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Sample records for analytical coordination chemistry

  1. Science Update: Analytical Chemistry.

    ERIC Educational Resources Information Center

    Worthy, Ward

    1980-01-01

    Briefly discusses new instrumentation in the field of analytical chemistry. Advances in liquid chromatography, photoacoustic spectroscopy, the use of lasers, and mass spectrometry are also discussed. (CS)

  2. Frontiers in analytical chemistry

    SciTech Connect

    Amato, I.

    1988-12-15

    Doing more with less was the modus operandi of R. Buckminster Fuller, the late science genius, and inventor of such things as the geodesic dome. In late September, chemists described their own version of this maxim--learning more chemistry from less material and in less time--in a symposium titled Frontiers in Analytical Chemistry at the 196th National Meeting of the American Chemical Society in Los Angeles. Symposium organizer Allen J. Bard of the University of Texas at Austin assembled six speakers, himself among them, to survey pretty widely different areas of analytical chemistry.

  3. Analytical Chemistry in Russia.

    PubMed

    Zolotov, Yuri

    2016-09-06

    Research in Russian analytical chemistry (AC) is carried out on a significant scale, and the analytical service solves practical tasks of geological survey, environmental protection, medicine, industry, agriculture, etc. The education system trains highly skilled professionals in AC. The development and especially manufacturing of analytical instruments should be improved; in spite of this, there are several good domestic instruments and other satisfy some requirements. Russian AC has rather good historical roots.

  4. Quo vadis, analytical chemistry?

    PubMed

    Valcárcel, Miguel

    2016-01-01

    This paper presents an open, personal, fresh approach to the future of Analytical Chemistry in the context of the deep changes Science and Technology are anticipated to experience. Its main aim is to challenge young analytical chemists because the future of our scientific discipline is in their hands. A description of not completely accurate overall conceptions of our discipline, both past and present, to be avoided is followed by a flexible, integral definition of Analytical Chemistry and its cornerstones (viz., aims and objectives, quality trade-offs, the third basic analytical reference, the information hierarchy, social responsibility, independent research, transfer of knowledge and technology, interfaces to other scientific-technical disciplines, and well-oriented education). Obsolete paradigms, and more accurate general and specific that can be expected to provide the framework for our discipline in the coming years are described. Finally, the three possible responses of analytical chemists to the proposed changes in our discipline are discussed.

  5. Analytical Chemistry Laboratory

    NASA Technical Reports Server (NTRS)

    Anderson, Mark

    2013-01-01

    The Analytical Chemistry and Material Development Group maintains a capability in chemical analysis, materials R&D failure analysis and contamination control. The uniquely qualified staff and facility support the needs of flight projects, science instrument development and various technical tasks, as well as Cal Tech.

  6. Nuclear analytical chemistry

    SciTech Connect

    Brune, D.; Forkman, B.; Persson, B.

    1984-01-01

    This book covers the general theories and techniques of nuclear chemical analysis, directed at applications in analytical chemistry, nuclear medicine, radiophysics, agriculture, environmental sciences, geological exploration, industrial process control, etc. The main principles of nuclear physics and nuclear detection on which the analysis is based are briefly outlined. An attempt is made to emphasise the fundamentals of activation analysis, detection and activation methods, as well as their applications. The book provides guidance in analytical chemistry, agriculture, environmental and biomedical sciences, etc. The contents include: the nuclear periodic system; nuclear decay; nuclear reactions; nuclear radiation sources; interaction of radiation with matter; principles of radiation detectors; nuclear electronics; statistical methods and spectral analysis; methods of radiation detection; neutron activation analysis; charged particle activation analysis; photon activation analysis; sample preparation and chemical separation; nuclear chemical analysis in biological and medical research; the use of nuclear chemical analysis in the field of criminology; nuclear chemical analysis in environmental sciences, geology and mineral exploration; and radiation protection.

  7. Advances in analytical chemistry

    NASA Technical Reports Server (NTRS)

    Arendale, W. F.; Congo, Richard T.; Nielsen, Bruce J.

    1991-01-01

    Implementation of computer programs based on multivariate statistical algorithms makes possible obtaining reliable information from long data vectors that contain large amounts of extraneous information, for example, noise and/or analytes that we do not wish to control. Three examples are described. Each of these applications requires the use of techniques characteristic of modern analytical chemistry. The first example, using a quantitative or analytical model, describes the determination of the acid dissociation constant for 2,2'-pyridyl thiophene using archived data. The second example describes an investigation to determine the active biocidal species of iodine in aqueous solutions. The third example is taken from a research program directed toward advanced fiber-optic chemical sensors. The second and third examples require heuristic or empirical models.

  8. ENVIRONMENTAL ANALYTICAL CHEMISTRY OF ...

    EPA Pesticide Factsheets

    Within the scope of a number of emerging contaminant issues in environmental analysis, one area that has received a great deal of public interest has been the assessment of the role of pharmaceuticals and personal care products (PPCPs) as stressors and agents of change in ecosystems as well as their role in unplanned human exposure. The relationship between personal actions and the occurrence of PPCPs in the environment is clear-cut and comprehensible to the public. In this overview, we attempt to examine the separations aspect of the analytical approach to the vast array of potential analytes among this class of compounds. We also highlight the relationship between these compounds and endocrine disrupting compounds (EDCs) and between PPCPs and EDCs and the more traditional environmental analytes such as the persistent organic pollutants (POPs). Although the spectrum of chemical behavior extends from hydrophobic to hydrophilic, the current focus has shifted to moderately and highly polar analytes. Thus, emphasis on HPLC and LC/MS has grown and MS/MS has become a detection technique of choice with either electrospray ionization or atmospheric pressure chemical ionization. This contrasts markedly with the bench mark approach of capillary GC, GC/MS and electron ionization in traditional environmental analysis. The expansion of the analyte list has fostered new vigor in the development of environmental analytical chemistry, modernized the range of tools appli

  9. Ternary complexes in analytical chemistry.

    PubMed

    Babko, A K

    1968-08-01

    Reactions between a complex AB and a third component C do not always proceed by a displacement mechanism governed by the energy difference of the chemical bonds A-B and A-C. The third component often becomes part of the complex, forming a mixed co-ordination sphere or ternary complex. The properties of this ternary complex ABC are not additive functions of the properties of AB and AC. Such reactions are important in many methods in analytical chemistry, particularly in photometric analysis, extractive separation, masking, etc. The general properties of the four basic types of ternary complex are reviewed and examples given. The four types comprise the systems (a) metal ion, electronegative ligand, organic base, (b) one metal ion, two different electronegative ligands, (c) ternary heteropoly acids, and (d) two different metal ions, one ligand.

  10. Coordinate swapping in standard addition graphs for analytical chemistry: a simplified path for uncertainty calculation in linear and nonlinear plots.

    PubMed

    Meija, Juris; Pagliano, Enea; Mester, Zoltán

    2014-09-02

    Uncertainty of the result from the method of standard addition is often underestimated due to neglect of the covariance between the intercept and the slope. In order to simplify the data analysis from standard addition experiments, we propose x-y coordinate swapping in conventional linear regression. Unlike the ratio of the intercept and slope, which is the result of the traditional method of standard addition, the result of the inverse standard addition is obtained directly from the intercept of the swapped calibration line. Consequently, the uncertainty evaluation becomes markedly simpler. The method is also applicable to nonlinear curves, such as the quadratic model, without incurring any additional complexity.

  11. Ultrasound in analytical chemistry.

    PubMed

    Priego Capote, F; Luque de Castro, M D

    2007-01-01

    Ultrasound is a type of energy which can help analytical chemists in almost all their laboratory tasks, from cleaning to detection. A generic view of the different steps which can be assisted by ultrasound is given here. These steps include preliminary operations usually not considered in most analytical methods (e.g. cleaning, degassing, and atomization), sample preparation being the main area of application. In sample preparation ultrasound is used to assist solid-sample treatment (e.g. digestion, leaching, slurry formation) and liquid-sample preparation (e.g. liquid-liquid extraction, emulsification, homogenization) or to promote heterogeneous sample treatment (e.g. filtration, aggregation, dissolution of solids, crystallization, precipitation, defoaming, degassing). Detection techniques based on use of ultrasonic radiation, the principles on which they are based, responses, and the quantities measured are also discussed.

  12. Laser ablation in analytical chemistry.

    PubMed

    Russo, Richard E; Mao, Xianglei; Gonzalez, Jhanis J; Zorba, Vassilia; Yoo, Jong

    2013-07-02

    In 2002, we wrote an Analytical Chemistry feature article describing the Physics of Laser Ablation in Microchemical Analysis. In line with the theme of the 2002 article, this manuscript discusses current issues in fundamental research, applications based on detecting photons at the ablation site (LIBS and LAMIS) and by collecting particles for excitation in a secondary source (ICP), and directions for the technology.

  13. Analytical Chemistry and the Microchip.

    ERIC Educational Resources Information Center

    Lowry, Robert K.

    1986-01-01

    Analytical techniques used at various points in making microchips are described. They include: Fourier transform infrared spectrometry (silicon purity); optical emission spectroscopy (quantitative thin-film composition); X-ray photoelectron spectroscopy (chemical changes in thin films); wet chemistry, instrumental analysis (process chemicals);…

  14. Microcomputer Applications in Analytical Chemistry.

    ERIC Educational Resources Information Center

    Long, Joseph W.

    The first part of this paper addresses the following topics: (1) the usefulness of microcomputers; (2) applications for microcomputers in analytical chemistry; (3) costs; (4) major microcomputer systems and subsystems; and (5) which microcomputer to buy. Following these brief comments, the major focus of the paper is devoted to a discussion of…

  15. Analytical Chemistry as an Information Science.

    DTIC Science & Technology

    1981-06-01

    AD-AIOS 433 WASHINGTON UNIV SEATTLE LAB OR CHEMOMETRICS /7/ ANALYTICAL CHEMISTRY AS AN INFORMATION SCIENCE Ul NAb7/ .JUN 81 B A KO WALSKI NUUUIA 75C...AN INFORMATION SCIENCE by B. R. Kowalski Prepared for Publication in Trends in Analytical Chemistry University of Washington Department of Chemistry...S. TYPE OF REPORT & PERIOD COVERED Technical Report - Interim ANALYTICAL CHEMISTRY AS AN INFORMATION SCIENCE , 2/1981 - 6/1981 6. PERFORMING ORG

  16. Modern Analytical Chemistry in the Contemporary World

    ERIC Educational Resources Information Center

    Šíma, Jan

    2016-01-01

    Students not familiar with chemistry tend to misinterpret analytical chemistry as some kind of the sorcery where analytical chemists working as modern wizards handle magical black boxes able to provide fascinating results. However, this approach is evidently improper and misleading. Therefore, the position of modern analytical chemistry among…

  17. Green analytical chemistry--theory and practice.

    PubMed

    Tobiszewski, Marek; Mechlińska, Agata; Namieśnik, Jacek

    2010-08-01

    This tutorial review summarises the current state of green analytical chemistry with special emphasis on environmentally friendly sample preparation techniques. Green analytical chemistry is a part of the sustainable development concept; its history and origins are described. Miniaturisation of analytical devices and shortening the time elapsing between performing analysis and obtaining reliable analytical results are important aspects of green analytical chemistry. Solventless extraction techniques, the application of alternative solvents and assisted extractions are considered to be the main approaches complying with green analytical chemistry principles.

  18. Significant steps in the evolution of analytical chemistry--is the today's analytical chemistry only chemistry?

    PubMed

    Karayannis, Miltiades I; Efstathiou, Constantinos E

    2012-12-15

    In this review the history of chemistry and specifically the history and the significant steps of the evolution of analytical chemistry are presented. In chronological time spans, covering the ancient world, the middle ages, the period of the 19th century, and the three evolutional periods, from the verge of the 19th century to contemporary times, it is given information for the progress of chemistry and analytical chemistry. During this period, analytical chemistry moved gradually from its pure empirical nature to more rational scientific activities, transforming itself to an autonomous branch of chemistry and a separate discipline. It is also shown that analytical chemistry moved gradually from the status of exclusive serving the chemical science, towards serving, the environment, health, law, almost all areas of science and technology, and the overall society. Some recommendations are also directed to analytical chemistry educators concerning the indispensable nature of knowledge of classical analytical chemistry and the associated laboratory exercises and to analysts, in general, why it is important to use the chemical knowledge to make measurements on problems of everyday life.

  19. Emphasizing Mineral Chemistry in an Analytical Chemistry Unit.

    ERIC Educational Resources Information Center

    Dunn, Jeffrey G.; And Others

    1995-01-01

    Describes an analytical chemistry unit in the second year of the chemistry degree course at Curtin University that was designed to reflect the numerous employment opportunities for chemistry graduates in the mineral processing industries and private analytical laboratories. Presents the lecture syllabus, the laboratory course description, and…

  20. Analytical Chemistry in Microenvironments: Single Nerve Cells.

    DTIC Science & Technology

    1992-03-16

    AD-A251 491 * - OFFICE OF NAVAL RESEARCH GRANT or CONTRACT N00014-90-J-1161 R & T Code 4133030 Technical Report No. 012 Analytical Chemistry in...AGENCY USE ONLY (Leave oldnk) 2. REPORT DATE 1. R EP O R T T Y P E AND DATES COVERED 4. TITLE AND SUBTITLE S. FUNDING NUMBERS Analytical Chemistry in...CLASSIFICATION 20. LIMITATION OF ABSTRACT OF REPORT OF THIS PAGE OF ABSTRACT unclassified unclassified unclassified ANALYTICAL CHEMISTRY IN

  1. Teaching social responsibility in analytical chemistry.

    PubMed

    Valcárcel, M; Christian, G D; Lucena, R

    2013-07-02

    Analytical chemistry is key to the functioning of a modern society. From early days, ethics in measurements have been a concern and that remains today, especially as we have come to rely more on the application of analytical science in many aspects of our lives. The main aim of this Feature is to suggest ways of introducing the topic of social responsibility and its relation to analytical chemistry in undergraduate or graduate chemistry courses.

  2. The Mars Analytical Chemistry Experiment

    NASA Astrophysics Data System (ADS)

    Dissly, R. W.; Waite, J. H.; Chassefiere, E.; Sacks, R.; Block, B.; Scherer, S.; Young, D. T.; Miller, G. P.; Nicks, D. K.; Beauchamp, P. M.; Croonquist, A.; Berthelier, J.-J.; Jambon, A.

    2004-11-01

    Future missions to Mars will offer the opportunity to continue the search for organic molecules accessible from the surface, and to better quantify the cycling of volatile elements through geochemical pathways. This presentation describes an analytical instrument suite that is designed to measure elemental, isotopic, and potential organic signatures contained in the atmosphere and near surface reservoirs on Mars. The Mars Analytical Chemistry Experiment (MACE) combines two unique mass-spectrometer-based instruments to accomplish these measurements. The first instrument combines a sample handling system with a reusable pyrolysis oven for processing solid materials. Evolved volatile gases from the pyrolyzer are either oxidized for elemental analysis, or sent through a preconcentrator into a two-dimensional gas chromatograph for separation of organics. The processed gas stream is them sent to a high resolution dynamic time-of-flight mass spectrometer for detection. The second instrument is designed primarily for direct atmospheric measurements, using a combination of catalyst beds, getters, and cryogenic traps to separate and concentrate species of interest, such as noble gases. Concentrated gases are subsequently detected with a second mass spectrometer. This instrument can also be used to analyze evolved gases from the pyrolyzer in the first instrument. A breadboard version of each of these instruments has been demonstrated in the laboratory. In this presentaion, we will discuss the design, applicability, and capabilities of the MACE suite in more detail.

  3. Science and Technology Text Mining: Analytical Chemistry

    DTIC Science & Technology

    2001-01-01

    mainly) from analytical chemistry, will be presented. KEYWORDS: text mining; information retrieval; bibliometrics ; computational linguistics; information...analytical chemistry, will be presented. 15. SUBJECT TERMS text mining; information retrieval; bibliometrics ; computational linguistics; information...records. Our definition includes three components: 1) Bibliometrics ; 2) Computational Linguistics; 3) Clustering. For multi-field structured records

  4. The lanthanide contraction beyond coordination chemistry

    DOE PAGES

    Ferru, Geoffroy; Reinhart, Benjamin; Bera, Mrinal K.; ...

    2016-04-06

    Lanthanide chemistry is dominated by the ‘lanthanide contraction’, which is conceptualized traditionally through coordination chemistry. Here we break this mold, presenting evidence that the lanthanide contraction manifests outside of the coordination sphere, influencing weak interactions between groups of molecules that drive mesoscale-assembly and emergent behavior in an amphiphile solution. Furthermore, changes in these weak interactions correlate with differences in lanthanide ion transport properties, suggesting new forces to leverage rare earth separation and refining. Our results show that the lanthanide contraction paradigm extends beyond the coordination sphere, influencing structure and properties usually associated with soft matter science.

  5. Contained radiological analytical chemistry module

    DOEpatents

    Barney, David M.

    1990-01-01

    A system which provides analytical determination of a plurality of water chemistry parameters with respect to water samples subject to radiological contamination. The system includes a water sample analyzer disposed within a containment and comprising a sampling section for providing predetermined volumes of samples for analysis; a flow control section for controlling the flow through the system; and a gas analysis section for analyzing samples provided by the sampling system. The sampling section includes a controllable multiple port valve for, in one position, metering out sample of a predetermined volume and for, in a second position, delivering the material sample for analysis. The flow control section includes a regulator valve for reducing the pressure in a portion of the system to provide a low pressure region, and measurement devices located in the low pressure region for measuring sample parameters such as pH and conductivity, at low pressure. The gas analysis section which is of independent utility provides for isolating a small water sample and extracting the dissolved gases therefrom into a small expansion volume wherein the gas pressure and thermoconductivity of the extracted gas are measured.

  6. Contained radiological analytical chemistry module

    DOEpatents

    Barney, David M.

    1989-01-01

    A system which provides analytical determination of a plurality of water chemistry parameters with respect to water samples subject to radiological contamination. The system includes a water sample analyzer disposed within a containment and comprising a sampling section for providing predetermined volumes of samples for analysis; a flow control section for controlling the flow through the system; and a gas analysis section for analyzing samples provided by the sampling system. The sampling section includes a controllable multiple port valve for, in one position, metering out sample of a predetermined volume and for, in a second position, delivering the material sample for analysis. The flow control section includes a regulator valve for reducing the pressure in a portion of the system to provide a low pressure region, and measurement devices located in the low pressure region for measuring sample parameters such as pH and conductivity, at low pressure. The gas analysis section which is of independent utility provides for isolating a small water sample and extracting the dissolved gases therefrom into a small expansion volume wherein the gas pressure and thermoconductivity of the extracted gas are measured.

  7. Green Chemistry Metrics with Special Reference to Green Analytical Chemistry.

    PubMed

    Tobiszewski, Marek; Marć, Mariusz; Gałuszka, Agnieszka; Namieśnik, Jacek

    2015-06-12

    The concept of green chemistry is widely recognized in chemical laboratories. To properly measure an environmental impact of chemical processes, dedicated assessment tools are required. This paper summarizes the current state of knowledge in the field of development of green chemistry and green analytical chemistry metrics. The diverse methods used for evaluation of the greenness of organic synthesis, such as eco-footprint, E-Factor, EATOS, and Eco-Scale are described. Both the well-established and recently developed green analytical chemistry metrics, including NEMI labeling and analytical Eco-scale, are presented. Additionally, this paper focuses on the possibility of the use of multivariate statistics in evaluation of environmental impact of analytical procedures. All the above metrics are compared and discussed in terms of their advantages and disadvantages. The current needs and future perspectives in green chemistry metrics are also discussed.

  8. Modern analytical chemistry in the contemporary world

    NASA Astrophysics Data System (ADS)

    Šíma, Jan

    2016-12-01

    Students not familiar with chemistry tend to misinterpret analytical chemistry as some kind of the sorcery where analytical chemists working as modern wizards handle magical black boxes able to provide fascinating results. However, this approach is evidently improper and misleading. Therefore, the position of modern analytical chemistry among sciences and in the contemporary world is discussed. Its interdisciplinary character and the necessity of the collaboration between analytical chemists and other experts in order to effectively solve the actual problems of the human society and the environment are emphasized. The importance of the analytical method validation in order to obtain the accurate and precise results is highlighted. The invalid results are not only useless; they can often be even fatal (e.g., in clinical laboratories). The curriculum of analytical chemistry at schools and universities is discussed. It is referred to be much broader than traditional equilibrium chemistry coupled with a simple description of individual analytical methods. Actually, the schooling of analytical chemistry should closely connect theory and practice.

  9. Light-emitting diodes for analytical chemistry.

    PubMed

    Macka, Mirek; Piasecki, Tomasz; Dasgupta, Purnendu K

    2014-01-01

    Light-emitting diodes (LEDs) are playing increasingly important roles in analytical chemistry, from the final analysis stage to photoreactors for analyte conversion to actual fabrication of and incorporation in microdevices for analytical use. The extremely fast turn-on/off rates of LEDs have made possible simple approaches to fluorescence lifetime measurement. Although they are increasingly being used as detectors, their wavelength selectivity as detectors has rarely been exploited. From their first proposed use for absorbance measurement in 1970, LEDs have been used in analytical chemistry in too many ways to make a comprehensive review possible. Hence, we critically review here the more recent literature on their use in optical detection and measurement systems. Cloudy as our crystal ball may be, we express our views on the future applications of LEDs in analytical chemistry: The horizon will certainly become wider as LEDs in the deep UV with sufficient intensity become available.

  10. Analytical Chemistry of Nitric Oxide

    PubMed Central

    Hetrick, Evan M.

    2013-01-01

    Nitric oxide (NO) is the focus of intense research, owing primarily to its wide-ranging biological and physiological actions. A requirement for understanding its origin, activity, and regulation is the need for accurate and precise measurement techniques. Unfortunately, analytical assays for monitoring NO are challenged by NO’s unique chemical and physical properties, including its reactivity, rapid diffusion, and short half-life. Moreover, NO concentrations may span pM to µM in physiological milieu, requiring techniques with wide dynamic response ranges. Despite such challenges, many analytical techniques have emerged for the detection of NO. Herein, we review the most common spectroscopic and electrochemical methods, with special focus on the fundamentals behind each technique and approaches that have been coupled with modern analytical measurement tools or exploited to create novel NO sensors. PMID:20636069

  11. Analytical chemistry of nitric oxide.

    PubMed

    Hetrick, Evan M; Schoenfisch, Mark H

    2009-01-01

    Nitric oxide (NO) is the focus of intense research primarily because of its wide-ranging biological and physiological actions. To understand its origin, activity, and regulation, accurate and precise measurement techniques are needed. Unfortunately, analytical assays for monitoring NO are challenged by NO's unique chemical and physical properties, including its reactivity, rapid diffusion, and short half-life. Moreover, NO concentrations may span the picomolar-to-micromolar range in physiological milieus, requiring techniques with wide dynamic response ranges. Despite such challenges, many analytical techniques have emerged for the detection of NO. Herein, we review the most common spectroscopic and electrochemical methods, with a focus on the underlying mechanism of each technique and on approaches that have been coupled with modern analytical measurement tools to create novel NO sensors.

  12. Dielectric barrier discharges in analytical chemistry.

    PubMed

    Meyer, C; Müller, S; Gurevich, E L; Franzke, J

    2011-06-21

    The present review reflects the importance of dielectric barrier discharges in analytical chemistry. Special about this discharge is-and in contrast to usual discharges with direct current-that the plasma is separated from one or two electrodes by a dielectric barrier. This gives rise to two main features of the dielectric barrier discharges; it can serve as dissociation and excitation device and as ionization mechanism, respectively. The article portrays the various application fields for dielectric barrier discharges in analytical chemistry, for example the use for elemental detection with optical spectrometry or as ionization source for mass spectrometry. Besides the introduction of different kinds of dielectric barrier discharges used for analytical chemistry from the literature, a clear and concise classification of dielectric barrier discharges into capacitively coupled discharges is provided followed by an overview about the characteristics of a dielectric barrier discharge concerning discharge properties and the ignition mechanism.

  13. ANALYTICAL CHEMISTRY RESEARCH NEEDS FOR ...

    EPA Pesticide Factsheets

    The consensus among environmental scientists and risk assessors is that the fate and effects of pharmaceutical and personal care products (PPCPS) in the environment are poorly understood. Many classes of PPCPs have yet to be investigated. Acquisition of trends data for a suite of PPCPs (representatives from each of numerous significant classes), shown to recur amongst municipal wastewater treatment plants across the country, may prove of key importance. The focus of this paper is an overview of some of the analytical methods being developed at the Environmenental Protection Agency and their application to wastewater and surface water samples. Because PPCPs are generally micro-pollutants, emphasis is on development of enrichment and pre- concentration techniques using various means of solid-phase extraction. The research focused on in the subtasks is the development and application of state-of the-art technologies to meet the needs of the public, Office of Water, and ORD in the area of Water Quality. Located In the subtasks are the various research projects being performed in support of this Task and more in-depth coverage of each project. Briefly, each project's objective is stated below.Subtask 1: To integrate state-of-the-art technologies (polar organic chemical integrative samplers, advanced solid-phase extraction methodologies with liquid chromatography/electrospray/mass spectrometry) and apply them to studying the sources and fate of a select list of PPCP

  14. Analytical chemistry and measurement science: (What has DOE done for analytical chemistry. )

    SciTech Connect

    Shults, W.D.

    1989-01-01

    Over the past forty years, analytical scientists within the DOE complex have had a tremendous impact on the field of analytical chemistry. This paper suggests six ''high impact'' research/development areas that either originated within or were brought to maturity within the DOE laboratories. ''High impact'' means they lead to new subdisciplines or to new ways of doing business. 21 refs.

  15. Analytical Chemistry and Measurement Science: (What Has DOE Done for Analytical Chemistry?)

    DOE R&D Accomplishments Database

    Shults, W. D.

    1989-04-01

    Over the past forty years, analytical scientists within the DOE complex have had a tremendous impact on the field of analytical chemistry. This paper suggests six "high impact" research/development areas that either originated within or were brought to maturity within the DOE laboratories. "High impact" means they lead to new subdisciplines or to new ways of doing business.

  16. Analytical chemistry and measurement science; (What DOE has done for analytical chemistry)

    SciTech Connect

    Shults, W.D. . Analytical Chemistry Div.)

    1989-11-01

    Over the past forty years, analytical scientists within the Department of Energy (DOE) complex have had impact on the field of analytical chemistry. This paper suggests six research/development areas that either originated within or were brought to maturity with the DOE laboratories. These areas have lead to new subdisciplines or to new ways of doing business.

  17. Surface-Confined Supramolecular Coordination Chemistry

    NASA Astrophysics Data System (ADS)

    Lin, Nian; Stepanow, Sebastian; Ruben, Mario; Barth, Johannes V.

    The non-covalent synthesis of coordination compounds and networks provides promising avenues towards metal-containing supermolecules and nanostructured materials with ultimate feature definition. An important factor for their further development, and their integration and exploitation in nanoscale functional systems, is the capability to prepare or organize them at well-defined substrates or templated environments. Supramolecular engineering on atomistically controlled surfaces has been propelled by the direct insight into low-dimensional coordination systems provided by scanning tunneling microscopy observations. Here we discuss the principles of surface-confined supramolecular coordination chemistry, emphasizing self-assembly protocols conducted on surface atomic lattices employing metal centers to direct the organization of molecular ligands and the template-induced organization of prefabricated metallosupramolecular species. The presented exemplary molecular-level studies elucidate the arrangement of organic adsorbates and transition metal adatoms on low-index metal and graphite surfaces. They reveal the interplay between molecule-adatom, intermolecular, and adsorbate-substrate interactions, which need to be balanced for the fabrication of low-dimensional nanostructures. The control and understanding of both the nature of metal-ligand interactions and the resulting supramolecular organization on solid surfaces is decisive for the design of advanced architectures with concomitant functions. The realized metallosupramolecular compounds and arrays combine the properties of their constituent metal ions and organic ligands, and feature versatile structural characteristics as well as attractive functional aspects: their redox, magnetic, spin-state, and electronic transitions.

  18. Developments in the Coordination Chemistry of Europium(II)

    PubMed Central

    Garcia, Joel

    2012-01-01

    Recent advances in the coordination chemistry of Eu2+ are reviewed. Common synthetic routes for generating discrete Eu2+-containing complexes reported since 2000 are summarized, followed by a description of the reactivity of these complexes and their applications in reduction chemistry, polymerization, luminescence, and as contrast agents for magnetic resonance imaging. Rapid development of the coordination chemistry of Eu2+ has led to an upsurge in the utilization of Eu2+-containing complexes in synthetic chemistry, materials science, and medicine. PMID:23049283

  19. Improving Conceptions in Analytical Chemistry: The Central Limit Theorem

    ERIC Educational Resources Information Center

    Rodriguez-Lopez, Margarita; Carrasquillo, Arnaldo, Jr.

    2006-01-01

    This article describes the central limit theorem (CLT) and its relation to analytical chemistry. The pedagogic rational, which argues for teaching the CLT in the analytical chemistry classroom, is discussed. Some analytical chemistry concepts that could be improved through an understanding of the CLT are also described. (Contains 2 figures.)

  20. Analytical Chemistry Core Capability Assessment - Preliminary Report

    SciTech Connect

    Barr, Mary E.; Farish, Thomas J.

    2012-05-16

    The concept of 'core capability' can be nebulous one. Even at a fairly specific level, where core capability equals maintaining essential services, it is highly dependent upon the perspective of the requestor. Samples are submitted to analytical services because the requesters do not have the capability to conduct adequate analyses themselves. Some requests are for general chemical information in support of R and D, process control, or process improvement. Many analyses, however, are part of a product certification package and must comply with higher-level customer quality assurance requirements. So which services are essential to that customer - just those for product certification? Does the customer also (indirectly) need services that support process control and improvement? And what is the timeframe? Capability is often expressed in terms of the currently utilized procedures, and most programmatic customers can only plan a few years out, at best. But should core capability consider the long term where new technologies, aging facilities, and personnel replacements must be considered? These questions, and a multitude of others, explain why attempts to gain long-term consensus on the definition of core capability have consistently failed. This preliminary report will not try to define core capability for any specific program or set of programs. Instead, it will try to address the underlying concerns that drive the desire to determine core capability. Essentially, programmatic customers want to be able to call upon analytical chemistry services to provide all the assays they need, and they don't want to pay for analytical chemistry services they don't currently use (or use infrequently). This report will focus on explaining how the current analytical capabilities and methods evolved to serve a variety of needs with a focus on why some analytes have multiple analytical techniques, and what determines the infrastructure for these analyses. This information will be

  1. Surface-confined supramolecular coordination chemistry.

    PubMed

    Lin, Nian; Stepanow, Sebastian; Ruben, Mario; Barth, Johannes V

    2009-01-01

    The non-covalent synthesis of coordination compounds and networks provides promising avenues towardsmetal-containing supermolecules and nanostructured materials with ultimate feature definition. An importantfactor for their further development, and their integration and exploitation in nanoscale functional systems,is the capability to prepare or organize them at well-defined substrates or templated environments. Supramolecularengineering on atomistically controlled surfaces has been propelled by the direct insight into low-dimensionalcoordination systems provided by scanning tunneling microscopy observations. Here we discuss the principlesof surface-confined supramolecular coordination chemistry, emphasizingself-assembly protocols conducted on surface atomic lattices employing metal centers to direct the organizationof molecular ligands and the template-induced organization of prefabricated metallosupramolecular species.The presented exemplary molecular-level studies elucidate the arrangement of organic adsorbates and transitionmetal adatoms on low-index metal and graphite surfaces. They reveal the interplay between molecule-adatom,intermolecular, and adsorbate-substrate interactions, which need to be balanced for the fabricationof low-dimensional nanostructures. The control and understanding of both the nature of metal-ligandinteractions and the resulting supramolecular organization on solid surfaces is decisive for the designof advanced architectures with concomitant functions. The realized metallosupramolecular compounds andarrays combine the properties of their constituent metal ions and organic ligands, and feature versatilestructural characteristics as well as attractive functional aspects: their redox, magnetic, spin-state,and electronic transitions.

  2. Empirical analytic transformations between geographic and corrected geomagnetic coordinates

    NASA Technical Reports Server (NTRS)

    Comfort, R. H.

    1970-01-01

    Based upon a mathematical model of contours of constant corrected geomagnetic latitude in a polar projection of geographic coordinates, analytic equations are developed for converting geographic coordinates to corrected geomagnetic coordinates and vice versa. The equations were programmed for use on a small computer. This treatment is restricted to the Northern Hemisphere.

  3. Laser ablation in analytical chemistry - A review

    SciTech Connect

    Russo, Richard E.; Mao, Xianglei; Liu, Haichen; Gonzalez, Jhanis; Mao, Samuel S.

    2001-10-10

    Laser ablation is becoming a dominant technology for direct solid sampling in analytical chemistry. Laser ablation refers to the process in which an intense burst of energy delivered by a short laser pulse is used to sample (remove a portion of) a material. The advantages of laser ablation chemical analysis include direct characterization of solids, no chemical procedures for dissolution, reduced risk of contamination or sample loss, analysis of very small samples not separable for solution analysis, and determination of spatial distributions of elemental composition. This review describes recent research to understand and utilize laser ablation for direct solid sampling, with emphasis on sample introduction to an inductively coupled plasma (ICP). Current research related to contemporary experimental systems, calibration and optimization, and fractionation is discussed, with a summary of applications in several areas.

  4. Coordination Chemistry of Microbial Iron Transport

    PubMed Central

    2016-01-01

    Conspectus This Account focuses on the coordination chemistry of the microbial iron chelators called siderophores. The initial research (early 1970s) focused on simple analogs of siderophores, which included hydroxamate, catecholate, or hydroxycarboxylate ligands. The subsequent work increasingly focused on the transport of siderophores and their microbial iron transport. Since these are pseudo-octahedral complexes often composed of bidentate ligands, there is chirality at the metal center that in principle is independent of the ligand chirality. It has been shown in many cases that chiral recognition of the complex occurs. Many techniques have been used to elucidate the iron uptake processes in both Gram-positive (single membrane) and Gram-negative (double membrane) bacteria. These have included the use of radioactive labels (of ligand, metal, or both), kinetically inert metal complexes, and Mössbauer spectroscopy. In general, siderophore recognition and transport involves receptors that recognize the metal chelate portion of the iron–siderophore complex. A second, to date less commonly found, mechanism called the siderophore shuttle involves the receptor binding an apo-siderophore. Since one of the primary ways that microbes compete with each other for iron stores is the strength of their competing siderophore complexes, it became important early on to characterize the solution thermodynamics of these species. Since the acidity of siderophores varies significantly, just the stability constant does not give a direct measure of the relative competitive strength of binding. For this reason, the pM value is compared. The pM, like pH, is a measure of the negative log of the free metal ion concentration, typically calculated at pH 7.4, and standard total concentrations of metal and ligand. The characterization of the electronic structure of ferric siderophores has done much to help explain the high stability of these complexes. A new chapter in siderophore science

  5. Ab initio coordination chemistry for nickel chelation motifs.

    PubMed

    Sudan, R Jesu Jaya; Kumari, J Lesitha Jeeva; Sudandiradoss, C

    2015-01-01

    Chelation therapy is one of the most appreciated methods in the treatment of metal induced disease predisposition. Coordination chemistry provides a way to understand metal association in biological structures. In this work we have implemented coordination chemistry to study nickel coordination due to its high impact in industrial usage and thereby health consequences. This paper reports the analysis of nickel coordination from a large dataset of nickel bound structures and sequences. Coordination patterns predicted from the structures are reported in terms of donors, chelate length, coordination number, chelate geometry, structural fold and architecture. The analysis revealed histidine as the most favored residue in nickel coordination. The most common chelates identified were histidine based namely HHH, HDH, HEH and HH spaced at specific intervals. Though a maximum coordination number of 8 was observed, the presence of a single protein donor was noted to be mandatory in nickel coordination. The coordination pattern did not reveal any specific fold, nevertheless we report preferable residue spacing for specific structural architecture. In contrast, the analysis of nickel binding proteins from bacterial and archeal species revealed no common coordination patterns. Nickel binding sequence motifs were noted to be organism specific and protein class specific. As a result we identified about 13 signatures derived from 13 classes of nickel binding proteins. The specifications on nickel coordination presented in this paper will prove beneficial for developing better chelation strategies.

  6. Analytical Chemistry Laboratory progress report for FY 1989

    SciTech Connect

    Green, D.W.; Heinrich, R.R.; Graczyk, D.G.; Lindahl, P.C.; Erickson, M.D.

    1989-12-01

    The purpose of this report is to summarize the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year 1989 (October 1988 through September 1989). The Analytical Chemistry Laboratory is a full-cost-recovery service center, with the primary mission of providing a broad range of analytical chemistry support services to the scientific and engineering programs at ANL. In addition, the ACL conducts a research program in analytical chemistry, works on instrumental and methods development, and provides analytical services for governmental, educational, and industrial organizations. The ACL handles a wide range of analytical problems, from routine standard analyses to unique problems that require significant development of methods and techniques.

  7. Analytical Chemistry Laboratory progress report for FY 1991

    SciTech Connect

    Green, D.W.; Heinrich, R.R.; Graczyk, D.G.; Lindahl, P.C.; Boparai, A.S.

    1991-12-01

    The purpose of this report is to summarize the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year 1991 (October 1990 through September 1991). This is the eighth annual report for the ACL. The Analytical Chemistry Laboratory is a full-cost-recovery service center, with the primary mission of providing a broad range of analytical chemistry support services to the scientific and engineering programs at ANL. In addition, the ACL conducts a research program in analytical chemistry, works on instrumental and methods development, and provides analytical services for governmental, educational, and industrial organizations. The ACL handles a wide range of analytical problems, from routine standard analyses to unique problems that require significant development of methods and techniques.

  8. Analytical chemistry in the Aegean Sea region: current status.

    PubMed

    Samanidou, Victoria F

    2012-12-01

    The Eighth Aegean Analytical Chemistry Days Conference took place in Urla, İzmir, Turkey, from 16-20 September 2012. This conference is held every 2 years, organized alternately by analytical chemistry departments of Turkish and Greek universities, so that analytical chemists from the region around the Aegean Sea can exchange experience and knowledge based on their research in a large number of fields. This report summarizes the most interesting presentations and posters pertaining to bioanalytical work.

  9. From Metalloproteins to Coordination Chemistry: A Learning Exercise to Teach Transition Metal Chemistry

    ERIC Educational Resources Information Center

    Reglinski, John; Graham, Duncan; Kennedy, Alan R.; Gibson, Lorraine T.

    2004-01-01

    An exercise is organized to reinforce the fundamental rules of coordination chemistry through a biological study of metalloproteins. The work, which is divided into four well-defined activities, involves a major application of computer databases to address chemical problems.

  10. Incorporating Information Literacy Skills into Analytical Chemistry: An Evolutionary Step

    ERIC Educational Resources Information Center

    Walczak, Mary M.; Jackson, Paul T.

    2007-01-01

    The American Chemical Society (ACS) has recently decided to incorporate various information literacy skills for teaching analytical chemistry to the students. The methodology has been found to be extremely effective, as it provides better understanding to the students.

  11. INVESTIGATING ENVIRONMENTAL SINKS OF MACROLIDE ANTIBIOTICS WITH ANALYTICAL CHEMISTRY

    EPA Science Inventory

    Possible environmental sinks (wastewater effluents, biosolids, sediments) of macrolide antibiotics (i.e., azithromycin, roxithromycin and clarithromycin)are investigated using state-of-the-art analytical chemistry techniques.

  12. Analytical chemistry methods for mixed oxide fuel, March 1985

    SciTech Connect

    Not Available

    1985-03-01

    This standard provides analytical chemistry methods for the analysis of materials used to produce mixed oxide fuel. These materials are ceramic fuel and insulator pellets and the plutonium and uranium oxides and nitrates used to fabricate these pellets.

  13. Perspective: Status and Future of Analytical Chemistry in India.

    PubMed

    Verma, Krishna K

    2017-02-07

    Relative to many other areas in chemistry, analytical chemistry appears singularly lagging behind in India despite the commendable growth it had shown in the past both in teaching and research. Certain presumptions in policy making and current educational practices are believed to be the crux of the problem.

  14. The Renaissance of Metal-Pyrimidine Nucleobase Coordination Chemistry.

    PubMed

    Lippert, Bernhard; Sanz Miguel, Pablo J

    2016-08-16

    The significance of metal ions for the function and properties of DNA and RNA, long seen primarily under biological aspects and medicinal uses, has recently gained a renewed momentum. This is a consequence of the advent of novel applications in the fields of materials science, biotechnology, and analytical sensor chemistry that relate to the designed incorporation of transition metal ions into nucleic acid base pairs. Ag(+) and Hg(2+) ions, binding to pyrimidine (pym) nucleobases, represent major players in this development. Interestingly, these metal ions were the ones that some 60 years ago started the field! At the same time, the mentioned metal ions had demonstrated a "special relationship" with the pym nucleobases cytosine, thymine, and uracil! Parallel work conducted with oligonucleotides and model nucleobases fostered numerous significant details of these interactions, in particular when X-ray crystallography was involved, correcting earlier views occasionally. Our own activities during the past three to four decades have focused on, among others, the coordination chemistry of transition and main-group metal ions with pym model nucleobases, with an emphasis on Pt(II) and Pd(II). It has always been our goal to deduce, if possible, the potential relevance of our findings for biological processes. It is interesting to put our data, in particular for trans-a2Pt(II) (a = NH3 or amine), into perspective with those of other metal ions, notably Ag(+) and Hg(2+). Irrespective of major differences in kinetics and lability/inertness between d(8) and d(10) metal ions, there is also a lot of similarity in structural aspects as a result of the preferred linear coordination geometry of these species. Moreover, the apparent clustering of metal ions to the pym nucleobases, which is presumably essential for the formation of nanoclusters on oligonucleotide scaffolds, is impressively reflected in model systems, as are reasons for inter-nucleobase cross-links containing more

  15. A review of opportunities for electrospun nanofibers in analytical chemistry.

    PubMed

    Chigome, Samuel; Torto, Nelson

    2011-11-07

    Challenges associated with analyte and matrix complexities and the ever increasing pressure from all sectors of industry for alternative analytical devices, have necessitated the development and application of new materials in analytical chemistry. To date, nanomaterials have emerged as having excellent properties for analytical chemistry applications mainly due to their large surface area to volume ratio and the availability of a wide variety of chemical and morphological modification methods. Of the available nanofibrous material fabrication methods, electrospinning has emerged as the most versatile. It is the aim of this contribution to highlight some of the recent developments that harness the great potential shown by electrospun nanofibers for application in analytical chemistry. The review discusses the use of electrospun nanofibers as a platform for low resolution separation or as a chromatographic sorbent bed for high resolution separation. It concludes by discussing the applications of electrospun nanofibers in detection systems with a specific focus on the development of simple electrospun nanofiber based colorimetric probes.

  16. Analytical Chemistry Laboratory progress report for FY 1985

    SciTech Connect

    Green, D.W.; Heinrich, R.R.; Jensen, K.J.

    1985-12-01

    The Analytical Chemistry Laboratory is a full-cost-recovery service center, with the primary mission of providing a broad range of technical support services to the scientific and engineering programs at ANL. In addition, ACL conducts a research program in analytical chemistry, works on instrumental and methods development, and provides analytical services for governmental, educational, and industrial organizations. The ACL handles a wide range of analytical problems, from routine standard analyses to unique problems that require significant development of methods and techniques. The purpose of this report is to summarize the technical and administrative activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year 1985 (October 1984 through September 1985). This is the second annual report for the ACL. 4 figs., 1 tab.

  17. Teaching Analytical Chemistry with Automatic Analyzers

    ERIC Educational Resources Information Center

    Schubert, Leo

    1972-01-01

    Discusses the advantages of using automated analytical procedures in providing rapid, inexpensive alternatives to traditional methods and in teaching skills used in many professions and industry. (CP)

  18. The Professional Development of High School Chemistry Coordinators

    ERIC Educational Resources Information Center

    Hofstein, Avi; Carmeli, Miriam; Shore, Relly

    2004-01-01

    The implementation of new content and pedagogical standards in science education necessitates intensive, long-term professional development of science teachers. In this paper, we describe the rationale and structure of a comprehensive and intensive professional development program of school-based leaders, namely school chemistry coordinators. The…

  19. Coordination chemistry in the design of heterogeneous photocatalysts.

    PubMed

    Gao, Chao; Wang, Jin; Xu, Hangxun; Xiong, Yujie

    2017-04-03

    Heterogeneous catalysts have been widely used for photocatalysis, which is a highly important process for energy conversion, owing to their merits such as easy separation of catalysts from the reaction products and applicability to continuous chemical industry and recyclability. Yet, homogenous photocatalysis receives tremendous attention as it can offer a higher activity and selectivity with atomically dispersed catalytic sites and tunable light absorption. For this reason, there is a major trend to combine the advantages of both homogeneous and heterogeneous photocatalysts, in which coordination chemistry plays a role as the bridge. In this article, we aim to provide the first systematic review to give a clear picture of the recent progress from taking advantage of coordination chemistry. We specifically summarize the role of coordination chemistry as a versatile tool to engineer catalytically active sites, tune light harvesting and maneuver charge kinetics in heterogeneous photocatalysis. We then elaborate on the common fundamentals behind various materials systems, together with key spectroscopic characterization techniques and remaining challenges in this field. The typical applications of coordination chemistry in heterogeneous photocatalysis, including proton reduction, water oxidation, carbon dioxide reduction and organic reactions, are highlighted.

  20. The Professional Development of High School Chemistry Coordinators

    NASA Astrophysics Data System (ADS)

    Hofstein, Avi; Carmeli, Miriam; Shore, Relly

    2004-02-01

    The implementation of new content and pedagogical standards in science education necessitates intensive, long-term professional development of science teachers. In this paper, we describe the rationale and structure of a comprehensive and intensive professional development program of school-based leaders, namely school chemistry coordinators. The year-long program was designed so that the chemistry teachers who enrolled in the program were able to develop in three interrelated aspects: content knowledge, pedagogical content knowledge, and leadership ability. Several strategies for the development of these aspects were adopted from Loucks-Horsley, Hewson, Love, & Stiles (1998). The evaluation of the program focused on the changes that participating teachers underwent regarding their personal beliefs and their functioning as school chemistry coordinators in their schools.

  1. Cyclodextrins in analytical chemistry: host-guest type molecular recognition.

    PubMed

    Szente, Lajos; Szemán, Julianna

    2013-09-03

    Cyclodextrins are utilized in many diverse fields of analytical chemistry, due to their propensity to form reversible inclusion complexes and recognize analytes selectively. This Feature shows how these nanocavities can serve analysts in sample preparation, sensitivity and selectivity improvement, enantio-separation, creating single-molecule sensors, and automatizing DNA sequencing.

  2. Gatlinburg conference: barometer of progress in analytical chemistry

    SciTech Connect

    Shults, W.D.

    1981-01-01

    Much progress has been made in the field of analytical chemistry over the past twenty-five years. The AEC-ERDA-DOE family of laboratories contributed greatly to this progress. It is not surprising then to find a close correlation between program content of past Gatlinburg conferences and developments in analytical methodology. These conferences have proved to be a barometer of technical status.

  3. Analytical Chemistry Laboratory. Progress report for FY 1996

    SciTech Connect

    Green, D.W.; Boparai, A.S.; Bowers, D.L.

    1996-12-01

    The purpose of this report is to summarize the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year (FY) 1996. This annual report is the thirteenth for the ACL. It describes effort on continuing and new projects and contributions of the ACL staff to various programs at ANL. The ACL operates in the ANL system as a full-cost-recovery service center, but has a mission that includes a complementary research and development component: The Analytical Chemistry Laboratory will provide high-quality, cost-effective chemical analysis and related technical support to solve research problems of our clients -- Argonne National Laboratory, the Department of Energy, and others -- and will conduct world-class research and development in analytical chemistry and its applications. Because of the diversity of research and development work at ANL, the ACL handles a wide range of analytical chemistry problems. Some routine or standard analyses are done, but the ACL usually works with commercial laboratories if our clients require high-volume, production-type analyses. It is common for ANL programs to generate unique problems that require significant development of methods and adaption of techniques to obtain useful analytical data. Thus, much of the support work done by the ACL is very similar to our applied analytical chemistry research.

  4. Analytical chemistry: Sweet solution to sensing

    NASA Astrophysics Data System (ADS)

    Sia, Samuel K.; Chin, Curtis D.

    2011-09-01

    Glucose meters allow rapid and quantitative measurement of blood sugar levels for diabetes sufferers worldwide. Now a new method allows this proven technology to be used to quantify a much wider range of analytes.

  5. Analytical Chemistry Laboratory, progress report for FY 1993

    SciTech Connect

    Not Available

    1993-12-01

    The purpose of this report is to summarize the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year (FY) 1993 (October 1992 through September 1993). This annual report is the tenth for the ACL and describes continuing effort on projects, work on new projects, and contributions of the ACL staff to various programs at ANL. The Analytical Chemistry Laboratory is a full-cost-recovery service center, with the primary mission of providing a broad range of analytical chemistry support services to the scientific and engineering programs at ANL. The ACL also has research programs in analytical chemistry, conducts instrumental and methods development, and provides analytical services for governmental, educational, and industrial organizations. The ACL handles a wide range of analytical problems. Some routine or standard analyses are done, but it is common for the Argonne programs to generate unique problems that require development or modification of methods and adaption of techniques to obtain useful analytical data. The ACL is administratively within the Chemical Technology Division (CMT), its principal ANL client, but provides technical support for many of the technical divisions and programs at ANL. The ACL has four technical groups--Chemical Analysis, Instrumental Analysis, Organic Analysis, and Environmental Analysis--which together include about 45 technical staff members. Talents and interests of staff members cross the group lines, as do many projects within the ACL.

  6. Analytical Applications of NMR: Summer Symposium on Analytical Chemistry.

    ERIC Educational Resources Information Center

    Borman, Stuart A.

    1982-01-01

    Highlights a symposium on analytical applications of nuclear magnetic resonance spectroscopy (NMR), discussing pulse Fourier transformation technique, two-dimensional NMR, solid state NMR, and multinuclear NMR. Includes description of ORACLE, an NMR data processing system at Syracuse University using real-time color graphics, and algorithms for…

  7. Topological data analysis: A promising big data exploration tool in biology, analytical chemistry and physical chemistry.

    PubMed

    Offroy, Marc; Duponchel, Ludovic

    2016-03-03

    An important feature of experimental science is that data of various kinds is being produced at an unprecedented rate. This is mainly due to the development of new instrumental concepts and experimental methodologies. It is also clear that the nature of acquired data is significantly different. Indeed in every areas of science, data take the form of always bigger tables, where all but a few of the columns (i.e. variables) turn out to be irrelevant to the questions of interest, and further that we do not necessary know which coordinates are the interesting ones. Big data in our lab of biology, analytical chemistry or physical chemistry is a future that might be closer than any of us suppose. It is in this sense that new tools have to be developed in order to explore and valorize such data sets. Topological data analysis (TDA) is one of these. It was developed recently by topologists who discovered that topological concept could be useful for data analysis. The main objective of this paper is to answer the question why topology is well suited for the analysis of big data set in many areas and even more efficient than conventional data analysis methods. Raman analysis of single bacteria should be providing a good opportunity to demonstrate the potential of TDA for the exploration of various spectroscopic data sets considering different experimental conditions (with high noise level, with/without spectral preprocessing, with wavelength shift, with different spectral resolution, with missing data).

  8. Justifying instrumental techniques of analytical chemistry.

    PubMed

    Rothbart, Daniel; Kohout, Ladislav

    2003-05-01

    In this paper, we argue that the foundations of chemistry rely as much on the methods of measurement as they do on categories of chemical substance. To some degree, chemists perform the work of knowledge engineering: designing complex systems for the efficient retrieval of information. Indeed, in some cases, methods of instrumental detection move to the forefront of attention. For example, researchers are expected to deploy optimization methods designed to maximize desired signal and minimize the damaging effects of noise. But in his important contributions to the development of high-resolution NMR spectrometers, Hans Primas used stochastic methods to reveal beneficial effects of noise for characterizing physical systems, demonstrating the value of noisy signals for nonlinear physical systems in chemistry.

  9. Biochemical Applications in the Analytical Chemistry Lab

    ERIC Educational Resources Information Center

    Strong, Cynthia; Ruttencutter, Jeffrey

    2004-01-01

    An HPLC and a UV-visible spectrophotometer are identified as instruments that helps to incorporate more biologically-relevant experiments into the course, in order to increase the students understanding of selected biochemistry topics and enhances their ability to apply an analytical approach to biochemical problems. The experiment teaches…

  10. Applications of polydimethylsiloxane in analytical chemistry: a review.

    PubMed

    Seethapathy, Suresh; Górecki, Tadeusz

    2012-10-31

    Silicones have innumerable applications in many areas of life. Polydimethylsiloxane (PDMS), which belongs to the class of silicones, has been extensively used in the field of analytical chemistry owing to its favourable physicochemical properties. The use of PDMS in analytical chemistry gained importance with its application as a stationary phase in gas chromatographic separations. Since then it has been used in many sample preparation techniques such as solid phase microextraction (SPME), stir bar sorptive extraction (SBSE), thin-film extraction, permeation passive sampling, etc. Further, it is gaining importance in the manufacturing of lab-on-a-chip devices, which have revolutionized bio-analysis. Applications of devices containing PDMS and used in the field of analytical chemistry are reviewed in this paper.

