (interferometric, surface plasmon resonance, ?uorescence energy transfer, supramolecular recognition . . . ).
This book deals with the concept of moments, and how they find application in subsurface hydrologic problems-particularly those dealing with solute transport. Both temporal and spatial moments are dealt with in some detail for a wide variety of problems. Several examples using experimental data, both from laboratory columns and field experiments, are provided to give the readers a clear idea about the scope of this method.
Emerging Mass Spectrometric Tools for Analysis of Polymers and Polymer Additives, by Nina Aminlashgari and Minna Hakkarainen. Analysis of Polymer Additives and Impurities by Liquid Chromatography/Mass Spectrometry and Capillary Electrophoresis/Mass Spectrometry, by Wolfgang Buchberger and Martin Stiftinger. Direct Insertion Probe Mass Spectrometry of Polymers, by Jale Hacaloglu Mass Spectrometric Characterization of Oligo- and Polysaccharides and Their Derivatives, by Petra Mischnick. Electrospray Ionization-Mass Spectrometry for Molecular Level Understanding of Polymer Degradation, by Minna Hakkarainen.
The development of mechanistic organic chemistry is filled with claims of short-lived reactive intermediates connecting starting material to product. In many ways this book represents a personal odyssey of the editor in this area of chemistry. I well remember my introduction to organic chemistry as an undergraduate working in the laboratories of Shelton Bank at SUNY Albany in the early 1970s, and the excitement and frustration attending the piecing together of the details of a reaction mechanism by working backwards from the stable products of the reaction. In those days the reaction and the reactive intermediates flew by too rapidly to permit direct observation. Thus it came as something of a revelation to me as a graduate student at Yale that it was possible to slow down a reaction and actually "see" such ephemeral species as carbenes and biradicals by spectroscopic methods, by generating them photochemically at cryogenic temperatures. In this monograph several chap ters are devoted to low-temperature studies. Dougherty has described the matrix EPR spectra of biradicals, which were pure conjecture only ten years ago. Michl and Arnold have described the matrix spectroscopy of cyciobutadiene, a molecule that has fascinated organic chemists for over a hundred years. They have shown that by using a combination of matrix spec troscopic methods it is possible to learn nearly as much about the structure of cyciobutadiene, the prototypical antiaromatic biradicaloid, as about that of a common shelf-stable reagent."
Recognized experts present incisive analysis of both fundamental and applied problems in this continuation of a highly acclaimed series. Topics discussed include: A thorough and mathematical treatment of periodic phenomena, with consideration of new theories about the transition between `order' and `chaos'; Impedance spectroscopy as applied to the study of kinetics and mechanisms of electrode processes; The use of stoichiometric numbers in mechanism analysis; The electro-osmotic dewatering of clays with important implications for the processing of industrial waste and geotechnical; stabilization; Magnetic effects in electrolytic processes and the electrolytic Hall effect; and The computer analysis and modeling of mass transfer and fluid flow. These authoritative studies will be invaluable for researchers in engineering, electrochemistry, analytical chemistry, materials science, physical chemistry, and corrosion science.
Environmental chemistry is a fast developing science aimed at deciphering fundamental mechanisms ruling the behaviour of pollutants in ecosystems. Applying this knowledge to current environmental issues leads to the remediation of environmental media, and to new, low energy, low emission, sustainable processes. Nanotechnology applications for alternative energies such as solar power, fuel cells, hydrogen and lithium batteries are reviewed in the first section. Recent investigations on carbon nanotubes, nanocatalysts and cyclodextrins disclose unprecedented techniques to monitor and clean pollutants such as greenhouse gases, heavy metals, pesticides, pathogens occurring in water, air and soil. The second section reviews the risks for human health of critical pollutants such as endocrine disruptors, dioxins and heavy metals contaminating seafood and sediments. An exhaustive review of DDT isomers reveals unexpected mechanisms of DDT transfer to fishes. A chapter on pollutant geochronology using river sedimentary archives provides novel insights on pollution history since the beginning of the anthropocene. This book will be a valuable source of information for engineers and students developing novel applied techniques to monitor and clean pollutants in air, wastewater, soils and sediments. "
This book presents a unified outlook on counter-current, ion
size exclusion, supercritical fluids, high-performance thin layers,
and gas and size exclusion chromatographic techniques used for the
separation and purification of organic and inorganic analytes. It
also describes a number of green techniques, green sample
preparation methods and optimization of solvent consumption in the
chromatographic analysis of organic and inorganic analytes. This
book offers a valuable resource not only for learners, but also for
more experienced chromatographers, conveying a deeper understanding
of green chromatographic techniques, green solvents and preparation
methods.