  11. Bias Assessment of General Chemistry Analytes using Commutable Samples

    PubMed Central

    Koerbin, Gus; Tate, Jillian R; Ryan, Julie; Jones, Graham RD; Sikaris, Ken A; Kanowski, David; Reed, Maxine; Gill, Janice; Koumantakis, George; Yen, Tina; St John, Andrew; Hickman, Peter E; Simpson, Aaron; Graham, Peter

    2014-01-01

    Harmonisation of reference intervals for routine general chemistry analytes has been a goal for many years. Analytical bias may prevent this harmonisation. To determine if analytical bias is present when comparing methods, the use of commutable samples, or samples that have the same properties as the clinical samples routinely analysed, should be used as reference samples to eliminate the possibility of matrix effect. The use of commutable samples has improved the identification of unacceptable analytical performance in the Netherlands and Spain. The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) has undertaken a pilot study using commutable samples in an attempt to determine not only country specific reference intervals but to make them comparable between countries. Australia and New Zealand, through the Australasian Association of Clinical Biochemists (AACB), have also undertaken an assessment of analytical bias using commutable samples and determined that of the 27 general chemistry analytes studied, 19 showed sufficiently small between method biases as to not prevent harmonisation of reference intervals. Application of evidence based approaches including the determination of analytical bias using commutable material is necessary when seeking to harmonise reference intervals. PMID:25678726

  12. Synergistic relationships between Analytical Chemistry and written standards.

    PubMed

    Valcárcel, Miguel; Lucena, Rafael

    2013-07-25

    This paper describes the mutual impact of Analytical Chemistry and several international written standards (norms and guides) related to knowledge management (CEN-CWA 14924:2004), social responsibility (ISO 26000:2010), management of occupational health and safety (OHSAS 18001/2), environmental management (ISO 14001:2004), quality management systems (ISO 9001:2008) and requirements of the competence of testing and calibration laboratories (ISO 17025:2004). The intensity of this impact, based on a two-way influence, is quite different depending on the standard considered. In any case, a new and fruitful approach to Analytical Chemistry based on these relationships can be derived.

  13. Magnetic ionic liquids in analytical chemistry: A review.

    PubMed

    Clark, Kevin D; Nacham, Omprakash; Purslow, Jeffrey A; Pierson, Stephen A; Anderson, Jared L

    2016-08-31

    Magnetic ionic liquids (MILs) have recently generated a cascade of innovative applications in numerous areas of analytical chemistry. By incorporating a paramagnetic component within the cation or anion, MILs exhibit a strong response toward external magnetic fields. Careful design of the MIL structure has yielded magnetoactive compounds with unique physicochemical properties including high magnetic moments, enhanced hydrophobicity, and the ability to solvate a broad range of molecules. The structural tunability and paramagnetic properties of MILs have enabled magnet-based technologies that can easily be added to the analytical method workflow, complement needed extraction requirements, or target specific analytes. This review highlights the application of MILs in analytical chemistry and examines the important structural features of MILs that largely influence their physicochemical and magnetic properties.

  14. Analytical Chemistry Laboratory Progress Report for FY 1994

    SciTech Connect

    Green, D.W.; Boparai, A.S.; Bowers, D.L.

    1994-12-01

    The purpose of this report is to summarize the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year (FY) 1994 (October 1993 through September 1994). This annual report is the eleventh for the ACL and describes continuing effort on projects, work on new projects, and contributions of the ACL staff to various programs at ANL. The Analytical Chemistry Laboratory is a full-cost-recovery service center, with the primary mission of providing a broad range of analytical chemistry support services to the scientific and engineering programs at ANL. The ACL also has a research program in analytical chemistry, conducts instrumental and methods development, and provides analytical services for governmental, educational, and industrial organizations. The ACL handles a wide range of analytical problems. Some routine or standard analyses are done, but it is common for the Argonne programs to generate unique problems that require significant development of methods and adaption of techniques to obtain useful analytical data. The ACL has four technical groups -- Chemical Analysis, Instrumental Analysis, Organic Analysis, and Environmental Analysis -- which together include about 45 technical staff members. Talents and interests of staff members cross the group lines, as do many projects within the ACL. The Chemical Analysis Group uses wet- chemical and instrumental methods for elemental, compositional, and isotopic determinations in solid, liquid, and gaseous samples and provides specialized analytical services. Major instruments in this group include an ion chromatograph (IC), an inductively coupled plasma/atomic emission spectrometer (ICP/AES), spectrophotometers, mass spectrometers (including gas-analysis and thermal-ionization mass spectrometers), emission spectrographs, autotitrators, sulfur and carbon determinators, and a kinetic phosphorescence uranium analyzer.

  15. The coordination chemistry of silyl-substituted allyl ligands.

    PubMed

    Solomon, Sophia A; Layfield, Richard A

    2010-03-14

    Metal allyl complexes in which the ligands carry bulky silyl substituents frequently show stability that cannot be achieved with unsubstituted analogues. As a result, it has been possible to characterize a large family of structurally diverse metal silyl-allyls from the s-, p-, d- and f-blocks of the Periodic Table, and to study the coordination chemistry of compounds that often have no counterparts without bulky substituents. The fact that the majority of compounds discussed in this Perspective have been published since 2000 reflects the newness of the area, and the article summarizes the main developments in the structural chemistry of metal silyl-allyls and also selected synthetic and catalytic applications. Although organometallic chemistry is often regarded as transcending traditional boundaries between 'organic' and 'inorganic' chemistry, an understanding persists that those working in the field can be labelled 'inorganic organometallic' chemists or 'organic organometallic' chemists. It is hoped that chemists from a broad range of backgrounds will be able to use this review as an entry point to an exciting new direction in metal allyl chemistry.

  16. Contributions of Analytical Chemistry to the Clinical Laboratory.

    ERIC Educational Resources Information Center

    Skogerboe, Kristen J.

    1988-01-01

    Highlights several analytical techniques that are being used in state-of-the-art clinical labs. Illustrates how other advances in instrumentation may contribute to clinical chemistry in the future. Topics include: biosensors, polarization spectroscopy, chemiluminescence, fluorescence, photothermal deflection, and chromatography in clinical…

  17. Using Presentation Software to Flip an Undergraduate Analytical Chemistry Course

    ERIC Educational Resources Information Center

    Fitzgerald, Neil; Li, Luisa

    2015-01-01

    An undergraduate analytical chemistry course has been adapted to a flipped course format. Course content was provided by video clips, text, graphics, audio, and simple animations organized as concept maps using the cloud-based presentation platform, Prezi. The advantages of using Prezi to present course content in a flipped course format are…

  18. An Interactive Analytical Chemistry Summer Camp for Middle School Girls

    ERIC Educational Resources Information Center

    Robbins, Mary E.; Schoenfisch, Mark H.

    2005-01-01

    A summer outreach program, which was implemented for the first time in the summer of 2004, that provided middle school girls with an opportunity to conduct college-level analytical chemistry experiments under the guidance of female graduate students is explained. The program proved beneficial to participants at each level.

  19. Active Learning Strategies in the Analytical Chemistry Classroom.

    ERIC Educational Resources Information Center

    Ross, Michael R.; Fulton, Robert B.

    1994-01-01

    Describes an analytical chemistry course restructured around the use of cooperative groups to help students become active learners in a non-competitive environment. Five years of experience with the course indicates that the syllabus covers almost exactly the same content as old courses and that test scores compare favorably on the national level.…

  20. Analytical chemistry methods for metallic core components: Revision March 1985

    SciTech Connect

    Not Available

    1985-03-01

    This standard provides analytical chemistry methods for the analysis of alloys used to fabricate core components. These alloys are 302, 308, 316, 316-Ti, and 321 stainless steels and 600 and 718 Inconels and they may include other 300-series stainless steels.

  1. A Field Study Program in Analytical Chemistry for College Seniors.

    ERIC Educational Resources Information Center

    Langhus, D. L.; Flinchbaugh, D. A.

    1986-01-01

    Describes an elective field study program at Moravian College (Pennsylvania) in which seniors in analytical chemistry obtain first-hand experience at Bethlehem Steel Corporation. Discusses the program's planning phase, some method development projects done by students, experiences received in laboratory operations, and the evaluation of student…

  2. Analytical Chemistry Laboratory progress report for FY 1998.

    SciTech Connect

    Boparai, A. S.; Bowers, D. L.; Graczyk, D. G.; Green, D. W.; Lindahl, P. C.

    1999-03-29

    This report summarizes the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year (FY) 1998 (October 1997 through September 1998). This annual progress report, which is the fifteenth in this series for the ACL, describes effort on continuing projects, work on new projects, and contributions of the ACL staff to various programs at ANL.

  3. Analytical Chemistry Laboratory progress report for FY 1999

    SciTech Connect

    Green, D. W.; Boparai, A. S.; Bowers, D. L.; Graczyk, D. G.

    2000-06-15

    This report summarizes the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year (FY) 1999 (October 1998 through September 1999). This annual progress report, which is the sixteenth in this series for the ACL, describes effort on continuing projects, work on new projects, and contributions of the ACL staff to various programs at ANL.

  4. Spectroelectrochemical Sensing of Aqueous Iron: An Experiment for Analytical Chemistry

    ERIC Educational Resources Information Center

    Shtoyko, Tanya; Stuart, Dean; Gray, H. Neil

    2007-01-01

    We have designed a laboratory experiment to illustrate the use of spectroelectrochemical techniques for determination of aqueous iron. The experiment described in this article is applicable to an undergraduate laboratory course in analytical chemistry. Students are asked to fabricate spectroelectrochemical sensors, make electrochemical and optical…

  5. An Experimental Introduction to Interlaboratory Exercises in Analytical Chemistry

    ERIC Educational Resources Information Center

    Puignou, L.; Llaurado, M.

    2005-01-01

    An experimental exercise on analytical proficiency studies in collaborative trials is proposed. This practical provides students in advanced undergraduate courses in chemistry, pharmacy, and biochemistry, with the opportunity to improve their quality assurance skills. It involves an environmental analysis, determining the concentration of a…

  6. Chemometrics tools used in analytical chemistry: an overview.

    PubMed

    Kumar, Naveen; Bansal, Ankit; Sarma, G S; Rawal, Ravindra K

    2014-06-01

    This article presents various important tools of chemometrics utilized as data evaluation tools generated by various hyphenated analytical techniques including their application since its advent to today. The work has been divided into various sections, which include various multivariate regression methods and multivariate resolution methods. Finally the last section deals with the applicability of chemometric tools in analytical chemistry. The main objective of this article is to review the chemometric methods used in analytical chemistry (qualitative/quantitative), to determine the elution sequence, classify various data sets, assess peak purity and estimate the number of chemical components. These reviewed methods further can be used for treating n-way data obtained by hyphenation of LC with multi-channel detectors. We prefer to provide a detailed view of various important methods developed with their algorithm in favor of employing and understanding them by researchers not very familiar with chemometrics.

  7. Analytical Chemistry Laboratory progress report for FY 1984

    SciTech Connect

    Green, D.W.; Heinrich, R.R.; Jensen, K.J.; Stetter, J.R.

    1985-03-01

    Technical and administrative activities of the Analytical Chemistry Laboratory (ACL) are reported for fiscal year 1984. The ACL is a full-cost-recovery service center, with the primary mission of providing a broad range of technical support services to the scientific and engineering programs at ANL. In addition, ACL conducts a research program in analytical chemistry, works on instrumental and methods development, and provides analytical services for governmental, educational, and industrial organizations. The ACL is administratively within the Chemical Technology Division, the principal user, but provides technical support for all of the technical divisions and programs at ANL. The ACL has three technical groups - Chemical Analysis, Instrumental Analysis, and Organic Analysis. Under technical activities 26 projects are briefly described. Under professional activities, a list is presented for publications and reports, oral presentations, awards and meetings attended. 6 figs., 2 tabs.

  8. Analytical Chemistry at the Interface Between Materials Science and Biology

    SciTech Connect

    O'Brien, Janese C.

    2000-09-21

    Likedlessentid sciences, anal~cd chetis~continues toreinvent itself. Moving beyond its traditional roles of identification and quantification, analytical chemistry is now expanding its frontiers into areas previously reserved to other disciplines. This work describes several research efforts that lie at the new interfaces between analytical chemistry and two of these disciplines, namely materials science and biology. In the materials science realm, the search for new materials that may have useful or unique chromatographic properties motivated the synthesis and characterization of electrically conductive sol-gels. In the biology realm, the search for new surface fabrication schemes that would permit or even improve the detection of specific biological reactions motivated the design of miniaturized biological arrays. Collectively, this work represents some of analytical chemistry’s newest forays into these disciplines. The introduction section to this dissertation provides a literature review on several of the key aspects of this work. In advance of the materials science discussion, a brief introduction into electrochemically-modulated liquid chromatography (EMLC) and sol-gel chemistry is provided. In advance of the biological discussions, brief overviews of scanning force microscopy (SFM) and the oxidative chemistry used to construct our biological arrays are provided. This section is followed by four chapters, each of which is presented as a separate manuscript, and focuses on work that describes some of our cross-disciplinary efforts within materials science and biology. This dissertation concludes with a general summary and future prospectus.

  9. The surface coordination chemistry of cuprate high-temperature superconductors

    NASA Astrophysics Data System (ADS)

    Xu, Feng

    The goals of the research described in this dissertation were: (1) to explore the surface coordination chemistry of cuprate high-temperature superconductors (HTSCs); (2) to develop chemical methodology for directly tailoring the surface and interfacial properties of cuprate HTSCs. This thesis documents the first survey of the surface coordination chemistry of a cuprate HTSC, YBa2Cu3O7-delta. Functional groups that can chemically bind to YBa2Cu3O 7-delta have been determined using cyclic voltammetry in conjunction with a series of redox-active ferrocenyl containing adsorbate molecules. Primary alkylamines have emerged as the optimum adsorbates for HTSCs, forming stable and robust monolayer films with no apparent damage to the bulk properties of the underlying superconductors. The interactions between alkylamine adsorbates and YBa2Cu3O7-delta have been shown to involve Cu(II)-NR3 coordination chemistry. The influence of organic monolayers on the properties of YBa2Cu3O 7-delta has been examined using cyclic voltammetry, X-ray powder diffraction, atomic force microscopy, and resistivity vs. temperature measurements. The presence of H2O in the soaking solution adversely affects the adsorption process due to a competing corrosion reaction. However, stable monolayers form on HTSC substrates under rigorously dry conditions. Significantly, monolayer modified HTSCs are substantially more stable to corrosion environmental reagents. The formation kinetics of redox-active alkylamine monolayers on ceramic YBa2Cu3O7-delta are proposed to involve two major processes: a fast adsorption process and a relatively slow pore diffusion process. Surface-solution adsorbate exchange is very dynamic and reversible, which appears to occur via an associative pathway. Monolayers on c-axis-oriented thin films have been shown to be more densely-packed and stable than those on ceramic substrates. Notably, the surface alkylamine "ligands" display traits of Cu(II)-based coordination chemistry

  10. Chemistry and application of flexible porous coordination polymers*

    PubMed Central

    Bureekaew, Sareeya; Shimomura, Satoru; Kitagawa, Susumu

    2008-01-01

    Porous coordination polymers (PCPs), which are microporous materials, have been given much attention from both scientific and commercial aspects regarding their application to gas storage, gas separation and catalytic reaction because of the regularity of their pore shape and pore size, accompanied with the functionality. Moreover, in recent years, flexible PCPs, which are structurally transformable depending upon external stimuli, have been attractive because they provide unique properties, dissimilar to those of zeolites. In this review, the chemistry and application of flexible crystalline PCPs are summarized and discussed. PMID:27877934

  11. Green analytical chemistry introduction to chloropropanols determination at no economic and analytical performance costs?

    PubMed

    Jędrkiewicz, Renata; Orłowski, Aleksander; Namieśnik, Jacek; Tobiszewski, Marek

    2016-01-15

    In this study we perform ranking of analytical procedures for 3-monochloropropane-1,2-diol determination in soy sauces by PROMETHEE method. Multicriteria decision analysis was performed for three different scenarios - metrological, economic and environmental, by application of different weights to decision making criteria. All three scenarios indicate capillary electrophoresis-based procedure as the most preferable. Apart from that the details of ranking results differ for these three scenarios. The second run of rankings was done for scenarios that include metrological, economic and environmental criteria only, neglecting others. These results show that green analytical chemistry-based selection correlates with economic, while there is no correlation with metrological ones. This is an implication that green analytical chemistry can be brought into laboratories without analytical performance costs and it is even supported by economic reasons.

  12. Role-Playing in Analytical Chemistry: The Alumni Speak

    NASA Astrophysics Data System (ADS)

    Jackson, Paul T.; Walters, John P.

    2000-08-01

    Cooperative learning constructs take a variety of forms. Over the last 15 years, one such pedagogical structure, role-playing, has been used in the analytical chemistry curriculum at St. Olaf College. A long-term assessment of this teaching method was conducted through use of a survey distributed to alumni graduating between 1987 and 1997. The graduates overwhelmingly indicated that the use of role-playing had a positive impact on their careers as well as their lives. Furthermore, many non-achievement learning outcomes attributed to cooperative learning experiences were reinforced through the survey response. Role-playing created an effective environment in which to develop communication and collaborative skills in addition to the technical skills that are essential to analytical chemistry. These results support continued evolutionary development of this teaching method.

  13. Analytical chemistry laboratory. Progress report for FY 1997

    SciTech Connect

    Green, D.W.; Boparai, A.S.; Bowers, D.L.

    1997-12-01

    The purpose of this report is to summarize the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year (FY) 1997 (October 1996 through September 1997). This annual progress report is the fourteenth in this series for the ACL, and it describes continuing effort on projects, work on new projects, and contributions of the ACL staff to various programs at ANL.

  14. Application of Multidimensional Spectrum Analysis for Analytical Chemistry

    SciTech Connect

    Hatsukawa, Yuichi; Hayakawa, Takehito; Toh, Yosuke; Shinohara, Nobuo; Oshima, Masumi

    1999-12-31

    Feasibility of application of the multidimensional {gamma} ray spectroscopy for analytical chemistry was examined. Two reference igneous rock (JP-1, JB-1a) samples issued by the Geological Survey of Japan (GSJ) were irradiated at a research reactor with thermal neutrons, and {gamma} rays from the radioisotopes produced by neutron capture reactions were measured using a {gamma}-ray detector array. Simultaneously 27 elements were observed with no chemical separation.

  15. MAR flow mapping of Analytical Chemistry Operations (Preliminary Report)

    SciTech Connect

    Barr, Mary E.; Farish, Thomas J.

    2012-06-13

    The recently released Supplemental Directive, NA-1 SD 1027, updates the radionuclide threshold values in DOE-STD-1027-92 CN1 to reflect the use of modern parameters for dose conversion factors and breathing rates. The directive also corrects several arithmetic errors within the original standard. The result is a roughly four-fold increase in the amount of weapons-grade nuclear material allowed within a designated radiological facility. Radiological laboratory space within the recently constructed Radiological Laboratory Office and Utility Building (RLUOB) is slated to house selected analytical chemistry support activities in addition to small-scale actinide R&D activities. RLUOB is within the same facility operations envelope as TA-55. Consolidation of analytical chemistry activities to RLUOB and PF-4 offers operational efficiency improvements relative to the current pre-CMRR plans of dividing these activities between RLUOB, PF-4, and CMR. RLUOB is considered a Radiological Facility under STD-1027 - 'Facilities that do not meet or exceed Category 3 threshold criteria but still possess some amount of radioactive material may be considered Radiological Facilities.' The supplemental directive essentially increases the allowable material-at-risk (MAR) within radiological facilities from 8.4 g to 38.6 g for {sup 239}Pu. This increase in allowable MAR provides a unique opportunity to establish additional analytical chemistry support functions in RLUOB without negatively impacting either R&D activities or facility operations. Individual radiological facilities are tasked to determine MAR limits (up to the Category 3 thresholds) appropriate to their operational conditions. This study presents parameters that impact establishing MAR limits for RLUOB and an assessment of how various analytical chemistry support functions could operate within the established MAR limits.

  16. Application of multidimensional spectrum analysis for analytical chemistry

    SciTech Connect

    Hatsukawa, Yuichi; Hayakawa, Takehito; Toh, Yosuke; Shinohara, Nobuo; Oshima, Masumi

    1999-11-16

    Feasibility of application of the multidimensional {gamma} ray spectroscopy for analytical chemistry was examined. Two reference igneous rock (JP-1, JB-1a) samples issued by the Geological Survey of Japan (GSJ) were irradiated at a research reactor with thermal neutrons, and {gamma} rays from the radioisotopes produced by neutron capture reactions were measured using a {gamma}-ray detector array. Simultaneously 27 elements were observed with no chemical separation.

  17. Chemiluminescence microarrays in analytical chemistry: a critical review.

    PubMed

    Seidel, Michael; Niessner, Reinhard

    2014-09-01

    Multi-analyte immunoassays on microarrays and on multiplex DNA microarrays have been described for quantitative analysis of small organic molecules (e.g., antibiotics, drugs of abuse, small molecule toxins), proteins (e.g., antibodies or protein toxins), and microorganisms, viruses, and eukaryotic cells. In analytical chemistry, multi-analyte detection by use of analytical microarrays has become an innovative research topic because of the possibility of generating several sets of quantitative data for different analyte classes in a short time. Chemiluminescence (CL) microarrays are powerful tools for rapid multiplex analysis of complex matrices. A wide range of applications for CL microarrays is described in the literature dealing with analytical microarrays. The motivation for this review is to summarize the current state of CL-based analytical microarrays. Combining analysis of different compound classes on CL microarrays reduces analysis time, cost of reagents, and use of laboratory space. Applications are discussed, with examples from food safety, water safety, environmental monitoring, diagnostics, forensics, toxicology, and biosecurity. The potential and limitations of research on multiplex analysis by use of CL microarrays are discussed in this review.

  18. 78 FR 4170 - License Amendment Request for Analytical Bio-Chemistry Laboratories, Inc., Columbia, MO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-18

    ... COMMISSION License Amendment Request for Analytical Bio-Chemistry Laboratories, Inc., Columbia, MO AGENCY... issuance of a license amendment to Materials License No. 24-13365-01 issued to Analytical Bio-Chemistry... accession numbers are: 1. Analytical Bio-Chemistry Laboratories, Inc., Licensee amendment request...

  19. Membrane-based microextraction techniques in analytical chemistry: A review.

    PubMed

    Carasek, Eduardo; Merib, Josias

    2015-06-23

    The use of membrane-based sample preparation techniques in analytical chemistry has gained growing attention from the scientific community since the development of miniaturized sample preparation procedures in the 1990s. The use of membranes makes the microextraction procedures more stable, allowing the determination of analytes in complex and "dirty" samples. This review describes some characteristics of classical membrane-based microextraction techniques (membrane-protected solid-phase microextraction, hollow-fiber liquid-phase microextraction and hollow-fiber renewal liquid membrane) as well as some alternative configurations (thin film and electromembrane extraction) used successfully for the determination of different analytes in a large variety of matrices, some critical points regarding each technique are highlighted.

  20. Elucidating the coordination chemistry and mechanism of biological nitrogen fixation.

    PubMed

    Dance, Ian

    2007-08-03

    How does the enzyme nitrogenase reduce the inert molecule N2 to NH3 under ambient conditions that are so different from the energy-expensive conditions of the best industrial practices? This review focuses on recent theoretical investigations of the catalytic site, the iron-molybdenum cofactor FeMo-co, and the way in which it is hydrogenated by protons and electrons and then binds N2. Density functional calculations provide reaction profiles and activation energies for possible mechanistic steps. This establishes a conceptual framework and the principles for the coordination chemistry of FeMo-co that are essential to the chemical mechanism of catalysis. The model advanced herein explains relevant experimental data.

  1. The evolution of analytical chemistry methods in foodomics.

    PubMed

    Gallo, Monica; Ferranti, Pasquale

    2016-01-08

    The methodologies of food analysis have greatly evolved over the past 100 years, from basic assays based on solution chemistry to those relying on the modern instrumental platforms. Today, the development and optimization of integrated analytical approaches based on different techniques to study at molecular level the chemical composition of a food may allow to define a 'food fingerprint', valuable to assess nutritional value, safety and quality, authenticity and security of foods. This comprehensive strategy, defined foodomics, includes emerging work areas such as food chemistry, phytochemistry, advanced analytical techniques, biosensors and bioinformatics. Integrated approaches can help to elucidate some critical issues in food analysis, but also to face the new challenges of a globalized world: security, sustainability and food productions in response to environmental world-wide changes. They include the development of powerful analytical methods to ensure the origin and quality of food, as well as the discovery of biomarkers to identify potential food safety problems. In the area of nutrition, the future challenge is to identify, through specific biomarkers, individual peculiarities that allow early diagnosis and then a personalized prognosis and diet for patients with food-related disorders. Far from the aim of an exhaustive review of the abundant literature dedicated to the applications of omic sciences in food analysis, we will explore how classical approaches, such as those used in chemistry and biochemistry, have evolved to intersect with the new omics technologies to produce a progress in our understanding of the complexity of foods. Perhaps most importantly, a key objective of the review will be to explore the development of simple and robust methods for a fully applied use of omics data in food science.

  2. Nucleic Acid i-Motif Structures in Analytical Chemistry.

    PubMed

    Alba, Joan Josep; Sadurní, Anna; Gargallo, Raimundo

    2016-09-02

    Under the appropriate experimental conditions of pH and temperature, cytosine-rich segments in DNA or RNA sequences may produce a characteristic folded structure known as an i-motif. Besides its potential role in vivo, which is still under investigation, this structure has attracted increasing interest in other fields due to its sharp, fast and reversible pH-driven conformational changes. This "on/off" switch at molecular level is being used in nanotechnology and analytical chemistry to develop nanomachines and sensors, respectively. This paper presents a review of the latest applications of this structure in the field of chemical analysis.

  3. Tunable lasers and their application in analytical chemistry

    NASA Technical Reports Server (NTRS)

    Steinfeld, J. I.

    1975-01-01

    The impact that laser techniques might have in chemical analysis is examined. Absorption, scattering, and heterodyne detection is considered. Particular emphasis is placed on the advantages of using frequency-tunable sources, and dye solution lasers are regarded as the outstanding example of this type of laser. Types of spectroscopy that can be carried out with lasers are discussed along with the ultimate sensitivity or minimum detectable concentration of molecules that can be achieved with each method. Analytical applications include laser microprobe analysis, remote sensing and instrumental methods such as laser-Raman spectroscopy, atomic absorption/fluorescence spectrometry, fluorescence assay techniques, optoacoustic spectroscopy, and polarization measurements. The application of lasers to spectroscopic methods of analysis would seem to be a rewarding field both for research in analytical chemistry and for investments in instrument manufacturing.

  4. Applications of Optical Microcavity Resonators in Analytical Chemistry.

    PubMed

    Wade, James H; Bailey, Ryan C

    2016-06-12

    Optical resonator sensors are an emerging class of analytical technologies that use recirculating light confined within a microcavity to sensitively measure the surrounding environment. Bolstered by advances in microfabrication, these devices can be configured for a wide variety of chemical or biomolecular sensing applications. We begin with a brief description of optical resonator sensor operation, followed by discussions regarding sensor design, including different geometries, choices of material systems, methods of sensor interrogation, and new approaches to sensor operation. Throughout, key developments are highlighted, including advancements in biosensing and other applications of optical sensors. We discuss the potential of alternative sensing mechanisms and hybrid sensing devices for more sensitive and rapid analyses. We conclude with our perspective on the future of optical microcavity sensors and their promise as versatile detection elements within analytical chemistry.

  5. Clinical chemistry: challenges for analytical chemistry and the nanosciences from medicine.

    PubMed

    Durner, Jürgen

    2010-02-01

    Clinical chemistry and laboratory medicine can look back over more than 150 years of eventful history. The subject encompasses all the medicinal disciplines as well as the remaining natural sciences. Clinical chemistry demonstrates how new insights from basic research in biochemical, biological, analytical chemical, engineering, and information technology can be transferred into the daily routine of medicine to improve diagnosis, therapeutic monitoring, and prevention. This Review begins with a presentation of the development of clinical chemistry. Individual steps between the drawing of blood and interpretation of laboratory data are then illustrated; here not only are pitfalls described, but so are quality control systems. The introduction of new methods and trends into medicinal analysis is explored, along with opportunities and problems associated with personalized medicine.

  6. Pyridine coordination chemistry for molecular assemblies on surfaces.

    PubMed

    de Ruiter, Graham; Lahav, Michal; van der Boom, Milko E

    2014-12-16

    CONSPECTUS: Since the first description of coordination complexes, many types of metal-ligand interactions have creatively been used in the chemical sciences. The rich coordination chemistry of pyridine-type ligands has contributed significantly to the incorporation of diverse metal ions into functional materials. Here we discuss molecular assemblies (MAs) formed with a variety of pyridine-type compounds and a metal containing cross-linker (e.g., PdCl2(PhCN2)). These MAs are formed using Layer-by-Layer (LbL) deposition from solution that allows for precise fitting of the assembly properties through molecular programming. The position of each component can be controlled by altering the assembly sequence, while the degree of intermolecular interactions can be varied by the level of π-conjugation and the availability of metal coordination sites. By setting the structural parameters (e.g., bond angles, number of coordination sites, geometry) of the ligand, control over MA structure was achieved, resulting in surface-confined metal-organic networks and oligomers. Unlike MAs that are constructed with organic ligands, MAs with polypyridyl complexes of ruthenium, osmium, and cobalt are active participants in their own formation and amplify the growth of the incoming molecular layer. Such a self-propagating behavior for molecular systems is rare, and the mechanism of their formation will be discussed. These exponentially growing MAs are capable of storing metal salts that can be used during the buildup of additional molecular layers. Various parameters influencing the film growth mechanism will be presented, including (i) the number of binding sites and geometry of the organic ligands, (ii) the metal and the structure of the polypyridyl complexes, (iii) the influence of the metal cross-linker (e.g., second or third row transition metals), and (iv) the deposition conditions. By systematic variation of these parameters, switching between linear and exponential growth could

  7. Spectroscopic and computational investigation of actinium coordination chemistry

    SciTech Connect

    Ferrier, Maryline Ghislaine; Batista, Enrique Ricardo; Berg, John M.; Birnbaum, Eva R.; Cross, Justin Neil; Engle, Jonathan Ward; La Pierre, Henry S.; Kozimor, Stosh Anthony; Lezama Pacheco, Juan S.; Stein, Benjamin W.; Stieber, S. Chantal E.; Wilson, Justin J.

    2016-08-17

    Actinium-225 is a promising isotope for targeted-α therapy. Unfortunately, progress in developing chelators for medicinal applications has been hindered by a limited understanding of actinium chemistry. This knowledge gap is primarily associated with handling actinium, as it is highly radioactive and in short supply. Hence, AcIII reactivity is often inferred from the lanthanides and minor actinides (that is, Am, Cm), with limited success. Here we overcome these challenges and characterize actinium in HCl solutions using X-ray absorption spectroscopy and molecular dynamics density functional theory. The Ac–Cl and Ac–OH2O distances are measured to be 2.95(3) and 2.59(3) Å, respectively. The X-ray absorption spectroscopy comparisons between AcIII and AmIII in HCl solutions indicate AcIII coordinates more inner-sphere Cl1– ligands (3.2±1.1) than AmIII (0.8±0.3). Finally, these results imply diverse reactivity for the +3 actinides and highlight the unexpected and unique AcIII chemical behaviour.

  8. Spectroscopic and computational investigation of actinium coordination chemistry

    DOE PAGES

    Ferrier, Maryline Ghislaine; Batista, Enrique Ricardo; Berg, John M.; ...

    2016-08-17

    Actinium-225 is a promising isotope for targeted-α therapy. Unfortunately, progress in developing chelators for medicinal applications has been hindered by a limited understanding of actinium chemistry. This knowledge gap is primarily associated with handling actinium, as it is highly radioactive and in short supply. Hence, AcIII reactivity is often inferred from the lanthanides and minor actinides (that is, Am, Cm), with limited success. Here we overcome these challenges and characterize actinium in HCl solutions using X-ray absorption spectroscopy and molecular dynamics density functional theory. The Ac–Cl and Ac–OH2O distances are measured to be 2.95(3) and 2.59(3) Å, respectively. The X-raymore » absorption spectroscopy comparisons between AcIII and AmIII in HCl solutions indicate AcIII coordinates more inner-sphere Cl1– ligands (3.2±1.1) than AmIII (0.8±0.3). Finally, these results imply diverse reactivity for the +3 actinides and highlight the unexpected and unique AcIII chemical behaviour.« less

  9. Spectroscopic and computational investigation of actinium coordination chemistry.

    PubMed

    Ferrier, Maryline G; Batista, Enrique R; Berg, John M; Birnbaum, Eva R; Cross, Justin N; Engle, Jonathan W; La Pierre, Henry S; Kozimor, Stosh A; Lezama Pacheco, Juan S; Stein, Benjamin W; Stieber, S Chantal E; Wilson, Justin J

    2016-08-17

    Actinium-225 is a promising isotope for targeted-α therapy. Unfortunately, progress in developing chelators for medicinal applications has been hindered by a limited understanding of actinium chemistry. This knowledge gap is primarily associated with handling actinium, as it is highly radioactive and in short supply. Hence, Ac(III) reactivity is often inferred from the lanthanides and minor actinides (that is, Am, Cm), with limited success. Here we overcome these challenges and characterize actinium in HCl solutions using X-ray absorption spectroscopy and molecular dynamics density functional theory. The Ac-Cl and Ac-OH2O distances are measured to be 2.95(3) and 2.59(3) Å, respectively. The X-ray absorption spectroscopy comparisons between Ac(III) and Am(III) in HCl solutions indicate Ac(III) coordinates more inner-sphere Cl(1-) ligands (3.2±1.1) than Am(III) (0.8±0.3). These results imply diverse reactivity for the +3 actinides and highlight the unexpected and unique Ac(III) chemical behaviour.

  10. Spectroscopic and computational investigation of actinium coordination chemistry

    NASA Astrophysics Data System (ADS)

    Ferrier, Maryline G.; Batista, Enrique R.; Berg, John M.; Birnbaum, Eva R.; Cross, Justin N.; Engle, Jonathan W.; La Pierre, Henry S.; Kozimor, Stosh A.; Lezama Pacheco, Juan S.; Stein, Benjamin W.; Stieber, S. Chantal E.; Wilson, Justin J.

    2016-08-01

    Actinium-225 is a promising isotope for targeted-α therapy. Unfortunately, progress in developing chelators for medicinal applications has been hindered by a limited understanding of actinium chemistry. This knowledge gap is primarily associated with handling actinium, as it is highly radioactive and in short supply. Hence, AcIII reactivity is often inferred from the lanthanides and minor actinides (that is, Am, Cm), with limited success. Here we overcome these challenges and characterize actinium in HCl solutions using X-ray absorption spectroscopy and molecular dynamics density functional theory. The Ac-Cl and Ac-OH2O distances are measured to be 2.95(3) and 2.59(3) Å, respectively. The X-ray absorption spectroscopy comparisons between AcIII and AmIII in HCl solutions indicate AcIII coordinates more inner-sphere Cl1- ligands (3.2+/-1.1) than AmIII (0.8+/-0.3). These results imply diverse reactivity for the +3 actinides and highlight the unexpected and unique AcIII chemical behaviour.

  11. Spectroscopic and computational investigation of actinium coordination chemistry

    PubMed Central

    Ferrier, Maryline G.; Batista, Enrique R.; Berg, John M.; Birnbaum, Eva R.; Cross, Justin N.; Engle, Jonathan W.; La Pierre, Henry S.; Kozimor, Stosh A.; Lezama Pacheco, Juan S.; Stein, Benjamin W.; Stieber, S. Chantal E.; Wilson, Justin J.

    2016-01-01

    Actinium-225 is a promising isotope for targeted-α therapy. Unfortunately, progress in developing chelators for medicinal applications has been hindered by a limited understanding of actinium chemistry. This knowledge gap is primarily associated with handling actinium, as it is highly radioactive and in short supply. Hence, AcIII reactivity is often inferred from the lanthanides and minor actinides (that is, Am, Cm), with limited success. Here we overcome these challenges and characterize actinium in HCl solutions using X-ray absorption spectroscopy and molecular dynamics density functional theory. The Ac–Cl and Ac–OH2O distances are measured to be 2.95(3) and 2.59(3) Å, respectively. The X-ray absorption spectroscopy comparisons between AcIII and AmIII in HCl solutions indicate AcIII coordinates more inner-sphere Cl1– ligands (3.2±1.1) than AmIII (0.8±0.3). These results imply diverse reactivity for the +3 actinides and highlight the unexpected and unique AcIII chemical behaviour. PMID:27531582

  12. Analytical Chemistry Division annual progress report: For period ending December 31, 1987

    SciTech Connect

    Not Available

    1988-05-01

    This report is divided into analytical spectroscopy; radioactive materials analysis; inorganic chemistry; organic chemistry; ORNL environmental programs; quality assurance, safety, and training; supplementary activities; and presentation of research results.

  13. Selectivity in analytical chemistry: two interpretations for univariate methods.

    PubMed

    Dorkó, Zsanett; Verbić, Tatjana; Horvai, George

    2015-01-01

    Selectivity is extremely important in analytical chemistry but its definition is elusive despite continued efforts by professional organizations and individual scientists. This paper shows that the existing selectivity concepts for univariate analytical methods broadly fall in two classes: selectivity concepts based on measurement error and concepts based on response surfaces (the response surface being the 3D plot of the univariate signal as a function of analyte and interferent concentration, respectively). The strengths and weaknesses of the different definitions are analyzed and contradictions between them unveiled. The error based selectivity is very general and very safe but its application to a range of samples (as opposed to a single sample) requires the knowledge of some constraint about the possible sample compositions. The selectivity concepts based on the response surface are easily applied to linear response surfaces but may lead to difficulties and counterintuitive results when applied to nonlinear response surfaces. A particular advantage of this class of selectivity is that with linear response surfaces it can provide a concentration independent measure of selectivity. In contrast, the error based selectivity concept allows only yes/no type decision about selectivity.

  14. Reflections on my career in analytical chemistry and biochemistry.

    PubMed

    Sweeley, Charles C

    2010-01-01

    My career has been focused in two major areas, analytical chemistry and biochemistry of complex lipids and glycoconjugates. Included here are the pioneering work on the gas chromatography of long-chain sphingolipid bases, carbohydrates, steroids and urinary organic acids. Mass spectrometry was utilized extensively in structural studies of sphingolipids, fatty acids, carbohydrates, steroids, urinary organic acids, polyisoprenoid alcohols, and juvenile hormone. Computer systems were developed for the acquisition and analysis of mass spectra, and were used for development of automated metabolic profiling of complex mixtures of metabolites. Fabry's disease was discovered to be a glycosphingolipidosis. Enzymes of lysosomal metabolism of glycosphingolipids were purified, characterized, and used in one of the first demonstrations of the feasibility of enzyme replacement therapy in a lysosomal storage disorder (Fabry's disease). Extracellular sialidases were studied to evaluate the hypothesis that they might be involved in the regulation of membrane growth factor receptors. The enzyme for hematoside synthesis was purified and characterized.

  15. Microfluidics: applications for analytical purposes in chemistry and biochemistry.

    PubMed

    Ohno, Ken-ichi; Tachikawa, Kaoru; Manz, Andreas

    2008-11-01

    In this review, we present recent advancements and novel developments in fluidic systems for applied analytical purposes in chemistry, biochemistry, and life science in general that employ and reflect the full benefits of microfluidics. A staggering rise in publications related to integrated, all-in-one microfluidic chips capable of separation, reaction, and detection have been observed, all of which realise the principal of micro total analysis systems or lab-on-a-chip. These integrated chips actively adopt the scaling law concepts, utilising the highly developed fabrication techniques. Their aim is to multi-functionalise and fully automate devices believed to assist the future advancements of point-of-care, clinical, and medical diagnostics.

  16. A New Project-Based Lab for Undergraduate Environmental and Analytical Chemistry

    ERIC Educational Resources Information Center

    Adami, Gianpiero

    2006-01-01

    A new project-based lab was developed for third year undergraduate chemistry students based on real world applications. The experience suggests that the total analytical procedure (TAP) project offers a stimulating alternative for delivering science skills and developing a greater interest for analytical chemistry and environmental sciences and…

  17. Analytical chemistry at the interface between materials science and biology

    NASA Astrophysics Data System (ADS)

    O'Brien, Janese Christine

    This work describes several research efforts that lie at the new interfaces between analytical chemistry and other disciplines, namely materials science and biology. In the materials science realm, the search for new materials that may have useful or unique chromatographic properties motivated the synthesis and characterization of electrically conductive sol-gels. In the biology realm, the search for new surface fabrication schemes that would permit or even improve the detection of specific biological reactions motivated the design of miniaturized biological arrays. Collectively, this work represents some of analytical chemistry's newest forays into these disciplines. This dissertation is divided into six chapters. Chapter 1 is an introductory chapter that provides background information pertinent to several key aspects of the work contained in this dissertation. Chapter 2 describes the synthesis and characterization of electrically conductive sol-gels derived from the acid-catalyzed hydrolysis of a vanadium alkoxide. Specifically, this chapter describes our attempts to increase the conductivity of vanadium sol-gels by optimizing the acidic and drying conditions used during synthesis. Chapter 3 reports the construction of novel antigenic immunosensing platforms of increased epitope density using Fab'-SH antibody fragments on gold. Here, X-ray photoelectron spectroscopy (XPS), thin-layer cell (TLC) and confocal fluorescence spectroscopies, and scanning force microscopy (SFM) are employed to characterize the fragment-substrate interaction, to quantify epitope density, and to demonstrate fragment viability and specificity. Chapter 4 presents a novel method for creating and interrogating double-stranded DNA (dsDNA) microarrays suitable for screening protein:dsDNA interactions. Using the restriction enzyme ECoR1, we demonstrate the ability of the atomic force microscope (AFM) to detect changes in topography that result from the enzymatic cleavage of dsDNA microarrays

  18. Synthesis and lanthanide coordination chemistry of trifluoromethyl derivatives of phosphinoylmethyl pyridine N-oxides

    SciTech Connect

    Pailloux, Sylvie; Shirima, Cornel Edicome; Duesler, Eileen N.; Smith, Karen Ann; Paine, Robert T.; Klaehn, John D.; McIlwain, Michael E; Hay, Benjamin

    2009-01-01

    A synthetic route for the formation of 2-[bis-(2-trifluoromethyl-phenyl)-phosphinoylmethyl]-pyridine N-oxide (1c) and 2-[bis-(3,5-trifluoromethyl-phenyl)-phosphinoylmethyl]-pyridine N-oxide (1d) was developed and the new ligands characterized by spectroscopic methods and single crystal X-ray diffraction analyses. The coordination chemistry of the ligands was examined with early and late lanthanide ions. The molecular structure of one complex, [Yb(1c)(NO3)3(DMF)](DMF)(H2O)0.5, was determined by single crystal X-ray diffraction methods and the ligand found to coordinate in a bidentate fashion. This coordination chemistry is compared against lanthanide coordination chemistry observed for the related ligand, [Ph2P(O)CH2] C5H4NO.

  19. Analytical chemistry of the citrate process for flue gas desulfurization

    SciTech Connect

    Marchant, W.N.; May, S.L.; Simpson, W.W.; Winter, J.K.; Beard, H.R.

    1980-01-01

    The citrate process for flue gas desulfurization (FGD) is a product of continuing research by the US Bureau of Mines to meet the goal of minimizing the objectionable effects of minerals industry operations upon the environment. The reduction of SO/sub 2/ in solution by H/sub 2/S to produce elemental sulfur by the citrate process is extremely complex and results in solutions that contain at least nine different sulfur species. Process solution analysis is essential to a clear understanding of process chemistry and its safe, efficient operation. The various chemical species, the approximate ranges of their concentrations in citrate process solutions, and the analytical methods evolved to determine them are hydrogen sulfide (approx. 0M to 0.06M) by specific ion electrode, polysulfides (unknown) by ultraviolet (uv) spectrophotometry, elemental sulfur (approx. 0M to approx. 0.001M dissolved, approx. 0M to approx. 0.1M suspended) by uv spectrophotometry, thiosulfate (approx. 0M to approx. 0.25M) by iodometry or high performance liquid chromatography (HPLC), polythionates (approx. 0M to approx. 0.01M) by thin layer chromatography (TLC), dithionite (searched for but not detected in process solutions) by polarography or TLC, bisulfite (approx. 0M to 0.2M) by iodometry, sulfate (approx. 0M to 1M) by a Bureau-developed gravimetric procedure, citric acid (approx. 0M to 0.5M) by titration or visible colorimetry, glycolic acid (approx. 0M to 1M) by HPLC, sodium (approx. 1.5M) by flame photometry, and chloride by argentometric titration.

  20. Stereoisomerism in Coordination Chemistry: A Laboratory Experiment for Undergraduate Students.

    ERIC Educational Resources Information Center

    Gargallo, Maria Fe; And Others

    1988-01-01

    Describes an experimental procedure to acquaint inorganic chemistry students with stereochemical concepts using tris-(2,3-butanediamine)cobalt(III). Notes two isomeric forms exist and both form metal chelates. Separation is accomplished by chromatography and analysis is by NMR and infrared spectroscopy. Provides spectra of isomers. (MVL)

  1. Black Boxes in Analytical Chemistry: University Students' Misconceptions of Instrumental Analysis

    ERIC Educational Resources Information Center

    Carbo, Antonio Domenech; Adelantado, Jose Vicente Gimeno; Reig, Francisco Bosch

    2010-01-01

    Misconceptions of chemistry and chemical engineering university students concerning instrumental analysis have been established from coordinated tests, tutorial interviews and laboratory lessons. Misconceptions can be divided into: (1) formal, involving specific concepts and formulations within the general frame of chemistry; (2)…

  2. Analytical Thinking, Analytical Action: Using Prelab Video Demonstrations and e-Quizzes to Improve Undergraduate Preparedness for Analytical Chemistry Practical Classes

    ERIC Educational Resources Information Center

    Jolley, Dianne F.; Wilson, Stephen R.; Kelso, Celine; O'Brien, Glennys; Mason, Claire E.

    2016-01-01

    This project utilizes visual and critical thinking approaches to develop a higher-education synergistic prelab training program for a large second-year undergraduate analytical chemistry class, directing more of the cognitive learning to the prelab phase. This enabled students to engage in more analytical thinking prior to engaging in the…

  3. The role of analytical chemistry in Niger Delta petroleum exploration: a review.

    PubMed

    Akinlua, Akinsehinwa

    2012-06-12

    Petroleum and organic matter from which the petroleum is derived are composed of organic compounds with some trace elements. These compounds give an insight into the origin, thermal maturity and paleoenvironmental history of petroleum, which are essential elements in petroleum exploration. The main tool to acquire the geochemical data is analytical techniques. Due to progress in the development of new analytical techniques, many hitherto petroleum exploration problems have been resolved. Analytical chemistry has played a significant role in the development of petroleum resources of Niger Delta. Various analytical techniques that have aided the success of petroleum exploration in the Niger Delta are discussed. The analytical techniques that have helped to understand the petroleum system of the basin are also described. Recent and emerging analytical methodologies including green analytical methods as applicable to petroleum exploration particularly Niger Delta petroleum province are discussed in this paper. Analytical chemistry is an invaluable tool in finding the Niger Delta oils.

  4. ICRPG WORKING GROUP ON ANALYTICAL CHEMISTRY ROUND ROBIN NO. 22 -- EUDIOMETRIC ANALYSIS OF POWDERED ALUMINUM,

    DTIC Science & Technology

    Analytical Chemistry voted to conduct a round robin to estimate the interlaboratory reproducibility. The round robin was designed to facilitate statistical analysis of the data. Three samples representing different purity levels as

  5. A conflict of analysis: analytical chemistry and milk adulteration in Victorian Britain.

    PubMed

    Steere-Williams, Jacob

    2014-08-01

    This article centres on a particularly intense debate within British analytical chemistry in the late nineteenth century, between local public analysts and the government chemists of the Inland Revenue Service. The two groups differed in both practical methodologies and in the interpretation of analytical findings. The most striking debates in this period were related to milk analysis, highlighted especially in Victorian courtrooms. It was in protracted court cases, such as the well known Manchester Milk Case in 1883, that analytical chemistry was performed between local public analysts and the government chemists, who were often both used as expert witnesses. Victorian courtrooms were thus important sites in the context of the uneven professionalisation of chemistry. I use this tension to highlight what Christopher Hamlin has called the defining feature of Victorian public health, namely conflicts of professional jurisdiction, which adds nuance to histories of the struggle of professionalisation and public credibility in analytical chemistry.

  6. Integration of Environmental Analytical Chemistry with Environmental Law: The Development of a Problem-Based Laboratory.

    ERIC Educational Resources Information Center

    Cancilla, Devon A.

    2001-01-01

    Introduces an undergraduate level problem-based analytical chemistry laboratory course integrated with an environmental law course. Aims to develop an understanding among students on the use of environmental indicators for environmental evaluation. (Contains 30 references.) (YDS)

  7. Chemometric classification techniques as a tool for solving problems in analytical chemistry.

    PubMed

    Bevilacqua, Marta; Nescatelli, Riccardo; Bucci, Remo; Magrì, Andrea D; Magrì, Antonio L; Marini, Federico

    2014-01-01

    Supervised pattern recognition (classification) techniques, i.e., the family of chemometric methods whose aim is the prediction of a qualitative response on a set of samples, represent a very important assortment of tools for solving problems in several areas of applied analytical chemistry. This paper describes the theory behind the chemometric classification techniques most frequently used in analytical chemistry together with some examples of their application to real-world problems.

  8. Iron(III)-siderophore coordination chemistry: Reactivity of marine siderophores.

    PubMed

    Butler, Alison; Theisen, Roslyn M

    2010-02-01

    Two remarkable features of many siderophores produced by oceanic bacteria are the prevalence of an α-hydroxy-carboxylic acid functionality either in the form of the amino acid β-hydroxy aspartic acid or in the form of citric acid, as well as the predominance of amphiphilic siderophores. This review will provide an overview of the photoreactivity that takes place when siderophores containing β-hydroxy aspartic acid and citric acid are coordinated to iron(III). This photoreactivity raises questions about the role of this photochemistry in microbial iron acquisition as well as upper-ocean iron cycling. The self-assembly of amphiphilic siderophores and the coordination-induced phase-change of the micelle-to-vesicle transformation will also be reviewed. The distinctive photosensitive and self-assembly properties of marine siderophores hint at possibly new microbial iron acquisition mechanisms.

  9. Effects of Computer Based Learning on Students' Attitudes and Achievements towards Analytical Chemistry

    ERIC Educational Resources Information Center

    Akcay, Hüsamettin; Durmaz, Asli; Tüysüz, Cengiz; Feyzioglu, Burak

    2006-01-01

    The aim of this study was to compare the effects of computer-based learning and traditional method on students' attitudes and achievement towards analytical chemistry. Students from Chemistry Education Department at Dokuz Eylul University (D.E.U) were selected randomly and divided into three groups; two experimental (Eg-1 and Eg-2) and a control…

  10. Evaluating the Effectiveness of the Chemistry Education by Using the Analytic Hierarchy Process

    ERIC Educational Resources Information Center

    Yüksel, Mehmet

    2012-01-01

    In this study, an attempt was made to develop a method of measurement and evaluation aimed at overcoming the difficulties encountered in the determination of the effectiveness of chemistry education based on the goals of chemistry education. An Analytic Hierarchy Process (AHP), which is a multi-criteria decision technique, is used in the present…

  11. 75 FR 8147 - Notice of Consideration of Amendment Request for Decommissioning of Analytical Bio-Chemistry...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-23

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Notice of Consideration of Amendment Request for Decommissioning of Analytical Bio-Chemistry...-Chemistry Laboratories, Inc. (the Licensee) pursuant to 10 CFR part 30. By application dated October...

  12. Integrating Bio-Inorganic and Analytical Chemistry into an Undergraduate Biochemistry Laboratory

    ERIC Educational Resources Information Center

    Erasmus, Daniel J.; Brewer, Sharon E.; Cinel, Bruno

    2015-01-01

    Undergraduate laboratories expose students to a wide variety of topics and techniques in a limited amount of time. This can be a challenge and lead to less exposure to concepts and activities in bio-inorganic chemistry and analytical chemistry that are closely-related to biochemistry. To address this, we incorporated a new iron determination by…

  13. Hybrid halide perovskite solar cell precursors: colloidal chemistry and coordination engineering behind device processing for high efficiency.

    PubMed

    Yan, Keyou; Long, Mingzhu; Zhang, Tiankai; Wei, Zhanhua; Chen, Haining; Yang, Shihe; Xu, Jianbin

    2015-04-08

    The precursor of solution-processed perovskite thin films is one of the most central components for high-efficiency perovskite solar cells. We first present the crucial colloidal chemistry visualization of the perovskite precursor solution based on analytical spectra and reveal that perovskite precursor solutions for solar cells are generally colloidal dispersions in a mother solution, with a colloidal size up to the mesoscale, rather than real solutions. The colloid is made of a soft coordination complex in the form of a lead polyhalide framework between organic and inorganic components and can be structurally tuned by the coordination degree, thereby primarily determining the basic film coverage and morphology of deposited thin films. By utilizing coordination engineering, particularly through employing additional methylammonium halide over the stoichiometric ratio for tuning the coordination degree and mode in the initial colloidal solution, along with a thermal leaching for the selective release of excess methylammonium halides, we achieved full and even coverage, the preferential orientation, and high purity of planar perovskite thin films. We have also identified that excess organic component can reduce the colloidal size of and tune the morphology of the coordination framework in relation to final perovskite grains and partial chlorine substitution can accelerate the crystalline nucleation process of perovskite. This work demonstrates the important fundamental chemistry of perovskite precursors and provides genuine guidelines for accurately controlling the high quality of hybrid perovskite thin films without any impurity, thereby delivering efficient planar perovskite solar cells with a power conversion efficiency as high as 17% without distinct hysteresis owing to the high quality of perovskite thin films.

  14. Energetic lanthanide complexes: coordination chemistry and explosives applications

    NASA Astrophysics Data System (ADS)

    Manner, V. W.; Barker, B. J.; Sanders, V. E.; Laintz, K. E.; Scott, B. L.; Preston, D. N.; Sandstrom, M.; Reardon, B. L.

    2014-05-01

    Metals are generally added to organic molecular explosives in a heterogeneous composite to improve overall heat and energy release. In order to avoid creating a mixture that can vary in homogeneity, energetic organic molecules can be directly bonded to high molecular weight metals, forming a single metal complex with Angstrom-scale separation between the metal and the explosive. To probe the relationship between the structural properties of metal complexes and explosive performance, a new series of energetic lanthanide complexes has been prepared using energetic ligands such as NTO (5-nitro-2,4-dihydro-1,2,4-triazole-3-one). These are the first examples of lanthanide NTO complexes where no water is coordinated to the metal, demonstrating novel control of the coordination environment. The complexes have been characterized by X-ray crystallography, NMR and IR spectroscopies, photoluminescence, and sensitivity testing. The structural and energetic properties are discussed in the context of enhanced blast effects and detection. Cheetah calculations have been performed to fine-tune physical properties, creating a systematic method for producing explosives with 'tailor made' characteristics. These new complexes will be benchmarks for further study in the field of metalized high explosives.

  15. Energetic Lanthanide Complexes: Coordination Chemistry and Explosives Applications

    NASA Astrophysics Data System (ADS)

    Manner, Virginia; Barker, Beau; Sanders, Eric; Laintz, Kenneth; Scott, Brian; Preston, Daniel; Sandstrom, Mary; Reardon, Bettina

    2013-06-01

    Metals are generally added to organic molecular explosives in a heterogeneous composite to improve overall heat and energy release. In order to avoid creating a mixture that can vary in homogeneity, energetic organic molecules can be directly bonded to high molecular weight metals, forming a single metal complex with Angstrom-scale separation between the metal and the explosive. To probe the relationship between the structural properties of metal complexes and explosive performance, a new series of energetic lanthanide complexes has been prepared using energetic ligands such as NTO (5-nitro-2,4-dihydro-1,2,4-triazole-3-one). These are the first examples of lanthanide NTO complexes where no water is coordinated to the metal, demonstrating novel control of the coordination environment. The complexes have been characterized by X-ray crystallography, NMR and IR spectroscopies, photoluminescence, and sensitivity testing. The structural and energetic properties are discussed in the context of enhanced blast effects and detection. Cheetah calculations have been performed to fine-tune physical properties, creating a systematic method for producing explosives with ``tailor made'' characteristics. These new complexes will be benchmarks for further study in the field of metalized high explosives.

  16. Using Mathematical Software to Introduce Fourier Transforms in Physical Chemistry to Develop Improved Understanding of Their Applications in Analytical Chemistry

    ERIC Educational Resources Information Center

    Miller, Tierney C.; Richardson, John N.; Kegerreis, Jeb S.

    2016-01-01

    This manuscript presents an exercise that utilizes mathematical software to explore Fourier transforms in the context of model quantum mechanical systems, thus providing a deeper mathematical understanding of relevant information often introduced and treated as a "black-box" in analytical chemistry courses. The exercise is given to…

  17. Fifty years of continuous improvement: (What has DOE done for analytical chemistry?)

    SciTech Connect

    Shults, W.D.

    1993-11-01

    Over the past fifty years, analytical scientist within the DOE complex have had a tremendous impact on the field of analytical chemistry. This paper suggests six ``high impact`` research/development areas that either originated within or were brought to maturity within the DOE laboratories. ``High impact`` means they lead to new subdisciplines or to new ways of doing business.

  18. Analytical Chemistry Laboratory (ACL) procedure compendium. Volume 1, Administrative

    SciTech Connect

    Not Available

    1992-06-01

    Covered are: analytical laboratory operations (ALO) sample receipt and control, ALO data report/package preparation review and control, single shell tank (PST) project sample tracking system, sample receiving, analytical balances, duties and responsibilities of sample custodian, sample refrigerator temperature monitoring, security, assignment of staff responsibilities, sample storage, data reporting, and general requirements for glassware.

  19. Synthesis and coordination chemistry of tri-substituted benzamidrazones.

    PubMed

    Crimmin, Mark R; Colby, Denise A; Ellman, Jonathan A; Bergman, Robert G

    2011-01-14

    A series of N(1),N(1),N(3)-tri-substituted benzamidrazones of the general formula [PhC(NHR)=NNMe(2)] (R = Me, n-Pr, i-Pr, n-Bu, Bn, Ph; 1a-f) was synthesized via condensation of 1,1-dimethylhydrazine with the corresponding imidoyl chloride, [PhC(Cl)=NR]. Multinuclear NMR data, and zero-point energy DFT calculations conducted with the B3LYP functional and 6-31G+(d,p) basis set, suggest that these compounds exist as a single tautomer in solution; possessing a weak intramolecular hydrogen bond and a structure dominated by the localised resonance structure ArC(NHR)=N-NMe(2). An X-ray crystallographic study upon PhC(NHPh)=NNMe(2) (1f) demonstrated that this compound adopts an identical tautomer in the solid state. Reactions of [PhC(NHMe)=NNMe(2)] (1a) with [LMCl(2)](2) (M = Ru, L = cymene; M = Rh, Ir, L = Cp*) results in the stoichiometric formation of products of the formula [LM{PhC(=NMe)NHNMe(2)}Cl](+)Cl(-) (2a-c) in which the amidrazone chelates the metal in a κ(2)-N(1),N(3)-coordination mode. Formation of this five-membered chelate occurs with a concomitant tautomerisation of the amidrazone ligand to an alternative tautomer, i.e. [PhC(=NMe)NHNMe(2)], the latter tautomer is expected to be readily energetically accessible based upon the aforementioned DFT calculations. This series of salts may be deprotonated with lithium hexamethyldisilazide to form the corresponding charge neutral complexes [LM{PhC(NMe)=NNMe(2)}] (3a-c). In contrast, the reaction of N(1),N(1),N(3)-tri-substituted benzamidrazones with [(cymene)RuCl(2)](2) in the presence of NaOAc yielded a mixture of cyclometallation (C-H activation) and amidrazone chelation/deprotonation (N-H activation) products. Reaction of 1a yielded an inseparable mixture of products, whilst the reaction of 1c resulted in formation of the cyclometallated product [LM{C(6)H(5)C(=N(i)Pr)NHNMe(2)}] (L = cymene, M = Ru; 4a) in a modest 62% yield. This latter complex could be isolated as a crystalline orange solid, full

  20. Synthesis and coordination chemistry of tri-substituted benzamidrazones

    PubMed Central

    Crimmin, Mark R.; Colby, Denise A.

    2011-01-01

    A series of N1,N1,N3-tri-substituted benzamidrazones of the general formulae [PhC(NHR)=NNMe2] (R = Me, n-Pr, i-Pr, n-Bu, Bn, Ph; 1a–f) was synthesized via condensation of 1,1-dimethylhydrazine with the corresponding imidoyl chloride, [PhC(Cl)=NR]. Multinuclear NMR data, and zero-point energy DFT calculations conducted with the B3LYP functional and 6-31G+(d,p) basis set, suggest that these compounds exist as a single tautomer in solution; possessing a weak intramolecular hydrogen bond and a structure dominated by the localised resonance structure ArC(NHR)=N-NMe2. An X-ray crystallographic study upon PhC(NHPh)=NNMe2 (1f) demonstrated that this compound adopts an identical tautomer in the solid state. Reactions of [PhC(NHMe)=NNMe2] (1a) with [LMCl2]2 (M = Ru, L = cymene; M = Rh, Ir, L = Cp*) results in the stoichiometric formation of products of the formula [LM{PhC(=NMe)NHNMe2}Cl]+Cl− (2a–c) in which the amidrazone chelates the metal in a κ2-N1,N3-coordination mode. Formation of this five-membered chelate occurs with a concomitant tautomerisation of the amidrazone ligand to an alternative tautomer, i.e. [PhC(=NMe)NHNMe2], the latter tautomer is expected to be readily energetically accessible based upon the aforementioned DFT calculations. This series of salts may be deprotonated with lithium hexamethyldisilazide to form the corresponding charge neutral complexes [LM{PhC(NMe)=NNMe2}] (3a–c). In contrast, the reaction of N1,N1,N3-tri-substituted benzamidrazones with [(cymene)RuCl2]2 in the presence of NaOAc yielded a mixture of cyclometallation (C-H activation) and amidrazone chelation/deprotonation (N-H activation) products. Reaction of 1a yielded an inseparable mixture of products, whilst the reaction of 1c resulted in formation of the cyclometallated product [LM{C6H5C(=NiPr)NHNMe2}] (L = cymene, M = Ru; 4a) in a modest 62% yield. This latter complex could be isolated as a crystalline orange solid, full characterisation including single crystal X

  1. Expanding the coordination chemistry of donor-stabilized group-14 metalenes.

    PubMed

    Cabeza, Javier A; García-Álvarez, Pablo; Polo, Diego

    2013-02-07

    The transformation of an amidinate germylene, equipped with just one accessible lone pair of electrons on the Ge atom, into a bidentate 4-electron donor κ(2)Ge,N-ligand, has been achieved for the first time, opening new doors to the non-carbene-like coordination chemistry of heavier carbene analogues.

  2. Coordination chemistry of N-heterocyclic nitrenium-based ligands.

    PubMed

    Tulchinsky, Yuri; Kozuch, Sebastian; Saha, Prasenjit; Mauda, Assaf; Nisnevich, Gennady; Botoshansky, Mark; Shimon, Linda J W; Gandelman, Mark

    2015-05-04

    Comprehensive studies on the coordination properties of tridentate nitrenium-based ligands are presented. N-heterocyclic nitrenium ions demonstrate general and versatile binding abilities to various transition metals, as exemplified by the synthesis and characterization of Rh(I) , Rh(III) , Mo(0) , Ru(0) , Ru(II) , Pd(II) , Pt(II) , Pt(IV) , and Ag(I) complexes based on these unusual ligands. Formation of nitrenium-metal bonds is unambiguously confirmed both in solution by selective (15) N-labeling experiments and in the solid state by X-ray crystallography. The generality of N-heterocyclic nitrenium as a ligand is also validated by a systematic DFT study of its affinity towards all second-row transition and post-transition metals (Y-Cd) in terms of the corresponding bond-dissociation energies.

  3. Recent Applications of Carbon-Based Nanomaterials in Analytical Chemistry: Critical Review

    PubMed Central

    Scida, Karen; Stege, Patricia W.; Haby, Gabrielle; Messina, Germán A.; García, Carlos D.

    2011-01-01

    The objective of this review is to provide a broad overview of the advantages and limitations of carbon-based nanomaterials with respect to analytical chemistry. Aiming to illustrate the impact of nanomaterials on the development of novel analytical applications, developments reported in the 2005–2010 period have been included and divided into sample preparation, separation, and detection. Within each section, fullerenes, carbon nanotubes, graphene, and composite materials will be addressed specifically. Although only briefly discussed, included is a section highlighting nanomaterials with interesting catalytic properties that can be used in the design of future devices for analytical chemistry. PMID:21458626

  4. Recent applications of carbon-based nanomaterials in analytical chemistry: critical review.

    PubMed

    Scida, Karen; Stege, Patricia W; Haby, Gabrielle; Messina, Germán A; García, Carlos D

    2011-04-08

    The objective of this review is to provide a broad overview of the advantages and limitations of carbon-based nanomaterials with respect to analytical chemistry. Aiming to illustrate the impact of nanomaterials on the development of novel analytical applications, developments reported in the 2005-2010 period have been included and divided into sample preparation, separation, and detection. Within each section, fullerenes, carbon nanotubes, graphene, and composite materials will be addressed specifically. Although only briefly discussed, included is a section highlighting nanomaterials with interesting catalytic properties that can be used in the design of future devices for analytical chemistry.

  5. Lanthanide Chemistry: From Coordination in Chemical Complexes Shaping Our Technology to Coordination in Enzymes Shaping Bacterial Metabolism.

    PubMed

    Martinez-Gomez, Norma Cecilia; Vu, Huong N; Skovran, Elizabeth

    2016-10-17

    Lanthanide chemistry has only been extensively studied for the last 2 decades, when it was recognized that these elements have unusual chemical characteristics including fluorescent and potent magnetic properties because of their unique 4f electrons.1,2 Chemists are rapidly and efficiently integrating lanthanides into numerous compounds and materials for sophisticated applications. In fact, lanthanides are often referred to as "the seeds of technology" because they are essential for many technological devices including smartphones, computers, solar cells, batteries, wind turbines, lasers, and optical glasses.3-6 However, the effect of lanthanides on biological systems has been understudied. Although displacement of Ca(2+) by lanthanides in tissues and enzymes has long been observed,7 only a few recent studies suggest a biological role for lanthanides based on their stimulatory properties toward some plants and bacteria.8,9 Also, it was not until 2011 that the first biochemical evidence for lanthanides as inherent metals in bacterial enzymes was published.10 This forum provides an overview of the classical and current aspects of lanthanide coordination chemistry employed in the development of technology along with the biological role of lanthanides in alcohol oxidation. The construction of lanthanide-organic frameworks will be described. Examples of how the luminescence field is rapidly evolving as more information about lanthanide-metal emissions is obtained will be highlighted, including biological imaging and telecommunications.11 Recent breakthroughs and observations from different exciting areas linked to the coordination chemistry of lanthanides that will be mentioned in this forum include the synthesis of (i) macrocyclic ligands, (ii) antenna molecules, (iii) coordination polymers, particularly nanoparticles, (iv) hybrid materials, and (v) lanthanide fuel cells. Further, the role of lanthanides in bacterial metabolism will be discussed, highlighting the

  6. Analytical Chemistry for Homeland Defense and National Security

    SciTech Connect

    S.Randolph Long; Dan rock; Gary Eiceman; Chris Rowe Taitt; Robert J.Cotter; Dean D.Fetterolf; David R.Walt; Basil I. Swanson; Scott A McLuckey; Robin L.Garrell; Scott D. Cunningham

    2002-08-18

    The budget was requested to support speaker expenses to attend and speak in the day long symposium at the ACS meeting. The purpose of the symposium was to encourage analytical chemists to contribute to national security.

  7. Analytical Pharmaceutical Chemistry--Bridging Disciplines and Interests

    ERIC Educational Resources Information Center

    Smith, Robert V.

    1977-01-01

    Because of their interest and expertise in the analysis of drugs in biological fluids, analytical pharmaceutical chemists can contribute significantly to interdisciplinary research and teaching efforts. Suggestions for such efforts are described. (Author/LBH)

  8. Coordination chemistry of phosphinocarbynes: phosphorus vs. carbyne site selectivity.

    PubMed

    Colebatch, Annie L; Hill, Anthony F

    2017-03-13

    The phosphinocarbyne complex [W([triple bond, length as m-dash]CPPh2)(CO)2(Tp*)] (1: Tp* = hydrotris(dimethylpyrazolyl)borate) coordinates transition metal fragments via the phosphine to form bimetallic species [W{[triple bond, length as m-dash]CPPh2RhCl2(Cp*)}(CO)2(Tp*)] (2) and [W([triple bond, length as m-dash]CPPh2AuCl)(CO)2(Tp*)] (3). Appropriately tailored sterics allow for complexation of a second equivalent of AuCl to afford the trimetallic complex [W{η(2)-C(AuCl)PPh2AuCl}(CO)2(Tp*)] (4), containing an Au-W-C dimetallacyclopropene connectivity. Similarly, AuCl binds to the carbyne linkage in [W{[triple bond, length as m-dash]CP([double bond, length as m-dash]S)Ph2}(CO)2(Tp*)], yielding [W{η(2)-C(AuCl)P([double bond, length as m-dash]S)Ph2}(CO)2(Tp*)] (5). In the case of auration of the ditungsten species [W2(μ-C2PPh)(CO)4(Tp*)2] (6), variation in the stoichiometry leads to trimetallic [W2(μ-C2PPhAuCl)(CO)4(Tp*)2] (7) and pentametallic [W2{μ-(η(2)-CAuCl)2PPhAuCl}(CO)4(Tp*)2] (8) complexes, via a proposed tetrametallic intermediate [W2{μ-(η(2)-CAuCl)2PPh}(CO)4(Tp*)2], the site selectivity being dictated by aurophilic interactions.

  9. An Experiential Research-Focused Approach: Implementation in a Nonlaboratory-Based Graduate-Level Analytical Chemistry Course

    ERIC Educational Resources Information Center

    Toh, Chee-Seng

    2007-01-01

    A project is described which incorporates nonlaboratory research skills in a graduate level course on analytical chemistry. This project will help students to grasp the basic principles and concepts of modern analytical techniques and also help them develop relevant research skills in analytical chemistry.

  10. Experimental and Analytical Studies of Solar System Chemistry

    NASA Technical Reports Server (NTRS)

    Burnett, Donald S.

    2003-01-01

    The cosmochemistry research funded by this grant resulted in the publications given in the attached Publication List. The research focused in three areas: (1) Experimental studies of trace element partitioning. (2) Studies of the minor element chemistry and O isotopic compositions of MgAlO4 spinels from Ca-Al-Rich Inclusions in carbonaceous chondrite meteorites, and (3) The abundances and chemical fractionations of Th and U in chondritic meteorites.

  11. Influence of a Regular, Standardized Meal on Clinical Chemistry Analytes

    PubMed Central

    Salvagno, Gian Luca; Lippi, Giuseppe; Gelati, Matteo; Montagnana, Martina; Danese, Elisa; Picheth, Geraldo; Guidi, Gian Cesare

    2012-01-01

    Background Preanalytical variability, including biological variability and patient preparation, is an important source of variability in laboratory testing. In this study, we assessed whether a regular light meal might bias the results of routine clinical chemistry testing. Methods We studied 17 healthy volunteers who consumed light meals containing a standardized amount of carbohydrates, proteins, and lipids. We collected blood for routine clinical chemistry tests before the meal and 1, 2, and 4 hr thereafter. Results One hour after the meal, triglycerides (TG), albumin (ALB), uric acid (UA), phosphatase (ALP), Ca, Fe, and Na levels significantly increased, whereas blood urea nitrogen (BUN) and P levels decreased. TG, ALB, Ca, Na, P, and total protein (TP) levels varied significantly. Two hours after the meal, TG, ALB, Ca, Fe, and Na levels remained significantly high, whereas BUN, P, UA, and total bilirubin (BT) levels decreased. Clinically significant variations were recorded for TG, ALB, ALT, Ca, Fe, Na, P, BT, and direct bilirubin (BD) levels. Four hours after the meal, TG, ALB, Ca, Fe, Na, lactate dehydrogenase (LDH), P, Mg, and K levels significantly increased, whereas UA and BT levels decreased. Clinically significant variations were observed for TG, ALB, ALT, Ca, Na, Mg, K, C-reactive protein (CRP), AST, UA, and BT levels. Conclusions A significant variation in the clinical chemistry parameters after a regular meal shows that fasting time needs to be carefully considered when performing tests to prevent spurious results and reduce laboratory errors, especially in an emergency setting. PMID:22779065

  12. Surface and coordination chemistry related to GaAs

    NASA Astrophysics Data System (ADS)

    Keys, Andrea

    The vapor phase structures of Al(tBU)3 and Ga(tBU)3 have been investigated by gas phase electron diffraction and consist of planar three-coordinate monomers. Salient structural parameters (ra) include: Al-C = 2.005(3) A, Ga-C = 2.034(2) A. The geometries are controlled by inter-ligand interactions. The electron diffraction structures are compared to those determined by ab initio calculations for M(tBU)3 (M = Al, Ga, In). To understand the most suitable linkages for the surface of GaAs, model compounds were synthesized by reacting Ga(tBU)3 and [tBu2Ga(mu-Cl]2 with one molar equivalent of varying ligands. The synthesized compounds include chlorides, benzenethiolate, dithiocarbamates, carboxylates, amides, benzohydroxamate, and phenylphosphonate. The Ga ⋯ Ga and Ga-ligand interatomic distances for these compounds, as well as Group 15 and 16 donor bridging ligands, are compared to the values for the surface of GaAs and cubic-GaS in order to determine their suitability as linkage groups for self-assembled monolayers. The most suitable linkages were determined to be benzenethiol and phenylphophonic acid, and these were used to grow self-assembled monolayers on {100} GaAs. Carboxylic acid was also used, to determine the success of the organometallic model compounds in predicting the suitability of ligands for surface reaction. Self-assembled monolayers were also grown on Al2O3, using carboxylic acids and phenylphosphonic acids as the surface linkages. Metallo-organic chemical vapor deposition was performed using single-source precursors ( tBU)2Ga(S2CNR2). The tert -butyl gallium bis-dialkyl-dithiocarbamate compounds, (tBu)Ga(S2CNR2)2, are formed as minor products via ligand disproportionation reactions. Gallium sulfide (GaS) thin films have been grown at 375-425°C by atmospheric pressure metal-organic chemical vapor deposition using compounds (tBu) 2Ga(S2CNMe2) and (tBu)2Ga(S 2CNEt2) as single source precursors. Polycrystalline samples of the chalcogenides InSe, In2Se3

  13. Selected uses of enzymes with critical fluids in analytical chemistry.

    PubMed

    Turner, Charlotta; King, Jerry W; McKeon, Thomas

    2004-01-01

    The use of enzymes coupled with supercritical fluid (SF)-based analytical techniques, such as supercritical fluid extraction (SFE), provides a safer environment platform for the analytical chemist and reduces the use of organic solvents. Incorporation of such techniques not only reduces the use of solvent in analytical laboratories, but it can also lead to overall method simplification and time savings. In this review, some of the fundamental aspects of using enzymes in the presence of SF media are discussed, particularly the influence of extraction (reaction) pressure, temperature, and water content of the extracting fluid and/or the sample matrix. Screening of optimal conditions for conducting reactions in the presence of SF media can be readily accomplished with automated serial or parallel SFE instrumentation, including selection of the proper enzyme. Numerous examples are cited, many based on lipase-initiated conversions of lipid substrates, to form useful analytical derivatives for gas chromatography, liquid chromatography, or SF chromatography analysis. In certain cases, enzymatic-aided processing of samples can permit the coupling of the extraction, sample preparation, and final analysis steps. The derived methods/techniques find application in nutritional food analyses, assays of industrial products, and micro analyses of specific samples.

  14. Manual of analytical methods for the Industrial Hygiene Chemistry Laboratory

    SciTech Connect

    Greulich, K.A.; Gray, C.E.

    1991-08-01

    This Manual is compiled from techniques used in the Industrial Hygiene Chemistry Laboratory of Sandia National Laboratories in Albuquerque, New Mexico. The procedures are similar to those used in other laboratories devoted to industrial hygiene practices. Some of the methods are standard; some, modified to suit our needs; and still others, developed at Sandia. The authors have attempted to present all methods in a simple and concise manner but in sufficient detail to make them readily usable. It is not to be inferred that these methods are universal for any type of sample, but they have been found very reliable for the types of samples mentioned.

  15. Analytical Chemistry Division annual progress report for period ending December 31, 1985

    SciTech Connect

    Shultz, W.D.

    1986-05-01

    Progress reports are presented for the four major sections of the division: analytical spectroscopy, radioactive materials laboratories, inorganic chemistry, and organic chemistry. A brief discussion of the division's role in the Laboratory's Environmental Restoration and Facilities Upgrade is given. Information about quality assurance and safety programs is presented, along with a tabulation of analyses rendered. Publications, oral presentations, professional activities, educational programs, and seminars are cited.

  16. Waste minimization in analytical chemistry through innovative sample preparation techniques.

    SciTech Connect

    Smith, L. L.

    1998-05-28

    Because toxic solvents and other hazardous materials are commonly used in analytical methods, characterization procedures result in significant and costly amount of waste. We are developing alternative analytical methods in the radiological and organic areas to reduce the volume or form of the hazardous waste produced during sample analysis. For the radiological area, we have examined high-pressure, closed-vessel microwave digestion as a way to minimize waste from sample preparation operations. Heated solutions of strong mineral acids can be avoided for sample digestion by using the microwave approach. Because reactivity increases with pressure, we examined the use of less hazardous solvents to leach selected contaminants from soil for subsequent analysis. We demonstrated the feasibility of this approach by extracting plutonium from a NET reference material using citric and tartaric acids with microwave digestion. Analytical results were comparable to traditional digestion methods, while hazardous waste was reduced by a factor often. We also evaluated the suitability of other natural acids, determined the extraction performance on a wider variety of soil types, and examined the extraction efficiency of other contaminants. For the organic area, we examined ways to minimize the wastes associated with the determination of polychlorinated biphenyls (PCBs) in environmental samples. Conventional methods for analyzing semivolatile organic compounds are labor intensive and require copious amounts of hazardous solvents. For soil and sediment samples, we have a method to analyze PCBs that is based on microscale extraction using benign solvents (e.g., water or hexane). The extraction is performed at elevated temperatures in stainless steel cells containing the sample and solvent. Gas chromatography-mass spectrometry (GC/MS) was used to quantitate the analytes in the isolated extract. More recently, we developed a method utilizing solid-phase microextraction (SPME) for natural

  17. The role of coordination chemistry in the development of copper and rhenium radiopharmaceuticals.

    PubMed

    Donnelly, Paul S

    2011-02-07

    There are several isotopes of copper and rhenium that are of interest in the development of new molecular imaging or radiotherapeutic agents. This perspective article highlights the role of coordination chemistry in the design of copper and rhenium radiopharmaceuticals engineered to selectively target tissue of interest such as cancer cells or pathological features associated with Alzheimer's disease. The coordination chemistry of copper bis(thiosemicarbazone) derivatives and copper macrocyclic complexes is discussed in terms of their potential application as targeted positron emission tomography tracers for non-invasive diagnostic imaging. A range of rhenium complexes with different ligands with rhenium in different oxidation states are introduced and their potential to be translated to new radiotherapeutic agents discussed.

  18. Allosteric activation of membrane-bound glutamate receptors using coordination chemistry within living cells

    NASA Astrophysics Data System (ADS)

    Kiyonaka, Shigeki; Kubota, Ryou; Michibata, Yukiko; Sakakura, Masayoshi; Takahashi, Hideo; Numata, Tomohiro; Inoue, Ryuji; Yuzaki, Michisuke; Hamachi, Itaru

    2016-10-01

    The controlled activation of proteins in living cells is an important goal in protein-design research, but to introduce an artificial activation switch into membrane proteins through rational design is a significant challenge because of the structural and functional complexity of such proteins. Here we report the allosteric activation of two types of membrane-bound neurotransmitter receptors, the ion-channel type and the G-protein-coupled glutamate receptors, using coordination chemistry in living cells. The high programmability of coordination chemistry enabled two His mutations, which act as an artificial allosteric site, to be semirationally incorporated in the vicinity of the ligand-binding pockets. Binding of Pd(2,2‧-bipyridine) at the allosteric site enabled the active conformations of the glutamate receptors to be stabilized. Using this approach, we were able to activate selectively a mutant glutamate receptor in live neurons, which initiated a subsequent signal-transduction pathway.

  19. Pi-metal complexes of tetrapyrrolic systems. A novel coordination mode in "porphyrin-like" chemistry.

    PubMed

    Cuesta, Luciano; Sessler, Jonathan L

    2009-09-01

    The coordination chemistry of porphyrins and related tetrapyrrolic ligands has traditionally centered around the ability of these systems to form pyrrole N-ligated complexes via the formation of sigma bonds, either within the N(4) core or displaced above it. In fact, such sigma-complexes are known with almost every metal cation in the periodic table. However, a growing number of pi-complexes derived from tetrapyrrolic ligands have been reported in recent years. The underlying coordination mode, while still novel in the context of "porphyrin-like" chemistry, is already being recognized for the effects it can impart over the reactivity, as well as the spectroscopic, redox, electronic, and optical properties of various oligopyrrolic macrocycles. This critical review summarizes accomplishments made in this fast-emerging field (59 references).

  20. Bibliometric mapping: eight decades of analytical chemistry, with special focus on the use of mass spectrometry.

    PubMed

    Waaijer, Cathelijn J F; Palmblad, Magnus

    2015-01-01

    In this Feature we use automatic bibliometric mapping tools to visualize the history of analytical chemistry from the 1920s until the present. In particular, we have focused on the application of mass spectrometry in different fields. The analysis shows major shifts in research focus and use of mass spectrometry. We conclude by discussing the application of bibliometric mapping and visualization tools in analytical chemists' research.

  1. Analytical chemistry in water quality monitoring during manned space missions

    NASA Astrophysics Data System (ADS)

    Artemyeva, Anastasia A.

    2016-09-01

    Water quality monitoring during human spaceflights is essential. However, most of the traditional methods require sample collection with a subsequent ground analysis because of the limitations in volume, power, safety and gravity. The space missions are becoming longer-lasting; hence methods suitable for in-flight monitoring are demanded. Since 2009, water quality has been monitored in-flight with colorimetric methods allowing for detection of iodine and ionic silver. Organic compounds in water have been monitored with a second generation total organic carbon analyzer, which provides information on the amount of carbon in water at both the U.S. and Russian segments of the International Space Station since 2008. The disadvantage of this approach is the lack of compound-specific information. The recently developed methods and tools may potentially allow one to obtain in-flight a more detailed information on water quality. Namely, the microanalyzers based on potentiometric measurements were designed for online detection of chloride, potassium, nitrate ions and ammonia. The recent application of the current highly developed air quality monitoring system for water analysis was a logical step because most of the target analytes are the same in air and water. An electro-thermal vaporizer was designed, manufactured and coupled with the air quality control system. This development allowed for liberating the analytes from the aqueous matrix and further compound-specific analysis in the gas phase.

  2. The Analytical Chemistry of Drug Monitoring in Athletes

    NASA Astrophysics Data System (ADS)

    Bowers, Larry D.

    2009-07-01

    The detection and deterrence of the abuse of performance-enhancing drugs in sport are important to maintaining a level playing field among athletes and to decreasing the risk to athletes’ health. The World Anti-Doping Program consists of six documents, three of which play a role in analytical development: The World Anti-Doping Code, The List of Prohibited Substances and Methods, and The International Standard for Laboratories. Among the classes of prohibited substances, three have given rise to the most recent analytical developments in the field: anabolic agents; peptide and protein hormones; and methods to increase oxygen delivery to the tissues, including recombinant erythropoietin. Methods for anabolic agents, including designer steroids, have been enhanced through the use of liquid chromatography/tandem mass spectrometry and gas chromatography/combustion/isotope-ratio mass spectrometry. Protein and peptide identification and quantification have benefited from advances in liquid chromatography/tandem mass spectrometry. Incorporation of techniques such as flow cytometry and isoelectric focusing have supported the detection of blood doping.

  3. The analytical chemistry of drug monitoring in athletes.

    PubMed

    Bowers, Larry D

    2009-01-01

    The detection and deterrence of the abuse of performance-enhancing drugs in sport are important to maintaining a level playing field among athletes and to decreasing the risk to athletes' health. The World Anti-Doping Program consists of six documents, three of which play a role in analytical development: The World Anti-Doping Code, The List of Prohibited Substances and Methods, and The International Standard for Laboratories. Among the classes of prohibited substances, three have given rise to the most recent analytical developments in the field: anabolic agents; peptide and protein hormones; and methods to increase oxygen delivery to the tissues, including recombinant erythropoietin. Methods for anabolic agents, including designer steroids, have been enhanced through the use of liquid chromatography/tandem mass spectrometry and gas chromatography/combustion/isotope-ratio mass spectrometry. Protein and peptide identification and quantification have benefited from advances in liquid chromatography/tandem mass spectrometry. Incorporation of techniques such as flow cytometry and isoelectric focusing have supported the detection of blood doping.

  4. Disruptive by design: a perspective on engineering in analytical chemistry.

    PubMed

    Herr, Amy E

    2013-08-20

    Perhaps paradoxically, we argue that the biological sciences are "data-limited". In contrast to the glut of DNA sequencing data available, high-throughput protein analysis is expensive and largely inaccessible. Hence, we posit that access to robust protein-level data is inadequate. Here, we use the framework of the formal engineering design process to both identify and understand the problems facing measurement science in the 21st century. In particular, discussion centers on the notable challenge of realizing protein analyses that are as effective (and transformative) as genomics tools. This Perspective looks through the lens of a case study on protein biomarker validation and verification, to highlight the importance of iterative design in realizing significant advances over currently available measurement capabilities in the candidate or targeted proteomics space. The Perspective follows a podium presentation given by the author at The 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences (μTAS 2012), specifically focusing on novel targeted proteomic measurement tools based in microfluidic design. The role of unmet needs identification, iteration in concept generation and development, and the existing gap in rapid prototyping tools for separations are all discussed.

  5. Disruptive by Design: A perspective on engineering in analytical chemistry

    PubMed Central

    Herr, Amy E.

    2013-01-01

    Perhaps paradoxically, we argue that the biological sciences are ‘data-limited’. In contrast to the glut of DNA sequencing data available, high-throughput protein analysis is expensive and largely inaccessible. Hence we posit that access to robust protein-level data is inadequate. Here we use the framework of the formal engineering design process to both identify and understand the problems facing measurement science in the 21st century. In particular, discussion centers on the notable challenge of realizing protein analyses that are as effective (and transformative) as genomics tools. This Perspective looks through the lens of a case study on protein biomarker validation and verification, to highlight the importance of iterative design in realizing significant advances over currently available measurement capabilities in the candidate or targeted proteomics space. The Perspective follows a podium presentation given by the author at The 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences (μTAS 2012), specifically focusing on novel targeted proteomic measurement tools based in microfluidic design. The role of unmet needs identification, iteration in concept generation and development, and the existing gap in rapid prototyping tools for separations are all discussed. PMID:23924345

  6. Determination of Mercury in Milk by Cold Vapor Atomic Fluorescence: A Green Analytical Chemistry Laboratory Experiment

    ERIC Educational Resources Information Center

    Armenta, Sergio; de la Guardia, Miguel

    2011-01-01

    Green analytical chemistry principles were introduced to undergraduate students in a laboratory experiment focused on determining the mercury concentration in cow and goat milk. In addition to traditional goals, such as accuracy, precision, sensitivity, and limits of detection in method selection and development, attention was paid to the…

  7. Liquid-Liquid Extraction of Insecticides from Juice: An Analytical Chemistry Laboratory Experiment

    ERIC Educational Resources Information Center

    Radford, Samantha A.; Hunter, Ronald E., Jr.; Barr, Dana Boyd; Ryan, P. Barry

    2013-01-01

    A laboratory experiment was developed to target analytical chemistry students and to teach them about insecticides in food, sample extraction, and cleanup. Micro concentrations (sub-microgram/mL levels) of 12 insecticides spiked into apple juice samples are extracted using liquid-liquid extraction and cleaned up using either a primary-secondary…

  8. Island Explorations: Discovering Effects of Environmental Research-Based Lab Activities on Analytical Chemistry Students

    ERIC Educational Resources Information Center

    Tomasik, Janice Hall; LeCaptain, Dale; Murphy, Sarah; Martin, Mary; Knight, Rachel M.; Harke, Maureen A.; Burke, Ryan; Beck, Kara; Acevedo-Polakovich, I. David

    2014-01-01

    Motivating students in analytical chemistry can be challenging, in part because of the complexity and breadth of topics involved. Some methods that help encourage students and convey real-world relevancy of the material include incorporating environmental issues, research-based lab experiments, and service learning projects. In this paper, we…

  9. A Comprehensive Microfluidics Device Construction and Characterization Module for the Advanced Undergraduate Analytical Chemistry Laboratory

    ERIC Educational Resources Information Center

    Piunno, Paul A. E.; Zetina, Adrian; Chu, Norman; Tavares, Anthony J.; Noor, M. Omair; Petryayeva, Eleonora; Uddayasankar, Uvaraj; Veglio, Andrew

    2014-01-01

    An advanced analytical chemistry undergraduate laboratory module on microfluidics that spans 4 weeks (4 h per week) is presented. The laboratory module focuses on comprehensive experiential learning of microfluidic device fabrication and the core characteristics of microfluidic devices as they pertain to fluid flow and the manipulation of samples.…

  10. Quantitative Ultrasound-Assisted Extraction for Trace-Metal Determination: An Experiment for Analytical Chemistry

    ERIC Educational Resources Information Center

    Lavilla, Isela; Costas, Marta; Pena-Pereira, Francisco; Gil, Sandra; Bendicho, Carlos

    2011-01-01

    Ultrasound-assisted extraction (UAE) is introduced to upper-level analytical chemistry students as a simple strategy focused on sample preparation for trace-metal determination in biological tissues. Nickel extraction in seafood samples and quantification by electrothermal atomic absorption spectrometry (ETAAS) are carried out by a team of four…

  11. Incorporating Students' Self-Designed, Research-Based Analytical Chemistry Projects into the Instrumentation Curriculum

    ERIC Educational Resources Information Center

    Gao, Ruomei

    2015-01-01

    In a typical chemistry instrumentation laboratory, students learn analytical techniques through a well-developed procedure. Such an approach, however, does not engage students in a creative endeavor. To foster the intrinsic motivation of students' desire to learn, improve their confidence in self-directed learning activities and enhance their…

  12. [Analytical chemistry in works of Maria Skłodowska-Curie].

    PubMed

    Hulanicki, Adam

    2012-01-01

    Maria Skłodowska-Curie--a Nobel Prize winner in chemistry--the elements of learning of chemistry gained just by a dint of work of more than ten months in Warsaw in the Institute of Industry and Agriculture Museum. The Nobel Prize concerned a contribution to the progress of chemistry through the discovery of radium and polonium, separation of radium and study of properties of this amazing element. It was awarded for an extremely arduous work, during which the chemical reactions being the principles of analytical chemistry were realized. Unlike to a typical analytical procedure, an initial attempt here was the thousands of kilograms of uranium ore: pitchblende. The final effect was small amounts of new elements: polonium and radium. Both the knowledge and the intuition of the researcher let her have a triumph. The difficulties she experienced because the properties of the searched chemical elements could only be evaluated thanks to the knowledge on other chemical elements. A significant achievement was the determination of the samples by means of radioactivity measurement, which gave rise to radiochemical analytical methods. An extreme analytical precision was demanded in multiple processes of fractional crystallization and precipitation which finally led to the calculation of the atomic mass of radium.

  13. An Attenuated Total Reflectance Sensor for Copper: An Experiment for Analytical or Physical Chemistry

    ERIC Educational Resources Information Center

    Shtoyko, Tanya; Zudans, Imants; Seliskar, Carl J.; Heineman, William R.; Richardson, John N.

    2004-01-01

    A sensor experiment which can be applied to advanced undergraduate laboratory course in physical or analytical chemistry is described along with certain concepts like the demonstration of chemical sensing, preparation of thin films on a substrate, microtitration, optical determination of complex ion stoichiometry and isosbestic point. It is seen…

  14. Student Learning and Evaluation in Analytical Chemistry Using a Problem-Oriented Approach and Portfolio Assessment

    ERIC Educational Resources Information Center

    Boyce, Mary C.; Singh, Kuki

    2008-01-01

    This paper describes a student-focused activity that promotes effective learning in analytical chemistry. Providing an environment where students were responsible for their own learning allowed them to participate at all levels from designing the problem to be addressed, planning the laboratory work to support their learning, to providing evidence…

  15. Juicing the Juice: A Laboratory-Based Case Study for an Instrumental Analytical Chemistry Course

    ERIC Educational Resources Information Center

    Schaber, Peter M.; Dinan, Frank J.; St. Phillips, Michael; Larson, Renee; Pines, Harvey A.; Larkin, Judith E.

    2011-01-01

    A young, inexperienced Food and Drug Administration (FDA) chemist is asked to distinguish between authentic fresh orange juice and suspected reconstituted orange juice falsely labeled as fresh. In an advanced instrumental analytical chemistry application of this case, inductively coupled plasma (ICP) spectroscopy is used to distinguish between the…

  16. Online Video Tutorials Increase Learning of Difficult Concepts in an Undergraduate Analytical Chemistry Course

    ERIC Educational Resources Information Center

    He, Yi; Swenson, Sandra; Lents, Nathan

    2012-01-01

    Educational technology has enhanced, even revolutionized, pedagogy in many areas of higher education. This study examines the incorporation of video tutorials as a supplement to learning in an undergraduate analytical chemistry course. The concepts and problems in which students faced difficulty were first identified by assessing students'…

  17. [Recent progress on analytical chemistry and biochemistry of D-amino acids].

    PubMed

    Imai, K; Kato, M; Huang, Y; Ichihara, H; Fukushima, T; Santa, T; Homma, H

    1997-11-01

    Recent findings that D-amino acids, especially D-aspartic acid and D-serine, exist in vivo in the mammalian tissues (brain and peripheries), prompted us now to investigate their biological and pathological roles in mammals. In this review, the overview of the progress of analytical chemistry and biochemistry of D-amino acids is described.

  18. Analytical Chemistry Division annual progress report for period ending December 31, 1992

    SciTech Connect

    Shults, W.D.

    1993-04-01

    This report is divided into: Analytical spectroscopy (optical spectroscopy, organic mass spectrometry, inorganic mass spectrometry, secondary ion mass spectrometry), inorganic and radiochemistry (transuranium and activation analysis, low-level radiochemical analysis, inorganic analysis, radioactive materials analysis, special projects), organic chemistry (organic spectroscopy, separations and synthesis, special projects, organic analysis, ORNL/UT research program), operations (quality assurance/quality control, environmental protection, safety, analytical improvement, training, radiation control), education programs, supplementary activities, and presentation of research results. Tables are included for articles reviewed or refereed for periodicals, analytical service work, division manpower and financial summary, and organization chart; a glossary is also included.

  19. Exploration of Antarctic Subglacial environments: a challenge for analytical chemistry

    NASA Astrophysics Data System (ADS)

    Traversi, R.; Becagli, S.; Castellano, E.; Ghedini, C.; Marino, F.; Rugi, F.; Severi, M.; Udisti, R.

    2009-12-01

    The large number of subglacial lakes detected in the Dome C area in East Antarctica suggests that this region may be a valuable source of paleo-records essential for understanding the evolution of the Antarctic ice cap and climate changes in the last several millions years. In the framework of the Project on “Exploration and characterization of Concordia Lake, Antarctica”, supported by Italian Program for Antarctic Research (PNRA), a glaciological investigation of the Dome C “Lake District” are planned. Indeed, the glacio-chemical characterisation of the ice column over subglacial lakes will allow to evaluate the fluxes of major and trace chemical species along the ice column and in the accreted ice and, consequently, the availability of nutrients and oligo-elements for possible biological activity in the lake water and sediments. Melting and freezing at the base of the ice sheet should be able to deliver carbon and salts to the lake, as observed for the Vostok subglacial lake, which are thought to be able to support a low concentration of micro-organisms for extended periods of time. Thus, this investigation represents the first step for exploring the subglacial environments including sampling and analysis of accreted ice, lake water and sediments. In order to perform reliable analytical measurements, especially of trace chemical species, clean sub-sampling and analytical techniques are required. For this purpose, the techniques already used by the CHIMPAC laboratory (Florence University) in the framework of international Antarctic drilling Projects (EPICA - European Project for Ice Coring in Antarctica, TALDICE - TALos Dome ICE core, ANDRILL MIS - ANTarctic DRILLing McMurdo Ice Shelf) were optimised and new techniques were developed to ensure a safe sample handling. CHIMPAC laboratory has been involved since several years in the study of Antarctic continent, primarily focused on understanding the bio-geo-chemical cycles of chemical markers and the

  20. The Efficacy of Problem-Based Learning in an Analytical Laboratory Course for Pre-Service Chemistry Teachers

    ERIC Educational Resources Information Center

    Yoon, Heojeong; Woo, Ae Ja; Treagust, David; Chandrasegaran, A. L.

    2014-01-01

    The efficacy of problem-based learning (PBL) in an analytical chemistry laboratory course was studied using a programme that was designed and implemented with 20 students in a treatment group over 10 weeks. Data from 26 students in a traditional analytical chemistry laboratory course were used for comparison. Differences in the creative thinking…

  1. Increasing Efficiency and Quality by Consolidation of Clinical Chemistry and Immunochemistry Systems with MODULAR ANALYTICS SWA

    PubMed Central

    Mocarelli, Paolo; Horowitz, Gary L.; Gerthoux, Pier Mario; Cecere, Rossana; Imdahl, Roland; Ruinemans-Koerts, Janneke; Luthe, Hilmar; Calatayud, Silvia Pesudo; Salve, Marie Luisa; Kunst, Albert; McGovern, Margaret; Ng, Katherine; Stockmann, Wolfgang

    2008-01-01

    MODULAR ANALYTICS Serum Work Area (in USA Integrated MODULAR ANALYTICS, MODULAR ANALYTICS is a trademark of a member of the Roche Group) represents a further approach to automation in the laboratory medicine. This instrument combines previously introduced modular systems for the clinical chemistry and immunochemistry laboratory and allows customised combinations for various laboratory workloads. Functionality, practicability, and workflow behaviour of MODULAR ANALYTICS Serum Work Area were evaluated in an international multicenter study at six laboratories. Across all experiments, 236000 results from 32400 samples were generated using 93 methods. Simulated routine testing which included provocation incidents and anomalous situations demonstrated good performance and full functionality. Heterogeneous immunoassays, performed on the E-module with the electrochemiluminescence technology, showed reproducibility at the same level of the general chemistry tests, which was well within the clinical demands. Sample carryover cannot occur due to intelligent sample processing. Workflow experiments for the various module combinations, with menus of about 50 assays, yielded mean sample processing times of <38 minutes for combined clinical chemistry and immunochemistry requests; <50 minutes including automatically repeated samples. MODULAR ANALYTICS Serum Work Area offered simplified workflow by combining various laboratory segments. It increased efficiency while maintaining or even improving quality of laboratory processes. PMID:18401449

  2. Priority survey between indicators and analytic hierarchy process analysis for green chemistry technology assessment

    PubMed Central

    Kim, Sungjune; Hong, Seokpyo; Ahn, Kilsoo; Gong, Sungyong

    2015-01-01

    Objectives This study presents the indicators and proxy variables for the quantitative assessment of green chemistry technologies and evaluates the relative importance of each assessment element by consulting experts from the fields of ecology, chemistry, safety, and public health. Methods The results collected were subjected to an analytic hierarchy process to obtain the weights of the indicators and the proxy variables. Results These weights may prove useful in avoiding having to resort to qualitative means in absence of weights between indicators when integrating the results of quantitative assessment by indicator. Conclusions This study points to the limitations of current quantitative assessment techniques for green chemistry technologies and seeks to present the future direction for quantitative assessment of green chemistry technologies. PMID:26206364

  3. Hard Cap Espresso Machines in Analytical Chemistry: What Else?

    PubMed

    Armenta, Sergio; de la Guardia, Miguel; Esteve-Turrillas, Francesc A

    2016-06-21

    A hard cap espresso machine has been used in combination with liquid chromatography with molecular fluorescence detection for the determination of polycyclic aromatic hydrocarbons (PAHs) from contaminated soils and sediments providing appropriate extraction efficiencies and quantitative results. Naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benz[b]fluoranthene, benz[k]fluoranthene, benz[a]pyrene, dibenz[a,h]anthracene, benz[ghi]perylene, and indeno[1,2,3-cd]pyrene were used as target compounds. It should be mentioned that the pairs benz[a]anthracene-chrysene and dibenz[a,h]anthracene-benz[ghi]perylene peaks coelute under the employed chromatographic conditions; thus, those compounds were determined together. PAHs were extracted from 5.0 g of soil, previously homogenized, freeze-dried, and sieved to 250 μm, with 50 mL of 40% (v/v) acetonitrile in water at a temperature of 72 ± 3 °C. The proposed procedure is really fast, with an extraction time of 11 s, and it reduces the required amount of organic solvent to do the sample preparation. The obtained limit of detection for the evaluated PAHs was from 1 to 38 μg kg(-1). Recoveries were calculated using clean soils spiked with 100, 500, 1000, and 2000 μg kg(-1) PAHs with values ranging from 81 to 121% and good precision with relative standard deviation values lower than 30%. The method was validated using soil and sediment certified reference materials and also using real samples by comparison with ultrasound-assisted extraction, as reference methodology, obtaining statistically comparable results. Thus, the use of hard cap espresso machines in the analytical laboratories offers tremendous possibilities as low cost extraction units for the extraction of solid samples.

  4. Bending nanofibers into nanospirals: coordination chemistry as a tool for shaping hydrophobic assemblies.

    PubMed

    Kossoy, Elizaveta; Weissman, Haim; Rybtchinski, Boris

    2015-01-02

    In the current work, we demonstrate how coordination chemistry can be employed to direct self-assembly based on strong hydrophobic interactions. To investigate the influence of coordination sphere geometry on aqueous self-assembly, we synthesized complexes of the amphiphilic perylene diimide terpyridine ligand with the first-row transition-metal centers (zinc, cobalt, and nickel). In aqueous medium, aggregation of these complexes is induced by hydrophobic interactions between the ligands. However, the final shapes of the resulting assemblies depend on the preferred geometry of the coordination spheres typical for the particular metal center. The self-assembly process was characterized by UV/Vis spectroscopy, zeta potential measurements, and cryogenic transmission electron microscopy (cryo-TEM). Coordination of zinc(II) and cobalt(II) leads to the formation of unique nanospiral assemblies, whereas complexation of nickel(II) leads to the formation of straight nanofibers. Notably, coordination bonds are utilized not as connectors between elementary building blocks, but as directing interactions, enabling control over supramolecular geometry.

  5. Analytical Chemistry (edited by R. Kellner, J.- M. Mermet, M. Otto, and H. M. Widmer)

    NASA Astrophysics Data System (ADS)

    Thompson, Reviewed By Robert Q.

    2000-04-01

    This text, written in English, was developed by the Division of Analytical Chemistry of the Federation of European Chemical Societies to support the university-level Eurocurriculum in analytical chemistry, a major effort of academics and other analytical scientists throughout Europe and an outgrowth of the economic unification of European countries. The goal of a uniform curriculum and text for analytical chemistry across national borders is laudable, and the editors, led by the late Robert Kellner, deserve commendation for their accomplishments. (The U.S., in contrast, has been late in considering the analytical chemistry curriculum and only recently has published a pamphlet, Curricular Developments in the Analytical Sciences, an outgrowth of several NSF-sponsored workshops.) I can't remember another analytical text that begins with mention of the "big bang" and the beginnings of the universe (!), but I don't believe that the authors and publisher are looking to export their curriculum to neighboring planets. However, I am sure that they are interested in the North American market and its strong analytical chemistry community. It is in this context and in comparison with leading analytical texts in the U.S. that I write this review. At first glance, Analytical Chemistry overwhelms. It is a large book of more than 900 pages, a mass of 2.3 kg, and a volume of nearly 3 L. It is not a book that is easy to stuff into a backpack for the trip to class or lab. Students also may resent paying top dollar for a book that might not last the semester, given that the pages of my review copy began to pull away from the binding after only a few days of gentle use. Beneath the snazzy cover there is a dearth of color printing and photographs. This, combined with a smallish font and figures that are inconsistent in size, quality, and font, makes for a book that is not especially easy on the eyes. The large margins provide ample space for the numerous figures, figure captions, and

  6. Coordination chemistry and antisolvent strategy to rare-earth solid solution colloidal spheres.

    PubMed

    Li, Cheng Chao; Zeng, Hua Chun

    2012-11-21

    We have devised in this work a general synthetic strategy for preparation of single- and multicomponent rare-earth coordination polymer colloidal spheres (RE-CPCSs). This strategy is based on an integration of coordination chemistry and antisolvent effect for synchronized precipitation. Highly monodisperse RE-CPCSs with homogeneous mixing of RE elements, which are not readily attainable by any existing methods, have been successfully prepared for the first time. In addition, the type and molar ratio of these colloidal spheres can be adjusted easily in accordance to the variety and dosage of precursor salts. The molar ratio of RE elements in as-prepared colloidal spheres shows a linear relationship to that of starting reactants. Furthermore, the RE-based core/shell colloidal spheres can be facilely prepared by introducing other metal salts (beyond lanthanide elements) owing to their different coordination chemistry and precipitation behavior. By adjusting concentrations of the ionic activators, luminescent properties can be tuned accordingly. Moreover, the RE-CPCSs can be transformed to monodisperse lanthanide oxide spheres via simple heat treatment. We believe that the present synthetic strategy provides a viable route to prepare other lanthanide-containing colloidal spheres that have enormous potential for future applications as optoelectronic devices, catalysts, gas sensors, and solar cells.

  7. Analytical Chemistry Division annual progress report for period ending December 31, 1988

    SciTech Connect

    Not Available

    1988-05-01

    The Analytical Chemistry Division of Oak Ridge National Laboratory (ORNL) is a large and diversified organization. As such, it serves a multitude of functions for a clientele that exists both in and outside of ORNL. These functions fall into the following general categories: (1) Analytical Research, Development, and Implementation. The division maintains a program to conceptualize, investigate, develop, assess, improve, and implement advanced technology for chemical and physicochemical measurements. Emphasis is on problems and needs identified with ORNL and Department of Energy (DOE) programs; however, attention is also given to advancing the analytical sciences themselves. (2) Programmatic Research, Development, and Utilization. The division carries out a wide variety of chemical work that typically involves analytical research and/or development plus the utilization of analytical capabilities to expedite programmatic interests. (3) Technical Support. The division performs chemical and physicochemical analyses of virtually all types. The Analytical Chemistry Division is organized into four major sections, each of which may carry out any of the three types of work mentioned above. Chapters 1 through 4 of this report highlight progress within the four sections during the period January 1 to December 31, 1988. A brief discussion of the division's role in an especially important environmental program is given in Chapter 5. Information about quality assurance, safety, and training programs is presented in Chapter 6, along with a tabulation of analyses rendered. Publications, oral presentations, professional activities, educational programs, and seminars are cited in Chapters 7 and 8.

  8. Preparation and Reactions of the 1,1-Dithiolato Complexes of Ni(II). An Undergraduate Coordination Chemistry Experiment.

    ERIC Educational Resources Information Center

    Ballester, L.; Perpinan, M. F.

    1988-01-01

    Described is an undergraduate coordination chemistry experiment that enables students to relate concepts developed in class about the stereochemistry and coordination numbers to the interpretation of the electronic and infrared spectra and their magnetic behavior. Indicates that thermal decomposition and x-ray diffraction studies can also be…

  9. Integrating bio-inorganic and analytical chemistry into an undergraduate biochemistry laboratory.

    PubMed

    Erasmus, Daniel J; Brewer, Sharon E; Cinel, Bruno

    2015-01-01

    Undergraduate laboratories expose students to a wide variety of topics and techniques in a limited amount of time. This can be a challenge and lead to less exposure to concepts and activities in bio-inorganic chemistry and analytical chemistry that are closely-related to biochemistry. To address this, we incorporated a new iron determination by atomic absorption spectroscopy exercise as part of a five-week long laboratory-based project on the purification of myoglobin from beef. Students were required to prepare samples for chemical analysis, operate an atomic absorption spectrophotometer, critically evaluate their iron data, and integrate these data into a study of myoglobin.