The aim of this volume is to review the state-of-the-art in analytical voltammetry with regard to theory and instrumentation, and show how these relate to the analysis of inorganic, organometallic, organic and biological molecules. Modern voltammetric techniques have practical applications in biological, pharmaceutical and environmental chemistry. The growing importance of voltammetry in the development of modified electrodes and biological electrodes and chemical and biological sensors is also highlighted.
"Microwave-Assisted Sample Preparation for Trace Element Analysis" describes the principles, equipment, and applications involved in sample preparation with microwaves for trace element analysis. The book covers well-established applications as well as new trends in this field. Hot topics such as sample preparation for speciation, metabolomics, and halogen determination, as well as the alternatives of sample preparation for special samples (for example, carbon nanotubes, polymers, petroleum products), are also discussed. The use of microwaves in sample preparation has increased in
recent decades. Several applications of microwaves for sample
preparation can be found in the literature for practically all
types of sample matrices, especially for the determination of trace
elements by atomic spectrometric techniques, safely and cleanly
reducing the time involved in this step. Microwave-assisted sample
preparation is not only a tool for research but also for routine
analysis laboratories; the state-of-the-art in sample preparation
in trace element analysis. This book is the only resource for
chemists specifically focused on this topic.
Several state-of-the-art applications of molten salts are presented, such as metal-molten salt systems, room temperature glass formation, and room temperature melts. Several recent examples of applications highlight the importance of molten salts in various industries (batteries, pyrochemical reprocessing of nuclear fuel, synthesis and catalysis). The basic concepts of the structure, dynamics, electrochemistry, interfacial and thermodynamic properties are detailed and relevant experimental methods described. Such fundamental concepts are essential for an in-depth understanding of the physicochemical properties of molten salts in general, including metal-molten salts, glass forming and low temperature melts. Experimental methods for investigating structural, dynamical, electrochemical thermodynamical and interfacial properties are detailed, as also are techniques for data collection and analysis. Scientists, engineers and technologists will find the volume a valuable reference source covering a wide spectrum of fundamental concepts and modern technologies.
Environmental chemistry is a fast developing science aimed at deciphering fundamental mechanisms ruling the behaviour of pollutants in ecosystems. Applying this knowledge to current environmental issues leads to the remediation of environmental media, and to new, low energy, low emission, sustainable processes. Chapters review analysis and remediation of pollutants such as greenhouse gases, chiral pharmaceuticals, dyes, chlorinated organics, arsenic, toxic metals and pathogen in air, water, plant and soil. Several highlights include the overlooked impact of air pollutants from buildings for health risk, innovative remediation techniques such as bioreactors for gas treatment, electrochemical cleaning of pharmaceuticals, sequestration on Fe-Mn nodules, phytoremediation and photocatalytical inactivation of microbial pathogens. This book will be a valuable source of information for engineers and students developing novel applied techniques to monitor and clean pollutants in air, wastewater, soils and sediments. "
The functionalization of surfaces on the nanoscale is one of the most fascinating and at the same time challenging topics in science. It is the key to tailoring catalysts, sensors, or devices for solar energy conversion, whose functional principle is based on the interaction of an active solid surface with another (liquid or gaseous) phase. As an example, planar transition metal complexes adsorbed on solid supports are promising candidates for novel heterogeneous catalysts. An important feature of these catalysts, compared to supported metal clusters, is the fact that the active sites, i. e. , the coordinated metal centers with their vacant axial coordination sites, are well de?ned and uniform. Metalloporphyrinoids are particularly suitable in this respect because they combine a structure forming element-the rigid molecular frame, which often induces long range order-with an active site, the coordinated metal ion. Its planar coordination environment leaves two axial coordination sites available for additional ligands. If adsorbed on a surface, one of these axial sites is occupied by the underlying substrate. The resulting electronic interaction with the surface can be used to tailor the electronic structure and thereby the reactivity of the metal center. The remaining site is free for the attachment of molecules (sensor functionality) and/or operates as a reaction center (single-site catalysis). Prototype examples are omnipresent in nature, where in particular metallo-tetrapyrrols play a decisive role in important biological processes, with the most prominent examples being iron porphyrins in heme, magnesium porphyrins in chlorophyll, and cobalt corrin in vitamin B12. |
You may like...
Medium Voltage DC System Architectures
Brandon Grainger, Rik W. Doncker
Hardcover
Insurance and Risk Management for…
Simon Grima, Ercan OEzen, …
Hardcover
R2,837
Discovery Miles 28 370
|