  10. Prebiotic coordination chemistry: The potential role of transition-metal complexes in the chemical evolution

    NASA Technical Reports Server (NTRS)

    Beck, M.

    1979-01-01

    In approaching the extremely involved and complex problem of the origin of life, consideration of the coordination chemistry appeared not only as a possibility but as a necessity. The first model experiments appear to be promising because of prebiotic-type synthesis by means of transition-metal complexes. It is especially significant that in some instances various types of vitally important substances (nucleic bases, amino acids) are formed simultaneously. There is ground to hope that systematic studies in this field will clarify the role of transition-metal complexes in the organizatorial phase of chemical evolution. It is obvious that researchers working in the fields of the chemistry of cyano and carbonyl complexes, and of the catalytic effect of transition-metal complexes are best suited to study these aspects of the attractive and interesting problem of the origin of life.

  11. Chemistry of porous coordination polymers having multimodal nanospace and their multimodal functionality.

    PubMed

    Seo, Joobeom; Sakamoto, Hirotoshi; Matsuda, Ryotaro; Kitagawa, Susumu

    2010-01-01

    Remarkable advances in the recent development of porous coordination polymers (PCPs) or metal organic frameworks (MOFs) have paved the way toward functional chemistry having potential application such as molecular storage, separation, and catalysis. Moreover flexible PCPs, which are structurally transformable depending upon guest molecules adsorption/desorption, have received much attention because they provide unique properties, dissimilar to those of zeolites. PCPs can be categorized into structurally monomodal and multimodal classes. Monomodal PCPs possess single uniform pores in the framework. In contrast, multimodal PCPs have more than two types of pores in the framework. Interpenetrated PCPs can possess more than two types of pores with different sizes and shapes in the same framework depending on relative position of individual motifs, resulting in multimodal PCPs. Moreover, interpenetrated PCPs have several advantages, such as high thermal stability, flexibility, and ultramicropore for effective adsorption. In this review, chemistry of PCPs based on monomodal and multimodal PCPs are summarized and discussed.

  12. High-Relaxivity MRI Contrast Agents: Where Coordination Chemistry Meets Medical Imaging

    SciTech Connect

    Werner, Eric J.; Datta, Ankona; Jocher, Christoph J.; Raymond, Kenneth N.

    2008-01-15

    The desire to improve and expand the scope of clinical magnetic resonance imaging (MRI) has prompted the search for contrast agents of higher efficiency. The development of better agents requires consideration of the fundamental coordination chemistry of the gadolinium(III) ion and the parameters that affect its efficacy as a proton relaxation agent. In optimizing each parameter, other practical issues such as solubility and in vivo toxicity must also be addressed, making the attainment of safe, high-relaxivity agents a challenging goal. Here we present recent advances in the field, with an emphasis on the hydroxypyridinone family of Gd{sup III} chelates.

  13. Analytical Chemistry Division. Annual progress report for period ending December 31, 1981

    SciTech Connect

    Lyon, W. S.

    1982-04-01

    The functions of the Analytical Chemistry Division fall into three general categories: (1) analytical research, development, and implementation; (2) programmatic research, development and utilization; (3) technical support. The Division is organized into five major sections each of which may carry out any type of work falling into the thre categories mentioned above. Chapters 1 through 5 of this report highlight progress within the five sections which are: analytical methodology; mass and emission spectrometry; analytical technical support; bio/organic analysis section; and nuclear and radiochemical analysis. A short summary introduces each chapter to indicate work scope. Information about quality assurance and safety programs is presented in Chapter 6, along with a tabulation of analyses rendered. Chapter 7 covers supplementary activities. Chapter 8 is on presentation of research results (publications, articles reviewed or referred for periodicals). Approximately 56 articles, 31 proceedings publications and 33 reports have been published, and 119 oral presentations given during this reporting period.

  14. 75 years of the Division of Analytical Chemistry of the American Chemical Society.

    PubMed

    Hirsch, Roland F

    2013-04-02

    The Division of Analytical Chemistry is celebrating the 75th anniversary of its founding in 1938. We celebrate the continuing high importance of our discipline for all aspects of chemical science and for its applications in so many aspects of everyday life. We especially celebrate the accomplishments of our fellow analytical chemists through the years, and the impact we have had on the profession. This article is a short history of the Division within the context of the parallel development of our profession and our science.

  15. On the outside looking in: redefining the role of analytical chemistry in the biosciences.

    PubMed

    Hare, Dominic J; New, Elizabeth J

    2016-07-12

    Biomedical research has moved on from the study of the structure of organs, cells and organelles. Today, the key questions that must be addressed to understand the body in health and disease are related to fundamental biochemistry: the distribution and speciation of chemicals, the regulation of chemical reactions, and the control of chemical environments. To see advances in this field, it is essential for analytical chemists to actively engage in this process, from beginning to end. In this Feature Article, we review the progress that has been made towards gaining an understanding of the chemistry of the body, while commenting on the intrinsic disconnect between new innovations in the field of analytical chemistry and practical application within the biosciences. We identify the challenges that prevent chemists from making a greater impact in this field, and highlight key steps for moving forward.

  16. Quality Assurance Baseline Assessment Report to Los Alamos National Laboratory Analytical Chemistry Operations

    SciTech Connect

    Jordan, R. A.

    1998-09-01

    This report summarizes observations that were made during a Quality Assurance (QA) Baseline Assessment of the Nuclear Materials Technology Analytical Chemistry Group (NMT-1). The Quality and Planning personnel, for NMT-1, are spending a significant amount of time transitioning out of their roles of environmental oversight into production oversight. A team from the Idaho National Engineering and Environmental Laboratory Defense Program Environmental Surety Program performed an assessment of the current status of the QA Program. Several Los Alamos National Laboratory Analytical Chemistry procedures were reviewed, as well as Transuranic Waste Characterization Program (TWCP) QA documents. Checklists were developed and the assessment was performed according to an Implementation Work Plan, INEEL/EXT-98-00740.

  17. Analytical Chemistry with Silica Sol-Gels: Traditional Routes to New Materials for Chemical Analysis

    NASA Astrophysics Data System (ADS)

    Walcarius, Alain; Collinson, Maryanne M.

    2009-07-01

    The versatility of sol-gel chemistry enables us to generate a wide range of silica and organosilica materials with controlled structure, composition, morphology and porosity. These materials’ hosting and recognition properties, as well as their wide-open structures containing many easily accessible active sites, make them particularly attractive for analytical purposes. In this review, we summarize the importance of silica sol-gels in analytical chemistry by providing examples from the separation sciences, optical and electrochemical sensors, molecular imprinting, and biosensors. Recent work suggests that manipulating the structure and composition of these materials at different scales (from molecular to macromolecular states and/or from micro- to meso- and/or macroporous levels) promises to generate chemical and biochemical sensing devices with improved selectivity and sensitivity.

  18. The coordination chemistry of organo-hydride donors: new prospects for efficient multi-electron reduction.

    PubMed

    McSkimming, Alex; Colbran, Stephen B

    2013-06-21

    In biological reduction processes the dihydronicotinamides NAD(P)H often transfer hydride to an unsaturated substrate bound within an enzyme active site. In many cases, metal ions in the active site bind, polarize and thereby activate the substrate to direct attack by hydride from NAD(P)H cofactor. This review looks more widely at the metal coordination chemistry of organic donors of hydride ion--organo-hydrides--such as dihydronicotinamides, other dihydropyridines including Hantzsch's ester and dihydroacridine derivatives, those derived from five-membered heterocycles including the benzimidazolines and benzoxazolines, and all-aliphatic hydride donors such as hexadiene and hexadienyl anion derivatives. The hydride donor properties--hydricities--of organo-hydrides and how these are affected by metal ions are discussed. The coordination chemistry of organo-hydrides is critically surveyed and the use of metal-organo-hydride systems in electrochemically-, photochemically- and chemically-driven reductions of unsaturated organic and inorganic (e.g. carbon dioxide) substrates is highlighted. The sustainable electrocatalytic, photochemical or chemical regeneration of organo-hydrides such as NAD(P)H, including for driving enzyme-catalysed reactions, is summarised and opportunities for development are indicated. Finally, new prospects are identified for metal-organo-hydride systems as catalysts for organic transformations involving 'hydride-borrowing' and for sustainable multi-electron reductions of unsaturated organic and inorganic substrates directly driven by electricity or light or by renewable reductants such as formate/formic acid.

  19. Recent developments and future trends in solid phase microextraction techniques towards green analytical chemistry.

    PubMed

    Spietelun, Agata; Marcinkowski, Łukasz; de la Guardia, Miguel; Namieśnik, Jacek

    2013-12-20

    Solid phase microextraction find increasing applications in the sample preparation step before chromatographic determination of analytes in samples with a complex composition. These techniques allow for integrating several operations, such as sample collection, extraction, analyte enrichment above the detection limit of a given measuring instrument and the isolation of analytes from sample matrix. In this work the information about novel methodological and instrumental solutions in relation to different variants of solid phase extraction techniques, solid-phase microextraction (SPME), stir bar sorptive extraction (SBSE) and magnetic solid phase extraction (MSPE) is presented, including practical applications of these techniques and a critical discussion about their advantages and disadvantages. The proposed solutions fulfill the requirements resulting from the concept of sustainable development, and specifically from the implementation of green chemistry principles in analytical laboratories. Therefore, particular attention was paid to the description of possible uses of novel, selective stationary phases in extraction techniques, inter alia, polymeric ionic liquids, carbon nanotubes, and silica- and carbon-based sorbents. The methodological solutions, together with properly matched sampling devices for collecting analytes from samples with varying matrix composition, enable us to reduce the number of errors during the sample preparation prior to chromatographic analysis as well as to limit the negative impact of this analytical step on the natural environment and the health of laboratory employees.

  20. Fitting It All In: Adapting a Green Chemistry Extraction Experiment for Inclusion in an Undergraduate Analytical Laboratory

    ERIC Educational Resources Information Center

    Buckley, Heather L.; Beck, Annelise R.; Mulvihill, Martin J.; Douskey, Michelle C.

    2013-01-01

    Several principles of green chemistry are introduced through this experiment designed for use in the undergraduate analytical chemistry laboratory. An established experiment of liquid CO2 extraction of D-limonene has been adapted to include a quantitative analysis by gas chromatography. This facilitates drop-in incorporation of an exciting…

  1. Integration of Environmental Analytical Chemistry with Environmental Law: The Development of a Problem-Based Laboratory

    NASA Astrophysics Data System (ADS)

    Cancilla, Devon A.

    2001-12-01

    Environmental chemists face difficult challenges related to generating, interpreting, and communicating complex chemical data in a manner understandable by nonchemists. For this reason, it is essential that environmental chemistry students develop the skills necessary not only to collect and interpret complex data sets, but also to communicate their findings in a credible manner in nonscientific forums. Key to this requirement is an understanding of the quality assurance/quality control (QA/QC) elements used to support specific findings. This paper describes the development of a problem-based undergraduate environmental analytical chemistry laboratory and its integration with an undergraduate environmental law course. The course is designed to introduce students to the principles of performance-based analytical methods and the use of environmental indicators to perform environmental assessments. Conducting a series of chemical and toxicological tests, chemistry students perform an environmental assessment on the watershed of the mythical City of Rowan. Law students use these assessments to develop legal arguments under both the Safe Drinking Water Act and the Clean Water Act.

  2. Redox chemistry and natural organic matter (NOM): Geochemists' dream, analytical chemists' nightmare

    USGS Publications Warehouse

    Macalady, Donald L.; Walton-Day, Katherine

    2011-01-01

    Natural organic matter (NOM) is an inherently complex mixture of polyfunctional organic molecules. Because of their universality and chemical reversibility, oxidation/reductions (redox) reactions of NOM have an especially interesting and important role in geochemistry. Variabilities in NOM composition and chemistry make studies of its redox chemistry particularly challenging, and details of NOM-mediated redox reactions are only partially understood. This is in large part due to the analytical difficulties associated with NOM characterization and the wide range of reagents and experimental systems used to study NOM redox reactions. This chapter provides a summary of the ongoing efforts to provide a coherent comprehension of aqueous redox chemistry involving NOM and of techniques for chemical characterization of NOM. It also describes some attempts to confirm the roles of different structural moieties in redox reactions. In addition, we discuss some of the operational parameters used to describe NOM redox capacities and redox states, and describe nomenclature of NOM redox chemistry. Several relatively facile experimental methods applicable to predictions of the NOM redox activity and redox states of NOM samples are discussed, with special attention to the proposed use of fluorescence spectroscopy to predict relevant redox characteristics of NOM samples.

  3. Coordination chemistry study of hydrated and solvated lead(II) ions in solution and solid state.

    PubMed

    Persson, Ingmar; Lyczko, Krzysztof; Lundberg, Daniel; Eriksson, Lars; Płaczek, Anna

    2011-02-07

    The coordination chemistry of lead(II) in the oxygen donor solvents water, dimethylsulfoxide (dmso, Me(2)SO), N,N-dimethylformamide (dmf), N,N-dimethylacetamide (dma), N,N'-dimethylpropyleneurea (dmpu), and 1,1,3,3-tetramethylurea (tmu), as well as in the sulfur donor solvent N,N-dimethylthioformamide (dmtf), has been investigated by extended X-ray absorption fine structure (EXAFS) and/or large angle X-ray scattering (LAXS) in solution, and by single crystal X-ray diffraction and/or EXAFS of solid hydrates and solvates. Lead(II) may either form hemidirected complexes with large bond distance distribution and an apparent gap for excess electron density, or holodirected ones with a symmetric coordination sphere with normal bond distance distribution, depending on the strength of antibonding lead 6s/ligand np molecular orbital interactions and ligand-ligand interactions. The crystallographic data show that the solid lead(II) perchlorate and trifluoromethanesulfonate hydrate structures are hemidirected, while the solid lead(II) solvates of dma and dmpu have regular octahedral configuration with holodirected geometry and mean Pb-O bond distances in the range 2.50-2.52 Å. EXAFS data on the hydrated lead(II) ion in aqueous solution show broad bond distance distribution and a lack of inner-core multiple scattering contributions strongly indicating a hemidirected structure. The Pb-O bond distances found both by EXAFS and LAXS, 2.54(1) Å, point to a six-coordinate hydrated lead(II) ion in hemidirected fashion with an unevenly distributed electron density. The results obtained for the dmso solvated lead(II) ion in solution are ambiguous, but for the most part support a six-coordinate hemidirected complex. The mean Pb-O bond distances determined in dmf and dma solution by LAXS, 2.55(1) and 2.48(1) Å, respectively, indicate that in both solvate complexes lead(II) binds six solvent molecules with the former complex being hemidirected whereas the latter is holodirected. The

  4. Analytical Chemistry Division annual progress report for period ending December 31, 1989

    SciTech Connect

    Not Available

    1990-04-01

    The Analytical Chemistry Division of Oak Ridge National Laboratory (ORNL) is a large and diversified organization. As such, it serves a multitude of functions for a clientele that exists both in and outside of ORNL. These functions fall into the following general categories: Analytical Research, Development and Implementation; Programmatic Research, Development, and Utilization; and Technical Support. The Analytical Chemistry Division is organized into four major sections, each which may carry out any of the three types of work mentioned above. Chapters 1 through 4 of this report highlight progress within the four sections during the period January 1 to December 31, 1989. A brief discussion of the division's role in an especially important environmental program is given in Chapter 5. Information about quality assurance, safety, and training programs is presented in Chapter 6, along with a tabulation of analyses rendered. Publications, oral presentations, professional activities, educational programs, and seminars are cited in Chapters 7 and 8. Approximately 69 articles, 41 proceedings, and 31 reports were published, and 151 oral presentations were given during this reporting period. Some 308,981 determinations were performed.

  5. Heavy metal coordination chemistry in mercaptides and enzymes studied by TDPAC

    NASA Astrophysics Data System (ADS)

    Butz, T.

    1993-03-01

    Time differential perturbed angular correlation (TDPAC) studies of the coordination chemistry of the heavy metal atoms Cd and Hg via the nuclear quadrupole interaction are presented for the following systems; (i) mercury complexes with mercaptides, polymers with thiol groups, and ferrocenethiols. Mercury has a strong tendency to form linear or almost linear bonds with sulfur ligands. Evidence for 1,3-dithia-2-mercura[3]ferrocenophane formation is presented. (ii)111mCd-derivatives of the small electron transport proteins azurin, including a his 117gly mutant, and stellacyanin. The titration of the his 117gly mutant of azurin with imidazole was monitored in situ. (iii)111mCd- and199mHg-derivatives of the multi-Cu enzymes ascorbate oxidase and laccase. Reconstitution probabilities for Hg-reconstitution will be given as well as information on selective depletion and blocking of Cu-sites.

  6. Coordination Chemistry in magnesium battery electrolytes: how ligands affect their performance

    SciTech Connect

    Shao, Yuyan; Liu, Tianbiao L.; Li, Guosheng; Gu, Meng; Nie, Zimin; Engelhard, Mark H.; Xiao, Jie; Lu, Dongping; Wang, Chong M.; Zhang, Jiguang; Liu, Jun

    2013-11-04

    Magnesium battery is potentially a safe, cost-effective, and high energy density technology for large scale energy storage. However, the development of magnesium battery has been hindered by the limited performance and the lack of fundamental understandings of electrolytes. Here, we present a coordination chemistry study of Mg(BH4)2 in ethereal solvents. The O donor denticity, i.e. ligand strength of the ethereal solvents which act as ligands to form solvated Mg complexes, plays a significant role in enhancing coulombic efficiency of the corresponding solvated Mg complex electrolytes. A new and safer electrolyte is developed based on Mg(BH4)2, diglyme and optimized LiBH4 additive. The new electrolyte demonstrates 100% coulombic efficiency, no dendrite formation, and stable cycling performance with the cathode capacity retention of ~90% for 300 cycles in a prototype magnesium battery.

  7. Coordination Chemistry in magnesium battery electrolytes: how ligands affect their performance

    DOE PAGES

    Shao, Yuyan; Liu, Tianbiao L.; Li, Guosheng; ...

    2013-11-04

    Magnesium battery is potentially a safe, cost-effective, and high energy density technology for large scale energy storage. However, the development of magnesium battery has been hindered by the limited performance and the lack of fundamental understandings of electrolytes. Here, we present a coordination chemistry study of Mg(BH4)2 in ethereal solvents. The O donor denticity, i.e. ligand strength of the ethereal solvents which act as ligands to form solvated Mg complexes, plays a significant role in enhancing coulombic efficiency of the corresponding solvated Mg complex electrolytes. A new and safer electrolyte is developed based on Mg(BH4)2, diglyme and optimized LiBH4 additive.more » The new electrolyte demonstrates 100% coulombic efficiency, no dendrite formation, and stable cycling performance with the cathode capacity retention of ~90% for 300 cycles in a prototype magnesium battery.« less

  8. Coordination Chemistry in magnesium battery electrolytes: how ligands affect their performance

    PubMed Central

    Shao, Yuyan; Liu, Tianbiao; Li, Guosheng; Gu, Meng; Nie, Zimin; Engelhard, Mark; Xiao, Jie; Lv, Dongping; Wang, Chongmin; Zhang, Ji-Guang; Liu, Jun

    2013-01-01

    Magnesium battery is potentially a safe, cost-effective, and high energy density technology for large scale energy storage. However, the development of magnesium battery has been hindered by the limited performance and the lack of fundamental understandings of electrolytes. Here, we present a study in understanding coordination chemistry of Mg(BH4)2 in ethereal solvents. The O donor denticity, i.e. ligand strength of the ethereal solvents which act as ligands to form solvated Mg complexes, plays a significant role in enhancing coulombic efficiency of the corresponding solvated Mg complex electrolytes. A new electrolyte is developed based on Mg(BH4)2, diglyme and LiBH4. The preliminary electrochemical test results show that the new electrolyte demonstrates a close to 100% coulombic efficiency, no dendrite formation, and stable cycling performance for Mg plating/stripping and Mg insertion/de-insertion in a model cathode material Mo6S8 Chevrel phase. PMID:24185310

  9. Ubiquitous trisulfur radical anion: fundamentals and applications in materials science, electrochemistry, analytical chemistry and geochemistry.

    PubMed

    Chivers, Tristram; Elder, Philip J W

    2013-07-21

    The trisulfur radical anion [S3]˙(-) is well-known from inorganic chemistry textbooks as the blue chromophore in ultramarine blues in which this highly reactive species is trapped in a zeolitic framework. Recent findings have revealed that [S3]˙(-) has a multi-faceted role in a variety of media, including alkali metal-sulfur batteries, aqueous solutions at high temperatures and pressures, and ionic liquids; it has also been used to detect trace amounts of water in organic solvents. This tutorial review illustrates how various physical techniques are used to identify a reactive species in solution and shows how elucidation of electronic structures can be used to explain spectroscopic and structural properties. Examples of the function of [S3]˙(-) in materials science, electrochemistry, analytical chemistry and geochemistry are used to illustrate the widespread influence of this fundamentally important triatomic sulfur species.

  10. Graphene-based materials: fabrication and application for adsorption in analytical chemistry.

    PubMed

    Wang, Xin; Liu, Bo; Lu, Qipeng; Qu, Qishu

    2014-10-03

    Graphene, a single layer of carbon atoms densely packed into a honeycomb crystal lattice with unique electronic, chemical, and mechanical properties, is the 2D allotrope of carbon. Owing to the remarkable properties, graphene and graphene-based materials are likely to find potential applications as a sorbent in analytical chemistry. The current review focuses predominantly on the recent development of graphene-based materials and demonstrates their enhanced performance in adsorption of organic compounds, metal ions, and solid phase extraction as well as in separation science since mostly 2012.

  11. Portable microwave assisted extraction: An original concept for green analytical chemistry.

    PubMed

    Perino, Sandrine; Petitcolas, Emmanuel; de la Guardia, Miguel; Chemat, Farid

    2013-11-08

    This paper describes a portable microwave assisted extraction apparatus (PMAE) for extraction of bioactive compounds especially essential oils and aromas directly in a crop or in a forest. The developed procedure, based on the concept of green analytical chemistry, is appropriate to obtain direct in-field information about the level of essential oils in natural samples and to illustrate green chemical lesson and research. The efficiency of this experiment was validated for the extraction of essential oil of rosemary directly in a crop and allows obtaining a quantitative information on the content of essential oil, which was similar to that obtained by conventional methods in the laboratory.

  12. Development of a geovisual analytics environment using parallel coordinates with applications to tropical cyclone trend analysis

    NASA Astrophysics Data System (ADS)

    Steed, Chad Allen

    A global transformation is being fueled by unprecedented growth in the quality, quantity, and number of different parameters in environmental data through the convergence of several technological advances in data collection and modeling. Although these data hold great potential for helping us understand many complex and, in some cases, life-threatening environmental processes, our ability to generate such data is far outpacing our ability to analyze it. In particular, conventional environmental data analysis tools are inadequate for coping with the size and complexity of these data. As a result, users are forced to reduce the problem in order to adapt to the capabilities of the tools. To overcome these limitations, we must complement the power of computational methods with human knowledge, flexible thinking, imagination, and our capacity for insight by developing visual analysis tools that distill information into the actionable criteria needed for enhanced decision support. In light of said challenges, we have integrated automated statistical analysis capabilities with a highly interactive, multivariate visualization interface to produce a promising approach for visual environmental data analysis. By combining advanced interaction techniques such as dynamic axis scaling, conjunctive parallel coordinates, statistical indicators, and aerial perspective shading, we provide an enhanced variant of the classical parallel coordinates plot. Furthermore, the system facilitates statistical processes such as stepwise linear regression and correlation analysis to assist in the identification and quantification of the most significant predictors for a particular dependent variable. These capabilities are combined into a unique geovisual analytics system that is demonstrated via a pedagogical case study and three North Atlantic tropical cyclone climate studies using a systematic workflow. In addition to revealing several significant associations between environmental

  13. Eleventh international symposium on radiopharmaceutical chemistry

    SciTech Connect

    1995-12-31

    This document contains abstracts of papers which were presented at the Eleventh International Symposium on Radiopharmaceutical Chemistry. Sessions included: radiopharmaceuticals for the dopaminergic system, strategies for the production and use of labelled reactive small molecules, radiopharmaceuticals for measuring metabolism, radiopharmaceuticals for the serotonin and sigma receptor systems, labelled probes for molecular biology applications, radiopharmaceuticals for receptor systems, radiopharmaceuticals utilizing coordination chemistry, radiolabelled antibodies, radiolabelling methods for small molecules, analytical techniques in radiopharmaceutical chemistry, and analytical techniques in radiopharmaceutical chemistry.

  14. Functional Interfaces Constructed by Controlled/Living Radical Polymerization for Analytical Chemistry.

    PubMed

    Wang, Huai-Song; Song, Min; Hang, Tai-Jun

    2016-02-10

    The high-value applications of functional polymers in analytical science generally require well-defined interfaces, including precisely synthesized molecular architectures and compositions. Controlled/living radical polymerization (CRP) has been developed as a versatile and powerful tool for the preparation of polymers with narrow molecular weight distributions and predetermined molecular weights. Among the CRP system, atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer (RAFT) are well-used to develop new materials for analytical science, such as surface-modified core-shell particles, monoliths, MIP micro- or nanospheres, fluorescent nanoparticles, and multifunctional materials. In this review, we summarize the emerging functional interfaces constructed by RAFT and ATRP for applications in analytical science. Various polymers with precisely controlled architectures including homopolymers, block copolymers, molecular imprinted copolymers, and grafted copolymers were synthesized by CRP methods for molecular separation, retention, or sensing. We expect that the CRP methods will become the most popular technique for preparing functional polymers that can be broadly applied in analytical chemistry.

  15. Recent developments in computer vision-based analytical chemistry: A tutorial review.

    PubMed

    Capitán-Vallvey, Luis Fermín; López-Ruiz, Nuria; Martínez-Olmos, Antonio; Erenas, Miguel M; Palma, Alberto J

    2015-10-29

    Chemical analysis based on colour changes recorded with imaging devices is gaining increasing interest. This is due to its several significant advantages, such as simplicity of use, and the fact that it is easily combinable with portable and widely distributed imaging devices, resulting in friendly analytical procedures in many areas that demand out-of-lab applications for in situ and real-time monitoring. This tutorial review covers computer vision-based analytical (CVAC) procedures and systems from 2005 to 2015, a period of time when 87.5% of the papers on this topic were published. The background regarding colour spaces and recent analytical system architectures of interest in analytical chemistry is presented in the form of a tutorial. Moreover, issues regarding images, such as the influence of illuminants, and the most relevant techniques for processing and analysing digital images are addressed. Some of the most relevant applications are then detailed, highlighting their main characteristics. Finally, our opinion about future perspectives is discussed.

  16. Electronic Transitions as a Probe of Tetrahedral versus Octahedral Coordination in Nickel(II) Complexes: An Undergraduate Inorganic Chemistry Experiment.

    ERIC Educational Resources Information Center

    Filgueiras, Carlos A. L.; Carazza, Fernando

    1980-01-01

    Discusses procedures, theoretical considerations, and results of an experiment involving the preparation of a tetrahedral nickel(II) complex and its transformation into an octahedral species. Suggests that fundamental aspects of coordination chemistry can be demonstrated by simple experiments performed in introductory level courses. (Author/JN)

  17. Use of a Card Sort Task to Assess Students' Ability to Coordinate Three Levels of Representation in Chemistry

    ERIC Educational Resources Information Center

    Irby, Stefan M.; Phu, Andy L.; Borda, Emily J.; Haskell, Todd R.; Steed, Nicole; Meyer, Zachary

    2016-01-01

    There is much agreement among chemical education researchers that expertise in chemistry depends in part on the ability to coordinate understanding of phenomena on three levels: macroscopic (observable), sub-microscopic (atoms, molecules, and ions) and symbolic (chemical equations, graphs, etc.). We hypothesize this "level-coordination…

  18. Electrical field-induced extraction and separation techniques: promising trends in analytical chemistry--a review.

    PubMed

    Yamini, Yadollah; Seidi, Shahram; Rezazadeh, Maryam

    2014-03-03

    Sample preparation is an important issue in analytical chemistry, and is often a bottleneck in chemical analysis. So, the major incentive for the recent research has been to attain faster, simpler, less expensive, and more environmentally friendly sample preparation methods. The use of auxiliary energies, such as heat, ultrasound, and microwave, is one of the strategies that have been employed in sample preparation to reach the above purposes. Application of electrical driving force is the current state-of-the-art, which presents new possibilities for simplifying and shortening the sample preparation process as well as enhancing its selectivity. The electrical driving force has scarcely been utilized in comparison with other auxiliary energies. In this review, the different roles of electrical driving force (as a powerful auxiliary energy) in various extraction techniques, including liquid-, solid-, and membrane-based methods, have been taken into consideration. Also, the references have been made available, relevant to the developments in separation techniques and Lab-on-a-Chip (LOC) systems. All aspects of electrical driving force in extraction and separation methods are too specific to be treated in this contribution. However, the main aim of this review is to provide a brief knowledge about the different fields of analytical chemistry, with an emphasis on the latest efforts put into the electrically assisted membrane-based sample preparation systems. The advantages and disadvantages of these approaches as well as the new achievements in these areas have been discussed, which might be helpful for further progress in the future.

  19. Analytical Chemistry at the Laboratoire d'Electrochimie Physique et Analytique.

    PubMed

    Bondarenko, Alexandra; Cortés-Salazar, Fernando; Gasilova, Natalia; Lesch, Andreas; Qiao, Liang; Girault, Hubert H

    2015-01-01

    The Laboratoire d'Electrochimie Physique et Analytique (LEPA) has moved to the new Energypolis campus in Sion. This laboratory is involved in energy research in particular by studying charge transfer reactions at soft interfaces and developing interfacial redox electrocatalysis, by pioneering the concept of photo-ionic cells and by integrating redox flow batteries for the production of hydrogen at the pilot scale. Nonetheless, this laboratory has a long tradition in analytical chemistry with the development of microfabrication techniques such as laser photo-ablation, screen-printing and more recently inkjet printing for the design and fabrication of biosensors and immunosensors. As shown in the present review, the laboratory has recently pioneered new technologies for electrochemical and mass spectrometry imaging and for the screening of allergy in patients. The role of the laboratory in the Valais landscape will be to foster the collaboration with the HES to develop teaching and research in analytical chemistry as this field is a major source of employment for chemists.

  20. Analytical Chemistry Division annual progress report for period ending December 31, 1982

    SciTech Connect

    Lyon, W.S.

    1983-05-01

    The Analytical Chemistry Dvision of Oak Ridge National laboratory (ORNL) serves a multitude of functions for a clientele that exists both in and outside ORNL. These functions fall into the following general categories: (1) analytical research, development, and implementation; (2) programmatic research, development, and utilization; and (3) technical support. The Division is organized into five major sections, each of which may carry out any type of work falling in the three categories mentioned above. Chapters 1 through 5 of this report highlight progress within the five sections (analytical methodology, mass and emission spectrometry, radioactive materials, bio/organic analysis, and general and environmental analysis) during the period January 1, 1982 to December 31, 1982. A short summary introduces each chapter to indicate work scope. Information about quality assurance and safety programs is presented in Chapter 6, along with a tabulation of analyses rendered. Publications, oral presentations, professional activities, educational programs, and seminars are cited in Chapters 7 and 8. Approximately 61 articles, 32 proceedings publications and 37 reports have been published, and 107 oral presentations were given during this reporting period.

  1. Sample Acquisition and Analytical Chemistry Challenges to Verifying Compliance to Aviators Breathing Oxygen (ABO) Purity Specification

    NASA Technical Reports Server (NTRS)

    Graf, John

    2015-01-01

    NASA has been developing and testing two different types of oxygen separation systems. One type of oxygen separation system uses pressure swing technology, the other type uses a solid electrolyte electrochemical oxygen separation cell. Both development systems have been subjected to long term testing, and performance testing under a variety of environmental and operational conditions. Testing these two systems revealed that measuring the product purity of oxygen, and determining if an oxygen separation device meets Aviator's Breathing Oxygen (ABO) specifications is a subtle and sometimes difficult analytical chemistry job. Verifying product purity of cryogenically produced oxygen presents a different set of analytical chemistry challenges. This presentation will describe some of the sample acquisition and analytical chemistry challenges presented by verifying oxygen produced by an oxygen separator - and verifying oxygen produced by cryogenic separation processes. The primary contaminant that causes gas samples to fail to meet ABO requirements is water. The maximum amount of water vapor allowed is 7 ppmv. The principal challenge of verifying oxygen produced by an oxygen separator is that it is produced relatively slowly, and at comparatively low temperatures. A short term failure that occurs for just a few minutes in the course of a 1 week run could cause an entire tank to be rejected. Continuous monitoring of oxygen purity and water vapor could identify problems as soon as they occur. Long term oxygen separator tests were instrumented with an oxygen analyzer and with an hygrometer: a GE Moisture Monitor Series 35. This hygrometer uses an aluminum oxide sensor. The user's manual does not report this, but long term exposure to pure oxygen causes the aluminum oxide sensor head to bias dry. Oxygen product that exceeded the 7 ppm specification was improperly accepted, because the sensor had biased. The bias is permanent - exposure to air does not cause the sensor to

  2. Coordination chemistry of mercury(ii) with 2-pyridylnitrones: monomers to polymers.

    PubMed

    Azizpoor Fard, Mahmood; Behnia, Ava; Puddephatt, Richard J

    2017-03-14

    The coordination chemistry of mercury(ii) halides, HgX2, X = Cl, Br, I, with N-methyl-α-(2-pyridyl)nitrone, L1, and N-t-butyl-α-(2-pyridyl)nitrone, L2, is reported. The structures of 1 : 1 complexes [HgX2L], X = Cl, L = L1; X = Br, L = L2, 2 : 1 complexes [(HgX2)2L], X = Br or I, L = L1; X = Cl or I, L = L2, and a unique compound [(HgBr2)5(L2)3] have been determined. In the 1 : 1 and 1 : 2 complexes, the ligand L1 adopts the anti conformation, and is either monodentate or bridging, while the ligand L2 adopts the syn conformation and acts as a chelate ligand. In the compound [(HgBr2)5(L2)3] the ligand L2 is present in both syn-chelate and anti-bridging bonding modes. Secondary intermolecular bonding, involving OHg or XHg interactions, can lead to association of the molecular compounds to form polymers of several kinds. In solution, the complexes are labile and the crystalline products do not necessarily reflect the reaction stoichiometry.

  3. The Academic Tree of Howard V. Malmstadt: From Early Scientific Exploration to Modern Analytical Chemistry.

    PubMed

    Storey, Andrew P; Hieftje, Gary M

    2016-12-01

    Over the last several decades, science has benefited tremendously by the implementation of digital electronic components for analytical instrumentation. A pioneer in this area of scientific inquiry was Howard Malmstadt. Frequently, such revolutions in scientific history can be viewed as a series of discoveries without a great deal of attention as to how mentorship shapes the careers and methodologies of those who made great strides forward for science. This paper focuses on the verifiable relationships of those who are connected through the academic tree of Malmstadt and how their experiences and the context of world events influenced their scientific pursuits. Particular attention is dedicated to the development of American chemistry departments and the critical role played by many of the individuals in the tree in this process.

  4. Pollution Prevention Plan for the Y-12 Analytical Chemistry Organization Off-Site Union Valley Facility

    SciTech Connect

    Jackson, J. G.

    2010-03-01

    The Y-12 Analytical Chemistry Organization (ACO) Off-Site Union Valley Facility (Union Valley Facility) is managed by Babcock and Wilcox Technical Services Y-12, L.L.C. (B and W Y-12) through the Y-12 National Security Complex organization. Accordingly, the Y-12 Pollution Prevention Program encompasses the operations conducted at the Union Valley Facility. The Y-12 Program is designed to fully comply with state, federal and U.S. Department of Energy (DOE) requirements concerning waste minimization/pollution prevention as documented in the Y-12 Pollution Prevention Program Plan. The Program is formulated to reduce the generation and toxicity of all Y-12 wastes in all media, including those wastes generated by the Union Valley Facility operations. All regulatory and DOE requirements are met by the Y-12 Program Plan.

  5. Education: a microfluidic platform for university-level analytical chemistry laboratories.

    PubMed

    Greener, Jesse; Tumarkin, Ethan; Debono, Michael; Dicks, Andrew P; Kumacheva, Eugenia

    2012-02-21

    We demonstrate continuous flow acid-base titration reactions as an educational microfluidic platform for undergraduate and graduate analytical chemistry courses. A series of equations were developed for controlling and predicting the results of acid-base neutralisation reactions conducted in a microfluidic format, including the combinations of (i) a strong base and a strong acid, (ii) a strong base and a weak acid, and (iii) a strong base and a multiprotic acid. Microfluidic titrations yielded excellent repeatability. The small experimental footprint is advantageous in crowded teaching laboratories, and it offers limited waste and exposure to potentially hazardous acids and bases. This platform will help promote the utilisation of microfluidics at an earlier stage of students' careers.

  6. Teaching Effective Communication in a Writing-Intensive Analytical Chemistry Course

    NASA Astrophysics Data System (ADS)

    Whelan, Rebecca J.; Zare, Richard N.

    2003-08-01

    Effective writing and speaking skills are vital for chemical professionals, yet traditional academic preparation does little to develop these skills. In this report, we describe classroom-tested strategies for teaching writing and speaking. In the context of a required lecture and laboratory course in analytical chemistry, students gain extensive experience with reading, writing, revising, and speaking in the way that professional chemists do. Students improve their writing skills by preparing four laboratory reports that follow the conventions of the chemical literature. One of the reports is prepared collaboratively to reflect the real experience of professional chemists. Individualized conferences and critiques by more experienced peers lead to extensive revision of a graded report. Several activities encourage the students to develop an appreciation of the organization and strategy of a scientific article. Finally, the students practice oral communication by preparing and delivering a short presentation, including visual aids, based on a paper from the literature.

  7. Analytical Models of Exoplanetary Atmospheres. III. Gaseous C-H-O-N Chemistry with Nine Molecules

    NASA Astrophysics Data System (ADS)

    Heng, Kevin; Tsai, Shang-Min

    2016-10-01

    We present novel, analytical, equilibrium-chemistry formulae for the abundances of molecules in hot exoplanetary atmospheres that include the carbon, oxygen, and nitrogen networks. Our hydrogen-dominated solutions involve acetylene (C2H2), ammonia (NH3), carbon dioxide (CO2), carbon monoxide (CO), ethylene (C2H4), hydrogen cyanide (HCN), methane (CH4), molecular nitrogen (N2), and water (H2O). By considering only the gas phase, we prove that the mixing ratio of carbon monoxide is governed by a decic equation (polynomial equation of 10 degrees). We validate our solutions against numerical calculations of equilibrium chemistry that perform Gibbs free energy minimization and demonstrate that they are accurate at the ˜ 1 % level for temperatures from 500 to 3000 K. In hydrogen-dominated atmospheres, the ratio of abundances of HCN to CH4 is nearly constant across a wide range of carbon-to-oxygen ratios, which makes it a robust diagnostic of the metallicity in the gas phase. Our validated formulae allow for the convenient benchmarking of chemical kinetics codes and provide an efficient way of enforcing chemical equilibrium in atmospheric retrieval calculations.

  8. Analytical estimation on divergence and flutter vibrations of symmetrical three-phase induction stator via field-synchronous coordinates

    NASA Astrophysics Data System (ADS)

    Xia, Ying; Wang, Shiyu; Sun, Wenjia; Xiu, Jie

    2017-01-01

    The electromagnetically induced parametric vibration of the symmetrical three-phase induction stator is examined. While it can be analyzed by an approximate analytical or numerical method, more accurate and simple analytical method is desirable. This work proposes a new method based on the field-synchronous coordinates. A mechanical-electromagnetic coupling model is developed under this frame such that a time-invariant governing equation with gyroscopic term can be developed. With the general vibration theory, the eigenvalue is formulated; the transition curves between the stable and unstable regions, and response are all determined as closed-form expressions of basic mechanical-electromagnetic parameters. The dependence of these parameters on the instability behaviors is demonstrated. The results imply that the divergence and flutter instabilities can occur even for symmetrical motors with balanced, constant amplitude and sinusoidal voltage. To verify the analytical predictions, this work also builds up a time-variant model of the same system under the conventional inertial frame. The Floquét theory is employed to predict the parametric instability and the numerical integration is used to obtain the parametric response. The parametric instability and response are both well compared against those under the field-synchronous coordinates. The proposed field-synchronous coordinates allows a quick estimation on the electromagnetically induced vibration. The convenience offered by the body-fixed coordinates is discussed across various fields.

  9. Synthesis and structure of bivalent ytterbocenes and their coordination chemistry with pi-acceptor ligands

    SciTech Connect

    Schultz, Madeleine

    2000-05-01

    The bivalent lanthanide metallocenes [1,3-(Me3C)2C5H3]2Yb and (Me4C5H)2Yb have been synthesized and their structures have been determined by X-ray crystallography. Comparison with the known structures of (Me5C5)2Yb and [1,3 -(Me3Si)2C5H3]2Yb leads to an understanding of the role of intermolecular contacts in stabilizing these coordinatively unsaturated molecules. The optical spectra of the base-free ytterbocenes and their Lewis-base adducts have been measured; the position of the HOMO - LUMO transition can be correlated with the degree of bending of the complexes in solution according to a molecular orbital model. Electron - electron repulsion, resulting from additional σ-donor ligands, also affects the HOMO - LUMO transition by increasing the energy of the filled f-orbitals. The base-free metallocene (Me5C5)2Yb coordinates carbon monoxide, resulting in a decrease in Vco relative to that of fi-ee carbon monoxide. This behavior is reminiscent of d-transition metallocene chemistry. Other base-free ytterbocenes also coordinate carbon monoxide and the degree of back-donation is related to the substituents on the cyclopentadienide rings. Isocyanides are coordinated in a 1:2 ratio by the ytterbocenes, giving complexes having vcN higher than those of the free isocyanides. An electrostatic bonding model has been used to explain the changes in CN stretching frequencies. The optical spectra of the carbonyl and isocyanide complexes are consistent with the molecular orbital model of the variation in the HOMO - LUMO gap upon bending, and the increase in electron - electron repulsion due to the additional ligands. The complex (Me5C5)2Yb(bipy) exhibits optical, infrared and NMIZ spectroscopy and an X-ray crystal

  10. Applications of the New Family of Coherent Multidimensional Spectroscopies for Analytical Chemistry.

    PubMed

    Wright, John C

    2017-03-27

    A new family of vibrational and electronic spectroscopies has emerged, comprising the coherent analogs of traditional analytical methods. These methods are also analogs of coherent multidimensional nuclear magnetic resonance (NMR) spectroscopy. This new family is based on creating the same quantum mechanical superposition states called multiple quantum coherences (MQCs). NMR MQCs are mixtures of nuclear spin states that retain their quantum mechanical phase information for milliseconds. The MQCs in this new family are mixtures of vibrational and electronic states that retain their phases for picoseconds or shorter times. Ultrafast, high-intensity coherent beams rapidly excite multiple states. The excited MQCs then emit bright beams while they retain their phases. Time-domain methods measure the frequencies of the MQCs by resolving their phase oscillations, whereas frequency-domain methods measure the resonance enhancements of the output beam while scanning the excitation frequencies. The resulting spectra provide multidimensional spectral signatures that increase the spectroscopic selectivity required for analyzing complex samples. Expected final online publication date for the Annual Review of Analytical Chemistry Volume 10 is June 12, 2017. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

  11. Effect of repeated freezing and thawing on 18 clinical chemistry analytes in rat serum.

    PubMed

    Kale, Vijay P; Patel, Sweta G; Gunjal, Prashant S; Wakchaure, Santosh U; Sundar, Rajesh S; Ranvir, Ramchandra K; Jain, Mukul R

    2012-07-01

    In a preclinical research laboratory, using serum samples that have been frozen and thawed repeatedly is sometimes unavoidable when needing to confirm previous results or perform additional analysis. Here we determined the effects of multiple cycles of refrigeration or freezing and thawing of rat serum at 3 temperature conditions for different storage times on clinical chemistry analytes. Serum samples obtained from adult Wistar rats were stored at 2 to 8 °C and -10 to -20 °C for as long as 72 h and at -70 °C for as long as 30 d. At different time points (24, 48, and 72 h for samples stored at 2 to 8 °C or -10 to -20 °C and 1, 7, and 30 d for samples stored at -70 °C), the samples were brought to room temperature, analyzed, and then stored again at the designated temperature. The results obtained after each storage cycle were compared with those obtained from the initial analysis of fresh samples. Of the 18 serum analytes evaluated, 14 were stable without significant changes, even after 3 freeze-thaw cycles at the tested temperature ranges. Results from this study will help researchers working with rat serum to interpret the biochemical data obtained from serum samples that have been frozen and thawed repeatedly.

  12. Infrared Ion Spectroscopy at Felix: Applications in Peptide Dissociation and Analytical Chemistry

    NASA Astrophysics Data System (ADS)

    Oomens, Jos

    2016-06-01

    Infrared free electron lasers such as those in Paris, Berlin and Nijmegen have been at the forefront of the development of infrared ion spectroscopy. In this contribution, I will give an overview of new developments in IR spectroscopy of stored ions at the FELIX Laboratory. In particular, I will focus on recent developments made possible by the coupling of a new commercial ion trap mass spectrometer to the FELIX beamline. The possibility to record IR spectra of mass-selected molecular ions and their reaction products has in recent years shed new light on our understanding of collision induced dissociation (CID) reactions of protonated peptides in mass spectrometry (MS). We now show that it is possible to record IR spectra for the products of electron transfer dissociation (ETD) reactions [M + nH]n+ + A- → [M + nH](n-1)+ + A → {dissociation of analyte} These reactions are now widely used in novel MS-based protein sequencing strategies, but involve complex radical chemistry. The spectroscopic results allow stringent verification of computationally predicted product structures and hence reaction mechanisms and H-atom migration. The sensitivity and high dynamic range of a commercial mass spectrometer also allows us to apply infrared ion spectroscopy to analytes in complex "real-life" mixtures. The ability to record IR spectra with the sensitivity of mass-spectrometric detection is unrivalled in analytical sciences and is particularly useful in the identification of small (biological) molecules, such as in metabolomics. We report preliminary results of a pilot study on the spectroscopic identification of small metabolites in urine and plasma samples.

  13. Using a Practical Instructional Development Process to Show That Integrating Lab and Active Learning Benefits Undergraduate Analytical Chemistry

    ERIC Educational Resources Information Center

    Goacher, Robyn E.; Kline, Cynthia M.; Targus, Alexis; Vermette, Paul J.

    2017-01-01

    We describe how a practical instructional development process helped a first-year assistant professor rapidly develop, implement, and assess the impact on her Analytical Chemistry course caused by three changes: (a) moving the lab into the same semester as the lecture, (b) developing a more collaborative classroom environment, and (c) increasing…

  14. An Advanced Analytical Chemistry Experiment Using Gas Chromatography-Mass Spectrometry, MATLAB, and Chemometrics to Predict Biodiesel Blend Percent Composition

    ERIC Educational Resources Information Center

    Pierce, Karisa M.; Schale, Stephen P.; Le, Trang M.; Larson, Joel C.

    2011-01-01

    We present a laboratory experiment for an advanced analytical chemistry course where we first focus on the chemometric technique partial least-squares (PLS) analysis applied to one-dimensional (1D) total-ion-current gas chromatography-mass spectrometry (GC-TIC) separations of biodiesel blends. Then, we focus on n-way PLS (n-PLS) applied to…

  15. Tetraglyme Trap for the Determination of Volatile Organic Compounds in Urban Air: Projects for Undergraduate Analytical Chemistry

    ERIC Educational Resources Information Center

    Hope, Wilbert W.; Johnson, Clyde; Johnson, Leon P.

    2004-01-01

    The differences in the levels of volatile organic compounds (VOCs), in the ambient air from the two urban locations, were studied by the undergraduate analytical chemistry students. Tetraglyme is very widely used due to its simplicity and its potential for use to investigate VOCs in ambient and indoor air employing a purge-and-trap concentrator…

  16. The Quantitative Resolution of a Mixture of Group II Metal Ions by Thermometric Titration with EDTA. An Analytical Chemistry Experiment.

    ERIC Educational Resources Information Center

    Smith, Robert L.; Popham, Ronald E.

    1983-01-01

    Presents an experiment in thermometric titration used in an analytic chemistry-chemical instrumentation course, consisting of two titrations, one a mixture of calcium and magnesium, the other of calcium, magnesium, and barium ions. Provides equipment and solutions list/specifications, graphs, and discussion of results. (JM)

  17. Semi-analytical integration of the Earth's precession-nutation based on the GCRS coordinates of the CIP unit vector

    NASA Astrophysics Data System (ADS)

    Capitaine, N.; Folgueira, M.

    2012-12-01

    In a previous paper (Capitaine et al. 2006), referred here as Paper I, we demonstrated the possibility of integrating the Earth's rotational motion in terms of the coordinates (X, Y ) of the celestial intermediate pole (CIP) unit vector in the Geocentric celestial reference system (GCRS). Here, we report on the approach that has been followed for solving the equations in the case of an axially symmetric rigid Earth and the semi-analytical (X, Y ) solution obtained from the expression of the external torque acting on the Earth derived from the most complete semi-analytical solutions for the Earth, Moon and planets.

  18. Divergent Coordination Chemistry: Parallel Synthesis of [2×2] Iron(II) Grid‐Complex Tauto‐Conformers

    PubMed Central

    Schäfer, Bernhard; Greisch, Jean‐François; Faus, Isabelle; Bodenstein, Tilmann; Šalitroš, Ivan; Fuhr, Olaf; Fink, Karin; Schünemann, Volker; Kappes, Manfred M.

    2016-01-01

    Abstract The coordination of iron(II) ions by a homoditopic ligand L with two tridentate chelates leads to the tautomerism‐driven emergence of complexity, with isomeric tetramers and trimers as the coordination products. The structures of the two dominant [FeII 4 L 4]8+ complexes were determined by X‐ray diffraction, and the distinctness of the products was confirmed by ion‐mobility mass spectrometry. Moreover, these two isomers display contrasting magnetic properties (FeII spin crossover vs. a blocked FeII high‐spin state). These results demonstrate how the coordination of a metal ion to a ligand that can undergo tautomerization can increase, at a higher hierarchical level, complexity, here expressed by the formation of isomeric molecular assemblies with distinct physical properties. Such results are of importance for improving our understanding of the emergence of complexity in chemistry and biology. PMID:27411212

  19. Divergent Coordination Chemistry: Parallel Synthesis of [2×2] Iron(II) Grid-Complex Tauto-Conformers.

    PubMed

    Schäfer, Bernhard; Greisch, Jean-François; Faus, Isabelle; Bodenstein, Tilmann; Šalitroš, Ivan; Fuhr, Olaf; Fink, Karin; Schünemann, Volker; Kappes, Manfred M; Ruben, Mario

    2016-08-26

    The coordination of iron(II) ions by a homoditopic ligand L with two tridentate chelates leads to the tautomerism-driven emergence of complexity, with isomeric tetramers and trimers as the coordination products. The structures of the two dominant [Fe(II) 4 L4 ](8+) complexes were determined by X-ray diffraction, and the distinctness of the products was confirmed by ion-mobility mass spectrometry. Moreover, these two isomers display contrasting magnetic properties (Fe(II) spin crossover vs. a blocked Fe(II) high-spin state). These results demonstrate how the coordination of a metal ion to a ligand that can undergo tautomerization can increase, at a higher hierarchical level, complexity, here expressed by the formation of isomeric molecular assemblies with distinct physical properties. Such results are of importance for improving our understanding of the emergence of complexity in chemistry and biology.

  20. APPLICATION OF INFRARED SPECTROSCOPY TO THE ANALYSIS OF INORGANIC NITRATES. PHASE 1. SPECTRA OF INORGANIC NITRATES IN ACETONE AND THE USE OF SUCH SPECTRA IN ANALYTICAL CHEMISTRY

    DTIC Science & Technology

    A study was made of the spectra of soluble inorganic nitrates in acetone solution and the use of such spectra in analytical chemistry . The spectra of...solubilities of anhydrous inorganic nitrates in acetone. The applications of the spectra of inorganic nitrates in acetone to analytical chemistry is

  1. Analytical Chemistry Division annual progress report for period ending December 31, 1991

    SciTech Connect

    1992-01-01

    The following sentences highlight some of the technical activities carried out during 1991. They illustrate the diversity of programs and technical work performed within the Analytical Chemistry Division. Our neutron activation analysis laboratory at HFIR was placed into operation during 1991. We have combined inductively coupled plasma mass spectrometry (ICP/MS) with a preparation procedure developed at the Argonne National Laboratory to measure ultra-trace levels of U, Pu, Np, and Am in body fluids, primarily urine. Much progress has been made over the last year in the interfacing of an rf-powered glow discharge source to a double-focusing mass spectrometer. Preliminary experiments using electrospray ionization combined with ion trap mass spectrometry show much promise for the analysis of metals in solution. A secondary ion microprobe has been constructed that permits determination of the distribution of organic compounds less than a monolayer thick on samples as large as 1 cm diameter. Fourier transform mass spectrometry has been demonstrated to be a highly effective tool for the detailed characterization of biopolymers, especially normal and modified oligonucleotides. Much has been accomplished in understanding the fundamentals of quadrupole ion trap mass spectrometry. Work with ITMS instrumentation has led to the development of rapid methods for the detection of trace organics in environmental and physiological samples. A new type of time-of-flight mass spectrometer was designed for use with our positron ionization experiments. Fundamental research on chromatography at high concentrations and on gas-solid adsorption has continued. The preparation of a monograph on the chemistry of environmental tobacco smoke was completed this year.

  2. Rigid rotation symmetry of a marginally stable minimum B field and analytical expressions of the flux coordinates

    SciTech Connect

    Aagren, O.; Savenko, N.

    2005-04-15

    One of the main issues of the open ended plasma confining devices is to provide a magnetohydrodynamic stable plasma equilibrium. A nonaxisymmetric, marginally stable confining magnetic field for a conventional, single mirror device has been studied for a long thin flux tube. The marginally stable minimum B magnetic field is proven to have quadrupolar symmetry under the assumptions of a straight paraxial central flux line and zero plasma {beta}. The quadrupolar symmetry geometrically means that the flux lines are not twisted. The perpendicular drift of the gyro centers is zero. A possible external current distribution which can generate the magnetic field is determined. The most convenient set of flux coordinates for this magnetic field are (x{sub 0},y{sub 0},s), where x{sub 0} and y{sub 0} are Cartesian-like Clebsch coordinates and s is the arclength of the magnetic field line. Analytical expressions for the magnetic flux coordinates are derived for this magnetic field.

  3. Coordination chemistry of 2,2'-biphenylenedithiophosphinate and diphenyldithiophosphinate with U, Np, and Pu

    DOE PAGES

    Macor, Joseph A.; Brown, Jessie L.; Cross, Justin Neil; ...

    2015-01-01

    New members of the dithiophosphinic acid family of potential actinide extractants were prepared: heterocyclic 2,2'-biphenylenedithiophosphinic acids of stoichiometry HS2P(R2C12H6) (R = H or tBu). The time- and atom-efficient syntheses afforded multigram quantities of pure HS2P(R2C12H6) in reasonable yields (~60%). These compounds differed from other diaryldithiophosphinic acid extractants in that the two aryl groups were connected to one another at the ortho positions to form a 5-membered dibenzophosphole ring. These 2,2'-biphenylenedithiophosphinic acids were readily deprotonated to form S2P(R2C12H6)1- anions, which were crystallized as salts with tetraphenylpnictonium cations (ZPh41+; Z = P or As). Coordination chemistry between [S2P(tBu2C12H6)]1- and [S2P(C6H5)2]1- with U,more » Np, and Pu was comparatively investigated. The results showed that dithiophosphinate complexes of UIV and NpIV were redox stable relative to those of UIII, whereas reactions involving PuIV gave intractable material. For instance, reactions involving UIV and NpIV generated An[S2P(tBu2C12H6)]4 and An[S2P(C6H5)2]4 whereas reactions between PuIV and [S2P(C6H5)2]1- generated a mixture of products from which we postulated a transient PuIII species based on UV-Vis spectroscopy. However, the trivalent Pu[S2P(C6H5)2]3(NC5H5)2 compound is stable and could be isolated from reactions between [S2P(C6H5)2]1- and the trivalent PuI3(NC5H5)4 starting material. Attempts to synthesize analogous trivalent compounds with UIII provided the tetravalent U[S2P(C6H5)2]4 oxidation product.« less

  4. Analytical Chemistry Laboratory Quality Assurance Project Plan for the Transuranic Waste Characterization Program

    SciTech Connect

    Sailer, S.J.

    1996-08-01

    This Quality Assurance Project Plan (QAPJP) specifies the quality of data necessary and the characterization techniques employed at the Idaho National Engineering Laboratory (INEL) to meet the objectives of the Department of Energy (DOE) Waste Isolation Pilot Plant (WIPP) Transuranic Waste Characterization Quality Assurance Program Plan (QAPP) requirements. This QAPJP is written to conform with the requirements and guidelines specified in the QAPP and the associated documents referenced in the QAPP. This QAPJP is one of a set of five interrelated QAPjPs that describe the INEL Transuranic Waste Characterization Program (TWCP). Each of the five facilities participating in the TWCP has a QAPJP that describes the activities applicable to that particular facility. This QAPJP describes the roles and responsibilities of the Idaho Chemical Processing Plant (ICPP) Analytical Chemistry Laboratory (ACL) in the TWCP. Data quality objectives and quality assurance objectives are explained. Sample analysis procedures and associated quality assurance measures are also addressed; these include: sample chain of custody; data validation; usability and reporting; documentation and records; audits and 0385 assessments; laboratory QC samples; and instrument testing, inspection, maintenance and calibration. Finally, administrative quality control measures, such as document control, control of nonconformances, variances and QA status reporting are described.

  5. BredeQuery: Coordinate-Based Meta-analytic Search of Neuroscientific Literature from the SPM Environment

    NASA Astrophysics Data System (ADS)

    Wilkowski, Bartłomiej; Szewczyk, Marcin; Rasmussen, Peter Mondrup; Hansen, Lars Kai; Nielsen, Finn Årup

    Large amounts of neuroimaging studies are collected and have chan-ged our view on human brain function. By integrating multiple studies in meta-analysis a more complete picture is emerging. Brain locations are usually reported as coordinates with reference to a specific brain atlas, thus some of the databases offer so-called coordinate-based searching to the users (e.g. Brede, BrainMap). For such search, the publications, which relate to the brain locations represented by the user coordinates, are retrieved. We present BredeQuery - a plugin for the widely used SPM data analytic pipeline. BredeQuery offers a direct link from SPM to the Brede Database coordinate-based search engine. BredeQuery is able to 'grab' brain location coordinates from the SPM windows and enter them as a query for the Brede Database. Moreover, results of the query can be displayed in a MATLAB window and/or exported directly to some popular bibliographic file formats (BibTeX, Reference Manager, etc).

  6. Analytical solution of the problem of a shock wave in the collapsing gas in Lagrangian coordinates

    NASA Astrophysics Data System (ADS)

    Kuropatenko, V. F.; Shestakovskaya, E. S.

    2016-10-01

    It is proposed the exact solution of the problem of a convergent shock wave and gas dynamic compression in a spherical vessel with an impermeable wall in Lagrangian coordinates. At the initial time the speed of cold ideal gas is equal to zero, and a negative velocity is set on boundary of the sphere. When t > t0 the shock wave spreads from this point into the gas. The boundary of the sphere will move under the certain law correlated with the motion of the shock wave. The trajectories of the gas particles in Lagrangian coordinates are straight lines. The equations determining the structure of the gas flow between the shock front and gas border have been found as a function of time and Lagrangian coordinate. The dependence of the entropy on the velocity of the shock wave has been found too. For Lagrangian coordinates the problem is first solved. It is fundamentally different from previously known formulations of the problem of the self-convergence of the self-similar shock wave to the center of symmetry and its reflection from the center, which was built up for the infinite area in Euler coordinates.

  7. The coordination chemistry of tartronic acid with copper: magnetic studies of a quasi-equilateral tricopper triangle.

    PubMed

    Pascu, Gabriel; Deville, Claire; Clifford, Sarah E; Guenée, Laure; Besnard, Céline; Krämer, Karl W; Liu, Shi-Xia; Decurtins, Silvio; Tuna, Floriana; McInnes, Eric J L; Winpenny, Richard E P; Williams, Alan F

    2014-01-14

    The coordination chemistry of tartronic acid, , with copper(ii) has been investigated. Structures of two complexes are reported containing respectively the complex [Cu(-2H)2Cl](3-) where acts as a bidentate ligand through carboxylates, and [Cu3(-3H)3](3-) where the alcohol function is deprotonated to bridge two coppers in a triangular trinuclear complex. The latter species undergoes facile oxidation leading to carbon-carbon bond formation. The magnetic and EPR properties of the trinuclear complex have been studied in detail.

  8. Novel detection schemes of nuclear magnetic resonance and magnetic resonance imaging: applications from analytical chemistry to molecular sensors.

    PubMed

    Harel, Elad; Schröder, Leif; Xu, Shoujun

    2008-01-01

    Nuclear magnetic resonance (NMR) is a well-established analytical technique in chemistry. The ability to precisely control the nuclear spin interactions that give rise to the NMR phenomenon has led to revolutionary advances in fields as diverse as protein structure determination and medical diagnosis. Here, we discuss methods for increasing the sensitivity of magnetic resonance experiments, moving away from the paradigm of traditional NMR by separating the encoding and detection steps of the experiment. This added flexibility allows for diverse applications ranging from lab-on-a-chip flow imaging and biological sensors to optical detection of magnetic resonance imaging at low magnetic fields. We aim to compare and discuss various approaches for a host of problems in material science, biology, and physics that differ from the high-field methods routinely used in analytical chemistry and medical imaging.

  9. Coordination chemistry of 2,2'-biphenylenedithiophosphinate and diphenyldithiophosphinate with U, Np, and Pu

    SciTech Connect

    Macor, Joseph A.; Brown, Jessie L.; Cross, Justin Neil; Daly, Scott R.; Gaunt, Andrew James; Girolami, Gregory S.; Janicke, Michael Timothy; Kozimor, Stosh Anthony; Neu, Mary P.; Olson, Angela Christine; Reilly, Sean Douglas; Scott, Brian Lindley

    2015-01-01

    New members of the dithiophosphinic acid family of potential actinide extractants were prepared: heterocyclic 2,2'-biphenylenedithiophosphinic acids of stoichiometry HS2P(R2C12H6) (R = H or tBu). The time- and atom-efficient syntheses afforded multigram quantities of pure HS2P(R2C12H6) in reasonable yields (~60%). These compounds differed from other diaryldithiophosphinic acid extractants in that the two aryl groups were connected to one another at the ortho positions to form a 5-membered dibenzophosphole ring. These 2,2'-biphenylenedithiophosphinic acids were readily deprotonated to form S2P(R2C12H6)1- anions, which were crystallized as salts with tetraphenylpnictonium cations (ZPh41+; Z = P or As). Coordination chemistry between [S2P(tBu2C12H6)]1- and [S2P(C6H5)2]1- with U, Np, and Pu was comparatively investigated. The results showed that dithiophosphinate complexes of UIV and NpIV were redox stable relative to those of UIII, whereas reactions involving PuIV gave intractable material. For instance, reactions involving UIV and NpIV generated An[S2P(tBu2C12H6)]4 and An[S2P(C6H5)2]4 whereas reactions between PuIV and [S2P(C6H5)2]1- generated a mixture of products from which we postulated a transient PuIII species based on UV-Vis spectroscopy. However, the trivalent Pu[S2P(C6H5)2]3(NC5H5)2 compound is stable and could be isolated from reactions between [S2P(C6H5)2]1- and the

  10. General Procedure for the Easy Calculation of pH in an Introductory Course of General or Analytical Chemistry

    ERIC Educational Resources Information Center

    Cepriá, Gemma; Salvatella, Luis

    2014-01-01

    All pH calculations for simple acid-base systems used in introductory courses on general or analytical chemistry can be carried out by using a general procedure requiring the use of predominance diagrams. In particular, the pH is calculated as the sum of an independent term equaling the average pK[subscript a] values of the acids involved in the…

  11. Siderocalin outwits the coordination chemistry of vibriobactin, a siderophore of Vibrio cholerae.

    PubMed

    Allred, Benjamin E; Correnti, Colin; Clifton, Matthew C; Strong, Roland K; Raymond, Kenneth N

    2013-09-20

    The human protein siderocalin (Scn) inhibits bacterial iron acquisition by binding catechol siderophores. Several pathogenic bacteria respond by making stealth siderophores that are not recognized by Scn. Fluvibactin and vibriobactin, respectively of Vibrio fluvialis and Vibrio cholerae , include an oxazoline adjacent to a catechol. This chelating unit binds iron either in a catecholate or a phenolate-oxazoline coordination mode. The latter has been suggested to make vibriobactin a stealth siderophore without directly identifying the coordination mode in relation to Scn binding. We use Scn binding assays with the two siderophores and two oxazoline-substituted analogs and the crystal structure of Fe-fluvibactin:Scn to show that the oxazoline does not prevent Scn binding; hence, vibriobactin is not a stealth siderophore. We show that the phenolate-oxazoline coordination mode is present at physiological pH and is not bound by Scn. However, Scn binding shifts the coordination to the catecholate mode and thereby inactivates this siderophore.

  12. On the new analytical solution for a well in Cartesian coordinates with MODFLOW comparisons.

    PubMed

    Batu, Vedat

    2014-01-01

    In this paper, the comparison process of Batu (2012) generalized three-dimensional well hydraulics solution for confined aquifers in Cartesian coordinates with MODFLOW is presented. First, a brief description of Batu (2012) solution along with the governing equations and some of its key features are described. The final average drawdown expression in an observation well is given with the conversion expressions from Cartesian to radial coordinates. A generalized comparison using Batu (2012), Hantush (1964), and MODFLOW (Harbaugh et al. 2000), for vertical wells in horizontally isotropic aquifers, that is, ayx  = Ky /Kx  = 1, is presented. Comparisons are also presented with Batu (2012) and MODFLOW for horizontally anisotropic aquifers, that is, ayx  ≠ 1. After that comparisons are presented for horizontal wells between Batu (2012) and MODFLOW.

  13. Tensors and Differential Geometry Applied to Analytic and Numerical Coordinate Generation

    DTIC Science & Technology

    1981-01-01

    C., Space Through the Ages, Academic Press, New York (1970). [291 Thompson , J . F ., Thames, F. C., and Mastin, C. W., "Automatic Numerical Generation...in 1923). [35] Private communication from J. F. Thompson. [36] Warsi, Z. U. A., and Thompson , J . F ., "Numerical Generation of Two-Dimensional...Z. U. A., and Thompson , J . F ., "Machine Solutions of Partial Differential Equations in the Numerically Generated Coordinate Systems," Engineering

  14. Impacts of a new analytical stretching function for terrain following vertical coordinates

    NASA Astrophysics Data System (ADS)

    Furner, Rachel; Siddorn, John; O'Dea, Enda

    2013-04-01

    Terrain following vertical coordinates are commonly used in coastal ocean models as they allow an accurate representation of the bottom boundary layer. However, the depth dependence of these coordinates results in horizontal variation in grid cell heights, with these variations becoming large in model domains which span large depth ranges. In the surface layer in particular this causes problems. Inconsistencies in the depth of the surface layer results in non physically-justifiable differences in the way atmospheric fluxes are applied to the ocean model. Also, when coupling to atmospheric models the depth variation of the surface grid cell leads to discrepancy in what is meant by 'sea surface values' meaning the boundary conditions provided to the atmospheric model are inconsistent. Stretching functions are commonly used to limit the horizontal variation of vertical resolution in parts of the water column. However in models spanning large depth ranges, such as the Met Office's Forecasting Ocean Assimilation Model (FOAM) Atlantic Margin Model (AMM7), commonly used stretching functions cannot suitably limit this variation near the surface without causing unacceptable loss of resolution in other parts of the water column. A new stretching function for terrain following coordinates is presented. The new stretching function allows a user-prescribed, constant surface (and bottom) cell height whilst maintaining resolution throughout the water column, and allowing increased resolution at the surface or sea bed as required. The impact of this is tested on simulations of FOAM AMM7 and results presented.

  15. Proteomics Is Analytical Chemistry: Fitness-for-Purpose in the Application of Top-Down and Bottom-Up Analyses.

    PubMed

    Coorssen, Jens R; Yergey, Alfred L

    2015-12-03

    Molecular mechanisms underlying health and disease function at least in part based on the flexibility and fine-tuning afforded by protein isoforms and post-translational modifications. The ability to effectively and consistently resolve these protein species or proteoforms, as well as assess quantitative changes is therefore central to proteomic analyses. Here we discuss the pros and cons of currently available and developing analytical techniques from the perspective of the full spectrum of available tools and their current applications, emphasizing the concept of fitness-for-purpose in experimental design based on consideration of sample size and complexity; this necessarily also addresses analytical reproducibility and its variance. Data quality is considered the primary criterion, and we thus emphasize that the standards of Analytical Chemistry must apply throughout any proteomic analysis.

  16. Proteomics Is Analytical Chemistry: Fitness-for-Purpose in the Application of Top-Down and Bottom-Up Analyses

    PubMed Central

    Coorssen, Jens R.; Yergey, Alfred L.

    2015-01-01

    Molecular mechanisms underlying health and disease function at least in part based on the flexibility and fine-tuning afforded by protein isoforms and post-translational modifications. The ability to effectively and consistently resolve these protein species or proteoforms, as well as assess quantitative changes is therefore central to proteomic analyses. Here we discuss the pros and cons of currently available and developing analytical techniques from the perspective of the full spectrum of available tools and their current applications, emphasizing the concept of fitness-for-purpose in experimental design based on consideration of sample size and complexity; this necessarily also addresses analytical reproducibility and its variance. Data quality is considered the primary criterion, and we thus emphasize that the standards of Analytical Chemistry must apply throughout any proteomic analysis. PMID:28248279

  17. Coordination Chemistry of Cyclic Disilylated Germylenes and Stannylenes with Group 11 Metals

    PubMed Central

    2014-01-01

    Reactions of Et3P adducts of bissilylated germylenes and stannylenes with gold, silver, and copper cyanides led to cyanogermyl or -stannyl complexes of the respective metals. In the course of the reaction the phosphine moved to the metal, while the cyanide migrated to the low-coordinate group 14 element. The respective gold complexes were found to be monomeric, whereas the silver and copper complexes exhibited a tendency to dimerize in the solid state. Attempts to abstract the phosphine ligand with B(C6F5)3 led only to the formation of adducts with the borane coordinating to the cyanide nitrogen atom. PMID:25550678

  18. New Twists and Turns for Actinide Chemistry: Organometallic Infinite Coordination Polymers of Thorium Diazide.

    PubMed

    Monreal, Marisa J; Seaman, Lani A; Goff, George S; Michalczyk, Ryszard; Morris, David E; Scott, Brian L; Kiplinger, Jaqueline L

    2016-03-07

    Two organometallic 1D infinite coordination polymers and two organometallic monometallic complexes of thorium diazide have been synthesized and characterized. Steric control of these self-assembled arrays, which are dense in thorium and nitrogen, has also been demonstrated: infinite chains can be circumvented by using steric bulk either at the metallocene or with a donor ligand in the wedge.

  19. Valence-Bond Concepts in Coordination Chemistry and the Nature of Metal-Metal Bonds.

    ERIC Educational Resources Information Center

    Pauling, Linus; Herman, Zelek S.

    1984-01-01

    Discusses the valence-bond method, applying it to some coordination compounds of metals, especially those involving metal-metal bonds. Suggests that transition metals can form as many as nine covalent bonds, permitting valence-theory to be extended to transition metal compounds in a more effective way than has been possible before. (JN)

  20. ASVCP quality assurance guidelines: control of preanalytical, analytical, and postanalytical factors for urinalysis, cytology, and clinical chemistry in veterinary laboratories.

    PubMed

    Gunn-Christie, Rebekah G; Flatland, Bente; Friedrichs, Kristen R; Szladovits, Balazs; Harr, Kendal E; Ruotsalo, Kristiina; Knoll, Joyce S; Wamsley, Heather L; Freeman, Kathy P

    2012-03-01

    In December 2009, the American Society for Veterinary Clinical Pathology (ASVCP) Quality Assurance and Laboratory Standards committee published the updated and peer-reviewed ASVCP Quality Assurance Guidelines on the Society's website. These guidelines are intended for use by veterinary diagnostic laboratories and veterinary research laboratories that are not covered by the US Food and Drug Administration Good Laboratory Practice standards (Code of Federal Regulations Title 21, Chapter 58). The guidelines have been divided into 3 reports: (1) general analytical factors for veterinary laboratory performance and comparisons; (2) hematology, hemostasis, and crossmatching; and (3) clinical chemistry, cytology, and urinalysis. This particular report is one of 3 reports and documents recommendations for control of preanalytical, analytical, and postanalytical factors related to urinalysis, cytology, and clinical chemistry in veterinary laboratories and is adapted from sections 1.1 and 2.2 (clinical chemistry), 1.3 and 2.5 (urinalysis), 1.4 and 2.6 (cytology), and 3 (postanalytical factors important in veterinary clinical pathology) of these guidelines. These guidelines are not intended to be all-inclusive; rather, they provide minimal guidelines for quality assurance and quality control for veterinary laboratory testing and a basis for laboratories to assess their current practices, determine areas for improvement, and guide continuing professional development and education efforts.

  1. The Efficacy of Problem-based Learning in an Analytical Laboratory Course for Pre-service Chemistry Teachers

    NASA Astrophysics Data System (ADS)

    Yoon, Heojeong; Woo, Ae Ja; Treagust, David; Chandrasegaran, AL

    2014-01-01

    The efficacy of problem-based learning (PBL) in an analytical chemistry laboratory course was studied using a programme that was designed and implemented with 20 students in a treatment group over 10 weeks. Data from 26 students in a traditional analytical chemistry laboratory course were used for comparison. Differences in the creative thinking ability of students in both the treatment and control groups were evaluated before and at the end of the implementation of the programme, using the Torrance Tests of Creative Thinking. In addition, changes in students' self-regulated learning skills using the Self-Regulated Learning Interview Schedule (SRLIS) and their self-evaluation proficiency were evaluated. Analysis of covariance showed that the creative thinking ability of the treatment group had improved statistically significantly after the PBL course (p < 0.001) compared to that of the students in the comparison group. PBL was shown to have a positive effect on creative thinking ability. The SRLIS test showed that students in the treatment group used self-regulated learning strategies more frequently than students in the comparison group. According to the results of the self-evaluation, students became more positive and confident in problem-solving and group work as the semester progressed. Overall, PBL was shown to be an effective pedagogical instructional strategy for enhancing chemistry students' creative thinking ability, self-regulated learning skills and self-evaluation.

  2. Iron coordination chemistry with new ligands containing triazole and pyridine moieties. Comparison of the coordination ability of the N-donors.

    PubMed

    Ségaud, Nathalie; Rebilly, Jean-Noël; Sénéchal-David, Katell; Guillot, Régis; Billon, Laurianne; Baltaze, Jean-Pierre; Farjon, Jonathan; Reinaud, Olivia; Banse, Frédéric

    2013-01-18

    We report the synthesis, characterization, and solution chemistry of a series of new Fe(II) complexes based on the tetradentate ligand N-methyl-N,N'-bis(2-pyridyl-methyl)-1,2-diaminoethane or the pentadentate ones N,N',N'-tris(2-pyridyl-methyl)-1,2-diaminoethane and N,N',N'-tris(2-pyridyl-methyl)-1,3-diaminopropane, modified by propynyl or methoxyphenyltriazolyl groups on the amino functions. Six of these complexes are characterized by X-ray crystallography. In particular, two of them exhibit an hexadentate coordination environment around Fe(II) with two amino, three pyridyl, and one triazolyl groups. UV-visible and cyclic voltammetry experiments of acetonitrile solutions of the complexes allow to deduce accurately the structure of all Fe(II) species in equilibrium. The stability of the complexes could be ranked as follows: [L(5)Fe(II)-py](2+) > [L(5)Fe(II)-Cl](+) > [L(5)Fe(II)-triazolyl](2+) > [L(5)Fe(II)-(NCMe)](2+), where L(5) designates a pentadentate coordination sphere composed of the two amines of ethanediamine and three pyridines. For complexes based on propanediamine, the hierarchy determined is [L(5)Fe(II)-Cl](+) > [L(5)Fe(II)(OTf)](+) > [L(5)Fe(II)-(NCMe)](2+), and no ligand exchange could be evidenced for [L(5)Fe(II)-triazolyl](2+). Reactivity of the [L(5)Fe(II)-triazolyl](2+) complexes with hydrogen peroxide and PhIO is similar to the one of the parent complexes that lack this peculiar group, that is, generation of Fe(III)(OOH) and Fe(IV)(O), respectively. Accordingly, the ability of these complexes at catalyzing the oxidation of small organic molecules by these oxidants follows the tendencies of their previously reported counterparts. Noteworthy is the remarkable cyclooctene epoxidation activity by these complexes in the presence of PhIO.

  3. Analytical Solution in Curvilinear Coordinates for the Trajectory of a Projectile Subject to Aerodynamic Drag

    DTIC Science & Technology

    2011-12-01

    integration of α̇ over time could not be analytically achieved. Thus, while many variables are known in terms of the trajectory parameters , the time...H = 1 m at a velocity of 2000 m/s and a launch angle of 25◦. For these initial conditions, the value for the parameter B is 0.00145 m−1. In these...n, dsprint /9.806, -0.001, 1, 30./ PARAMETER (PI = 3.1415926) print *, ’Enter B, Vo, alpha0, H: ’ read (*,*) B, V0, a0, H write(7,’(’’B, V0, a0, H

  4. Alternative analytically calculation procedure of two-center kinetic energy integral in molecular coordinate system

    NASA Astrophysics Data System (ADS)

    Mamedov, Bahtiyar Akber; Copuroglu, Ebru

    2017-02-01

    By using the Löwdin-α function method, we have analytically calculated the two-center kinetic energy integrals over Slater type orbitals (STOs). The two-center kinetic energy integrals are presented in terms of the two-center overlap integrals. A new approach is applicable to accurate calculations of two-center kinetic energy integral over STOs for arbitrary values of scaling parameters and interatomic distances. Obtained results show that the proposed method is easy to apply to the real systems, and has better calculation CPU time with compared to the existing approximations.

  5. The influence of surface chemistry on GSR particles: using XPS to complement SEM/EDS analytical techniques

    NASA Astrophysics Data System (ADS)

    Schwoeble, A. J.; Strohmeier, Brian R.; Piasecki, John D.

    2010-06-01

    Gunshot residue particles (GSR) were examined using scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) to illustrate the size, shape, morphology, and elemental composition normally observed in particulate resulting from a discharged firearm. Determining the presence of lead (Pb), antimony (Sb), and barium (Ba), barring other elemental tags, fused together in a single particle with the correct morphology, is all that is required for the positive identification of GSR. X-ray photoelectron spectroscopy (XPS), however, can reveal more detailed information on surface chemistry than SEM/EDS. XPS is a highly surface-sensitive (<= ~10 nm), non-destructive, analytical technique that provides qualitative information for all elements except hydrogen and helium. Nanometer-scale sampling depth and its ability to provide unique chemical state information make XPS a potential technique for providing important knowledge on the surface chemistry of GSR that complements results obtained from SEM/EDS analysis.

  6. Coordination chemistry, thermodynamics and DFT calculations of copper(II) NNOS Schiff base complexes.

    PubMed

    Esmaielzadeh, Sheida; Azimian, Leila; Shekoohi, Khadijeh; Mohammadi, Khosro

    2014-12-10

    Synthesis, magnetic and spectroscopy techniques are described for five copper(II) containing tetradentate Schiff bases are synthesized from methyl-2-(N-2'-aminoethane), (1-methyl-2'-aminoethane), (3-aminopropylamino)cyclopentenedithiocarboxylate. Molar conductance and infrared spectral evidences indicate that the complexes are four-coordinate in which the Schiff bases are coordinated as NNOS ligands. Room temperature μeff values for the complexes are 1.71-1.80B.M. corresponding to one unpaired electron respectively. The formation constants and free energies were measured spectrophotometrically, at constant ionic strength 0.1M (NaClO4), at 25˚C in DMF solvent. Also, the DFT calculations were carried out to determine the structural and the geometrical properties of the complexes. The DFT results are further supported by the experimental formation constants of these complexes.

  7. Analytical Chemistry Division annual progress report for period ending December 31, 1979

    SciTech Connect

    Shults, W.D.; Lyon, W.S.

    1980-05-01

    The progress is reported in the following sections: analytical methodology, mass and emission spectrometry, technical support, bio-organic analysis, nuclear and radiochemical analysis, and quality assurance. (DLC)

  8. Hydrothermal synthesis of copper coordination polymers based on molybdates: Chemistry issues

    NASA Astrophysics Data System (ADS)

    Pavani, K.; Ramanan, A.; Whittingham, M. S.

    2006-08-01

    Crystal engineering of metal organic coordination polymers or metal organic frameworks have been attracting unprecedented efforts in the past few years due to potential applications in the area of catalysis, gas separation and storage. Hydrothermal synthesis is a popular soft chemical route employed by a number of researchers to grow suitable single crystals for unambiguous structural characterization. The structural diversity of the various solid frameworks is attributed to the choice of metal, its ability to exist in multiple oxidation states exhibiting different coordination geometry and multidentate nature of organic ligands. Polyoxomolybdate is another interesting class of inorganic materials that are potential catalysts. A contemporary theme is to develop porous solids combining the acidic properties of oligomeric molybdates integrated with first-row transition metal ions that can form coordination polymers with suitable multidentate ligands. A bottleneck to this problem is to develop reliable synthetic protocols that can produce reproducible materials with designed structural characteristics. In this paper, we present our results on the formation of self-assembled metal organic hybrid solids from acidified aqueous molybdate solution containing cupric ions and one of the multidentate organic ligands (pyrazine, 2-pyrazine carboxylic acid or isonicotinic acid). We propose a molecular mechanism to rationalize the formation of solids.

  9. Porous solids arising from synergistic and competing modes of assembly: combining coordination chemistry and covalent bond formation.

    PubMed

    Dutta, Ananya; Koh, Kyoungmoo; Wong-Foy, Antek G; Matzger, Adam J

    2015-03-23

    Design and synthesis of porous solids employing both reversible coordination chemistry and reversible covalent bond formation is described. The combination of two different linkage modes in a single material presents a link between two distinct classes of porous materials as exemplified by metal-organic frameworks (MOFs) and covalent organic frameworks (COFs). This strategy, in addition to being a compelling material-discovery method, also offers a platform for developing a fundamental understanding of the factors influencing the competing modes of assembly. We also demonstrate that even temporary formation of reversible connections between components may be leveraged to make new phases thus offering design routes to polymorphic frameworks. Moreover, this approach has the striking potential of providing a rich landscape of structurally complex materials from commercially available or readily accessible feedstocks.

  10. Adsorption of pentacene on (100) vicinal surfaces: role of coordination, surface chemistry and vdWs effects

    NASA Astrophysics Data System (ADS)

    Matos, Jeronimo; Kara, Abdelkader

    2015-03-01

    In contrast to low miller index surfaces, vicinal surfaces are characterized by steps and step edges that not only present an interesting atomic landscape for the adsorption organic molecules, but also a unique electronic structure resulting in part from the low coordinated atoms at the step edges. The adsorption of pentacene on the stepped (511), (711), (911) surfaces (respectively 3, 4 and 5-atom wide terraces) of Cu and Ag (coinage transition metals); Pt (reactive transition metal); and Ni (reactive, magnetic transition metal) are studied using density functional theory, in order to investigate the support effects arising from differing surface chemistry. We compare the adsorption energy, adsorption geometry and electronic structure predicted by the PBE functional with those obtained from one of the optimized vdW-DF methods: optB88-vdW. Work supported by the U.S. Department of Energy Basic Energy Science under Contract No. DE-FG02-11ER16243.

  11. The Abbott Architect c8000: analytical performance and productivity characteristics of a new analyzer applied to general chemistry testing.

    PubMed

    Pauli, Daniela; Seyfarth, Michael; Dibbelt, Leif

    2005-01-01

    Applying basic potentiometric and photometric assays, we evaluated the fully automated random access chemistry analyzer Architect c8000, a new member of the Abbott Architect system family, with respect to both its analytical and operational performance and compared it to an established high-throughput chemistry platform, the Abbott Aeroset. Our results demonstrate that intra- and inter-assay imprecision, inaccuracy, lower limit of detection and linear range of the c8000 generally meet actual requirements of laboratory diagnosis; there were only rare exceptions, e.g. assays for plasma lipase or urine uric acid which apparently need to be improved by additional rinsing of reagent pipettors. Even with plasma exhibiting CK activities as high as 40.000 U/l, sample carryover by the c8000 could not be detected. Comparison of methods run on the c8000 and the Aeroset revealed correlation coefficients of 0.98-1.00; if identical chemistries were applied on both analyzers, slopes of regression lines approached unity. With typical laboratory workloads including 10-20% STAT samples and up to 10% samples with high analyte concentrations demanding dilutional reruns, steady-state throughput numbers of 700 to 800 tests per hour were obtained with the c8000. The system generally responded to STAT orders within 2 minutes yielding analytical STAT order completion times of 5 to 15 minutes depending on the type and number of assays requested per sample. Due to its extended test and sample processing capabilities and highly comfortable software, the c8000 may meet the varying needs of clinical laboratories rather well.

  12. Gas-Phase Chemistry of Multiply Charged Bioions in Analytical Mass Spectrometry

    PubMed Central

    Huang, Teng-Yi; McLuckey, Scott A.

    2011-01-01

    Ion chemistry has long played an important role in molecular mass spectrometry (MS), as it is central to the use of MS as a structural characterization tool. With the advent of ionization methods capable of producing gaseous ions from large biomolecules, the chemistry of gaseous bioions has become a highly active area of research. Gas-phase biomolecule-ion reactions are usually driven by interactions with neutral molecules, photons, electrons, ions, or surfaces. Ion dissociation or transformation into different ion types can be achieved. The types of reaction products observed depend on the characteristics of the ions, the transformation methods, and the time frame of observation. This review focuses on the gas-phase chemistries of ions derived from the electrospray ionization of peptides, proteins, and oligonucleotides, with particular emphasis on their utility in bioanalysis. Various ion-transformation strategies, which further facilitate structural interrogation by converting ions from one type to another, are also summarized. PMID:20636047

  13. Coordination chemistry and reactivity of zinc complexes supported by a phosphido pincer ligand.

    PubMed

    D'Auria, Ilaria; Lamberti, Marina; Mazzeo, Mina; Milione, Stefano; Roviello, Giuseppina; Pellecchia, Claudio

    2012-02-20

    The preparation and characterization of new Zn(II) complexes of the type [(PPP)ZnR] in which R = Et (1) or N(SiMe(3))(2) (2) and PPP is a tridentate monoanionic phosphido ligand (PPP-H = bis(2-diphenylphosphinophenyl)phosphine) are reported. Reaction of ZnEt(2) and Zn[N(SiMe(3))(2)](2) with one equivalent of proligand PPP-H produced the corresponding tetrahedral zinc ethyl (1) and zinc amido (2) complexes in high yield. Homoleptic (PPP)(2) Zn complex 3 was obtained by reaction of the precursors with two equivalents of the proligand. Structural characterization of 1-3 was achieved by multinuclear NMR spectroscopy ((1)H, (13)C, and (31)P) and X-ray crystallography (3). Variable-temperature (1)H and (31)P NMR studies highlighted marked flexibility of the phosphido pincer ligand in coordination at the metal center. A DFT calculation on the compounds provided theoretical support for this behavior. The activities of 1 and 2 toward the ring-opening polymerization of ε-caprolactone and of L- and rac-lactide were investigated, also in combination with an alcohol as external chain-transfer agent. Polyesters with controlled molecular parameters (M(n), end groups) and low polydispersities were obtained. A DFT study on ring-opening polymerization promoted by these complexes highlighted the importance of the coordinative flexibility of the ancillary ligand to promote monomer coordination at the reactive zinc center. Preliminary investigations showed the ability of these complexes to promote copolymerization of L-lactide and ε-caprolactone to achieve random copolymers whose microstructure reproduces the composition of the monomer feed.

  14. Coordination Chemistry of Disilylated Stannylenes with Group 10 d10 Transition Metals: Silastannene vs Stannylene Complexation

    PubMed Central

    2013-01-01

    The coordination behavior of disilylated stannylenes toward zerovalent group 10 transition metal complexes was studied. This was accomplished by reactions of PEt3 adducts of disilylated stannylenes with zerovalent group 10 transition metal complexes. The thus obtained products differed between the first row example nickel and its heavier congeners. While with nickel stannylene complex formation was observed, coordination of the stannylenes to palladium and platinum compounds led to unusual silastannene complexes of these metals. A computational model study indicated that in each case metal stannylene complexes were formed first and that the disilylstannylene/silastannene rearrangement occurs only after complexation to the group 10 metal. The isomerization is a two-step process with relatively small barriers, suggesting a thermodynamic control of product formation. In addition, the results of the computational investigation revealed a subtle balance of steric and electronic effects, which determines the relative stability of the metalastannylene complex relative to its silastannene isomer. In the case of cyclic disilylstannylenes, the Pd(0) and Pt(0) silastannene complexes are found to be more stable, while with acyclic disilylstannylenes the Ni(0) stannylene complex is formed preferentially. PMID:23627362

  15. Synthesis and characterization of nitrogen-rich macrocyclic ligands and an investigation of their coordination chemistry with lanthanum(III).

    PubMed

    Wilson, Justin J; Birnbaum, Eva R; Batista, Enrique R; Martin, Richard L; John, Kevin D

    2015-01-05

    Derivatives of the ligand 1,4,7,10-tetraazacyclododecane (cyclen) containing pendant N-heterocyclic donors were prepared. The heterocycles pyridine, pyridazine, pyrimidine, and pyrazine were conjugated to cyclen to give 1,4,7,10-tetrakis(pyridin-2-ylmethyl)-1,4,7,10-tetraazacyclododecane (L(py)), 1,4,7,10-tetrakis(3-pyridazylmethyl)-1,4,7,10-tetraazacyclododecane (L(pyd)), 1,4,7,10-tetrakis(4-pyrimidylmethyl)-1,4,7,10-tetraazacyclododecane (L(pyr)), and 1,4,7,10-tetrakis(2-pyrazinylmethyl)-1,4,7,10-tetraazacyclododecane (L(pz)), respectively. The coordination chemistry of these ligands was explored using the La(3+) ion. Accordingly, complexes of the general formula [La(L)(OTf)](OTf)2, where OTf = trifluoromethanesulfonate and L = L(py) (1), L(pyd) (2), L(pyr) (3), and L(pz) (4), were synthesized and characterized by NMR spectroscopy. Crystal structures of 1 and 2 were also determined by X-ray diffraction studies, which revealed 9-coordinate capped, twisted square-antiprismatic coordination geometries for the central La(3+) ion. The conformational dynamics of 1-4 in solution were investigated by variable-temperature NMR spectroscopy. Dynamic line-shape and Eyring analyses enabled the determination of the activation parameters for the interconversion of enantiomeric forms of the complexes. Unexpectedly, the different pendant N-heterocycles of 1-4 give rise to varying values for the enthalpies and entropies of activation for this process. Density functional theory calculations were carried out to investigate the mechanism of this enantiomeric interconversion. Computed activation parameters were consistent with those experimentally determined for 1 but differed somewhat from those of 2-4.

  16. Incorporating Course-Based Undergraduate Research Experiences into Analytical Chemistry Laboratory Curricula

    ERIC Educational Resources Information Center

    Kerr, Melissa A.; Yan, Fei

    2016-01-01

    A continuous effort within an undergraduate university setting is to improve students' learning outcomes and thus improve students' attitudes about a particular field of study. This is undoubtedly relevant within a chemistry laboratory. This paper reports the results of an effort to introduce a problem-based learning strategy into the analytical…

  17. A Multidisciplinary Science Summer Camp for Students with Emphasis on Environmental and Analytical Chemistry

    ERIC Educational Resources Information Center

    Schwarz, Gunnar; Frenzel, Wolfgang; Richter, Wolfgang M.; Ta¨uscher, Lothar; Kubsch, Georg

    2016-01-01

    This paper presents the course of events of a five-day summer camp on environmental chemistry with high emphasis on chemical analysis. The annual camp was optional and open for students of all disciplines and levels. The duration of the summer camp was five and a half days in the Feldberg Lake District in northeast Germany (federal state of…

  18. Using Cooperative Learning to Teach Chemistry: A Meta-Analytic Review

    ERIC Educational Resources Information Center

    Warfa, Abdi-Rizak M.

    2016-01-01

    A meta-analysis of recent quantitative studies that examine the effects of cooperative learning (CL) on achievement outcomes in chemistry is presented. Findings from 25 chemical education studies involving 3985 participants (N[subscript treatment] = 1,845; N[subscript control] = 2,140) and published since 2001 show positive association between…

  19. Analytical solutions for solute transport in groundwater and riverine flow using Green's Function Method and pertinent coordinate transformation method

    NASA Astrophysics Data System (ADS)

    Sanskrityayn, Abhishek; Suk, Heejun; Kumar, Naveen

    2017-04-01

    In this study, analytical solutions of one-dimensional pollutant transport originating from instantaneous and continuous point sources were developed in groundwater and riverine flow using both Green's Function Method (GFM) and pertinent coordinate transformation method. Dispersion coefficient and flow velocity are considered spatially and temporally dependent. The spatial dependence of the velocity is linear, non-homogeneous and that of dispersion coefficient is square of that of velocity, while the temporal dependence is considered linear, exponentially and asymptotically decelerating and accelerating. Our proposed analytical solutions are derived for three different situations depending on variations of dispersion coefficient and velocity, respectively which can represent real physical processes occurring in groundwater and riverine systems. First case refers to steady solute transport situation in steady flow in which dispersion coefficient and velocity are only spatially dependent. The second case represents transient solute transport in steady flow in which dispersion coefficient is spatially and temporally dependent while the velocity is spatially dependent. Finally, the third case indicates transient solute transport in unsteady flow in which both dispersion coefficient and velocity are spatially and temporally dependent. The present paper demonstrates the concentration distribution behavior from a point source in realistically occurring flow domains of hydrological systems including groundwater and riverine water in which the dispersivity of pollutant's mass is affected by heterogeneity of the medium as well as by other factors like velocity fluctuations, while velocity is influenced by water table slope and recharge rate. Such capabilities give the proposed method's superiority about application of various hydrological problems to be solved over other previously existing analytical solutions. Especially, to author's knowledge, any other solution doesn

  20. Opening Remarks for "Analytical Chemistry, Monitoring, and Environmental Fate and Transport" Session at Fluoros 2015

    EPA Science Inventory

    There have been a number of revolutionary developments during the past decade that have led to a much more comprehensive understanding of per- and polyfluoroalkyl substances (PFASs) in the environment. Improvements in analytical instrumentation have made liquid chromatography tri...

  1. Synthesis and Lanthanide Coordination Chemistry of Phosphine Oxide Decorated Dibenzothiophene and Dibenzothiophene Sulfone Platforms

    SciTech Connect

    Rosario-Amorin, Daniel; Ouizem, Sabrina; Dickie, D. A.; Paine, Robert T.; Cramer, Roger E.; Hay, Benjamin; Podair, Julien; Delmau, Laetitia Helene

    2014-01-01

    Syntheses for new ligands based upon dibenzothiophene and dibenzothiophene sulfone platforms, decorated with phosphine oxide and methylphosphine oxide donor groups, are described. Coordination chem. of 4, 6- bis(diphenylphosphinoylmethyl) dibenzothiophene (8) , 4, 6- bis(diphenylphosphinoylmethyl) dibenzothiophene- 5, 5- dioxide (9) and 4, 6- bis(diphenylphosphinoyl) dibenzothiophene- 5, 5- dioxide (10) with lanthanide nitrates, Ln(NO3) 3 (H2O) n is outlined, and crystal structure detns. reveal a range of chelation interactions on Ln(III) ions. The HNO3 dependence of the solvent extn. performance of 9 and 10 in 1, 2- dichloroethane for Eu(III) and Am(III) is described and compared against the extn. behavior of related dibenzofuran ligands (2, 3; R = Ph) and n- octyl(phenyl) - N, N- diisobutylcarbamoylmethyl phosphine oxide (4) measured under identical conditions.

  2. Steric Effects on the Structures, Reactivity, and Coordination Chemistry of Tris(2-pyridyl)aluminates.

    PubMed

    García-Rodríguez, Raúl; Wright, Dominic S

    2015-10-12

    Introducing substituents in the 6-position of the 2-pyridyl rings of tris(pyridyl)aluminate anions, of the type [EtAl(2-py')3 ](-) (py'=a substituted 2-pyridyl group), has a large impact on their metal coordination characteristics. This is seen most remarkably in the desolvation of the THF solvate [EtAl(6-Me-2-py)3 Li⋅THF] to give the monomer [EtAl(6-Me-2-py)3 Li] (1), containing a pyramidal, three-coordinate Li(+) cation. Similar monomeric complexes are observed for [EtAl(6-CF3 -2-py)3 Li] (2) and [EtAl(6-Br-2-py)3 Li] (3), which contain CF3 and Br substituents (R). This steric influence can be exploited in the synthesis of a new class of terminal Al-OH complexes, as is seen in the controlled hydrolysis of 2 and 3 to give [EtAl(OH)(6-R-2-py)2 ](-) anions, as in the dimer [EtAl(OH)(6-Br-2-py)2 Li]2 (5). Attempts to deprotonate the Al-OH group of 5 using Et2 Zn led only to the formation of the zincate complex [LiZn(6-Br-py)3 ]2 (6), while reactions of the 6-Br substituted 3 and the unsubstituted complex [EtAl(2-py)3 Li] with MeOH give [EtAl(OMe)(6-Br-2-py)2 Li]2 (7) and [EtAl(OMe)(2-py)2 Li]2 (8), respectively, having similar dimeric arrangements to 5. The combined studies presented provide key synthetic methods for the functionalization and elaboration of tris(pyridyl)aluminate ligands.

  3. Coordination chemistry and reactivity of a cupric hydroperoxide species featuring a proximal H-bonding substituent.

    PubMed

    Kim, Sunghee; Saracini, Claudio; Siegler, Maxime A; Drichko, Natalia; Karlin, Kenneth D

    2012-12-03

    At -90 °C in acetone, a stable hydroperoxo complex [(BA)Cu(II)OOH](+) (2) (BA, a tetradentate N(4) ligand possessing a pendant -N(H)CH(2)C(6)H(5) group) is generated by reacting [(BA)Cu(II)(CH(3)COCH(3))](2+) with only 1 equiv of H(2)O(2)/Et(3)N. The exceptional stability of 2 is ascribed to internal H-bonding. Species 2 is also generated in a manner not previously known in copper chemistry, by adding 1.5 equiv of H(2)O(2) (no base) to the cuprous complex [(BA)Cu(I)](+). The broad implications for this finding are discussed. Species 2 slowly converts to a μ-1,2-peroxodicopper(II) analogue (3) characterized by UV-vis and resonance Raman spectroscopies. Unlike a close analogue not possessing internal H-bonding, 2 affords no oxidative reactivity with internal or external substrates. However, 2 can be protonated to release H(2)O(2), but only with HClO(4), while 1 equiv Et(3)N restores 2.

  4. Selected clinical chemistry analytes correlate with the pathogenesis of inclusion body hepatitis experimentally induced by fowl aviadenoviruses.

    PubMed

    Matos, Miguel; Grafl, Beatrice; Liebhart, Dieter; Schwendenwein, Ilse; Hess, Michael

    2016-10-01

    In the present study, clinical chemistry was applied to assess the pathogenesis and progression of experimentally induced inclusion body hepatitis (IBH). For this, five fowl aviadenovirus (FAdV) strains from recent IBH field outbreaks were used to orally inoculate different groups of day-old specific pathogen-free chickens, which were weighed, sampled and examined during necropsy by sequential killing. Mortalities of 50% and 30% were recorded in two groups between 6 and 9 days post-infection (dpi), along with a decreased weight of 23% and 20%, respectively, compared to the control group. Macroscopical changes were seen in the liver and kidney between 6 and 10 dpi, with no lesions being observed in the other organs. Histological lesions were observed in the liver and pancreas during the same period. Plasma was collected from killed birds of each group at each time point and the following clinical chemistry analytes were investigated: aspartate aminotransferase (AST), glutamate dehydrogenase (GLDH), bile acids, total protein, albumin, uric acid and lipase. Plasma protein profile, AST and GLDH, together with bile acids values paralleled the macroscopical and histopathological lesions in the liver, while plasma lipase activity levels coincided with lesions observed in pancreas. In agreement with the histology and clinical chemistry, viral load in the target organs, liver and pancreas, was highest at 7 dpi. Thus, clinical chemistry was found to be a valuable tool in evaluating and monitoring the progression of IBH in experimentally infected birds, providing a deeper knowledge of the underlying pathophysiological mechanisms of a FAdV infection in chickens.

  5. Thiodiacetate-manganese chemistry with N ligands: unique control of the supramolecular arrangement over the metal coordination mode.

    PubMed

    Grirrane, Abdessamad; Pastor, Antonio; Galindo, Agustín; Alvarez, Eleuterio; Mealli, Carlo; Ienco, Andrea; Orlandini, Annabella; Rosa, Patrick; Caneschi, Andrea; Barra, Anne-Laure; Sanz, Javier Fernández

    2011-09-12

    Compounds based on the Mn-tda unit (tda=S(CH(2)COO)(2)(-2) ) and N co-ligands have been analyzed in terms of structural, spectroscopic, magnetic properties and DFT calculations. The precursors [Mn(tda)(H(2)O)](n) (1) and [Mn(tda)(H(2)O)(3)]·H(2)O (2) have been characterized by powder and X-ray diffraction, respectively. Their derivatives with bipyridyl-type ligands have formulas [Mn(tda)(bipy)](n) (3), [{Mn(N-N)}(2)(μ-H(2)O)(μ-tda)(2)](n) (N-N=4,4'-Me(2)bipy (4), 5,5'-Me(2)bipy, (5)) and [Mn(tda){(MeO)(2)bipy}·2H(2)O](n) (6). Depending on the presence/position of substituents at bipy, the supramolecular arrangement can affect the metal coordination type. While all the complexes consist of 1D coordination polymers, only 3 has a copper-acetate core with local trigonal prismatic metal coordination. The presence of substituents in 4-6, together with water co-ligands, reduces the supramolecular interactions and typical octahedral Mn(II) ions are observed. The unicity of 3 is also supported by magnetic studies and by DFT calculations, which confirm that the unusual Mn coordination is a consequence of extended noncovalent interactions (π-π stacking) between bipy ligands. Moreover, 3 is an example of broken paradigm for supramolecular chemistry. In fact, the desired stereochemical properties are achieved by using rigid metal building blocks, whereas in 3 the accumulation of weak noncovalent interactions controls the metal geometry. Other N co-ligands have also been reacted with 1 to give the compounds [Mn(tda)(phen)](2)·6H(2)O (7) (phen=1,10-phenanthroline), [Mn(tda)(terpy)](n) (8) (terpy=2,2':6,2''-terpyridine), [Mn(tda)(pyterpy)](n) (9) (pyterpy=4'-(4-pyridyl)-2,2':6,2''-terpyridine), [Mn(tda)(tpt)(H(2)O)]·2H(2)O (10) and [Mn(tda)(tpt)(H(2)O)](2)·2H(2)O (11) (tpt=2,4,6-tris(2-pyridyl)-1,3,5-triazine). Their identified mono-, bi- or polynuclear structures clearly indicate that hydrogen bonding is variously competitive with π-π stacking.

  6. Coordination chemistry of 1,4-bis-carboxymethylcyclam, H(2)(1,4-bcc).

    PubMed

    Tonei, Deborah M; Ware, David C; Brothers, Penelope J; Plieger, Paul G; Clark, George R

    2006-01-07

    Zinc metal reduction of the cobalt(III) complex [Co(1,4-bcc)](+) (1,4-bcc = 1,4-bis-carboxymethylcyclam) produces the corresponding cobalt(II) complex which crystallises as the coordination polymer {[Co(1,4-bcc)]ZnCl(2)}(n). A method has been developed for removal of the cobalt(III) ion from [Co(1,4-bcc)](+) and isolation of the free ligand as its hydrochloride salt, H(2)(1,4-bcc).4HCl. This has been used for the preparation of new metal complexes, and the syntheses and characterisation of the copper(ii), nickel(ii), zinc(ii) and chromium(iii) complexes containing the 1,4-bcc ligand are described. X-Ray crystal structures of {[Co(1,4-bcc)]ZnCl(2)}(n).2.5H(2)O, {[Cu(1,4-bcc)]CuCl(2)}(n).0.25MeOH.H(2)O and [Cu(1,4-bcc)H]ClO(4) show the complexes to have the trans(O) geometry of the 1,4-bcc ligand, while the structure of [Cr(1,4-bcc)H(0.5)](ClO(4))(1.5).EtOH exhibits the cis(O) configuration.

  7. Soluble diamagnetic model for malaria pigment: coordination chemistry of gallium(III)protoporphyrin-IX.

    PubMed

    Bohle, D Scott; Dodd, Erin L; Pinter, Tyler B J; Stillman, Martin J

    2012-10-15

    The facile axial ligand exchange properties of gallium(III) protoporphyrin IX in methanol solution were utilized to explore self-association interactions by NMR techniques. Structural changes were observed, as well as competitive behavior with the ligands acetate and fluoride, which differed from that seen with the synthetic analogue gallium(III) octaethylporphyrin which lacks acid groups in its side-chains and has less solution heterogeneity as indicated by absorption and MCD spectroscopies. The propionic acid side chains of protoporphyrin IX are implicated in all such interactions of PPIX, and both dynamic metal-propionic interactions and the formation of propionate-bridged dimers are observed. Fluoride coordination provides an unusual example of slow ligand exchange, and this allows for the identification of a fluoride bridged dimer in solution. An improved synthesis of the chloride and hydroxide complexes of gallium(III) protoporphyrin IX is reported. An insoluble gallium analogue of hematin anhydride is described. In general, the interactions between solvent and the metal are found to confer very high solubility, making [Ga(PPIX)](+) a useful model for ferric heme species.

  8. Coordination chemistry of several radius-sensitive complexones and applications to lanthanide-actinide separations

    SciTech Connect

    Potter, M.W.

    1981-10-01

    The relationships between the lanthanide complex formation equilibria and the lanthanide-actinide separation application of three radius sensitive ligands have been studied. The consecutive stepwise formation constants of the 1:1, 2:1, and 3:1 chelate species formed by the interaction of DHDMB and the tripositive lanthanides and yttrium were determined potentiometrically at 0.1 M ionic strength and 25/sup 0/C. Results indicate that three different coordination modes, one tridentate and two bidentate are in evidence. Tracer level /sup 241/Am - /sup 155/Eu cation-exchange experiments utilizing DHDMB eluents indicate that this dihydroxycarboxylate does not form a sufficiently strong americium complex to elute that actinide ahead of europium. The overall stability of the americium 3:1 complex appears intermediate between samarium and europium. Cation-exchange elutions of /sup 241/Am, /sup 155/Eu, and /sup 160/Tb mixtures with EEDTA solutions prove that the EEDTA ligand is capable of eluting americium ahead of all of the tripositive lanthanide cations. The minimum separation occurs with terbium, where the Am-Tb separation factor is 1.71. 1,5-diaminopentane-N,N,N',N'-tetraacetic acid (PMDTA) was synthesized using cation exchange. A mathematical method was developed for the formation constants of the protonated and unprotonated lanthanide-PMDTA complexes from potentiometry. Cation-exchange elutions of tracer quantities of Am, Eu, and Tb revealed that terbium is eluted ahead of both americium and europium.

  9. 2-Acylpyrroles as mono-anionic O,N-chelating ligands in silicon coordination chemistry.

    PubMed

    Kämpfe, Alexander; Brendler, Erica; Kroke, Edwin; Wagler, Jörg

    2014-07-21

    Kryptopyrrole (2,4-dimethyl-3-ethylpyrrole) was acylated with, for example, benzoyl chloride to afford 2-benzoyl-3,5-dimethyl-4-ethylpyrrole (L(1)H). With SiCl4 this ligand reacts under liberation of HCl and formation of the complex L(1)2SiCl2. In related reactions with HSiCl3 or H2SiCl2, the same chlorosilicon complex is formed under liberation of HCl and H2 or liberation of H2, respectively. The chlorine atoms of L(1)2SiCl2 can be replaced by fluoride and triflate using ZnF2 and Me3Si-OTf, respectively. The use of a supporting base (triethylamine) is required for the complexation of phenyltrichlorosilane and diphenyldichlorosilane. The complexes L(1)2SiCl2, L(1)2SiF2, L(1)2Si(OTf)2, L(1)2SiPhCl, and L(1)2SiPh2 exhibit various configurations of the octahedral silicon coordination spheres (i.e. cis or trans configuration of the monodentate substituents, different orientations of the bidentate chelating ligands relative to each other). Furthermore, cationic silicon complexes L(1)3Si(+) and L(1) SiPh(+) were synthesized by chloride abstraction with GaCl3. In contrast, reaction of L(1)2SiCl2 with a third equivalent of L(1)H in the presence of excess triethylamine produced a charge-neutral hexacoordinate Si complex with a new tetradentate chelating ligand which formed by Si-templated C-C coupling of two ligands L(1).

  10. Supramolecular coordination chemistry in aqueous solution: lanthanide ion-induced triple helix formation.

    PubMed

    Lessmann, J J; Horrocks, W D

    2000-07-24

    The self-assembly of dinuclear triple helical lanthanide ion complexes (helicates), in aqueous solution, is investigated utilizing laser-induced, lanthanide luminescence spectroscopy. A series of dinuclear lanthanide (III) helicates (Ln(III)) based on 2,6-pyridinedicarboxylic acid (dipicolinic acid, dpa) coordinating units was synthesized by linking two dpa moieties using the organic diamines (1R,2R)-diaminocyclohexane (chxn-R,R) and 4,4'-diaminodiphenylmethane (dpm). Luminescence excitation spectroscopy of the Eu3+ 7F0-->5D0 transition shows the apparent cooperative formation of neutral triple helical complexes in aqueous solution, with a [Eu2L3] stoichiometry. Eu3+ excitation peak wavelengths and excited-state lifetimes correspond to those of the [Eu(dpa)3]3- model complex. CD studies of the Nd(III) helicate Nd2(dpa-chxn-R,R)3 reveal optical activity of the f-f transitions, indicating that the chiral linking group induces a stable chirality at the metal ion center. Molecular mechanics calculations using CHARMm suggest that the delta delta configuration at the Nd3+ ion centers is induced by the chxn-R,R linker. Stability constants were determined for both ligands with Eu3+, yielding identical results: log K = 31.6 +/- 0.2 (K in units of M-4). Metal-metal distances calculated from Eu3+-->Nd3+ energy-transfer experiments show that the complexes have metal-metal distances close to those calculated by molecular modeling. The fine structure in the Tb3+ emission bands is consistent with the approximate D3 symmetry as anticipated for helicates.

  11. Instrumental Analysis of Biodiesel Content in Commercial Diesel Blends: An Experiment for Undergraduate Analytical Chemistry

    ERIC Educational Resources Information Center

    Feng, Z. Vivian; Buchman, Joseph T.

    2012-01-01

    The potential of replacing petroleum fuels with renewable biofuels has drawn significant public interest. Many states have imposed biodiesel mandates or incentives to use commercial biodiesel blends. We present an inquiry-driven experiment where students are given the tasks to gather samples, develop analytical methods using various instrumental…

  12. The intrinsic fluorescence of FAD and its application in analytical chemistry: a review.

    PubMed

    Galbán, Javier; Sanz-Vicente, Isabel; Navarro, Jesús; de Marcos, Susana

    2016-12-19

    This review (with 106 references) mainly deals with the analytical applications of flavin-adenine dinucleotide (FAD) fluorescence. In the first section, the spectroscopic properties of this compound are reviewed at the light of his different acid-base, oxidation and structural forms; the chemical and spectroscopic properties of flavin mononucleotide (FMN) and other flavins will be also briefly discussed. The second section discusses how the properties of FAD fluorescence changes in flavoenzymes (FvEs), again considering the different chemical and structural forms; the glucose oxidase (GOx) and the choline oxidase (ChOx) cases will be commented. Since almost certainly the most reported analytical application of FAD fluorescence is as an auto-indicator in enzymatic methods catalysed by FvE oxidoreductases, it is important to know how the concentrations of the different forms of FAD changes along the reaction and, consequently, the fluorescence and the analytical signals. An approach to do this will be presented in section 3. The fourth part of the paper compiles the analytical applications which have been reported until now based in these fluorescence properties. Finally, some suggestions about tentative future research are also given.

  13. Analytical Chemistry Division. Annual progress report for period ending December 31, 1980

    SciTech Connect

    Lyon, W.S.

    1981-05-01

    This report is divided into: analytical methodology; mass and emission spectrometry; technical support; bio/organic analysis; nuclear and radiochemical analysis; quality assurance, safety, and tabulation of analyses; supplementary activities; and presentation of research results. Separate abstracts were prepared for the technical support, bio/organic analysis, and nuclear and radiochemical analysis. (DLC)

  14. Data Acquisition Programming (LabVIEW): An Aid to Teaching Instrumental Analytical Chemistry.

    ERIC Educational Resources Information Center

    Gostowski, Rudy

    A course was developed at Austin Peay State University (Tennessee) which offered an opportunity for hands-on experience with the essential components of modern analytical instruments. The course aimed to provide college students with the skills necessary to construct a simple model instrument, including the design and fabrication of electronic…

  15. Analytical Chemistry Division annual progress report for period ending December 31, 1984

    SciTech Connect

    Lyon, W.S.

    1985-04-01

    Progress reports are presented for the following sections: analytical methodology; mass and emission spectroscopy; radioactive materials analysis; bio/organic analysis; and general and environmental analysis; quality assurance, safety, and tabulation analyses. In addition a list of publications and oral presentations and supplemental activities are included.

  16. Analytical Chemistry Division annual progress report for period ending December 31, 1983

    SciTech Connect

    Lyon, W.S.

    1984-05-01

    Progress and activities are reported in: analytical methodology, mass and emission spectrometry, radioactive materials analysis, bio/organic analysis, general and environmental analysis, and quality assurance and safety. Supplementary activities are also discussed, and a bibliography of publications is also included. (DLC)

  17. Charge Density Quantification of Polyelectrolyte Polysaccharides by Conductometric Titration: An Analytical Chemistry Experiment

    ERIC Educational Resources Information Center

    Farris, Stefano; Mora, Luigi; Capretti, Giorgio; Piergiovanni, Luciano

    2012-01-01

    An easy analytical method for determination of the charge density of polyelectrolytes, including polysaccharides and other biopolymers, is presented. The basic principles of conductometric titration, which is used in the pulp and paper industry as well as in colloid and interface science, were adapted to quantify the charge densities of a…

  18. Thirty-seventh ORNL/DOE conference on analytical chemistry in energy technology: Abstracts of papers

    SciTech Connect

    1997-12-31

    Abstracts only are given for papers presented during the following topical sessions: Opportunities for collaboration: Industry, academic, national laboratories; Developments in sensor technology; Analysis in containment facilities; Improving the quality of environmental data; Process analysis; Field analysis; Radiological separations; Interactive analytical seminars; Measurements and chemical industry initiatives; and Isotopic measurements and mass spectroscopy.

  19. Structural Isomer Identification via NMR: A Nuclear Magnetic Resonance Experiment for Organic, Analytical, or Physical Chemistry.

    ERIC Educational Resources Information Center

    Szafran, Zvi

    1985-01-01

    Background information, procedures used, and typical results obtained are provided for an experiment that examines the ability of nuclear magnetic resonance (NMR) to distinguish between structural isomers via resonance multiplicities and chemical shifts. Reasons for incorporating the experiment into organic, analytical, or physical chemistry…

  20. The intrinsic fluorescence of FAD and its application in analytical chemistry: a review

    NASA Astrophysics Data System (ADS)

    Galbán, Javier; Sanz-Vicente, Isabel; Navarro, Jesús; de Marcos, Susana

    2016-12-01

    This review (with 106 references) mainly deals with the analytical applications of flavin-adenine dinucleotide (FAD) fluorescence. In the first section, the spectroscopic properties of this compound are reviewed at the light of his different acid-base, oxidation and structural forms; the chemical and spectroscopic properties of flavin mononucleotide (FMN) and other flavins will be also briefly discussed. The second section discusses how the properties of FAD fluorescence changes in flavoenzymes (FvEs), again considering the different chemical and structural forms; the glucose oxidase (GOx) and the choline oxidase (ChOx) cases will be commented. Since almost certainly the most reported analytical application of FAD fluorescence is as an auto-indicator in enzymatic methods catalysed by FvE oxidoreductases, it is important to know how the concentrations of the different forms of FAD changes along the reaction and, consequently, the fluorescence and the analytical signals. An approach to do this will be presented in section 3. The fourth part of the paper compiles the analytical applications which have been reported until now based in these fluorescence properties. Finally, some suggestions about tentative future research are also given.

  1. Secondary interactions or ligand scrambling? Subtle steric effects govern the iridium(I) coordination chemistry of phosphoramidite ligands.

    PubMed

    Osswald, Tina; Rüegger, Heinz; Mezzetti, Antonio

    2010-01-25

    The like and unlike isomers of phosphoramidite (P*) ligands are found to react differently with iridium(I), which is a key to explaining the apparently inconsistent results obtained by us and other research groups in a variety of catalytic reactions. Thus, the unlike diastereoisomer (aR,S,S)-[IrCl(cod)(1 a)] (2 a; cod=1,5-cyclooctadiene, 1 a=(aR,S,S)-(1,1'-binaphthalene)-2,2'-diyl bis(1-phenylethyl)phosphoramidite) forms, upon chloride abstraction, the monosubstituted complex (aR,S,S)-[Ir(cod)(1,2-eta-1 a,kappaP)](+) (3 a), which contains a chelating P* ligand that features an eta(2) interaction between a dangling phenyl group and iridium. Under analogous conditions, the like analogue (aR,R,R)-1 a' gives the disubstituted species (aR,R,R)-[Ir(cod)(1 a',kappaP)(2)](+) (4 a') with monodentate P* ligands. The structure of 3 a was assessed by a combination of X-ray and NMR spectroscopic studies, which indicate that it is the configuration of the binaphthol moiety (and not that of the dangling benzyl N groups) that determines the configuration of the complex. The effect of the relative configuration of the P* ligand on its iridium(I) coordination chemistry is discussed in the context of our preliminary catalytic results and of apparently random results obtained by other groups in the iridium(I)-catalyzed asymmetric allylic alkylation of allylic acetates and in rhodium(I)-catalyzed asymmetric cycloaddition reactions. Further studies with the unlike ligand (aS,R,R)-(1,1'-binaphthalene)-2,2'-diyl bis{[1-(1-naphthalene-1-yl)ethyl]phosphoramidite} (1 b) showed a yet different coordination mode, that is, the eta(4)-arene-metal interaction in (aS,R,R)-[Ir(cod)(1,2,3,4-eta-1 b,kappaP)](+) (3 b).

  2. Peroxide induced ultra-weak chemiluminescence and its application in analytical chemistry.

    PubMed

    Lin, Zhen; Chen, Hui; Lin, Jin-Ming

    2013-09-21

    Chemiluminescence (CL), as a sensitive, rapid, and facile analytical method, has been widely applied in environmental monitoring, clinical diagnosis and food safety. Recently, the main challenge and research interest in the CL study have been focused on exploring new CL systems and obtaining new insight into the interaction between CL reagents. The peroxide induced ultra-weak CL reactions are some new arising systems that have received great attention and have been successfully applied in many fields. The peroxide includes hydrogen peroxide, peroxynitrite, peroxymonocarbonate, peroxomonosulphate and so on. This review paper covers the mechanism of the peroxide induced ultra-weak CL and the analytical applications of the CL have also been summarized. The future prospects for the peroxide induced ultra-weak CL are discussed.

  3. Computerized real-time quality control program for analytical chemistry laboratories

    SciTech Connect

    Dill, M.S.; Floyd, M.A.; Morrow, R.W.

    1985-10-01

    A unique computer program has been developed for complete quality control/quality assurance of the operation and statistical control of the testing in the analytical laboratory. The system operates similar to a scanner on a production line with effective checkpoints and furnishes immediate feedback by automatically generated mail messages to appropriate personnel when any non-conformance is encountered. Corrective action is required by the technician prior to proceeding with the analysis.

  4. Analyzing DNA Nanotechnology: A Call to Arms For The Analytical Chemistry Community.

    PubMed

    Mathur, Divita; Medintz, Igor L

    2017-03-07

    In order to fully realize the potential of DNA nanotechnology, it is crucial to overcome the lack of robust analytical techniques that continue to hinder the purification and characterization of DNA-based structures. In this Feature, we provide a snapshot of the current state of metrological techniques in DNA nanotechnology and look forward to emerging technologies that may offer new ways to probe and visualize these complex structures.

  5. Tetrapositive plutonium, neptunium, uranium, and thorium coordination complexes: chemistry revealed by electron transfer and collision induced dissociation.

    PubMed

    Gong, Yu; Tian, Guoxin; Rao, Linfeng; Gibson, John K

    2014-04-17

    The Pu(4+), Np(4+), and U(4+) ions, which have large electron affinities of ∼34.6, ∼33.6, and ∼32.6 eV, respectively, were stabilized from solution to the gas phase upon coordination by three neutral tetramethyl-3-oxa-glutaramide ligands (TMOGA). Both collision induced dissociation (CID) and electron transfer dissociation (ETD) of Pu(TMOGA)3(4+) reveal the propensity for reduction of Pu(IV) to Pu(III), by loss of TMOGA(+) in CID and by simple electron transfer in ETD. The reduction of Pu(IV) is in distinct contrast to retention of Th(IV) in both CID and ETD of Th(TMOGA)3(4+), where only the C-Oether bond cleavage product was observed. U(TMOGA)3(4+) behaves similarly to Th(TMOGA)3(4+) upon CID and ETD, while the fragmentation patterns of Np(TMOGA)3(4+) lie between those of Pu(TMOGA)3(4+) and U(TMOGA)3(4+). It is notable that the gas-phase fragmentation behaviors of these exceptional tetrapositive complexes parallel fundamental differences in condensed phase chemistry within the actinide series, specifically the tendency for reduction from the IV to III oxidation states.

  6. Comparison of the single channel and multichannel (multivariate) concepts of selectivity in analytical chemistry.

    PubMed

    Dorkó, Zsanett; Verbić, Tatjana; Horvai, George

    2015-07-01

    Different measures of selectivity are in use for single channel and multichannel linear analytical measurements, respectively. It is important to understand that these two measures express related but still distinctly different features of the respective measurements. These relationships are clarified by introducing new arguments. The most widely used selectivity measure of multichannel linear methods (which is based on the net analyte signal, NAS, concept) expresses the sensitivity to random errors of a determination where all bias from interferents is computationally eliminated using pure component spectra. The conventional selectivity measure of single channel linear measurements, on the other hand, helps to estimate the bias caused by an interferent in a biased measurement. In single channel methods expert knowledge about the samples is used to limit the possible range of interferent concentrations. The same kind of expert knowledge allows improved (lower mean squared error, MSE) analyte determinations also in "classical" multichannel measurements if those are intractable due to perfect collinearity or to high noise inflation. To achieve this goal bias variance tradeoff is employed, hence there remains some bias in the results and therefore the concept of single channel selectivity can be extended in a natural way to multichannel measurements. This extended definition and the resulting selectivity measure can also be applied to the so-called inverse multivariate methods like partial least squares regression (PLSR), principal component regression (PCR) and ridge regression (RR).

  7. Construction of Protein-Based Biosensors Using Ligand-Directed Chemistry for Detecting Analyte Binding.

    PubMed

    Yamaura, Kei; Kiyonaka, Shigeki; Hamachi, Itaru

    2017-01-01

    Protein-based fluorescent biosensors are powerful tools for quantitative detection of biomolecules or drugs with high sensitivity under physiological conditions. However, conventional methods for construction of biosensors require structural data with high resolution or amino acid sequence information in most cases, which hampers applicability of this method to structurally complicated receptor proteins. To sidestep such limitations, we recently developed a new method that employs ligand-directed chemistry coupled with a bimolecular fluorescence quenching and recovery system, which enabled the conversion of various kinds of membrane-bound receptors to "turn-on" type fluorescent sensors. Here, we describe a protocol for construction of "turn-on" type fluorescent biosensors based on the GABAA receptor which permits quantitative analysis of the ligand affinity.

  8. Analytical Chemistry Developmental Work Using a 243Am Solution

    SciTech Connect

    Spencer, Khalil J.; Stanley, Floyd E.; Porterfield, Donivan R.; Castro, Alonso

    2015-02-24

    This project seeks to reestablish our analytical capability to characterize Am bulk material and develop a reference material suitable to characterizing the purity and assay of 241Am oxide for industrial use. The tasks associated with this phase of the project included conducting initial separations experiments, developing thermal ionization mass spectrometry capability using the 243Am isotope as an isotope dilution spike , optimizing the spike for the determination of 241Pu-241 Am radiochemistry, and, additionally, developing and testing a methodology which can detect trace to ultra- trace levels of Pu (both assay and isotopics) in bulk Am samples .

  9. The development of paper microzone-based green analytical chemistry methods for determining the quality of wines.

    PubMed

    Vaher, M; Kaljurand, M

    2012-08-01

    The colorimetric determination of the concentration of polyphenols, flavonoids, and anthocyanins in wine samples, using a mobile phone camera for sample spot capture on a paper microzone and a remote computer with dedicated software for quantification, is presented as an illustrative application of green analytical chemistry. A comparison of the results with conventional spectrophotometry demonstrates that both methods yield similar results. Developing the assay took approximately 2 months, and the use of chemicals, compared with spectrophotometry, was reduced by about two orders of magnitude: the paper assay consumed 0.4 mL of reagent for 100 samples, whereas the spectrophotometric assay required 100 mL. The relative testing times for 100 samples were 7 h by spectrophotometry and 2 h for paper-a savings on the order of 3.5. No analytical instrumentation was used for the colorimetry on paper microzones. Instead, the assay took advantage of the existing communication technology and free software. The assay was found to be effective, with a nonlinear response at the concentration range of 0.2-5 g/L. The detection limit of the proposed method is in sub-grams per liter.

  10. Photography by Cameras Integrated in Smartphones as a Tool for Analytical Chemistry Represented by an Butyrylcholinesterase Activity Assay.

    PubMed

    Pohanka, Miroslav

    2015-06-11

    Smartphones are popular devices frequently equipped with sensitive sensors and great computational ability. Despite the widespread availability of smartphones, practical uses in analytical chemistry are limited, though some papers have proposed promising applications. In the present paper, a smartphone is used as a tool for the determination of cholinesterasemia i.e., the determination of a biochemical marker butyrylcholinesterase (BChE). The work should demonstrate suitability of a smartphone-integrated camera for analytical purposes. Paper strips soaked with indoxylacetate were used for the determination of BChE activity, while the standard Ellman's assay was used as a reference measurement. In the smartphone-based assay, BChE converted indoxylacetate to indigo blue and coloration was photographed using the phone's integrated camera. A RGB color model was analyzed and color values for the individual color channels were determined. The assay was verified using plasma samples and samples containing pure BChE, and validated using Ellmans's assay. The smartphone assay was proved to be reliable and applicable for routine diagnoses where BChE serves as a marker (liver function tests; some poisonings, etc.). It can be concluded that the assay is expected to be of practical applicability because of the results' relevance.

  11. Photography by Cameras Integrated in Smartphones as a Tool for Analytical Chemistry Represented by an Butyrylcholinesterase Activity Assay

    PubMed Central

    Pohanka, Miroslav

    2015-01-01

    Smartphones are popular devices frequently equipped with sensitive sensors and great computational ability. Despite the widespread availability of smartphones, practical uses in analytical chemistry are limited, though some papers have proposed promising applications. In the present paper, a smartphone is used as a tool for the determination of cholinesterasemia i.e., the determination of a biochemical marker butyrylcholinesterase (BChE). The work should demonstrate suitability of a smartphone-integrated camera for analytical purposes. Paper strips soaked with indoxylacetate were used for the determination of BChE activity, while the standard Ellman’s assay was used as a reference measurement. In the smartphone-based assay, BChE converted indoxylacetate to indigo blue and coloration was photographed using the phone’s integrated camera. A RGB color model was analyzed and color values for the individual color channels were determined. The assay was verified using plasma samples and samples containing pure BChE, and validated using Ellmans’s assay. The smartphone assay was proved to be reliable and applicable for routine diagnoses where BChE serves as a marker (liver function tests; some poisonings, etc.). It can be concluded that the assay is expected to be of practical applicability because of the results’ relevance. PMID:26110404

  12. ICL-Based OF-CEAS: A Sensitive Tool for Analytical Chemistry.

    PubMed

    Manfred, Katherine M; Hunter, Katharine M; Ciaffoni, Luca; Ritchie, Grant A D

    2017-01-03

    Optical-feedback cavity-enhanced absorption spectroscopy (OF-CEAS) using mid-infrared interband cascade lasers (ICLs) is a sensitive technique for trace gas sensing. The setup of a V-shaped optical cavity operating with a 3.29 μm cw ICL is detailed, and a quantitative characterization of the injection efficiency, locking stability, mode matching, and detection sensitivity is presented. The experimental data are supported by a model to show how optical feedback affects the laser frequency as it is scanned across several longitudinal modes of the optical cavity. The model predicts that feedback enhancement effects under strongly absorbing conditions can cause underestimations in the measured absorption, and these predictions are verified experimentally. The technique is then used in application to the detection of nitrous oxide as an exemplar of the utility of this technique for analytical gas phase spectroscopy. The analytical performance of the spectrometer, expressed as noise equivalent absorption coefficient, was estimated as 4.9 × 10(-9) cm (-1) Hz(-1/2), which compares well with recently reported values.

  13. The btp [2,6-bis(1,2,3-triazol-4-yl)pyridine] binding motif: a new versatile terdentate ligand for supramolecular and coordination chemistry.

    PubMed

    Byrne, Joseph P; Kitchen, Jonathan A; Gunnlaugsson, Thorfinnur

    2014-08-07

    Ligands containing the btp [2,6-bis(1,2,3-triazol-4-yl)pyridine] motif have appeared with increasing regularity over the last decade. This class of ligands, formed in a one pot ‘click’ reaction, has been studied for various purposes, such as for generating d and f metal coordination complexes and supramolecular self-assemblies, and in the formation of dendritic and polymeric networks, etc. This review article introduces btp as a novel and highly versatile terdentate building block with huge potential in inorganic supramolecular chemistry. We will focus on the coordination chemistry of btp ligands with a wide range of metals, and how it compares with other classical pyridyl and polypyridyl based ligands, and then present a selection of applications including use in catalysis, enzyme inhibition, photochemistry, molecular logic and materials, e.g. polymers, dendrimers and gels. The photovoltaic potential of triazolium derivatives of btp and its interactions with anions will also be discussed.

  14. ELISA and GC-MS as Teaching Tools in the Undergraduate Environmental Analytical Chemistry Laboratory

    NASA Astrophysics Data System (ADS)

    Wilson, Ruth I.; Mathers, Dan T.; Mabury, Scott A.; Jorgensen, Greg M.

    2000-12-01

    An undergraduate experiment for the analysis of potential water pollutants is described. Students are exposed to two complementary techniques, ELISA and GC-MS, for the analysis of a water sample containing atrazine, desethylatrazine, and simazine. Atrazine was chosen as the target analyte because of its wide usage in North America and its utility for students to predict environmental degradation products. The water sample is concentrated using solid-phase extraction for GC-MS, or diluted and analyzed using a competitive ELISA test kit for atrazine. The nature of the water sample is such that students generally find that ELISA gives an artificially high value for the concentration of atrazine. Students gain an appreciation for problems associated with measuring pollutants in the aqueous environment: sensitivity, accuracy, precision, and ease of analysis. This undergraduate laboratory provides an opportunity for students to learn several new analysis and sample preparation techniques and to critically evaluate these methods in terms of when they are most useful.

  15. Cationic terminal gallylene complexes by halide abstraction: coordination chemistry of a valence isoelectronic analogue of CO and N2.

    PubMed

    Coombs, Natalie D; Vidovic, Dragoslav; Day, Joanna K; Thompson, Amber L; Le Pevelen, Delphine D; Stasch, Andreas; Clegg, William; Russo, Luca; Male, Louise; Hursthouse, Michael B; Willock, David J; Aldridge, Simon

    2008-11-26

    While N(2) and CO have played central roles in developing models of electronic structure, and their interactions with transition metals have been widely investigated, the valence isoelectronic diatomic molecules EX (E = group 13 element, X = group 17 element) have yet to be isolated under ambient conditions, either as the "free" molecule or as a ligand in a simple metal complex. As part of a program designed to address this deficiency, together with wider issues of the chemistry of cationic systems [L(n)M(ER)](+) (E = B, Al, Ga; R = aryl, amido, halide), we have targeted complexes of the type [L(n)M(GaX)](+). Halide abstraction is shown to be a viable method for the generation of mononuclear cationic complexes containing gallium donor ligands. The ability to isolate tractable two-coordinate products, however, is strongly dependent on the steric and electronic properties of the metal/ligand fragment. In the case of complexes containing ancillary pi-acceptor ligands such as CO, cationic complexes can only be isolated as base-trapped adducts, even with bulky aryl substituents at gallium. Base-free gallylene species such as [Cp*Fe(CO)(2)(GaMes)](+) can be identified only in the vapor phase by electrospray mass spectrometry experiments. With bis(phosphine) donor sets at the metal, the more favorable steric/electronic environment allows for the isolation of two-coordinate ligand systems, even with halide substituents at gallium. Thus, [Cp*Fe(dppe)(GaI)](+)[BAr(f)(4)](-) (9) can be synthesized and shown crystallographically to feature a terminally bound GaI ligand; 9 represents the first experimental realization of a complex containing a valence isoelectronic group 13/group 17 analogue of CO and N(2). DFT calculations reveal a relatively weakly bound GaI ligand, which is confirmed experimentally by the reaction of 9 with CO to give [Cp*Fe(dppe)(CO)](+)[BAr(f)(4)](-). In the absence of such reagents, 9 is stable for weeks in fluorobenzene solution, presumably reflecting (i

  16. Development of a method for detecting trace metals in aqueous solutions based on the coordination chemistry of hexahydrotriazines.

    PubMed

    Wojtecki, Rudy J; Yuen, Alexander Y; Zimmerman, Thomas G; Jones, Gavin O; Horn, Hans W; Boday, Dylan J; Hedrick, James L; García, Jeannette M

    2015-08-07

    The detection of trace amounts (<10 ppb) of heavy metals in aqueous solutions is described using 1,3,5-hexahydro-1,3,5-triazines (HTs) as chemical indicators and a low cost fluorimeter-based detection system. This method takes advantage of the inherent properties of HTs to coordinate strongly with metal ions in solution, a fundamental property that was studied using a combination of analytical tools (UV-Vis titrations, (1)H-NMR titrations and computational modeling). Based on these fundamental studies that show significant changes in the HT UV signature when a metal ion is present, HT compounds were used to prepare indicator strips that resulted in significant fluorescence changes when a metal was present. A portable and economical approach was adopted to test the concept of utilizing HTs to detect heavy metals using a fluorimeter system that consisted of a low-pressure mercury lamp, a photo-detector, a monolithic photodiode and an amplifier, which produces a voltage proportional to the magnitude of the visible fluorescence emission. Readings of the prepared HT test strips were evaluated by exposure to two different heavy metals at the safe threshold concentration described by the U.S. Environmental Protection Agency (EPA) for Cr(3+) and Ag(2+) (100 μg L(-1) and 6.25, respectively). This method of detection could be used to the presence of either metal at these threshold concentrations.

  17. Developments in Analytical Chemistry: Acoustically Levitated Drop Reactors for Enzyme Reaction Kinetics and Single-Walled Carbon Nanotube-Based Sensors for Detection of Toxic Organic Phosphonates

    ERIC Educational Resources Information Center

    Field, Christopher Ryan

    2009-01-01

    Developments in analytical chemistry were made using acoustically levitated small volumes of liquid to study enzyme reaction kinetics and by detecting volatile organic compounds in the gas phase using single-walled carbon nanotubes. Experience gained in engineering, electronics, automation, and software development from the design and…

  18. Extraction and Quantitation of FD&C Red Dye #40 from Beverages Containing Cranberry Juice: A College-Level Analytical Chemistry Experiment

    ERIC Educational Resources Information Center

    Rossi, Henry F., III; Rizzo, Jacqueline; Zimmerman, Devon C.; Usher, Karyn M.

    2012-01-01

    A chemical separation experiment can be an interesting addition to an introductory analytical chemistry laboratory course. We have developed an experiment to extract FD&C Red Dye #40 from beverages containing cranberry juice. After extraction, the dye is quantified using colorimetry. The experiment gives students hands-on experience in using solid…

  19. Determination of Total Arsenic and Speciation in Apple Juice by Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry: An Experiment for the Analytical Chemistry Laboratory

    ERIC Educational Resources Information Center

    He, Ping; Colon, Luis A.; Aga, Diana S.

    2016-01-01

    A two-part laboratory experiment was designed for upper-level analytical chemistry students to provide hands-on experience in the use of high performance liquid chromatography (HPLC) for separation and inductively coupled plasma mass spectrometry (ICP-MS) for detection. In the first part of the experiment, the students analyze total arsenic in…

  20. Integrating Organic Matter Structure with Ecosystem Function using Advanced Analytical Chemistry Techniques

    NASA Astrophysics Data System (ADS)

    Boot, C. M.

    2012-12-01

    Microorganisms are the primary transformers of organic matter in terrestrial and aquatic ecosystems. The structure of organic matter controls its bioavailability and researchers have long sought to link the chemical characteristics of the organic matter pool to its lability. To date this effort has been primarily attempted using low resolution descriptive characteristics (e.g. organic matter content, carbon to nitrogen ratio, aromaticity, etc .). However, recent progress in linking these two important ecosystem components has been advanced using advanced high resolution tools (e.g. nuclear magnetic resonance (NMR) spectroscopy, and mass spectroscopy (MS)-based techniques). A series of experiments will be presented that highlight the application of high resolution techniques in a variety of terrestrial and aquatic ecosystems with the focus on how these data explicitly provide the foundation for integrating organic matter structure into our concept of ecosystem function. The talk will highlight results from a series of experiments including: an MS-based metabolomics and fluorescence excitation emission matrix approach evaluating seasonal and vegetation based changes in dissolved organic matter (DOM) composition from arctic soils; Fourier transform ion cyclotron resonance (FTICR) MS and MS metabolomics analysis of DOM from three lakes in an alpine watershed; and the transformation of 13C labeled glucose track with NMR during a rewetting experiment from Colorado grassland soils. These data will be synthesized to illustrate how the application of advanced analytical techniques provides novel insight into our understanding of organic matter processing in a wide range of ecosystems.

  1. Acid-Base Chemistry of White Wine: Analytical Characterisation and Chemical Modelling

    PubMed Central

    Prenesti, Enrico; Berto, Silvia; Toso, Simona; Daniele, Pier Giuseppe

    2012-01-01

    A chemical model of the acid-base properties is optimized for each white wine under study, together with the calculation of their ionic strength, taking into account the contributions of all significant ionic species (strong electrolytes and weak one sensitive to the chemical equilibria). Coupling the HPLC-IEC and HPLC-RP methods, we are able to quantify up to 12 carboxylic acids, the most relevant substances responsible of the acid-base equilibria of wine. The analytical concentration of carboxylic acids and of other acid-base active substances was used as input, with the total acidity, for the chemical modelling step of the study based on the contemporary treatment of overlapped protonation equilibria. New protonation constants were refined (L-lactic and succinic acids) with respect to our previous investigation on red wines. Attention was paid for mixed solvent (ethanol-water mixture), ionic strength, and temperature to ensure a thermodynamic level to the study. Validation of the chemical model optimized is achieved by way of conductometric measurements and using a synthetic “wine” especially adapted for testing. PMID:22566762

  2. Acid-base chemistry of white wine: analytical characterisation and chemical modelling.

    PubMed

    Prenesti, Enrico; Berto, Silvia; Toso, Simona; Daniele, Pier Giuseppe

    2012-01-01

    A chemical model of the acid-base properties is optimized for each white wine under study, together with the calculation of their ionic strength, taking into account the contributions of all significant ionic species (strong electrolytes and weak one sensitive to the chemical equilibria). Coupling the HPLC-IEC and HPLC-RP methods, we are able to quantify up to 12 carboxylic acids, the most relevant substances responsible of the acid-base equilibria of wine. The analytical concentration of carboxylic acids and of other acid-base active substances was used as input, with the total acidity, for the chemical modelling step of the study based on the contemporary treatment of overlapped protonation equilibria. New protonation constants were refined (L-lactic and succinic acids) with respect to our previous investigation on red wines. Attention was paid for mixed solvent (ethanol-water mixture), ionic strength, and temperature to ensure a thermodynamic level to the study. Validation of the chemical model optimized is achieved by way of conductometric measurements and using a synthetic "wine" especially adapted for testing.

  3. To address accuracy and precision using methods from analytical chemistry and computational physics.

    PubMed

    Kozmutza, Cornelia; Picó, Yolanda

    2009-04-01

    In this work the pesticides were determined by liquid chromatography-mass spectrometry (LC-MS). In present study the occurrence of imidacloprid in 343 samples of oranges, tangerines, date plum, and watermelons from Valencian Community (Spain) has been investigated. The nine additional pesticides were chosen as they have been recommended for orchard treatment together with imidacloprid. The Mulliken population analysis has been applied to present the charge distribution in imidacloprid. Partitioned energy terms and the virial ratios have been calculated for certain molecules entering in interaction. A new technique based on the comparison of the decomposed total energy terms at various configurations is demonstrated in this work. The interaction ability could be established correctly in the studied case. An attempt is also made in this work to address accuracy and precision. These quantities are well-known in experimental measurements. In case precise theoretical description is achieved for the contributing monomers and also for the interacting complex structure some properties of this latter system can be predicted to quite a good accuracy. Based on simple hypothetical considerations we estimate the impact of applying computations on reducing the amount of analytical work.

  4. Modular syntheses of H₄octapa and H₂dedpa, and yttrium coordination chemistry relevant to ⁸⁶Y/⁹⁰Y radiopharmaceuticals.

    PubMed

    Price, Eric W; Cawthray, Jacqueline F; Adam, Michael J; Orvig, Chris

    2014-05-21

    The ligands H2dedpa, H4octapa, p-SCN-Bn-H2dedpa, and p-SCN-Bn-H4octapa were synthesized using a new protection chemistry approach, with labile tert-butyl esters replacing the previously used methyl esters as protecting groups for picolinic acid moieties. Additionally, the ligands H2dedpa and p-SCN-Bn-H2dedpa were synthesized using nosyl protection chemistry for the first time. The use of tert-butyl esters allows for deprotection at room temperature in trifluoroacetic acid (TFA), which compares favorably to the harsh conditions of refluxing HCl (6 M) or LiOH that were previously required for methyl ester cleavage. H4octapa has recently been shown to be a very promising (111)In and (177)Lu ligand for radiopharmaceutical applications; therefore, coordination chemistry studies with Y(3+) are described to assess its potential for use with (86)Y/(90)Y. The solution chemistry of H4octapa with Y(3+) is shown to be suitable via solution NMR studies of the [Y(octapa)](-) complex and density functional theory (DFT) calculations of the predicted structure, suggesting properties similar to those of the analogous In(3+) and Lu(3+) complexes. The molecular electrostatic potential (MEP) was mapped onto the molecular surface of the DFT-calculated coordination structures, suggesting very similar and even charge distributions between both the Lu(3+) and Y(3+) complexes of octapa(4-), and coordinate structures between 8 (ligand only) and 9 (ligand and one H2O). Potentiometric titrations determined H4octapa to have a formation constant (log K(ML)) with Y(3+) of 18.3 ± 0.1, revealing high thermodynamic stability. This preliminary work suggests that H4octapa may be a competent ligand for future (86)Y/(90)Y radiopharmaceutical applications.

  5. Atmospheric Chemistry for Astrophysicists: A Self-consistent Formalism and Analytical Solutions for Arbitrary C/O

    NASA Astrophysics Data System (ADS)

    Heng, Kevin; Lyons, James R.; Tsai, Shang-Min

    2016-01-01

    We present a self-consistent formalism for computing and understanding the atmospheric chemistry of exoplanets from the viewpoint of an astrophysicist. Starting from the first law of thermodynamics, we demonstrate that the van’t Hoff equation (which describes the equilibrium constant), Arrhenius equation (which describes the rate coefficients), and procedures associated with the Gibbs free energy (minimization, rescaling) have a common physical and mathematical origin. We address an ambiguity associated with the equilibrium constant, which is used to relate the forward and reverse rate coefficients, and restate its two definitions. By necessity, one of the equilibrium constants must be dimensionless and equate to an exponential function involving the Gibbs free energy, while the other is a ratio of rate coefficients and must therefore possess physical units. We demonstrate that the Arrhenius equation takes on a functional form that is more general than previously stated without recourse to tagging on ad hoc functional forms. Finally, we derive analytical models of chemical systems, in equilibrium, with carbon, hydrogen, and oxygen. We include acetylene and are able to reproduce several key trends, versus temperature and carbon-to-oxygen ratio, published in the literature. The rich variety of behavior that mixing ratios exhibit as a function of the carbon-to-oxygen ratio is merely the outcome of stoichiometric book-keeping and not the direct consequence of temperature or pressure variations.

  6. Double-sided Microfluidic Device for Speciation Analysis of Iron in Water Samples: Towards Greener Analytical Chemistry.

    PubMed

    Youngvises, Napaporn; Thanurak, Porapichcha; Chaida, Thanatcha; Jukmunee, Jaroon; Alsuhaimi, Awadh

    2015-01-01

    Microfluidics minimize the amounts of reagents and generate less waste. While microdevices are commonly single-sided, producing a substrate with microchannels on multiple surfaces would increase their usefulness. Herein, a polymethymethacrylate substrate incorporating microchannel structures on two sides was sandwiched between two polydimethylsiloxane sheets to create a multi-analysis device, which was used for the spectrophotometric analysis of the ferrous ion (Fe(2+)) and the ferric ion (Fe(3+)), by utilizing colorimetric detection. To monitor the signals from both channel networks, dual optical sensors were integrated into the system. The linear ranges for Fe(2+) and Fe(3+) analyses were 0.1 - 20 mg L(-1) (R(2) = 0.9988) and 1.0 - 40 mg L(-1) (R(2) = 0.9974), respectively. The detection limits for Fe(2+) and Fe(3+) were 0.1 and 0.5 mg L(-1), respectively. The percent recoveries of Fe(2+) and Fe(3+) were 93.5 - 104.3 with an RSD < 8%. The microdevice demonstrated capabilities for simultaneous analysis, low waste generation (7.2 mL h(-1)), and high sample throughput (180 h(-1)), making it ideal for greener analytical chemistry applications.

  7. ATMOSPHERIC CHEMISTRY FOR ASTROPHYSICISTS: A SELF-CONSISTENT FORMALISM AND ANALYTICAL SOLUTIONS FOR ARBITRARY C/O

    SciTech Connect

    Heng, Kevin; Tsai, Shang-Min; Lyons, James R.

    2016-01-10

    We present a self-consistent formalism for computing and understanding the atmospheric chemistry of exoplanets from the viewpoint of an astrophysicist. Starting from the first law of thermodynamics, we demonstrate that the van’t Hoff equation (which describes the equilibrium constant), Arrhenius equation (which describes the rate coefficients), and procedures associated with the Gibbs free energy (minimization, rescaling) have a common physical and mathematical origin. We address an ambiguity associated with the equilibrium constant, which is used to relate the forward and reverse rate coefficients, and restate its two definitions. By necessity, one of the equilibrium constants must be dimensionless and equate to an exponential function involving the Gibbs free energy, while the other is a ratio of rate coefficients and must therefore possess physical units. We demonstrate that the Arrhenius equation takes on a functional form that is more general than previously stated without recourse to tagging on ad hoc functional forms. Finally, we derive analytical models of chemical systems, in equilibrium, with carbon, hydrogen, and oxygen. We include acetylene and are able to reproduce several key trends, versus temperature and carbon-to-oxygen ratio, published in the literature. The rich variety of behavior that mixing ratios exhibit as a function of the carbon-to-oxygen ratio is merely the outcome of stoichiometric book-keeping and not the direct consequence of temperature or pressure variations.

  8. Enhanced Raman spectroscopic study of the coordination chemistry of malononitrile on copper surfaces - Removal of nu(C=N) degeneracy through pi-coordination

    NASA Technical Reports Server (NTRS)

    Loo, B. H.; Lee, Y. G.; Frazier, D. O.

    1985-01-01

    Surface-enhanced Raman spectroscopy has been used to study the molecular interactions of malononitrile with copper electrode surfaces. The doubly degenerate CN stretching frequency at 2263/cm is removed when malononitrile adsorbs on copper. Two nu(CN) bands are observed at 2096 and 2204/cm at -0.6 V(SCE). The result shows that only one CN group is pi-coordinated with Cu, which contributes to the observed large shift (-167/cm) in nu(CN). The other CN group is not coordinated to the metal surface.

  9. Coordination chemistry and hydrolysis of Fe(III) in a peat humic acid studied by X-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Karlsson, Torbjörn; Persson, Per

    2010-01-01

    The speciation of iron (Fe) in soils, sediments and surface waters is highly dependent on chemical interactions with natural organic matter (NOM). However, the molecular structure and hydrolysis of the Fe species formed in association with NOM is still poorly described. In this study extended X-ray absorption fine structure (EXAFS) spectroscopy was used to determine the coordination chemistry and hydrolysis of Fe(III) in solution of a peat humic acid (5010-49,200 μg Fe g -1 dry weight, pH 3.0-7.2). Data were analyzed by both conventional EXAFS data fitting and by wavelet transforms in order to facilitate the identification of the nature of backscattering atoms. Our results show that Fe occurs predominantly in the oxidized form as ferric ions and that the speciation varies with pH and Fe concentration. At low Fe concentrations (5010-9920 μg g -1; pH 3.0-7.2) mononuclear Fe(III)-NOM complexes completely dominates the speciation. The determined bond distances for the Fe(III)-NOM complexes are similar to distances obtained for Fe(III) complexed by desferrioxamine B and oxalate indicating the formation of a five-membered chelate ring structure. At higher Fe concentrations (49,200 μg g -1; pH 4.2-6.9) we detect a mixture of mononuclear Fe(III)-NOM complexes and polymeric Fe(III) (hydr)oxides with an increasing amount of Fe(III) (hydr)oxides at higher pH. However, even at pH 6.9 and a Fe concentration of 49,200 μg g -1 our data indicates that a substantial amount of the total Fe (>50%) is in the form of organic complexes. Thus, in environments with significant amounts of organic matter organic Fe complexes will be of great importance for the geochemistry of Fe. Furthermore, the formation of five-membered chelate ring structures is in line with the strong complexation and limited hydrolytic polymerization of Fe(III) in our samples and also agrees with EXAFS derived structures of Fe(III) in organic soils.

  10. Solid-state and solution-state coordination chemistry of lanthanide(III) complexes with (pyrazol-1-yl)acetic acid.

    PubMed

    Chen, Xiao-Yan; Goff, George S; Scott, Brian L; Janicke, Michael T; Runde, Wolfgang

    2013-03-18

    As a precursor of carboxyl-functionalized task-specific ionic liquids (TSILs) for f-element separations, (pyrazol-1-yl)acetic acid (L) can be deprotonated as a functionalized pyrazolate anion to coordinate with hard metal cations. However, the coordination chemistry of L with f-elements remains unexplored. We reacted L with lanthanides in aqueous solution at pH = 5 and synthesized four lanthanide complexes of general formula [Ln(L)3(H2O)2]·nH2O (1, Ln = La, n = 2; 2, Ln = Ce, n = 2; 3, Ln = Pr, n = 2; 4, Ln = Nd, n = 1). All complexes were characterized by single crystal X-ray diffraction analysis revealing one-dimensional chain formations. Two distinct crystallographic structures are governed by the different coordination modes of carboxylate groups in L: terminal bidentate and bridging tridentate (1-3); terminal bidentate, bridging bidentate, and tridentate coordination in 4. Comparison of the solid state UV-vis-NIR diffuse reflectance spectra with solution state UV-vis-NIR spectra suggests a different species in solution and solid state. The different coordination in solid state and solution was verified by distinctive (13)C NMR signals of the carboxylate groups in the solid state NMR.

  11. The coordination chemistry of technetium and rhenium and applications to nuclear medicines. [Annual] technical report, April 1, 1993--December 31, 1993

    SciTech Connect

    Zubieta, J.

    1993-12-31

    The dramatic dependence of Re-binding to functionalized hydrazines on the nature of the coligands associated with the metal site has led to an examination of alkoxy and thiolato ligand types. The observation that multidentate thiolate ligands are highly effective in this latter role suggests the design and synthesis of new chelating polythiolate ligands with high binding affinities for radiometallic nuclides and of functionalized polythiolate ligands for the preparation of radionuclide-conjugated antibodies or peptides and the preparation and characterization of their complexes not only with the Group 7 metals Tc and Re but with the Group 13 metals Ga and In, which also possess radionuclides with useful properties. Since the rational design of these novel bifunctional conjugates requires a fundamental understanding of the coordination chemistry of relevant metals with polythiolate ligands whose syntheses and properties remain unexplored, effort has been directed toward the preparation of novel polythiolate ligands and the characterization of their complexes with Group 7 and Group 13 metals. This report describes studies on several complementary aspects of the coordination chemistry of the pyridinethiolate derived ligands 2-HSC{sub 5}NH{sub 3}-SiR{sub 3}, 2-HSC{sub 5}NH{sub 3}-6-SiR{sub 3} and 2-HSC{sub 5}NH{sub 2}-3,6-SiR{sub 3} and the potentially bifunctional polythiolate ligand HOOCCH{sub 2}Si(CH{sub 2}CH{sub 2}SH){sub 3} have been synthesized; of several aspects of rhenium-hydrazido and rhenium-thiolate chemistry have been developed; of Ga and In complexes of the 2-pyridinethiolate class of ligands have been synthesized and structurally characterized; and of the general coordination properties of the 2-pyrithinethiolate and related ligand types.

  12. Integrated assessment of runoff from livestock farming operations: analytical chemistry, in vitro bioassays, and in vivo fish exposures

    USGS Publications Warehouse

    Cavallin, Jenna E.; Durhan, Elizabeth J.; Evans, Nicola; Jensen, Kathleen M.; Kahl, Michael D.; Kolpin, Dana W.; Kolodziej, Edward P.; Foreman, William T.; LaLone, Carlie A.; Makynen, Elizabeth A.; Seidl, Sara M.; Thomas, Linnea M.; Villeneuve, Daniel L.; Weberg, Matthew A.; Wilson, Vickie S.; Ankley, Gerald T.

    2014-01-01

    Animal waste from livestock farming operations can contain varying levels of natural and synthetic androgens and/or estrogens, which can contaminate surrounding waterways. In the present study, surface stream water was collected from 6 basins containing livestock farming operations. Aqueous concentrations of 12 hormones were determined via chemical analyses. Relative androgenic and estrogenic activity was measured using in vitro cell assays (MDA-kb2 and T47D-Kbluc assays, respectively). In parallel, 48-h static-renewal in vivo exposures were conducted to examine potential endocrine-disrupting effects in fathead minnows. Mature fish were exposed to surface water dilutions (0%, 25%, 50%, and 100%) and 10-ng/L of 17α-ethynylestradiol or 50-ng/L of 17β-trenbolone as positive controls. Hepatic expression of vitellogenin and estrogen receptor α mRNA, gonadal ex vivo testosterone and 17β-estradiol production, and plasma vitellogenin concentrations were examined. Potentially estrogenic and androgenic steroids were detected at low nanogram per liter concentrations. In vitro estrogenic activity was detected in all samples, whereas androgenic activity was detected in only 1 sample. In vivo exposures to the surface water had no significant dose-dependent effect on any of the biological endpoints, with the exception of increased male testosterone production in 1 exposure. The present study, which combines analytical chemistry measurements, in vitro bioassays, and in vivo fish exposures, highlights the integrated value and future use of a combination of techniques to obtain a comprehensive characterization of an environmental chemical mixture. 

  13. Integrated assessment of runoff from livestock farming operations: Analytical chemistry, in vitro bioassays, and in vivo fish exposures.

    PubMed

    Cavallin, Jenna E; Durhan, Elizabeth J; Evans, Nicola; Jensen, Kathleen M; Kahl, Michael D; Kolpin, Dana W; Kolodziej, Edward P; Foreman, William T; LaLone, Carlie A; Makynen, Elizabeth A; Seidl, Sara M; Thomas, Linnea M; Villeneuve, Daniel L; Weberg, Matthew A; Wilson, Vickie S; Ankley, Gerald T

    2014-08-01

    Animal waste from livestock farming operations can contain varying levels of natural and synthetic androgens and/or estrogens, which can contaminate surrounding waterways. In the present study, surface stream water was collected from 6 basins containing livestock farming operations. Aqueous concentrations of 12 hormones were determined via chemical analyses. Relative androgenic and estrogenic activity was measured using in vitro cell assays (MDA-kb2 and T47D-Kbluc assays, respectively). In parallel, 48-h static-renewal in vivo exposures were conducted to examine potential endocrine-disrupting effects in fathead minnows. Mature fish were exposed to surface water dilutions (0%, 25%, 50%, and 100%) and 10-ng/L of 17α-ethynylestradiol or 50-ng/L of 17β-trenbolone as positive controls. Hepatic expression of vitellogenin and estrogen receptor α mRNA, gonadal ex vivo testosterone and 17β-estradiol production, and plasma vitellogenin concentrations were examined. Potentially estrogenic and androgenic steroids were detected at low nanogram per liter concentrations. In vitro estrogenic activity was detected in all samples, whereas androgenic activity was detected in only 1 sample. In vivo exposures to the surface water had no significant dose-dependent effect on any of the biological endpoints, with the exception of increased male testosterone production in 1 exposure. The present study, which combines analytical chemistry measurements, in vitro bioassays, and in vivo fish exposures, highlights the integrated value and future use of a combination of techniques to obtain a comprehensive characterization of an environmental chemical mixture.

  14. Earle K. Plyler Prize for Molecular Spectroscopy & Dynamics Lecture: Broadband Rotational Spectroscopy for Chemical Kinetics, Molecular Structure, and Analytical Chemistry

    NASA Astrophysics Data System (ADS)

    Pate, Brooks

    2013-03-01

    Advances in high-speed digital electronics have enabled a new generation of molecular rotational spectroscopy techniques that provide instantaneous broadband spectral coverage. These techniques use a chirped excitation pulse to coherently excite the molecular sample over a spectral bandwidth of 10 GHz or larger through rapid passage. The subsequent time-domain emission is recorded using high-speed digitizers (up to 100 Gigasample/s) and the frequency domain spectrum is produced by fast Fourier transformation. The chirped-pulse Fourier transform (CP-FT) method has been implemented in the microwave frequency range (2-40 GHz) for studies of cold samples in pulsed jet sources and in the mm-wave/terahertz (THz) frequency range for studies of samples at room-temperature. The method has opened new applications for molecular rotational spectroscopy in the area of chemical kinetics where dynamic rotational spectroscopy is used to measure the rates of unimolecular isomerization reactions in highly excited molecules prepared by pulsed infrared laser excitation. In these applications, the isomerization rate is obtained from an analysis of the overall line shapes which are modified by chemical exchange leading to coalescence behavior similar to the effect in NMR spectroscopy. The sensitivity of the method and the ability to extend it to low frequency (2-8 GHz) have significantly increased the size range of molecules and molecular clusters for structure determination using isotopic substitution to build up the 3D molecular structures atom-by-atom. Application to the structure of water clusters with up to 15 water molecules will be presented. When coupled with advances in solid-state mm-wave/THz devices, this method provides a direct digital technique for analytical chemistry of room-temperature gases based on molecular rotational spectroscopy. These high-throughput methods can analyze complex sample mixtures with unmatched chemical selectivity and short analysis times. Work

  15. Formation of an Oxidant-Sensible Pd(II) Coordination Compound and Its [superscript 1]H NMR Specific Characterization: A Preparative and Analytical Challenge in Current Coordination Chemistry

    ERIC Educational Resources Information Center

    Abraham, Maria L.; Oppel, Iris M.

    2014-01-01

    A three-part experiment that leads to the synthesis of palladium(II) complex starting from a C[subscript 3]-symmetric triaminoguanidinium-based ligand is presented. In the first part, the preparation of tris-benzylidenetriaminoguanidinium chloride ([H[subscript 6]Br[subscript 3]L]Cl) by an acidic catalyzed 3-fold imine formation reaction of…

  16. CLUSTER CHEMISTRY

    SciTech Connect

    Muetterties, Earl L.

    1980-05-01

    Metal cluster chemistry is one of the most rapidly developing areas of inorganic and organometallic chemistry. Prior to 1960 only a few metal clusters were well characterized. However, shortly after the early development of boron cluster chemistry, the field of metal cluster chemistry began to grow at a very rapid rate and a structural and a qualitative theoretical understanding of clusters came quickly. Analyzed here is the chemistry and the general significance of clusters with particular emphasis on the cluster research within my group. The importance of coordinately unsaturated, very reactive metal clusters is the major subject of discussion.

  17. A coordination chemistry study of hydrated and solvated cationic vanadium ions in oxidation states +III, +IV, and +V in solution and solid state.

    PubMed

    Krakowiak, Joanna; Lundberg, Daniel; Persson, Ingmar

    2012-09-17

    The coordination chemistry of hydrated and solvated vanadium(III), oxovanadium(IV), and dioxovanadium(V) ions in the oxygen-donor solvents water, dimethyl sulfoxide (DMSO), and N,N'-dimethylpropyleneurea (DMPU) has been studied in solution by extended X-ray absorption fine structure (EXAFS) and large-angle X-ray scattering (LAXS) and in the solid state by single-crystal X-ray diffraction and EXAFS. The hydrated vanadium(III) ion has a regular octahedral configuration with a mean V-O bond distance of 1.99 Å. In the hydrated and DMSO-solvated oxovanadium(IV) ions, vanadium binds strongly to an oxo group at ca. 1.6 Å. The solvent molecule trans to the oxo group is very weakly bound, at ca. 2.2 Å, while the remaining four solvent molecules, with a mean V-O bond distance of 2.0 Å, form a plane slightly below the vanadium atom; the mean O═V-O(perp) bond angle is ca. 98°. In the DMPU-solvated oxovanadium(IV) ion, the space-demanding properties of the DMPU molecule leave no solvent molecule in the trans position to the oxo group, which reduces the coordination number to 5. The O═V-O bond angle is consequently much larger, 107°, and the mean V═O and V-O bond distances decrease to 1.58 and 1.97 Å, respectively. The hydrated and DMSO-solvated dioxovanadium(V) ions display a very distorted octahedral configuration with the oxo groups in the cis position with a mean V═O bond distance of 1.6 Å and a O═V═O bond angle of ca. 105°. The solvent molecules trans to the oxo groups are weakly bound, at ca. 2.2 Å, while the remaining two have bond distances of 2.02 Å. The experimental studies of the coordination chemistry of hydrated and solvated vanadium(III,IV,V) ions are complemented by summarizing previously reported crystal structures to yield a comprehensive description of the coordination chemistry of vanadium with oxygen-donor ligands.

  18. Using an innovative combination of quality-by-design and green analytical chemistry approaches for the development of a stability indicating UHPLC method in pharmaceutical products.

    PubMed

    Boussès, Christine; Ferey, Ludivine; Vedrines, Elodie; Gaudin, Karen

    2015-11-10

    An innovative combination of green chemistry and quality by design (QbD) approach is presented through the development of an UHPLC method for the analysis of the main degradation products of dextromethorphan hydrobromide. QbD strategy was integrated to the field of green analytical chemistry to improve method understanding while assuring quality and minimizing environmental impacts, and analyst exposure. This analytical method was thoroughly evaluated by applying risk assessment and multivariate analysis tools. After a scouting phase aimed at selecting a suitable stationary phase and an organic solvent in accordance with green chemistry principles, quality risk assessment tools were applied to determine the critical process parameters (CPPs). The effects of the CPPs on critical quality attributes (CQAs), i.e., resolutions, efficiencies, and solvent consumption were further evaluated by means of a screening design. A response surface methodology was then carried out to model CQAs as function of the selected CPPs and the optimal separation conditions were determined through a desirability analysis. Resulting contour plots enabled to establish the design space (DS) (method operable design region) where all CQAs fulfilled the requirements. An experimental validation of the DS proved that quality within the DS was guaranteed; therefore no more robustness study was required before the validation. Finally, this UHPLC method was validated using the concept of total error and was used to analyze a pharmaceutical drug product.

  19. Pyridyl-functionalised 3H-1,2,3,4-triazaphospholes: synthesis, coordination chemistry and photophysical properties of low-coordinate phosphorus compounds.

    PubMed

    Sklorz, Julian A W; Hoof, Santina; Rades, Nadine; De Rycke, Nicolas; Könczöl, László; Szieberth, Dénes; Weber, Manuela; Wiecko, Jelena; Nyulászi, László; Hissler, Muriel; Müller, Christian

    2015-07-27

    Novel conjugated, pyridyl-functionalised triazaphospholes with either tBu or SiMe3 substituents at the 5-position of the N3 PC heterocycle have been prepared by a [3+2] cycloaddition reaction and compared with structurally related, triazole-based systems. Photoexcitation of the 2-pyridyl-substituted triazaphosphole gives rise to a significant fluorescence emission with a quantum yield of up to 12 %. In contrast, the all-nitrogen triazole analogue shows no emission at all. DFT calculations indicate that the 2-pyridyl substituted systems have a more rigid and planar structure than their 3- and 4-pyridyl isomers. Time-dependent (TD) DFT calculations show that only the 2-pyridyl-substituted triazaphosphole exhibits similar planar geometry, with matching conformational arrangements in the lowest energy excited state and the ground state; this helps to explain the enhanced emission intensity. The chelating P,N-hybrid ligand forms a Re(I) complex of the type [(N^N)Re(CO)3 Br] through the coordination of nitrogen atom N(2) to the metal centre rather than through the phosphorus donor. Both structural and spectroscopic data indicate substantial π-accepting character of the triazaphosphole, which is again in contrast to that of the all-nitrogen-containing triazoles. The synthesis and photophysical properties of a new class of phosphorus-containing extended π systems are described.

  20. Forensic chemistry.

    PubMed

    Bell, Suzanne

    2009-01-01

    Forensic chemistry is unique among chemical sciences in that its research, practice, and presentation must meet the needs of both the scientific and the legal communities. As such, forensic chemistry research is applied and derivative by nature and design, and it emphasizes metrology (the science of measurement) and validation. Forensic chemistry has moved away from its analytical roots and is incorporating a broader spectrum of chemical sciences. Existing forensic practices are being revisited as the purview of forensic chemistry extends outward from drug analysis and toxicology into such diverse areas as combustion chemistry, materials science, and pattern evidence.

  1. JPRS Report, Science & Technology, USSR: Chemistry

    DTIC Science & Technology

    2007-11-02

    This report contains foreign media information from the USSR concerning analytical chemistry, electrochemistry, environmental chemistry, inorganic compounds, organophosphorous compounds, polymers (rubber) and radiation chemistry.

  2. Syntheses and Characterization of Ruthenium(II) Tetrakis(pyridine)complexes: An Advanced Coordination Chemistry Experiment or Mini-Project

    ERIC Educational Resources Information Center

    Coe, Benjamin J.

    2004-01-01

    An experiment for third-year undergraduate a student is designed which provides synthetic experience and qualitative interpretation of the spectroscopic properties of the ruthenium complexes. It involves the syntheses and characterization of several coordination complexes of ruthenium, the element found directly beneath iron in the middle of the…

  3. Plutonium(IV) complexation by diglycolamide ligands--coordination chemistry insight into TODGA-based actinide separations.

    PubMed

    Reilly, Sean D; Gaunt, Andrew J; Scott, Brian L; Modolo, Giuseppe; Iqbal, Mudassir; Verboom, Willem; Sarsfield, Mark J

    2012-10-09

    Complexation of Pu(IV) with TMDGA, TEDGA, and TODGA diglycolamide ligands was followed by vis-NIR spectroscopy. A crystal structure determination reveals that TMDGA forms a 1 : 3 homoleptic Pu(IV) complex with the nitrate anions forced into the outer coordination sphere.

  4. Prevalence of Pre-Analytical Errors in Clinical Chemistry Diagnostic Labs in Sulaimani City of Iraqi Kurdistan

    PubMed Central

    2017-01-01

    Background Laboratory testing is roughly divided into three phases: a pre-analytical phase, an analytical phase and a post-analytical phase. Most analytical errors have been attributed to the analytical phase. However, recent studies have shown that up to 70% of analytical errors reflect the pre-analytical phase. The pre-analytical phase comprises all processes from the time a laboratory request is made by a physician until the specimen is analyzed at the lab. Generally, the pre-analytical phase includes patient preparation, specimen transportation, specimen collection and storage. In the present study, we report the first comprehensive assessment of the frequency and types of pre-analytical errors at the Sulaimani diagnostic labs in Iraqi Kurdistan. Materials and Methods Over 2 months, 5500 venous blood samples were observed in 10 public diagnostic labs of Sulaimani City. The percentages of rejected samples and types of sample inappropriateness were evaluated. The percentage of each of the following pre-analytical errors were recorded: delay in sample transportation, clotted samples, expired reagents, hemolyzed samples, samples not on ice, incorrect sample identification, insufficient sample, tube broken in centrifuge, request procedure errors, sample mix-ups, communication conflicts, misinterpreted orders, lipemic samples, contaminated samples and missed physician’s request orders. The difference between the relative frequencies of errors observed in the hospitals considered was tested using a proportional Z test. In particular, the survey aimed to discover whether analytical errors were recorded and examine the types of platforms used in the selected diagnostic labs. Results The analysis showed a high prevalence of improper sample handling during the pre-analytical phase. In appropriate samples, the percentage error was as high as 39%. The major reasons for rejection were hemolyzed samples (9%), incorrect sample identification (8%) and clotted samples (6

  5. The mechanistically significant coordination chemistry of dinitrogen at FeMo-co, the catalytic site of nitrogenase.

    PubMed

    Dance, Ian

    2007-02-07

    Reported here is a comprehensive theoretical investigation of the binding of N(2) to the Fe(7)MoS(9)N(homocitrate)(cysteine)(histidine) active site (FeMo-co) of the enzyme nitrogenase, as a prerequisite to elucidation of the chemical mechanism of the catalyzed reduction to NH(3). The degree and type of hydrogenation of FeMo-co, with H atoms and possibly an H(2) molecule, are key variables, following the Thorneley-Lowe kinetic scheme. Ninety-four local energy minima were located for N(2) coordinated in eta(2) (side) and eta(1) (end) modes at the endo and exo coordination positions of Fe2 and Fe6. The stabilities of 57 representative structures are assessed by calculation of the reaction profiles and activation energies for the association and dissociation of N(2). Barriers to association of N(2) depend mainly on the location of the hydrogenation and the location of N(2) coordination, while dissociation barriers depend primarily on whether N(2) is eta(2)- and eta(1)-coordinated, and secondarily on the location of the hydrogenation. Increased negative charge on FeMo-co increases the barriers, while C in place of N at the center of FeMo-co has little effect. The interactions of the models of ligated FeMo-co with the surrounding protein, including proteins with mutations of key amino acids, are assessed by in silico cofactor transplantations and calculations of protein strain energies. From these results, which identify models involving contacts and interactions with the surrounding residues that have been shown by mutation to affect the N(2) activity of nitrogenase, and from the N(2) coordination profiles, it is concluded that endo-eta(1)-N(2) coordination at Fe6 is most probable. There is strong reason to believe that the mechanism of nitrogenase will involve one or more of the preferred models presented here, and a detailed foundation of structures and principles is now available for postulation and calculation of the profiles of the steps in which H atoms bound to

  6. Synthesis, selected coordination chemistry and extraction behavior of a (phosphinoylmethyl)pyridyl N-oxide-functionalized ligand based upon a 1,4-diazepane platform

    SciTech Connect

    Ouizem, Sabrina; Rosario Amorin, Daniel; Dickie, Diane A.; Cramer, Roger E.; Campana, Charles F.; Hay, Benjamin P.; Podair, Julien; Delmau, Laetitia H.; Paine, Robert T.

    2015-05-09

    For syntheses of new multidentate chelating ligands ((6,6'4(1,4-diazepane-1,4-diyl)bis(methylene))bis(pyridine-6,2-diyl))bis(methylene))bis(diphenylphosphine oxide) (2) and 6,6'-((1,4-diazepane1,4-diyl)bis(methylene))bis(2-((diphenylphosphoryl)methyl)pyridine 1-oxide) (3), based upon a 1,4-diazepane platform functionalized with 2-(diphenylphosphinoylmethyl)pyridine P-oxide and 2-(diphenylphosphinoylmethyl)pyridine NP-dioxide fragments, respectively, the results are reported. Our results from studies of the coordination chemistry of the ligands with selected lanthanide nitrates and Cu(BF4)(2) are outlined, and crystal structures for two complexes, [Cu(2)](BF4)2 and [Cu(3)](BF4)2, are described along with survey Eu(III) and Am(III) solvent extraction analysis, for 3.

  7. Synthesis, selected coordination chemistry and extraction behavior of a (phosphinoylmethyl)pyridyl N-oxide-functionalized ligand based upon a 1,4-diazepane platform

    DOE PAGES

    Ouizem, Sabrina; Rosario Amorin, Daniel; Dickie, Diane A.; ...

    2015-05-09

    For syntheses of new multidentate chelating ligands ((6,6'4(1,4-diazepane-1,4-diyl)bis(methylene))bis(pyridine-6,2-diyl))bis(methylene))bis(diphenylphosphine oxide) (2) and 6,6'-((1,4-diazepane1,4-diyl)bis(methylene))bis(2-((diphenylphosphoryl)methyl)pyridine 1-oxide) (3), based upon a 1,4-diazepane platform functionalized with 2-(diphenylphosphinoylmethyl)pyridine P-oxide and 2-(diphenylphosphinoylmethyl)pyridine NP-dioxide fragments, respectively, the results are reported. Our results from studies of the coordination chemistry of the ligands with selected lanthanide nitrates and Cu(BF4)(2) are outlined, and crystal structures for two complexes, [Cu(2)](BF4)2 and [Cu(3)](BF4)2, are described along with survey Eu(III) and Am(III) solvent extraction analysis, for 3.

  8. New insights into the coordination chemistry and molecular structure of copper(II) histidine complexes in aqueous solutions.

    PubMed

    Mesu, J Gerbrand; Visser, Tom; Soulimani, Fouad; van Faassen, Ernst E; de Peinder, Peter; Beale, Andrew M; Weckhuysen, Bert M

    2006-03-06

    Aqueous solutions of Cu2+/histidine (his) (1:2) have been analyzed in parallel with infrared, Raman, ultraviolet/visible/near-infrared, electron spin resonance, and X-ray absorption spectroscopy in the pH range from 0 to 10. Comprehensive interpretation of the data has been used to extract complementary structural information in order to determine the relative abundance of the different complexes. The formation of six different, partly coexisting species is proposed. Structural proposals from literature have been unambiguously confirmed, refined, or, in several cases, corrected. At highly acidic conditions, Cu2+ and his are present as free ions, but around pH = 2, coordination starts via the deprotonated carboxylic acid group. This results in the intermediate species Cu2+[H3his+(Oc)] and Cu2+[H3his+(Oc)]2. The coordination via Oc is attended with a drop in the pKa value of the other receptor groups resulting in a concomitant conversion to the bidentates Cu2+[H2his0(Oc,Nam)] and Cu2+[H2his0(Oc,Nam)]2, with the latter being dominant at pH = 3.5. Coordination of the imidazole ring begins around pH = 3 and leads to the formation of the mixed ligand complexes Cu2+[H2his0(Oc,Nam)][Hhis-(Oc,Nam,Nim)] and Cu2+[Hhis-(Nam,Nim)][Hhis-(Oc,Nam,Nim)] around pH = 5. It is demonstrated that coordination of the imidazole ring occurs predominantly via the N(pi) atom. At pH > 7, the double-tridentate ligand complex Cu2+[Hhis-(Oc,Nam,Nim)]2 is the major species with the N atoms in the equatorial plane and the O atoms in the axial position. This complex decomposes at pH > 10 into a copper oxide/hydroxide precipitate. The overall results provide a consistent picture of the mechanism that drives the coordination and complex formation of the Cu2+/his system.

  9. Invertase-labeling gold-dendrimer for in situ amplified detection mercury(II) with glucometer readout and thymine-Hg(2+)-thymine coordination chemistry.

    PubMed

    Qiu, Zhenli; Shu, Jian; Jin, Guixiao; Xu, Mingdi; Wei, Qiaohua; Chen, Guonan; Tang, Dianping

    2016-03-15

    A simple, low-cost transducer with glucometer readout was designed for sensitive detection of mercury(II) (Hg(2+)), coupling with thymine-Hg(2+)-thymine (T-Hg(2+)-T) coordination chemistry and invertase-functionalized gold-dendrimer nanospheres for the signal amplification. Initially, nanogold-encapsulated poly(amidoamine) dendrimers (Au DENs) were synthesized by in-situ reduction of gold(III). Thereafter, the as-prepared Au DENs were utilized for the labeling of invertase and T-rich signal DNA probe. In the presence of target Hg(2+), the functionalized Au DENs were conjugated to capture DNA probe-modified electrode via T-Hg(2+)-T coordination chemistry. Accompanying the Au DENs, the labeled invertase could hydrolyze sucrose into glucose, which could be quantitatively monitored by an external personal glucometer (PGM). The PGM signal increased with the increasing target Hg(2+) in the sample. Under the optimal conditions, our designed sensing platform exhibited good PGM responses toward target Hg(2+), and allowed the detection of Hg(2+) at a concentration as low as 4.2 pM. This sensing system also displayed remarkable specificity relative to target Hg(2+) against other competing ions, and could be applied for reliable monitoring of spiked Hg(2+) into the environmental water samples with satisfactory results. With the advantages of cost-effectiveness, simplicity, portability, and convenience, our strategy provides a tremendous potential to be a promising candidate for point-of-use monitoring of non-glucose targets by the public.

  10. Technetium chemistry

    SciTech Connect

    Burns, C.; Bryan, J.; Cotton, F.; Ott, K.; Kubas, G.; Haefner, S.; Barrera, J.; Hall, K.; Burrell, A.

    1996-04-01

    Technetium chemistry is a young and developing field. Despite the limited knowledge of its chemistry, technetium is the workhorse for nuclear medicine. Technetium is also a significant environmental concern because it is formed as a byproduct of nuclear weapons production and fission-power generators. Development of new technetium radio-pharmaceuticals and effective environmental control depends strongly upon knowledge of basic technetium chemistry. The authors performed research into the basic coordination and organometallic chemistry of technetium and used this knowledge to address nuclear medicine and environmental applications. This is the final report of a three-year Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL).

  11. A novel hemilabile calix[4],quinoline-based P,N-ligand: coordination chemistry and complex characterisation.

    PubMed

    Marson, Angelica; Ernsting, Johanneke E; Lutz, Martin; Spek, Anthony L; van Leeuwen, Piet W N M; Kamer, Paul C J

    2009-01-28

    The synthesis of the calix[4]arene-based P,N-ligand 3 (5,11,17,23-tetra-tert-butyl-25-[(2-quinolylmethyl)oxy]-26,27,28-(mu3-phosphorustrioxy)calix[4]arene), in which the nitrogen atom-containing moiety has been introduced at the lower rim of the cavity prior to P-functionalisation, is described and its coordination properties investigated. In the crystal structure, the calix[4]-cavity adopts a cone conformation with an exo orientation of the phosphorus lone pair enabling P-N chelation. 1H, 13C, 31P and 1H{15N} HMQC NMR spectra indicated that, in complexes [PdCl(CH3)(3)] (4) and [Rh(CO)Cl(3)] (5), ligand 3 coordinates in a chelating fashion, while in cis-[PtC12(3)2] (6) and [Rh(acac)(CO)(3)] (7) it behaves as a monodentate ligand, coordinating via the phosphorus atom only. X-Ray crystal structure determinations were performed for [PdCl(CH3)(3)] (4) and cis-[PtCl2(3)2] (6). The cationic Pd complex [Pd(CH3)(CH3CN)(3)][PF5] (8) was found to be active in a CO/ethylene copolymerisation reaction. Good selectivities were observed for the Pd-catalysed allylic alkylation of cinnamyl acetate with in situ prepared catalysts. [Rh(acac)(CO)2] modified with ligand 3 catalyses the hydroformylation of 1-octene with low selectivities towards linear aldehydes. High-pressure NMR experiments on the hydrido carbonyl rhodium(3) were inconclusive, different species were formed.

  12. mer, fac, and Bidentate Coordination of an Alkyl-POP Ligand in the Chemistry of Nonclassical Osmium Hydrides.

    PubMed

    Esteruelas, Miguel A; García-Yebra, Cristina; Martín, Jaime; Oñate, Enrique

    2017-01-03

    Nonclassical and classical osmium polyhydrides containing the diphosphine 9,9-dimethyl-4,5-bis(diisopropylphosphino)xanthene (xant(P(i)Pr2)2), coordinated in κ(3)-mer, κ(3)-fac, and κ(2)-P,P fashions, have been isolated during the cyclic formation of H2 by means of the sequential addition of H(+) and H(-) or H(-) and H(+) to the classical trihydride OsH3Cl{xant(P(i)Pr2)2} (1). This complex adds H(+) to form the compressed dihydride dihydrogen complex [OsCl(H···H)(η(2)-H2){xant(P(i)Pr2)2}](+) (2). Under argon, cation 2 loses H2 and the resulting unsaturated fragment dimerizes to give [(Os(H···H){xant(P(i)Pr2)2})2(μ-Cl)2](2+) (3). During the transformation the phosphine changes its coordination mode from mer to fac. The benzofuran counterpart of 1, OsH3Cl{dbf(P(i)Pr2)2} (4; dbf(P(i)Pr2)2 = 4,6-bis(diisopropylphosphino)dibenzofuran), also adds H(+) to afford the benzofuran counterpart of 2, [OsCl(H···H)(η(2)-H2){xant(P(i)Pr2)2}](+) (5), which in contrast to the latter is stable and does not dimerize. Acetonitrile breaks the chloride bridge of 3 to form the dihydrogen [OsCl(η(2)-H2)(CH3CN){xant(P(i)Pr2)2}](+) (6), regenerating the mer coordination of the diphosphine. The hydride ion also breaks the chloride bridge of 3. The addition of KH to 3 leads to 1, closing a cycle for the formation of H2. Complex 1 reacts with a second hydride ion to give OsH4{xant(P(i)Pr2)2} (7) as consequence of the displacement of the chloride. Similarly to the latter, the oxygen atom of the mer-coordinated diphosphine of 7 has a tendency to be displaced by the hydride ion. Thus, the addition of KH to 7 yields [OsH5{xant(P(i)Pr2)2}](-) (8), containing a κ(2)-P,P-diphosphine. Complex 8 is easily protonated to afford OsH6{xant(P(i)Pr2)2} (9), which releases H2 to regenerate 7, closing a second cycle for the formation of molecular hydrogen.

  13. Experimental and theoretical studies on the coordination chemistry of the N1-hexyl substituted pyrimidines (uracil, 5-fluorouracil and cytosine).

    PubMed

    Barceló-Oliver, Miquel; Baquero, Beatriz Adriana; Bauzá, Antonio; García-Raso, Angel; Vich, Roberto; Mata, Ignasi; Molins, Elies; Terrón, Angel; Frontera, Antonio

    2013-06-07

    N(1)-Hexyl substituted pyrimidines were shown to present solubility properties closer to the real bases than the commonly used methyl and ethyl derivatives, yielding bi-layered structures in the solid state. The study of their coordination capabilities, mainly with Ag(I) and Hg(II), is presented in order to prove their reactivity. A series of coordination complexes, namely, [Hg(N(1)-hexyl-5-fluorouracilate)2]4·6H2O (1), (Ag(+))·[Ag(N(1)-hexyl-5-fluorouracilate)2](-) (2), [Ag(NO3)(N(1)-hexyluracil-κO(4))4] (3), [ZnBr2(N(1)-hexylcytosine)2] (4), [CdBr2(N(1)-hexylcytosine)2] (5), [HgBr2(N(1)-hexylcytosine)2] (6) and [CoBr2(N(1)-hexylcytosine)2] (7), have been synthesized in good yields and X-ray characterized. The presence of the hexyl chains and the fluorine atoms causes the formation of interesting 3D architectures in the solid state. Their structures have been further characterized by infrared spectra (IR) and elemental analyses. In addition, DFT-D3 calculations are used to study interesting noncovalent interactions observed in the solid state, like fluorine-fluorine, fluorine-π and hydrophobic interactions.

  14. Part I. Student success in intensive versus traditional introductory chemistry courses. Part II. Synthesis of salts of the weakly coordinating trisphat anion

    NASA Astrophysics Data System (ADS)

    Hall, Mildred V.

    Part I. Intensive courses have been shown to be associated with equal or greater student success than traditional-length courses in a wide variety of disciplines and education levels. Student records from intensive and traditional-length introductory general chemistry courses were analyzed to determine the effects, of the course format, the level of academic experience, life experience (age), GPA, academic major and gender on student success in the course. Pretest scores, GPA and ACT composite scores were used as measures of academic ability and prior knowledge; t-tests comparing the means of these variables were used to establish that the populations were comparable prior to the course. Final exam scores, total course points and pretest-posttest differences were used as measures of student success; t-tests were used to determine if differences existed between the populations. ANCOVA analyses revealed that student GPA, pretest scores and course format were the only variables tested that were significant in accounting for the variance of the academic success measures. In general, the results indicate that students achieved greater academic success in the intensive-format course, regardless of the level of academic experience, life experience, academic major or gender. Part II. Weakly coordinating anions have many important applications, one of which is to function as co-catalysts in the polymerization of olefins by zirconocene. The structure of tris(tetrachlorobenzenedialato) phosphate(V) or "trisphat" anion suggests that it might be an outstanding example of a weakly coordinating anion. Trisphat acid was synthesized and immediately used to prepare the stable tributylammonium trisphat, which was further reacted to produce trisphat salts of Group I metal cations in high yields. Results of the 35Cl NQR analysis of these trisphat salts indicate only very weak coordination between the metal cations and the chlorine atoms of the trisphat anion.

  15. "In situ" extraction of essential oils by use of Dean-Stark glassware and a Vigreux column inside a microwave oven: a procedure for teaching green analytical chemistry.

    PubMed

    Chemat, Farid; Perino-Issartier, Sandrine; Petitcolas, Emmanuel; Fernandez, Xavier

    2012-08-01

    One of the principal objectives of sustainable and green processing development remains the dissemination and teaching of green chemistry in colleges, high schools, and academic laboratories. This paper describes simple glassware that illustrates the phenomenon of extraction in a conventional microwave oven as energy source and a process for green analytical chemistry. Simple glassware comprising a Dean-Stark apparatus (for extraction of aromatic plant material and recovery of essential oils and distilled water) and a Vigreux column (as an air-cooled condenser inside the microwave oven) was designed as an in-situ extraction vessel inside a microwave oven. The efficiency of this experiment was validated for extraction of essential oils from 30 g fresh orange peel, a by-product in the production of orange juice. Every laboratory throughout the world can use this equipment. The microwave power is 100 W and the irradiation time 15 min. The method is performed at atmospheric pressure without added solvent or water and furnishes essential oils similar to those obtained by conventional hydro or steam distillation. By use of GC-MS, 22 compounds in orange peel were separated and identified; the main compounds were limonene (72.1%), β-pinene (8.4%), and γ-terpinene (6.9%). This procedure is appropriate for the teaching laboratory, does not require any special microwave equipment, and enables the students to learn the skills of extraction, and chromatographic and spectroscopic analysis. They are also exposed to a dramatic visual example of rapid, sustainable, and green extraction of an essential oil, and are introduced to successful sustainable and green analytical chemistry.

  16. Coordination chemistry of platinum and palladium in the solid-state: synthesis of imidazole and pyrazole complexes.

    PubMed

    Adams, Christopher J; Haddow, Mairi F; Hughes, Robert J I; Kurawa, Mukhtar A; Orpen, A Guy

    2010-04-21

    Solid-state reactions of palladium(II) and platinum(II) chloride complexes with imidazole (Him) and pyrazole (Hpz) or their hydrochloride salts are shown to produce metal complex salts and coordination compounds. Thus, K(2)[MCl(4)] or MCl(2) can be ground with imidazolium chloride ([H(2)im]Cl) to produce the salts [H(2)im](2)[MCl(4)] (M = Pd, 1; Pt, 5), which can then be dehydrochlorinated in the solid state to produce the coordination compounds trans-[PdCl(2)(Him)(2)] 3 or cis-[PtCl(2)(Him)(2)] 6. The complex cis-[PdCl(2)(Him)(2)] 2 is produced when Pd(OAc)(2) is ground with [H(2)im]Cl. Reaction of platinum chloride reagents with imidazole (Him) also produces cis-[PtCl(2)(Him)(2)] 6, but reaction of imidazole with analogous palladium chloride reagents first produces [Pd(Him)(4)]Cl(2) 4 which then slowly converts to trans-[PdCl(2)(Him)(2)] 3. Grinding pyrazolium chloride with K(2)[MCl(4)] produces [H(2)pz](2)[MCl(4)] (M = Pd, 7; Pt, 10), which may also be dehydrochlorinated in the solid state to produce the coordination compounds trans-[PdCl(2)(Hpz)(2)] 8 or cis-[PtCl(2)(Hpz)(2)] 11. Grinding K(2)[PdCl(4)] or PdCl(2) with pyrazole gives [Pd(Hpz)(4)]Cl(2) 9, which is then slowly converted into trans-[PdCl(2)(Hpz)(2)] 8. Grinding PtCl(2) with Hpz generates [Pt(Hpz)(4)]Cl(2) 12, but using K(2)PtCl(4) as the metal source does not generate the same product. The single-crystal structures of 8, a new polymorph of 11 and [H(2)pz](2)[PtCl(6)].2H(2)O (isolated as a decomposition product) are reported for the first time, and the structures of 5 and 10 have been solved ab ibitio from XRPD data.

  17. Coordination chemistry of 1,4-bis[bis(2-pyridylmethyl)aminomethyl]benzene with copper(II)

    NASA Astrophysics Data System (ADS)

    Louka, Febee R.; Spell, Mark L.; Grebowicz, Janusz; Albering, Jörg H.; Mautner, Franz A.; Massoud, Salah S.

    2011-05-01

    The interaction of 1,4-bis[bis(2-pyridylmethyl)aminomethyl]benzene ( p-Xy DPA) with CuCl 2·2H 2O has resulted in the isolation of the dinuclear compound [Cu 2( p-Xy DPA)Cl 4]·H 2O ( 1). When the reaction was performed in presence of sodium perchlorate, sodium azide, sodium dicyanamide (Nadca) and disodium squarate (Na 2C 4O 4) the compounds [Cu 2( p-Xy DPA)(ClO 4) 2Cl 2] ( 2), [Cu 2( p-Xy DPA)(N 3) 4]·2H 2O ( 3), [Cu 2( p-Xy DPA)(dca) 4]·4H 2O ( 4), and [Cu 2( p-Xy DPA)Cl 2(H 2O) 2](C 4O 4)·5.4H 2O ( 5) were obtained, respectively. The complexes were characterized by IR and UV-vis. spectroscopy. The visible spectra of the complexes revealed the square pyramidal geometry around the central Cu 2+ ions. The molecular structures of the complexes 2, 3, 4 and 5 were determined by single crystal X-ray crystallography. This study revealed the dinuclear nature of the complexes and showed that the Cu(II) centers have distorted five-coordinate square pyramidal geometry with N 3-donor atoms of the dipicolyl amine arms and the remaining coordination positions are occupied by the chloro and perchlorato ligands in 2, the monodentate azido ligands in 3 or the monodentate terminal nitrile dca in 4 and by the chloro and aqua ligands in 5 with the squarate dianion as counter ion.

  18. The coordination chemistry of weathering: I. Dissolution kinetics of δ- Al2O3 and BeO

    NASA Astrophysics Data System (ADS)

    Furrer, Gerhard; Stumm, Werner

    1986-09-01

    The dissolution kinetics of most slightly soluble oxides and silicates are controlled by chemical processes at the surface. The reaction controlling steps can be interpreted in terms of a surface coordination model. In dilute acid solutions, in the absence of complex-forming ligands, the dissolution kinetics are controlled by the surface bound protons. The rate of the proton-promoted reaction of δ- Al2O3 is RH = kH( CH3) 3 where C h3 is the proton concentration per unit area on the oxide surface. The mechanism can be described by the attachment of three protons to the reaction site prior to the detachment of an Al species into the solution. The dissolution rate of BeO is proportional to (C H2) 2. For δ- Al2O3 at pH ⩽ 3.5 dissolution rate is independent of pH; at this pH maximum surface concentration of protons is reached. The organic ligand-promoted dissolution, RL, is of first order with respect to concentration of surface chelates: R L = k L{M ?L} where {M ?L} is the concentration of surface chelates per unit area. Detachable surface complexes result from surface coordination of metal ions of the hydrous oxides with bidentate ligands. Especially efficient are bidentate ligands that form mononuclear surface complexes. The sequence of rate constants shows that five- and six-membered chelate rings (oxalate, catechol, malonate and salicylate) enhance the dissolution reactions to a greater extent than seven-membered rings (phthalate, succinate). Monodentate ligands (benzoate ion), though readily adsorbed, do not enhance dissolution rates. However, they can inhibit dissolution by displacing ligands that catalyze this reaction.

  19. Authentic Learning Enviroment in Analytical Chemistry Using Cooperative Methods and Open-Ended Laboratories in Large Lecture Courses

    NASA Astrophysics Data System (ADS)

    Wright, John C.

    1996-09-01

    It is recognized that a need exists to move from the passive learning styles that have characterized chemistry courses to an active style in which students participate and assume responsibility for their learning (1 - 5). In addition, it is argued that course reform should be linked to authentic student achievement, so that students can actively experience the feelings of practicing professionals (6). Course experiments where such changes have been introduced have proven successful but the number of examples of such changes is limited in the higher level courses or courses with large enrollments (7 - 11). In this paper, a one-semester introductory analytical chemistry course is described that accomplishes this goal by the use of open-ended laboratories, cooperative learning, and spreadsheet programs. The course uses many of the ideas described by Walters (7). It is offered at the upperclass level to nonmajors and at the freshman level to students with solid chemistry backgrounds from high school. Typically there are 90 students, who are divided into 5 sections. A teaching assistant is assigned to each section. The course has two 4-hour laboratories and two or three lectures each week (depending on whether it is the upperclass or freshman course). The heart of the course changes is the use of open-ended laboratory experiments in the last half of the course. A sample group project is to have the students develop a mixture of acid-base indicators that can serve as a spectroscopic pH meter. These projects are enhanced by dividing the students into teams of four who take charge of all aspects of accomplishing the projects' goals. Since there are many skills required to make these projects work, the first half of the course is spent developing the individual conceptual, computational, laboratory, problem solving, and group skills so students are prepared for the last half. These changes have markedly improved the student attitudes towards each other and towards learning

  20. Coordination Chemistry and Reactivity of a Cupric-hydroperoxide Species Featuring a Proximal H-bonding Substituent

    PubMed Central

    Kim, Sunghee; Saracini, Claudio; Siegler, Maxime A.; Drichko, Natalia; Karlin, Kenneth D.

    2012-01-01

    At −90 °C in acetone, a stable hydroperoxo complex [(BA)CuII-OOH]+ (2) (BA, a tetradentate N4 ligand possessing a pendant –N(H)CH2C6H5 group) is generated by reacting [(BA)CuII(CH3COCH3)]2+ with only one equiv H2O2/Et3N. The exceptional stability of 2 is ascribed to internal H-bonding. Species 2 is also generated in a manner not previously known in copper chemistry, by adding 3/2 equiv H2O2 (no base) to the cuprous complex [(BA)CuI]+. The broad implications for this finding are discussed. 2 slowly converts to a μ-1,2-peroxo dicopper(II) analogue (3) characterized by UV-Vis and resonance Raman spectroscopies. Unlike a close analogue not possessing internal H-bonding, [(BA)CuII-OOH]+ (2) affords no oxidative reactivity with internal or external substrates. However, 2 can be protonated to release H2O2, but only with HClO4, while one equiv Et3N restores 2. PMID:23153187

  1. Coordination chemistry of Ti(IV) in silicate glasses and melts: III. Glasses and melts from ambient to high temperatures

    NASA Astrophysics Data System (ADS)

    Farges, François; Brown, Gordon E.; Navrotsky, Alexandra; Gan, Hao; Rehr, John R.

    1996-08-01

    The local structural environment of Ti in five Na-, K-, and Ca-titanosilicate glass/melts with TiO 2 concentrations ranging from 2.7-30.5 wt% has been determined by in situ Ti K-edge x-ray absorption fine structure (XAFS) spectroscopy at temperatures ranging from 293-1650 K. In parallel, two Ti-model compounds (Ni 2.6Ti 0.7O 4 spinel and TiO 2 rutile) were studied under the same conditions to better understand the effects of temperature (anharmonicity) on the XAFS spectra. Temperature-induced anharmonicity was found to vary, largely as a function of the Ti-coordination, and increases significantly around Ti with increasing temperature when present as [6]Ti. In contrast, anharmonicity appears negligible around [4]Ti at temperatures below 1200 K. We predict that anharmonicity should be weak around [5]Ti as well. No clear evidence was found for a significant change in the average nearest-neighbor coordination environment of Ti in the Na- and K-titanosilicate glasses and melts that exhibit anomalous heat capacities variations just above their glass transition temperatures, Tg (860-930 K). The small (predicted and measured) linear thermal expansion of the ( [5]TiO 2+) sbnd O bond in these systems at high temperature is expected to have an insignificant effect on the local environment of [5]Ti during the glass-to-supercooled liquid transition. In the most dilute Ti-glass studied (KS1; 2.7 wt% TiO 2), the local environment around [4]Ti (especially the second-neighbor alkalis) is relatively ordered at ambient temperature, but this order decreases dramatically above Tg. Lower quench rates appear to favor [4]Ti over [5]Ti. The origin of the observed anomalous positive variations in heat capacities of these melts may be related to significant changes in the medium-range environment around Ti above Tg including the disappearance of percolation domains involving interfaces between alkali-rich and network-former rich regions during structural relaxation at Tg; these percolation

  2. International Federation of Clinical Chemistry. Use of artificial intelligence in analytical systems for the clinical laboratory. IFCC Committee on Analytical Systems.

    PubMed

    Place, J F; Truchaud, A; Ozawa, K; Pardue, H; Schnipelsky, P

    1994-12-16

    The incorporation of information-processing technology into analytical systems in the form of standard computing software has recently been advanced by the introduction of artificial intelligence (AI) both as expert systems and as neural networks. This paper considers the role of software in system operation, control and automation and attempts to define intelligence. AI is characterized by its ability to deal with incomplete and imprecise information and to accumulate knowledge. Expert systems, building on standard computing techniques, depend heavily on the domain experts and knowledge engineers that have programmed them to represent the real world. Neural networks are intended to emulate the pattern-recognition and parallel-processing capabilities of the human brain and are taught rather than programmed. The future may lie in a combination of the recognition ability of the neural network and the rationalization capability of the expert system. In the second part of this paper, examples are given of applications of AI in stand-alone systems for knowledge engineering and medical diagnosis and in embedded systems for failure detection, image analysis, user interfacing, natural language processing, robotics and machine learning, as related to clinical laboratories. It is concluded that AI constitutes a collective form of intellectual property and that there is a need for better documentation, evaluation and regulation of the systems already being used widely in clinical laboratories.

  3. Highly electron rich β-diketiminato systems: Synthesis and coordination chemistry of amino functionalized 'N-nacnac' ligands.

    PubMed

    Cao Huan Do, Dinh; Keyser, Ailsa; Protchenko, Andrey; Maitland, Brant; Pernik, Indrek; Niu, Haoyu; Kolychev, Eugene; Rit, Arnab; Vidovic, Dragoslav; Stasch, Andreas; Jones, Cameron; Aldridge, Simon

    2017-03-02

    The synthesis of a class of electron-rich amino-functionalized β-diketiminato (N-nacnac) ligands is reported, with two synthetic methodologies having been developed for systems bearing backbone NMe2 or NEt2 groups and a range of N-bound aryl substituents. In contrast to their (Nacnac)H counterparts, the structures of the protio-ligands feature the bis(imine) tautomer and a backbone CH2 group. Direct metallation with lithium, magnesium or aluminium alkyls allows access to the respective metal complexes via deprotonation of the methylene function; in each case X-ray structures are consistent with a delocalized imino-amide ligand description. Trans-metallation using lithium N-nacnac complexes has then been exploited to access p and f-block metal complexes which allow for like-for-like benchmarking of the N-nacnac ligand family against their more familiar Nacnac counterparts. In the case of SnII the degree of electronic perturbation effected by introduction of the backbone NR2 groups appears to be constrained by the inability of the amino group to achieve effective conjugation with the N2C3 heterocycle. More obvious divergence from established structural norms are observed for complexes of the larger, harder YbII ion, with azaallyl/imino and even azaallyl/NMe2 coordination modes being demonstrated by X-ray crystallography.

  4. Hydrolysis Studies and Quantitative Determination of Aluminum Ions Using [superscript 27]Al NMR: An Undergraduate Analytical Chemistry Experiment

    ERIC Educational Resources Information Center

    Curtin, Maria A.; Ingalls, Laura R.; Campbell, Andrew; James-Pederson, Magdalena

    2008-01-01

    This article describes a novel experiment focused on metal ion hydrolysis and the equilibria related to metal ions in aqueous systems. Using [superscript 27]Al NMR, the students become familiar with NMR spectroscopy as a quantitative analytical tool for the determination of aluminum by preparing a standard calibration curve using standard aluminum…

  5. Coordination chemistry in the solid state: synthesis and interconversion of pyrazolium salts, pyrazole complexes, and pyrazolate MOFs.

    PubMed

    Adams, Christopher J; Kurawa, Mukhtar A; Orpen, A Guy

    2010-08-14

    Solid pyrazole reacts with HCl gas to form pyrazolium chloride [H2pz]Cl, which reacts in the solid state, under grinding, with metal chlorides MCl2 (M = Co, Zn, Cu) to form the pyrazolium tetrachlorometallate salts [H2pz]2[MCl4] (M = Co 1, Zn 3, Cu 5). Salt 5 cannot be made in solution, and upon standing at room temperature spontaneously emits HCl to give the coordination compound [CuCl2(Hpz)2] (6). Compounds 1 and 3 do not exhibit this behaviour, but can be ground together with bases such as KOH or K2CO3 to effect the elimination of HCl and afford their respective [MCl2(Hpz)2] compounds (M = Co 2, Zn 4). 2, 4 and 6 can also be synthesised in the solid-state by direct reaction of the appropriate metal chloride with pyrazole, or by reaction of a basic metal salt such as the carbonate or hydroxide with pyrazolium chloride. 4 and 6 {and their nickel analogue [NiCl2(Hpz)2]} can be ground with a further two equivalents of base to make the known polymeric metal pyrazolates [M(pz)2]n (M = Ni 7, Cu 8, Zn 9); the same reaction appears to work for the cobalt analogue 2, but the presumed product [Co(pz)2]n10 then decomposes by oxidation. The imidazolate complexes [M(im)2] (M = Ni, 11; Cu, 12; Zn, 13; Co, 14) were similarly prepared by grinding the appropriate [M(Him)2Cl2] precursor with KOH.

  6. The effect of regioisomerism on the coordination chemistry and CEST properties of lanthanide(III) NB-DOTA-tetraamide chelates

    PubMed Central

    Slack, Jacqueline R.; Woods, Mark

    2014-01-01

    Chemical exchange saturation transfer (CEST) offers many advantages as a method of generating contrast in magnetic resonance images. However, many of the exogenous agents currently under investigation suffer from detection limits that are still somewhat short of what can be achieved with more traditional Gd3+ agents. To remedy this limitation we have undertaken an investigation of Ln3+ DOTA-tetraamide chelates (where DOTA is 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) that have unusually rigid ligand structures: the nitrobenzyl derivatives of DOTA-tetraamides with (2-phenylethyl)amide substituents. In this report we examine the effect of incorporating hydrophobic amide substituents on water exchange and CEST. The ligand systems chosen afforded a total of three CEST-active isomeric square antiprismatic chelates; each of these chelates was found to have different water exchange and CEST characteristics. The position of a nitrobenzyl substituent on the macrocyclic ring strongly influenced the way in which the chelate and Ln3+ coordination cage distorted. These differential distortions were found to affect the rate of water proton exchange in the chelates. But, by far the greatest effect arose from altering the position of the hydrophobic amide substituent, which, when forced upwards around the water binding site, caused a substantial reduction in the rate of water proton exchange. Such slow water proton exchange afforded a chelate that was 4.5 times more effective as a CEST agent than its isomeric counterparts in dry acetonitrile and at low temperatures and very low presaturation powers. PMID:24287873

  7. Analytical Challenges in Biotechnology.

    ERIC Educational Resources Information Center

    Glajch, Joseph L.

    1986-01-01

    Highlights five major analytical areas (electrophoresis, immunoassay, chromatographic separations, protein and DNA sequencing, and molecular structures determination) and discusses how analytical chemistry could further improve these techniques and thereby have a major impact on biotechnology. (JN)

  8. Geometric isomerism in coordination cages based on tris-chelate vertices: a tool to control both assembly and host/guest chemistry.

    PubMed

    Metherell, Alexander J; Ward, Michael D

    2016-10-18

    This 'Perspective' article summarises recent work from the authors' research group on the exploitation of the simple fac/mer geometric isomerism of octahedral metal tris-chelates as a tool to control the chemistry of coordination cages based on bis(pyrazolyl-pyridine) ligands, in two different respects. Firstly this geometric isomerism plays a major role in controlling the guest binding properties of cages because a fac tris-chelate arrangement of pyrazolyl-pyridine chelates around a metal ion vertex results in formation of a convergent set of inwardly-directed C-H protons in a region of high positive electrostatic potential close to a metal cation. This collection of δ+ protons therefore provides a charge-assisted hydrogen-bond donor site, which interacts with the electron-rich regions of guest molecules that are of the correct size and shape to occupy the cage cavity, and the strength of this hydrogen-bonding interaction plays a major role in guest recognition in non-aqueous solvents. Secondly the ability to prepare mononuclear complexes with either a fac or mer arrangement of ligands provides an entry into the controlled, stepwise assembly of heterometallic cages based on a combination of kinetically inert and kinetically labile metal ions at different sites. This has allowed introduction of useful physical properties such as redox activity or luminescence, commonly associated with inert metal ions which are not amenable to participation in thermodynamic self-assembly processes, to be incorporated in a predictable way into the superstructures of coordination cages at specific sites.

  9. Establishing the Coordination Chemistry of Antimony(V) Cations: Systematic Assessment of Ph4 Sb(OTf) and Ph3 Sb(OTf)2 as Lewis Acceptors.

    PubMed

    Robertson, Alasdair P M; Chitnis, Saurabh S; Jenkins, Hilary A; McDonald, Robert; Ferguson, Michael J; Burford, Neil

    2015-05-18

    The coordination chemistry of the stiboranes Ph4 Sb(OTf) (1 a, OTf = OSO2 CF3 ) and Ph3 Sb(OTf)2 (3) with Lewis bases has been investigated. The significant steric encumbrance of the Sb center in 1 a precludes interaction with most ligands, but the relatively low steric demands of 4-methylpyridine-N-oxide (OPyrMe) and OPMe3 enabled the characterization of [Ph4 Sb(OPyrMe)][OTf] (2 a) and [Ph4 Sb(OPMe3 )][OTf] (2 b), rare examples of structurally characterized complexes of stibonium acceptors. In contrast, 3 was found to engage a variety of Lewis bases, forming stable isolable complexes of the form [Ph3 Sb(donor)2 ][OTf]2 [donor=OPMe3 (6 a), OPCy3 (6 b, Cy=cyclohexyl), OPPh3 (6 c), OPyrMe (6 d)], [Ph3 Sb(dmap)2 (OTf)][OTf] (6 e, dmap=4-(dimethylamino)pyridine) and [Ph3 Sb(donor)(OTf)][OTf] [donor=1,10-phenanthroline (7 a) or 2,2'-bipy (7 b, bipy=bipyridine)]. These compounds exhibit significant structural diversity in the solid-state, and undergo ligand exchange reactions in line with their assignment as coordination complexes. Compound 3 did not form stable complexes with phosphine donors, with reactions instead leading to redox processes yielding SbPh3 and products of phosphine oxidation.

  10. USSR Report, Chemistry.

    DTIC Science & Technology

    2007-11-02

    This chemistry Report from the USSR contains articles mainly on Adsorption, Analytical Chemistry, Biochemistry, Catalysis, Chemical Industry, Coal ... Gasification , Electrochemistry, Fertilizers, Food Technology, Inorganic Compounds, Nitrogen Compounds and Organometallic Compounds.

  11. Harmonising Adult and Paediatric Reference Intervals in Australia and New Zealand: An Evidence-Based Approach for Establishing a First Panel of Chemistry Analytes

    PubMed Central

    Tate, Jillian R; Sikaris, Ken A; Jones, Graham RD; Yen, Tina; Koerbin, Gus; Ryan, Julie; Reed, Maxine; Gill, Janice; Koumantakis, George; Hickman, Peter; Graham, Peter

    2014-01-01

    Scientific evidence supports the use of common reference intervals (RIs) for many general chemistry analytes, in particular those with sound calibration and traceability in place. Already the Nordic countries and United Kingdom have largely achieved harmonised RIs. Following a series of workshops organised by the Australasian Association of Clinical Biochemists (AACB) between 2012 and 2014 at which an evidence-based approach for determination of common intervals was developed, pathology organisations in Australia and New Zealand have reached a scientific consensus on what adult and paediatric intervals we should use across Australasia. The aim of this report is to describe the processes that the AACB and the Royal College of Pathologists of Australasia have taken towards recommending the implementation of a first panel of common RIs for use in Australasia. PMID:25678727

  12. Hybrid scorpionate/cyclopentadienyl magnesium and zinc complexes: synthesis, coordination chemistry, and ring-opening polymerization studies on cyclic esters.

    PubMed

    Garcés, Andrés; Sánchez-Barba, Luis F; Alonso-Moreno, Carlos; Fajardo, Mariano; Fernández-Baeza, Juan; Otero, Antonio; Lara-Sánchez, Agustín; López-Solera, Isabel; Rodríguez, Ana María

    2010-03-15

    The reaction of the hybrid scorpionate/cyclopentadienyl lithium salt [Li(bpzcp)(THF)] [bpzcp = 2,2-bis(3,5-dimethylpyrazol-1-yl)-1,1-diphenylethylcyclopentadienyl] with 1 equiv of RMgCl proceeds cleanly to give very high yields of the corresponding monoalkyl kappa(2)-NN-eta(5)-C(5)H(4) magnesium complexes [Mg(R)(kappa(2)-eta(5)-bpzcp)] (R = Me 1, Et 2, (n)Bu 3, (t)Bu 4, CH(2)SiMe(3) 5, CH(2)Ph 6). Hydrolysis of the hybrid lithium salt [Li(bpzcp)(THF)] with NH(4)Cl/H(2)O in ether cleanly affords the two previously described regioisomers: (bpzcpH) 1-[2,2-bis(3,5-dimethylpyrazol-1-yl)-1,1-diphenylethyl]-1,3-cyclopentadiene (a) and 2-[2,2-bis(3,5-dimethylpyrazol-1-yl)-1,1-diphenylethyl]-1,3-cyclopentadiene (b). Subsequent reaction of the bpzcpH hybrid ligand with ZnR(2) quantitatively yields the monoalkyl kappa(2)-NN-eta(1)(pi)-C(5)H(4) zinc complexes [Zn(R){kappa(2)-eta(1)(pi)-bpzcp}] (R = Me 7, Et 8, (t)Bu 9, CH(2)SiMe(3) 10). Additionally, magnesium alkyls 1, 2, 4, and 5 can act as excellent cyclopentadienyl and alkyl transfers to the zinc metal center and yield zinc alkyls 7-10 in good yields. The single-crystal X-ray structures of the derivatives 4, 5, 7, and 10 confirm a 4-coordinative structure with the metal center in a distorted tetrahedral geometry. Interestingly, whereas alkyl magnesium derivatives 4 and 5 present a eta(5) coordination mode for the cyclopentadienyl fragment, zinc derivatives 7 and 10 feature a peripheral eta(1)(pi) arrangement in the solid state. Furthermore, the reaction of the hybrid lithium salt [Li(bpzcp)(THF)] with 1 equiv of ZnCl(2) in tetrahydrofuran (THF) affords very high yields of the chloride complex [ZnCl{kappa(2)-eta(1)(pi)-bpzcp}] (11). Compound 11 was used as a convenient starting material for the synthesis of the aromatic amide zinc compound [Zn(NH-4-MeC(6)H(4)){kappa(2)-eta(1)(pi)-bpzcp}] (12), by reaction with the corresponding aromatic primary amide lithium salt. Alternatively, aliphatic amide and alkoxide derivatives were

  13. Analytical performance evaluation of ADVIA Chemistry Carbamazepine_2 assay: minimal cross-reactivity with carbamazepine 10, 11-epoxide and none with hydroxyzine or cetirizine.

    PubMed

    Dasgupta, Amitava; Reyes, Meredith A; Davis, Barbara G; Marlow, Anne M; Johnson, Myrtle

    2010-01-01

    Carbamazepine is an anticonvulsant requiring routine therapeutic drug monitoring. Recently, Siemens Healthcare Diagnostic Division released a new carbamazepine assay: ADVIA Chemistry Carbamazepine_2 (Carbamazepine_2) for application on ADVIA analyzers. We evaluated the analytical performance of this assay as well as its potential cross-reactivities with carbamazepine 10, 11-epoxide, hydroxyzine, and cetirizine. The within-run and between-run precisions of the Carbamzepine-2 assay were <6% and limit of detection was 0.5 microg/ml using ADVIA 1800 analyzer. The assay was linear up to a carbamazepine concentration of 20.0 microg/ml. The new method compared well with a widely used carbamazepine EMIT 2000 assay on the Hitachi 917 analyzer. Using 75 patients' specimens (where carbamazepine concentrations varied from 0.5 to 21.7 microg/ml) and carbamazepine EMIT 2000 as the reference method (x-axis), we observed the following regression equation: y=1.04 x+0.32 (r=0.99). The new carbazepine_2 method was not affected by a hemoglobin concentration of 1,000 mg/dl, conjugated or unconjugated bilirubin concentration of 60 mg/dl, and triglyceride concentration of 1,000 mg/dl. In addition, this assay showed no cross-reactivity with hydroxyzine or cetirizine and demonstrated minimal cross-reactivity with carbamazepine 10, 11-epoxide. We conclude that the ADVIA Chemistry carbamazepine_2 assay has adequate precision and accuracy for routine therapeutic drug monitoring of carbamazepine in clinical laboratories.

  14. Coordination Chemistry of Diiodine and Implications for the Oxidation Capacity of the Synergistic Ag(+) /X2 (X=Cl, Br, I) System.

    PubMed

    Malinowski, Przemysław J; Himmel, Daniel; Krossing, Ingo

    2016-08-01

    The synergistic Ag(+) /X2 system (X=Cl, Br, I) is a very strong, but ill-defined oxidant-more powerful than X2 or Ag(+) alone. Intermediates for its action may include [Agm (X2 )n ](m+) complexes. Here, we report on an unexpectedly variable coordination chemistry of diiodine towards this direction: (A)Ag-I2 -Ag(A), [Ag2 (I2 )4 ](2+) (A(-) )2 and [Ag2 (I2 )6 ](2+) (A(-) )2 ⋅(I2 )x≈0.65 form by reaction of Ag(A) (A=Al(OR(F) )4 ; R(F) =C(CF3 )3 ) with diiodine (single crystal/powder XRD, Raman spectra and quantum-mechanical calculations). The molecular (A)Ag-I2 -Ag(A) is ideally set up to act as a 2 e(-) oxidant with stoichiometric formation of 2 AgI and 2 A(-) . Preliminary reactivity tests proved this (A)Ag-I2 -Ag(A) starting material to oxidize n-C5 H12 , C3 H8 , CH2 Cl2 , P4 or S8 at room temperature. A rough estimate of its electron affinity places it amongst very strong oxidizers like MF6 (M=4d metals). This suggests that (A)Ag-I2 -Ag(A) will serve as an easily in bulk accessible, well-defined, and very potent oxidant with multiple applications.

  15. Spectroscopic characterization of the coordination chemistry and hydrolysis of gallium(III) in the presence of aquatic organic matter

    NASA Astrophysics Data System (ADS)

    Hagvall, Kristoffer; Persson, Per; Karlsson, Torbjörn

    2014-12-01

    Interactions between metals and natural organic matter (NOM) are of great environmental importance and one of the key factors influencing hydrolysis, solubility, and speciation of the metals. However, studying geochemically relevant metals like Al, Fe, and Cu is sometimes associated with analytical problems; for example Fe and Cu are both redox active. Gallium (Ga) is a non-redox active metal that usually occurs at very low concentrations in environmental samples and therefore a wide concentration range of metal(III)-NOM species can be explored by adding Ga(III) to such samples. This makes Ga(III) a good probe and analogue for other metal ions, in particular Al. In addition, due to the increased usage of Ga in society, a better understanding of how Ga interacts with NOM is of importance but such studies are scarce. In this work, Ga(III) interactions with two different organic materials (Suwannee River natural organic matter and Suwannee River fulvic acid) were studied using infrared (IR) and extended X-ray absorption fine structure (EXAFS) spectroscopy in a large experimental range (101-84,076 μg Ga g-1 dry weight; pH 3-8). Our IR spectroscopic results showed that Ga(III) is bonded mainly to carboxylic functional groups and suggested that only a fraction of the total number of carboxylic sites in the samples was actively involved in the bonding. Modeling of the EXAFS data revealed that Ga(III) formed mononuclear chelate complexes with NOM that strongly suppressed the hydrolysis and polymerization of Ga(III). At low Ga(III) concentrations (1675-16,649 μg g-1) organic complexes, consisting of 1-3 chelate ring structures, were the dominating species in the entire pH range while at higher concentrations (67,673-84,076 μg g-1, pH 3.0-7.0) we detected mixtures of mononuclear organic Ga(III) complexes, Ga(III) (hydr)oxide, and free Ga(III) (here defined as the hydrated Ga(III) ion and its soluble hydrolysis products). Moreover, the EXAFS results showed significantly

  16. Effects of Tailored Surface Chemistry on Desorption Electrospray Ionization Mass Spectrometry: a Surface-Analytical Study by XPS and AFM

    NASA Astrophysics Data System (ADS)

    Penna, Andrea; Careri, Maria; Spencer, Nicholas D.; Rossi, Antonella

    2015-08-01

    Since it was proposed for the first time, desorption electrospray ionization-mass spectrometry (DESI-MS) has been evaluated for applicability in numerous areas. Elucidations of the ionization mechanisms and the subsequent formation of isolated gas-phase ions have been proposed so far. In this context, the role of both surface and pneumatic effects on ion-formation yield has recently been investigated. Nevertheless, the effect of the surface chemistry has not yet been completely understood. Functionalized glass surfaces have been prepared, in order to tailor surface performance for ion formation. Three substrates were functionalized by depositing three different silanes [3-mercaptopropyltriethoxysilane (MTES), octyltriethoxysilane (OTES), and 1H,1H,2H,2H-perfluorooctyltriethoxy-silane (FOTES)] from toluene solution onto standard glass slides. Surface characterization was carried out by contact-angle measurements, tapping-mode atomic force microscopy, and X-ray photoelectron spectroscopy. Morphologically homogeneous and thickness-controlled films in the nm range were obtained, with surface free energies lying between 15 and 70 mJ/m2. These results are discussed, together with those of DESI-MS on low-molecular-weight compounds such as melamine, tetracycline, and lincomycin, also taking into account the effects of the sprayer potential and its correlation with surface wettability. The results demonstrate that ion-formation efficiency is affected by surface wettability, and this was demonstrated operating above and below the onset of the electrospray.

  17. ;Click; analytics for ;click; chemistry - A simple method for calibration-free evaluation of online NMR spectra

    NASA Astrophysics Data System (ADS)

    Michalik-Onichimowska, Aleksandra; Kern, Simon; Riedel, Jens; Panne, Ulrich; King, Rudibert; Maiwald, Michael

    2017-04-01

    Driven mostly by the search for chemical syntheses under biocompatible conditions, so called ;click; chemistry rapidly became a growing field of research. The resulting simple one-pot reactions are so far only scarcely accompanied by an adequate optimization via comparably straightforward and robust analysis techniques possessing short set-up times. Here, we report on a fast and reliable calibration-free online NMR monitoring approach for technical mixtures. It combines a versatile fluidic system, continuous-flow measurement of 1H spectra with a time interval of 20 s per spectrum, and a robust, fully automated algorithm to interpret the obtained data. As a proof-of-concept, the thiol-ene coupling between N-boc cysteine methyl ester and allyl alcohol was conducted in a variety of non-deuterated solvents while its time-resolved behaviour was characterized with step tracer experiments. Overlapping signals in online spectra during thiol-ene coupling could be deconvoluted with a spectral model using indirect hard modeling and were subsequently converted to either molar ratios (using a calibration-free approach) or absolute concentrations (using 1-point calibration). For various solvents the kinetic constant k for pseudo-first order reaction was estimated to be 3.9 h-1 at 25 °C. The obtained results were compared with direct integration of non-overlapping signals and showed good agreement with the implemented mass balance.

  18. "Click" analytics for "click" chemistry - A simple method for calibration-free evaluation of online NMR spectra.

    PubMed

    Michalik-Onichimowska, Aleksandra; Kern, Simon; Riedel, Jens; Panne, Ulrich; King, Rudibert; Maiwald, Michael

    2017-03-01

    Driven mostly by the search for chemical syntheses under biocompatible conditions, so called "click" chemistry rapidly became a growing field of research. The resulting simple one-pot reactions are so far only scarcely accompanied by an adequate optimization via comparably straightforward and robust analysis techniques possessing short set-up times. Here, we report on a fast and reliable calibration-free online NMR monitoring approach for technical mixtures. It combines a versatile fluidic system, continuous-flow measurement of (1)H spectra with a time interval of 20s per spectrum, and a robust, fully automated algorithm to interpret the obtained data. As a proof-of-concept, the thiol-ene coupling between N-boc cysteine methyl ester and allyl alcohol was conducted in a variety of non-deuterated solvents while its time-resolved behaviour was characterized with step tracer experiments. Overlapping signals in online spectra during thiol-ene coupling could be deconvoluted with a spectral model using indirect hard modeling and were subsequently converted to either molar ratios (using a calibration-free approach) or absolute concentrations (using 1-point calibration). For various solvents the kinetic constant k for pseudo-first order reaction was estimated to be 3.9h(-1) at 25°C. The obtained results were compared with direct integration of non-overlapping signals and showed good agreement with the implemented mass balance.

  19. Applying the Power of Reticular Chemistry to Finding the Missing alb-MOF Platform Based on the (6,12)-Coordinated Edge-Transitive Net.

    PubMed

    Chen, Zhijie; Weseliński, Łukasz J; Adil, Karim; Belmabkhout, Youssef; Shkurenko, Aleksander; Jiang, Hao; Bhatt, Prashant M; Guillerm, Vincent; Dauzon, Emilie; Xue, Dong-Xu; O'Keeffe, Michael; Eddaoudi, Mohamed

    2017-03-01

    Highly connected and edge-transitive nets are of prime importance in crystal chemistry and are regarded as ideal blueprints for the rational design and construction of metal-organic frameworks (MOFs). We report the design and synthesis of highly connected MOFs based on reticulation of the sole two edge-transitive nets with a vertex figure as double six-membered-ring (d6R) building unit, namely the (4,12)-coordinated shp net (square and hexagonal-prism) and the (6,12)-coordinated alb net (aluminum diboride, hexagonal-prism and trigonal-prism). Decidedly, the combination of our recently isolated 12-connected (12-c) rare-earth (RE) nonanuclear [RE9(μ3-OH)12(μ3-O)2(O2C-)12] carboxylate-based cluster, points of extension matching the 12 vertices of hexagonal-prism d6R, with 4-connected (4-c) square porphyrinic tetracarboxylate ligand led to the formation of the targeted RE-shp-MOF. This is the first time that RE-MOFs based on 12-c molecular building blocks (MBBs), d6R building units, have been deliberately targeted and successfully isolated, paving the way for the long-awaited (6,12)-c MOF with alb topology. Indeed, combination of a custom-designed hexacarboxylate ligand with RE salts led to the formation of the first related alb-MOF, RE-alb-MOF. Intuitively, we successfully transplanted the alb topology to another chemical system and constructed the first indium-based alb-MOF, In-alb-MOF, by employing trinuclear [In3(μ3-O)(O2C-)6] as the requisite 6-connected trigonal-prism and purposely made a dodecacarboxylate ligand as a compatible 12-c MBB. Prominently, the dodecacarboxylate ligand was employed to transplant shp topology into copper-based MOFs by employing the copper paddlewheel [Cu2(O2C-)4] as the complementary square building unit, affording the first Cu-shp-MOF. We revealed that highly connected edge-transitive nets such shp and alb are ideal for topological transplantation and deliberate construction of related MOFs based on minimal edge-transitive nets.

  20. Evaluation of innovative stationary phase ligand chemistries and analytical conditions for the analysis of basic drugs by supercritical fluid chromatography.

    PubMed

    Desfontaine, Vincent; Veuthey, Jean-Luc; Guillarme, Davy

    2016-03-18

    Similar to reversed phase liquid chromatography, basic compounds can be highly challenging to analyze by supercritical fluid chromatography (SFC), as they tend to exhibit poor peak shape, especially those with high pKa values. In this study, three new stationary phase ligand chemistries available in sub -2 μm particle sizes, namely 2-picolylamine (2-PIC), 1-aminoanthracene (1-AA) and diethylamine (DEA), were tested in SFC conditions for the analysis of basic drugs. Due to the basic properties of these ligands, it is expected that the repulsive forces may improve peak shape of basic substances, similarly to the widely used 2-ethypyridine (2-EP) phase. However, among the 38 tested basic drugs, less of 10% displayed Gaussian peaks (asymmetry between 0.8 and 1.4) using pure CO2/methanol on these phases. The addition of 10mM ammonium formate as mobile phase additive, drastically improved peak shapes and increased this proportion to 67% on 2-PIC. Introducing the additive in the injection solvent rather than in the organic modifier, gave acceptable results for 2-PIC only, with 31% of Gaussian peaks with an average asymmetry of 1.89 for the 38 selected basic drugs. These columns were also compared to hybrid silica (BEH), DIOL and 2-EP stationary phases, commonly employed in SFC. These phases commonly exhibit alternative retention and selectivity. In the end, the two most interesting ligands used as complementary columns were 2-PIC and BEH, as they provided suitable peak shapes for the basic drugs and almost orthogonal selectivities.

  1. Spectroscopic Studies on Physicochemical Natures of Ion Exchangers and Highly Functional Polymers and Their Application to Analytical Chemistry

    NASA Astrophysics Data System (ADS)

    Yoshimura, Kazuhisa

    The absorption spectra or NMR spectra of chemical species adsorbed on ion exchangers and highly functional polymers such as crosslinked dextran could be directly measured by the corresponding solution methods. Spectrophotometric measurements of a target species in the solid phase have been extended to solid phase spectrometry (SPS), based on the direct measurement of light-absorption by the solid phase, which has adsorbed the target analyte. SPS has employed two different procedures; i.e., batch and flow methods. The Lambert-Beer law could be applicable to the solid particle layer system. The sensitivity was proportional to the volume ratio of the solid and sample solution, giving more than 100 times the sensitivity obtainable with the combination of a 0.1 cm3 solid and a 10-100 cm3 sample for the batch method. An online measurement of the light attenuation by the adsorbed species in the flow-through cell made it possible to both significantly reduce the sample solution volume and to simplify the respective procedures for the derivatization of the analyte and packing the solid particles into the cell. Because the cross-linked dextran and similar glucopyranoside-based gels have polyol moieties in their gel matrix, they could be used as oxo acid-selective adsorbents without introducing any special functional groups. Especially, in the case of boric acid, 11B NMR spectroscopy was one of the best tools for elucidating the nature of the interaction between boric acid/borate and polyols. Its combination with other methods enabled basic understanding of the chemical reactions. Reaction paths for 1:1 complexation are in general divided into two groups, i.e., neutral polyols that directly react with tetrahedral borate, and acidic polyols that react with trigonal boric acid in a 1:1 complexation. Both of the reactions produce tetrahedral anionic complexes, followed by a condensation reaction between the 1:1 monochelate complex and the undissociated diols to yield the 1

  2. Optoacoustic spectroscopy for real-time monitoring of strongly light-absorbing solutions in applications to analytical chemistry.

    PubMed

    Filimonova, Tatyana A; Volkov, Dmitry S; Proskurnin, Mikhail A; Pelivanov, Ivan M

    2013-12-01

    An optoacoustic technique for solutions of strongly light-absorbing analytes at 0.1-0.01 mol l(-1) is proposed. The technique is based on the wide-band forward mode detection of temporal profiles of laser-generated ultrasonic pulses (optoacoustic signals). The leading edge of the signal repeats the distribution of the laser fluence in the medium, which makes it possible to determine its optical absorption and investigate its dynamics during a reaction. The range of light-absorption coefficients starts from 1 to 5 and reaches 10(4) to 10(5) cm(-1). The determination of iron(II) as ferroin shows the possibility of probing 0.1 mol l(-1) of iron(II), which was not previously achieved for this reaction by optical spectroscopy. To further prove the concept, kinetic measurements for ferroin decomposition at the level of 0.1 mol l(-1) and at high pHs are performed. The results are compared with spectrophotometry at lower concentrations and show good reproducibility and accuracy of kinetic constants.

  3. Temperature-controlled micro-TLC: a versatile green chemistry and fast analytical tool for separation and preliminary screening of steroids fraction from biological and environmental samples.

    PubMed

    Zarzycki, Paweł K; Slączka, Magdalena M; Zarzycka, Magdalena B; Bartoszuk, Małgorzata A; Włodarczyk, Elżbieta; Baran, Michał J

    2011-11-01

    whole range of target substances as well as chemo-taxonomic studies and fingerprinting of complex mixtures, which are present in biological or environmental samples. Due to low consumption of eluent (usually 0.3-1mL/run) mainly composed of water-alcohol binary mixtures, this method can be considered as environmentally friendly and green chemistry focused analytical tool, supplementary to analytical protocols involving column chromatography or planar micro-fluidic devices.

  4. High resolution analytical electron microscopy reveals cell culture media induced changes to the chemistry of silver nanowires

    PubMed Central

    Chen, Shu; Theodorou, Ioannis G.; Goode, Angela E.; Gow, Andrew; Schwander, Stephan; Zhang, Junfeng (Jim); Chung, Kian Fan; Tetley, Teresa D.; Shaffer, Milo S.; Ryan, Mary P.; Porter, Alexandra E.

    2014-01-01

    There is a growing concern about the potential adverse effects on human health upon exposure to engineered silver nanomaterials (particles, wires and plates). However, the majority of studies testing the toxicity of silver nanomaterials have examined nominally ‘as-synthesized’ materials without considering the fate of the materials in biologically relevant fluids. Here, in-house silver nanowires (AgNWs) were prepared by a modified polyol process and were incubated in three cell culture media (DMEM, RPMI-1640 and DCCM-1) to examine the impact of AgNW-medium interactions on the physicochemical properties of the AgNWs. High-resolution analytical transmission electron microscopy revealed that Ag2S crystals form on the surface of AgNWs within 1 hour of incubation in DCCM-1. In contrast, the incubation of AgNWs in RPMI-1640 or DMEM did not lead to sulfidation. When the DCCM-1 cell culture medium was separated into its small molecule solutes and salts and protein components, the AgNWs were found to sulfidize in the fraction containing small molecule solutes and salts, but not in the fraction containing the protein component of the media. Further investigation showed the AgNWs did not readily sulfidize in the presence of isolated sulfur containing amino acids or proteins, such as cysteine or bovine serum albumin (BSA). The results demonstrate that the AgNWs can be transformed by the media before and during the incubation with cells and therefore the effects of cell culture media must be considered in the analysis of toxicity assays. Appropriate media and material controls must be in place to allow accurate predictions about the toxicity, and ultimately, the health risk of this commercially relevant class of nanomaterial. PMID:24160871

  5. Developments in the analytical chemistry of arsenic to support teaching and learning through research in environmental topics

    NASA Astrophysics Data System (ADS)

    Ampiah-Bonney, Richmond Jerry

    Two manifolds were designed to determine phosphate concentrations. The linear range for the 2-channel manifold was 0 to 30 mg L-1, and that for the 3-channel manifold was 0 to 400 mg L-1. Optimized conditions for the determination of arsenic with molybdenum-blue method were 0.5% w/v ascorbic acid, 0.4 M sulfuric acid in the molybdate solution and 80°C reaction temperature. A method for determination of arsenic using pervaporation flow injection hydride generation with visible spectrophotometry was developed. The method was sensitive for low arsenic concentrations (≤ 10 mug L-1), with sensitivity decreasing as arsenic concentration increased. There was no heating required, and the pervaporation membrane transferred only arsine. The analytical performance of two arsenic test kits was assessed. The Alpha Environmental kit cannot be recommended for arsenic measurement in water. The Hach kit was reliable for measuring arsenic concentrations greater than 70 mug L-1. A modified reaction tube was constructed that allowed NaBH4 solution to be delivered into the reaction mixture to replace zinc powder in the Hach kit, with no loss of gases. A more quantitative way of measuring arsenic using the Hach kit was developed by measuring the B-value of the color of jpeg images of test strips taken by a desktop scanner. Leersia oryzoides grown in soil amended with 110 mg kg-1arsenic extracted up to 305 mug g-1 and 272 mug g-1 arsenic into its shoots and roots respectively, giving a shoot:root quotient (SRQ) of 1.12 and phytoextraction coefficients (PEC) up to 1.3 in greenhouse experiments. Five supervised arsenic-related projects were reported. All except one of these reports fell short of the standards acceptable for a publishable manuscript. Factors such as high expectations, competitive entrance requirements and good motivation were responsible for the publishable report. For the remaining reports, problems with working in a team, relatively low expectations and lack of

  6. JPRS Report, Science & Technology, USSR: Chemistry

    DTIC Science & Technology

    2007-11-02

    This report contains foreign media information from the USSR concerning analytical chemistry, electrochemistry, environmental chemistry, inorganic compounds, organophosphorous compounds, petroleum coal processing and polymers.

  7. JPRS Report, Science & Technology, USSR: Chemistry

    DTIC Science & Technology

    2007-11-02

    This report contains foreign media information from the USSR concerning analytical chemistry, catalysis, electrochemistry, inorganic compounds, organometallic compounds, organophosphorous compounds, polymers and radiation chemistry.

  8. (Chemistry of the global atmosphere)

    SciTech Connect

    Marland, G.

    1990-09-27

    The traveler attended the conference The Chemistry of the Global Atmosphere,'' and presented a paper on the anthropogenic emission of carbon dioxide (CO{sub 2}) to the atmosphere. The conference included meetings of the International Global Atmospheric Chemistry (IGAC) programme, a core project of the International Geosphere/Biosphere Programme (IGBP) and the traveler participated in meetings on the IGAC project Development of Global Emissions Inventories'' and agreed to coordinate the working group on CO{sub 2}. Papers presented at the conference focused on the latest developments in analytical methods, modeling and understanding of atmospheric CO{sub 2}, CO, CH{sub 4}, N{sub 2}O, SO{sub 2}, NO{sub x}, NMHCs, CFCs, and aerosols.

  9. Efficient Biostimulation of Native and Introduced Quorum-Quenching Rhodococcus erythropolis Populations Is Revealed by a Combination of Analytical Chemistry, Microbiology, and Pyrosequencing

    PubMed Central

    Cirou, Amélie; Mondy, Samuel; An, Shu; Charrier, Amélie; Sarrazin, Amélie; Thoison, Odile; DuBow, Michael

    2012-01-01

    Degradation of the quorum-sensing (QS) signals known as N-acylhomoserine lactones (AHL) by soil bacteria may be useful as a beneficial trait for protecting crops, such as potato plants, against the worldwide pathogen Pectobacterium. In this work, analytical chemistry and microbial and molecular approaches were combined to explore and compare biostimulation of native and introduced AHL-degrading Rhodococcus erythropolis populations in the rhizosphere of potato plants cultivated in farm greenhouses under hydroponic conditions. We first identified gamma-heptalactone (GHL) as a novel biostimulating agent that efficiently promotes plant root colonization by AHL-degrading R. erythropolis population. We also characterized an AHL-degrading biocontrol R. erythropolis isolate, R138, which was introduced in the potato rhizosphere. Moreover, root colonization by AHL-degrading bacteria receiving different combinations of GHL and R138 treatments was compared by using a cultivation-based approach (percentage of AHL-degrading bacteria), pyrosequencing of PCR-amplified rrs loci (total bacterial community), and quantitative PCR (qPCR) of the qsdA gene, which encodes an AHL lactonase in R. erythropolis. Higher densities of the AHL-degrading R. erythropolis population in the rhizosphere were observed when GHL treatment was associated with biocontrol strain R138. Under this condition, the introduced R. erythropolis population displaced the native R. erythropolis population. Finally, chemical analyses revealed that GHL, gamma-caprolactone (GCL), and their by-products, gamma-hydroxyheptanoic acid and gamma-hydroxycaproic acid, rapidly disappeared from the rhizosphere and did not accumulate in plant tissues. This integrative study highlights biostimulation as a potential innovative approach for improving root colonization by beneficial bacteria. PMID:22081576

  10. Millimeter-Wave Spectroscopy for Analytical Chemistry: Thermal Evolution of Low Volatility Impurities and Detection with a Fourier Transform Molecular Rotational Resonance Spectrometer (tev Ft-Mrr

    NASA Astrophysics Data System (ADS)

    Harris, Brent; Fields, Shelby S.; Neill, Justin L.; Pulliam, Robin; Muckle, Matt; Pate, Brooks

    2016-06-01

    Recent advances in Fourier transform millimeter-wave spectroscopy techniques have renewed the application reach of molecular rotational spectroscopy for analytical chemistry. We present a sampling method for sub ppm analysis of low volatility impurities by thermal evolution from solid powders using a millimeter-wave Fourier transform molecular rotational resonance (FT-MRR) spectrometer for detection. This application of FT-MRR is relevant to the manufacturing of safe oral pharmaceuticals. Low volatility impurities can be challenging to detect at 1 ppm levels with chromatographic techniques. One such example of a potentially mutagenic impurity is acetamide (v.p. 1 Torr at 40 C, m.p. 80 C). We measured the pure reference spectrum of acetamide by flowing the sublimated vapor pressure of acetamide crystals through the FT-MRR spectrometer. The spectrometer lower detection level (LDL) for a broadband (> 20 GHz, 10 min.) spectrum is 300 nTorr, 30 pmol, or 2 ng. For a 50 mg powder, perfect sample transfer efficiency can yield a w/w % detection limit of 35 ppb. We extended the sampling method for the acetamide reference measurement to an acetaminophen sample spiked with 5000 ppm acetamide in order to test the sample transfer efficiency when liberated from an pharmaceutical powder. A spectral reference matching algorithm detected the presence of several impurities including acetaldehyde, acetic acid, and acetonitrile that evolved at the melting point of acetaminophen, demonstrating the capability of FT-MRR for identification without a routine chemical standard. The method detection limit (MDL) without further development is less than 10 ppm w/w %. Resolved FT-MRR mixture spectra will be presented with a description of sampling methods.

  11. Unexpected metal ion-assisted transformations leading to unexplored bridging ligands in Ni(II) coordination chemistry: the case of PO3F(2-) group.

    PubMed

    Dermitzaki, Despina; Raptopoulou, Catherine P; Psycharis, Vassilis; Escuer, Albert; Perlepes, Spyros P; Stamatatos, Theocharis C

    2014-10-21

    The initial 'accidental', metal ion-assisted hydrolysis of PF6(-) to PO3F(2-) has been evolved in a systematic investigation of the bridging affinity of the latter group in Ni(II)/oximate chemistry; mono-, di- and trinuclear complexes have been prepared and confirmed both the rich reactivity of PO3F(2-) and its potential for further use as bridging ligand in high-nuclearity 3d-metal cluster chemistry.

  12. Reactions with a Metalloid Tin Cluster {Sn10[Si(SiMe3)3]4}(2-): Ligand Elimination versus Coordination Chemistry.

    PubMed

    Schrenk, Claudio; Gerke, Birgit; Pöttgen, Rainer; Clayborne, Andre; Schnepf, Andreas

    2015-05-26

    Chemistry that uses metalloid tin clusters as a starting material is of fundamental interest towards understanding the reactivity of such compounds. Since we identified {Sn10[Si(SiMe3)3]4}(2-) 7 as an ideal candidate for such reactions, we present a further step in the understanding of metalloid tin cluster chemistry. In contrast to germanium chemistry, ligand elimination seems to be a major reaction channel, which leads to the more open metalloid cluster {Sn10[Si(SiMe3)3]3}(-) 9, in which the Sn core is only shielded by three Si(SiMe3)3 ligands. Compound 9 is obtained through different routes and is crystallised together with two different countercations. Besides the structural characterisation of this novel metalloid tin cluster, the electronic structure is analysed by (119)Sn Mössbauer spectroscopy. Additionally, possible reaction pathways are discussed. The presented first step into the chemistry of metalloid tin clusters thus indicates that, with respect to metalloid germanium clusters, more reaction channels are accessible, thereby leading to a more complex reaction system.

  13. Solid-state and solution-state coordination chemistry of the zinc triad with the mixed N,S donor ligand bis(2-methylpyridyl) sulfide.

    PubMed

    Berry, Steven M; Bebout, Deborah C; Butcher, Raymond J

    2005-01-10

    The binding of group 12 metal ions to bis(2-methylpyridyl) sulfide (1) was investigated by X-ray crystallography and NMR. Seven structures of the chloride and perchlorate salts of Hg(II), Cd(II), and Zn(II) with 1 are reported. Hg(1)(2)(ClO(4))(2), Cd(1)(2)(ClO(4))(2), and Zn(1)(2)(ClO(4))(2).CH(3)CN form mononuclear, six-coordinate species in the solid state with 1 binding in a tridentate coordination mode. Hg(1)(2)(ClO(4))(2) has a distorted trigonal prismatic coordination geometry while Cd(1)(2)(ClO(4))(2) and Zn(1)(2)(ClO(4))(2).CH(3)CN have distorted octahedral geometries. With chloride anions, the 1:1 metal to ligand complexes Hg(1)Cl(2), [Cd(1)Cl(2)](2), and Zn(1)Cl(2) are formed. A bidentate binding mode that lacks thioether coordination is observed for 1 in the four-coordinate, distorted tetrahedral complexes Zn(1)Cl(2) and Hg(1)Cl(2). [Cd(1)Cl(2)](2) is dimeric with a distorted octahedral coordination geometry and a tridentate 1. Hg(1)Cl(2) is comprised of pairs of loosely associated monomers and Zn(1)Cl(2) is monomeric. In addition, Hg(2)(1)Cl(4) is formed with alternating chloride and thioether bridges. The distorted square pyramidal Hg(II) centers result in a supramolecular zigzagging chain in the solid state. The solution (1)H NMR spectra of [Hg(1)(2)](2+) and [Hg(1)(NCCH(3))(x)()](2+) reveal (3)(-)(5)J((199)Hg(1)H) due to slow ligand exchange found in these thioether complexes. Implications for use of Hg(II) as a metallobioprobe are discussed.

  14. An Advanced Chemistry Laboratory Program.

    ERIC Educational Resources Information Center

    Wise, John H.

    The Advanced Chemistry Laboratory Program is a project designed to devise experiments to coordinate the use of instruments in the laboratory programs of physical chemistry, instrumental analysis, and inorganic chemistry at the advanced undergraduate level. It is intended that such experiments would incorporate an introduction to the instrument…

  15. Analytical mass spectrometry

    SciTech Connect

    Not Available

    1990-01-01

    This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)

  16. Analytical mass spectrometry. Abstracts

    SciTech Connect

    Not Available

    1990-12-31

    This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)

  17. Synthesis and coordination chemistry of two N2-donor chelating di(indazolyl)methane ligands: structural characterization and comparison of their metal chelation aptitudes.

    PubMed

    Pettinari, Claudio; Marinelli, Alessandro; Marchetti, Fabio; Ngoune, Jean; Galindo, Agustín; Álvarez, Eleuterio; Gómez, Margarita

    2010-11-15

    The N(2)-donor bidentate ligands di(1H-indazol-1-yl)methane (L(1)) and di(2H-indazol-2-yl)methane (L(2)) (L in general) have been synthesized, and their coordination behavior toward Zn(II), Cd(II), and Hg(II) salts has been studied. Reaction of L(1) and L(2) with ZnX(2) (X = Cl, Br, or I) yields [ZnX(2)L] species (1-6), that, in the solid state, show a tetrahedral structure with dihapto ligand coordination via the pyrazolyl arms. The reaction of L(1) and L(2) with Zn(NO(3))(2)·6H(2)O is strongly dependent on the reaction conditions and on the ligand employed. Reaction of L(1) with equimolar quantities of Zn(NO(3))(2)·6H(2)O yields the neutral six-coordinate species [Zn(NO(3))(2)(L(1))], 7. On the other hand the use of L(1) excess gives the 2:1 adduct [Zn(NO(3))(2)(L(1))(2)], 8 where both nitrates act as a unidentate coordinating ligand. Analogous stoichiometry is found in the compound obtained from the reaction of L(2) with Zn(NO(3))(2)·6H(2)O which gives the ionic [Zn(NO(3))(L(2))(2)](NO(3)), 10. Complete displacement of both nitrates from the zinc coordination sphere is observed when the reaction between L(1) excess and the zinc salt was carried out in hydrothermal conditions. The metal ion type is also determining structure and stoichiometry: the reaction of L(2) with CdCl(2) gave the 2:1 adduct [CdCl(2)(L(2))(2)] 11 where both chlorides complete the coordination sphere of the six-coordinate cadmium center; on the other hand from the reaction of L(1) with CdBr(2) the polynuclear [CdBr(2)(L(1))](n) 12 is obtained, the Br(-) anion acting as bridging ligands in a six-coordinate cadmium coordination environment. The reaction of L(1) and L(2) with HgX(2) (X = Cl, I, SCN) is also dependent on the reaction conditions and the nature of X, two different types of adducts being formed [HgX(L)] (14: L = L(1), 16, 17: L = L(1) or L(2), X = I, 19: L = L(2), X = SCN) and [HgX(L)(2)] (15: L = L(2), X = Cl, 18: L = L(1), X = SCN). The X-ray diffraction analyses of compounds 1

  18. I. the Synthesis and Coordination Chemistry of Novel 6Pi-Electron Ligands. II. Improvement of Student Writing Skills in General Chemistry Lab Reports through the Use of Calibrated Peer Review

    ERIC Educational Resources Information Center

    William, Wilson Ngambeki

    2011-01-01

    Abstract I. The goal of this study was to synthesize and characterize a set of coordination complexes containing 6pi-cationic ligands. These compounds could be extremely useful as catalysts for the polymerization of olefins that are widely used in the synthetic polymer industry. The original strategy was to synthesize the 6pi-cationic ligands…

  19. Five coordinate M(II)-diphenolate [M = Zn(II), Ni(II), and Cu(II)] Schiff base complexes exhibiting metal- and ligand-based redox chemistry.

    PubMed

    Franks, Mark; Gadzhieva, Anastasia; Ghandhi, Laura; Murrell, David; Blake, Alexander J; Davies, E Stephen; Lewis, William; Moro, Fabrizio; McMaster, Jonathan; Schröder, Martin

    2013-01-18

    Five-coordinate Zn(II), Ni(II), and Cu(II) complexes containing pentadentate N(3)O(2) Schiff base ligands [1A](2-) and [1B](2-) have been synthesized and characterized. X-ray crystallographic studies reveal five coordinate structures in which each metal ion is bound by two imine N-donors, two phenolate O-donors, and a single amine N-donor. Electron paramagnetic resonance (EPR) spectroscopic studies suggest that the N(3)O(2) coordination spheres of [Cu(1A)] and [Cu(1B)] are retained in CH(2)Cl(2) solution and solid-state superconducting quantum interference device (SQUID) magnetometric studies confirm that [Ni(1A)] and [Ni(1B)] adopt high spin (S = 1) configurations. Each complex exhibits two reversible oxidation processes between +0.05 and +0.64 V vs [Fc](+)/[Fc]. The products of one- and two-electron oxidations have been studied by UV/vis spectroelectrochemistry and by EPR spectroscopy which confirm that each oxidation process for the Zn(II) and Cu(II) complexes is ligand-based with sequential formation of mono- and bis-phenoxyl radical species. In contrast, the one-electron oxidation of the Ni(II) complexes generates Ni(III) products. This assignment is supported by spectroelectrochemical and EPR spectroscopic studies, density functional theory (DFT) calculations, and the single crystal X-ray structure of [Ni(1A)][BF(4)] which contains Ni in a five-coordinate distorted trigonal bipyramidal geometry.

  20. Coordination chemistry of tetradentate N-donor ligands containing two pyrazolyl-pyridine units separated by a 1,8-naphthyl spacer: dodecanuclear and tetranuclear coordination cages and cyclic helicates.

    PubMed

    Argent, Stephen P; Adams, Harry; Riis-Johannessen, Thomas; Jeffery, John C; Harding, Lindsay P; Mamula, Olimpia; Ward, Michael D

    2006-05-15

    The tetradentate ligand L(naph) contains two N-donor bidentate pyrazolyl-pyridine units connected to a 1,8-naphthyl core via methylene spacers; L45 and L56 are chiral ligands with a structure similar to that of L(naph) but bearing pinene groups fused to either C4 and C5 or C5 and C6 of the terminal pyridyl rings. The complexes [Cu(L(naph))](OTf) and [Ag(L(naph))](BF4) have unremarkable mononuclear structures, with Cu(I) being four-coordinate and Ag(I) being two-coordinate with two additional weak interactions (i.e., "2 + 2" coordinate). In contrast, [Cu4(L(naph))4][BF4]4 is a cyclic tetranuclear helicate with a tetrafluoroborate anion in the central cavity, formed by an anion-templating effect; electrospray mass spectrometry (ESMS) spectra show the presence of other cyclic oligomers in solution. The chiral ligands show comparable behavior, with [Cu(L45)](BF4) and [Ag(L45)](ClO4) having similar mononuclear crystal structures and with the ligands being tetradentate chelates. In contrast, [Ag4(L56)4](BF4)4 is a cyclic tetranuclear helicate in which both diastereomers of the complex are present in the crystal; the two diastereomers have similar gross geometries but are significantly different in detail. Despite their different crystal structures, [Ag(L45)](ClO4) and [Ag4(L56)4](BF4)4 behave similarly in solution according to ESMS studies, with a range of cyclic oligomers (up to Ag9L9) forming. With transition-metal dications Co(II), Cu(II), and Cd(II), L(naph) generates a series of unusual dodecanuclear coordination cages [M12(L(naph))18]X24 (X- = ClO4- or BF4-) in which the 12 metal ions occupy the vertices of a truncated tetrahedron and a bridging ligand spans each of the 18 edges. The central cavity of each cage can accommodate four counterions, and each cage molecule is chiral, with all 12 metal trischelates being homochiral; the crystals are racemic. Extensive aromatic stacking between ligands around the periphery of the cages appears to be a significant factor in

  1. Coordination chemistry of the alkaline earth metal ions with Zwitterionic forms of the Schift bases. X-Ray studies and other spectroscopic properties

    NASA Astrophysics Data System (ADS)

    Tajmir-Riahi, H. A.; Lotfipoor, M.

    The non-ionized forms of tetradentate Schiff bases NN'-ethylenebis(salicylideneimine), H 2L and NN'-propane-1,3-diylbis(salicylideneimine), H 2L' react with hydrated alkaline earth halide and nitrate to give complexes of the type: M(H 2L)Cl 2· nH 2O [M = Mg(II), Ca(II), Sr(II); n = 0-4], M(H 2L) 2Cl 2 [M = Ca(II), Sr(II), M(H 2L) nBr 2 [M = Ca(II), Sr(II); n = 2, 3 and Mg 2(H 2L) 3Br 4], M(H 2L) nI 2 [M = Mg(II), Ca(II), Sr(II), Ba(II); n = 2, 3)], M(H 2L) n(NO 3) 2 and M(H 2L') n(NO 1) 2[M = Mg(II), Ca(II); n = 1, 2)]. Because of distinct spectral similarities with structurally known Ca(H 2L')(NO 3) 2 compound, the Schiff bases are coordinated through the negatively charged phenolic oxygen atoms and not the nitrogen atoms of the azomethine groups, which carry the protons transferred from phenolic groups on complexation. Halide and nitrate are coordinated to the central metal ion except in 2:1 nitrato complexes where the presence of both ionic and coordinated nitrate groups are evident and also in 3:1 halide complexes where the presence of non-coordinated halide cannot be excluded. X-Ray powder photographs showed no marked similarities between Ca(H 2L')(NO 3) 2 and Mg(H 2L')(NO 3) 2 while there are some isomorphic features between the same types of halide complexes. Infrared spectra and other structural information revealed the polymeric nature of the complexes. Therefore the coordination numbers exhibited by the alkaline earth metal cations would be 4, 6 or 8 in these series of Schiff base complexes.

  2. Using Modern Solid-State Analytical Tools for Investigations of an Advanced Carbon Capture Material: Experiments for the Inorganic Chemistry Laboratory

    ERIC Educational Resources Information Center

    Wriedt, Mario; Sculley, Julian P.; Aulakh, Darpandeep; Zhou, Hong-Cai

    2016-01-01

    A simple and straightforward synthesis of an ultrastable porous metal-organic framework (MOF) based on copper(II) and a mixed N donor ligand system is described as a laboratory experiment for chemistry undergraduate students. These experiments and the resulting analysis are designed to teach students basic research tools and procedures while…

  3. Quantitative Analysis of Heavy Metals in Children's Toys and Jewelry: A Multi-Instrument, Multitechnique Exercise in Analytical Chemistry and Public Health

    ERIC Educational Resources Information Center

    Finch, Lauren E.; Hillyer, Margot M.; Leopold, Michael C.

    2015-01-01

    For most chemistry curricula, laboratory-based activities in quantitative and instrumental analysis continue to be an important aspect of student development/training, one that can be more effective if conceptual understanding is delivered through an inquiry-based process relating the material to relevant issues of public interest and student…

  4. Estimating the Analytical and Surface Enhancement Factors in Surface-Enhanced Raman Scattering (SERS): A Novel Physical Chemistry and Nanotechnology Laboratory Experiment

    ERIC Educational Resources Information Center

    Pavel, Ioana E.; Alnajjar, Khadijeh S.; Monahan, Jennifer L.; Stahler, Adam; Hunter, Nora E.; Weaver, Kent M.; Baker, Joshua D.; Meyerhoefer, Allie J.; Dolson, David A.

    2012-01-01

    A novel laboratory experiment was successfully implemented for undergraduate and graduate students in physical chemistry and nanotechnology. The main goal of the experiment was to rigorously determine the surface-enhanced Raman scattering (SERS)-based sensing capabilities of colloidal silver nanoparticles (AgNPs). These were quantified by…

  5. Bismuth coordination chemistry with allyl, alkoxide, aryloxide, and tetraphenylborate ligands and the {[2,6-(Me2NCH2)2C6H3]2Bi}+ cation.

    PubMed

    Casely, Ian J; Ziller, Joseph W; Mincher, Bruce J; Evans, William J

    2011-02-21

    A series of bis(aryl) bismuth compounds containing (N,C,N)-pincer ligands, [2,6-(Me(2)NCH(2))(2)C(6)H(3)](-) (Ar'), have been synthesized and structurally characterized to compare the coordination chemistry of Bi(3+) with similarly sized lanthanide ions, Ln(3+). Treatment of Ar'(2)BiCl, 1, with ClMg(CH(2)CH═CH(2)) affords the allyl complex Ar'(2)Bi(η(1)-CH(2)CH═CH(2)), 2, in which only one allyl carbon atom coordinates to bismuth. Complex 1 reacts with KO(t)Bu and KOC(6)H(3)Me(2)-2,6 to yield the alkoxide Ar'(2)Bi(O(t)Bu), 3, and aryloxide Ar'(2)Bi(OC(6)H(3)Me(2)-2,6), 4, respectively, but the analogous reaction with the larger KOC(6)H(3)(t)Bu(2)-2,6 forms [Ar'(2)Bi][OC(6)H(3)(t)Bu(2)-2,6], 6, in which the aryloxide ligand acts as an outer sphere anion. Chloride is removed from 1 by NaBPh(4) to form [Ar'(2)Bi][BPh(4)], 5, which crystallizes from THF in an unsolvated form with tetraphenylborate as an outer sphere counteranion.

  6. Reactivity of [Ge9 {Si(SiMe3 )3 }3 ](-) Towards Transition-Metal M(2+) Cations: Coordination and Redox Chemistry.

    PubMed

    Kysliak, Oleksandr; Schrenk, Claudio; Schnepf, Andreas

    2016-12-23

    Recently the metalloid cluster compound [Ge9 Hyp3 ](-) (1; Hyp=Si(SiMe3 )3 ) was oxidatively coupled by an iron(II) salt to give the largest metalloid Group 14 cluster [Ge18 Hyp6 ]. Such redox chemistry is also possible with different transition metal (TM) salts TM(2+) (TM=Fe, Co, Ni) to give the TM(+) complexes [Fe(dppe)2 ][Ge9 Hyp3 ] (3; dppe=1,2-bis(diphenylphosphino)ethane), [Co(dppe)2 ][Ge9 Hyp3 ] (4), [Ni(dppe)(Ge9 Hyp3 )] (5) and [Ni(dppe)2 (Ge9 Hyp3 )](+) (6). Such a redox reaction does not proceed for Mn, for which a salt metathesis gives the first open shell [Hyp3 Ge9 -M-Ge9 Hyp3 ] cluster (2; M=Mn). The bonding of the transition metal atom to 1 is also possible for Ni (e.g., compound 6), in which one or even two nickel atoms can bind to 1. In contrast to this in case of the Fe and Co compounds 3 and 4, respectively, the transition-metal atom is not bound to the Ge9 core of 1. The synthesis and the experimentally determined structures of 2-6 are presented. Additionally the bonding within 2-6 is analyzed and discussed with the aid of EPR measurements and quantum chemical calculations.

  7. Low-Cost Method for Quantifying Sodium in Coconut Water and Seawater for the Undergraduate Analytical Chemistry Laboratory: Flame Test, a Mobile Phone Camera, and Image Processing

    ERIC Educational Resources Information Center

    Moraes, Edgar P.; da Silva, Nilbert S. A.; de Morais, Camilo de L. M.; das Neves, Luiz S.; de Lima, Kassio M. G.

    2014-01-01

    The flame test is a classical analytical method that is often used to teach students how to identify specific metals. However, some universities in developing countries have difficulties acquiring the sophisticated instrumentation needed to demonstrate how to identify and quantify metals. In this context, a method was developed based on the flame…

  8. Developing and Implementing Inquiry-Based, Water Quality Laboratory Experiments for High School Students to Explore Real Environmental Issues Using Analytical Chemistry

    ERIC Educational Resources Information Center

    Mandler, Daphna; Blonder, Ron; Yayon, Malka; Mamlok-Naaman, Rachel; Hofstein, Avi

    2014-01-01

    This paper describes the rationale and the implementation of five laboratory experiments; four of them, intended for high-school students, are inquiry-based activities that explore the quality of water. The context of water provides students with an opportunity to study the importance of analytical methods and how they influence our everyday…

  9. Influence of biphenyl spacer appended to the flexible phosphonate arms in modulating the dimensionality of the coordination polymers: Synthesis, structural chemistry and magnetic properties

    SciTech Connect

    Tripuramallu, Bharat Kumar; Das, Samar K.

    2013-01-15

    Two new compounds [Co (2,2 Prime -bipy) (H{sub 2}dbp)]{sub n} (1) and [Ni (2,2 Prime -bipy){sub 2}(H{sub 2}dbp)(H{sub 2}O)]{center_dot}H{sub 2}O (2) based on the flexible ligand 4,4 Prime -dimethylenebiphenyldiphosphonic acid (H{sub 4}dbp) with 2,2 Prime -bipyridine as secondary ligand have been synthesized under hydrothermal conditions. Both the compounds are well characterized by routine elemental analysis, IR, electronic spectroscopies, thermogravimetric analysis and finally by single crystal X-ray diffraction analysis. Compound 1 is a 1D extended coordination polymer and 2 is a discrete molecular compound. A comparative study between the geometries of H{sub 4}dbp ligand (in compounds 1 and 2, present study) and p-xylylenediphosphonic acid (H{sub 4}pxp) ligand (in previously reported compounds [Cu(2,2 Prime -bipy)(H{sub 2}pxp)]{center_dot}nH{sub 2}O (1A) and Ni(2,2 Prime -bipy){sub 2}H{sub 4}pxp]{sub n}[H{sub 2}pxp]{sub n} (2A), see text) demonstrate the effect of the twisting in the benzene rings in changing higher dimensional H{sub x}pxp (x refers to number of protonated hydroxyl groups) compounds to lower dimensional H{sub x}dbp compounds. The eight membered Co-dimer rings formed in compound 1 represents the simple and isolated Co-dimer, exhibiting weak antiferromagnetic exchange between metal centers through OPO bridges. - Graphical abstract: Two new compounds based on the dimethylenebiphenyldiphosphonic acid have been synthesized. The effect of twisting of benzene rings in the biphenyl spacer containing multidentate ligands alters dimensionality of final compounds. Highlights: Black-Right-Pointing-Pointer Cobalt containing coordination polymer and a nickel discrete compound have been synthesized. Black-Right-Pointing-Pointer Flexible ligand 4,4'-dimethylenebiphenyldiphosphonic acid has been employed. Black-Right-Pointing-Pointer Co(II) and Ni(II) ions are square pyramidal and octahedral respectively. Black-Right-Pointing-Pointer The effect of the twisting

  10. I. The synthesis and coordination chemistry of novel 6pi-electron ligands. II. Improvement of student writing skills in general chemistry lab reports through the use of Calibrated Peer Review

    NASA Astrophysics Data System (ADS)

    William, Wilson Ngambeki

    Abstract I. The goal of this study was to synthesize and characterize a set of coordination complexes containing 6pi-cationic ligands. These compounds could be extremely useful as catalysts for the polymerization of olefins that are widely used in the synthetic polymer industry. The original strategy was to synthesize the 6pi-cationic ligands using (Ph2P) 3CH (1) and (Me2P)3CH (10) as precursors; however, both precursors 1 and 10 were found to be highly reactive leading to the fragmentation products (Ph 2P)2CH2 and (Me2P)2CH 2 respectively. In trying to control the reactivity, precursor 1 was coordinated to the group 6B metal carbonyl in two modes, Mo(CO)3(C 2H5CN)(Ph2P)2CHPPh2 and W(CO) 3(C2H5CN)(Ph2P)2CHPPh 2. In these novel compounds, two of the three phosphorus atoms are chelated to the metal. These complexes were isolated and characterized by X-ray analysis, elemental analysis, NMR and infrared spectroscopy. When these metal complexes were reacted with B(C6F5)3, the complexes were stabilized, and no molecular fragmentation was observed. Instead, a second mode of coordination was observed by 31P{1H} NMR spectroscopy, where all three phosphorus atoms are bonded to the metal in a tridentate fashion, yielding the novel product EtCNB(C6F 5)3, which was characterized by X-ray analysis. However, because there was no hydride abstraction from the tertiary carbon in either compound, further studies will be required to develop a strategy for hydride abstraction to produce a cationic ligand. Another strategy for the synthesis of 6pi-cationic ligands was to directly synthesize the halogenated version of the tertiary carbon atom of compound 10. Fractional recrystallization of the crude product yielded two compounds of 2,4,6-trimethypyridinium bromide and (PMe2)3CBr. (PMe2)3CBr was determined to be pure as revealed by 31P{1H} NMR. It is expected that oxidation of the bromide should yield the 6pi-cationic ligand. In the next strategy, density function theory calculations (DFT

  11. Process chemistry {ampersand} statistics quality assurance plan

    SciTech Connect

    Meznarich, H.K.

    1996-08-01

    This document provides quality assurance guidelines and quality control requirements for Process Chemistry and Statistics. This document is designed on the basis of Hanford Analytical Services Quality Assurance Plan (HASQAP) technical guidelines and is used for governing process chemistry activities.

  12. The physical chemistry of coordinated aqua-, ammine-, and mixed-ligand Co2+ complexes: DFT studies on the structure, energetics, and topological properties of the electron density.

    PubMed

    Varadwaj, Pradeep R; Marques, Helder M

    2010-03-07

    Spin-unrestricted DFT-X3LYP/6-311++G(d,p) calculations have been performed on a series of complexes of the form [Co(H(2)O)(6-n)(NH(3))(n)](2+) (n = 0-6) to examine their equilibrium gas-phase structures, energetics, and electronic properties in their quartet electronic ground states. In all cases Co(2+) in the energy-minimised structures is in a pseudo-octahedral environment. The calculations overestimate the Co-O and Co-N bond lengths by 0.04 and 0.08 A, respectively, compared to the crystallographically observed mean values. There is a very small Jahn-Teller distortion in the structure of [Co(H(2)O)(6)](2+) which is in contrast to the very marked distortions observed in most (but not all) structures of this cation that have been observed experimentally. The successive replacement of ligated H(2)O by NH(3) leads to an increase in complex stability by 6 +/- 1 kcal mol(-1) per additional NH(3) ligand. Calculations using UB3LYP give stabilisation energies of the complexes about 5 kcal mol(-1) smaller and metal-ligand bond lengths about 0.005 A longer than the X3LYP values since the X3LYP level accounts for the London dispersion energy contribution to the overall stabilisation energy whilst it is largely missing at the B3LYP level. From a natural population analysis (NPA) it is shown that the formation of these complexes is accompanied by ligand-to-metal charge transfer the extent of which increases with the number of NH(3) ligands in the coordination sphere of Co(2+). From an examination of the topological properties of the electron charge density using Bader's quantum theory of atoms in molecules it is shown that the electron density rho(c) at the Co-O bond critical points is generally smaller than that at the Co-N bond critical points. Hence Co-O bonds are weaker than Co-N bonds in these complexes and the stability increases as NH(3) replaces H(2)O in the metal's coordination sphere. Several indicators, including the sign and magnitude of the Laplacian of the

  13. Direct analysis of six antibiotics in wastewater samples using rapid high-performance liquid chromatography coupled with diode array detector: a chemometric study towards green analytical chemistry.

    PubMed

    Vosough, Maryam; Rashvand, Masoumeh; Esfahani, Hadi M; Kargosha, Kazem; Salemi, Amir

    2015-04-01

    In this work, a rapid HPLC-DAD method has been developed for the analysis of six antibiotics (amoxicillin, metronidazole, sulfamethoxazole, ofloxacine, sulfadiazine and sulfamerazine) in the sewage treatment plant influent and effluent samples. Decreasing the chromatographic run time to less than 4 min as well as lowering the cost per analysis, were achieved through direct injection of the samples into the HPLC system followed by chemometric analysis. The problem of the complete separation of the analytes from each other and/or from the matrix ingredients was resolved as a posteriori. The performance of MCR/ALS and U-PLS/RBL, as second-order algorithms, was studied and comparable results were obtained from implication of these modeling methods. It was demonstrated that the proposed methods could be used promisingly as green analytical strategies for detection and quantification of the targeted pollutants in wastewater samples while avoiding the more complicated high cost instrumentations.

  14. Biosynthetic inorganic chemistry.

    PubMed

    Lu, Yi

    2006-08-25

    Inorganic chemistry and biology can benefit greatly from each other. Although synthetic and physical inorganic chemistry have been greatly successful in clarifying the role of metal ions in biological systems, the time may now be right to utilize biological systems to advance coordination chemistry. One such example is the use of small, stable, easy-to-make, and well-characterized proteins as ligands to synthesize novel inorganic compounds. This biosynthetic inorganic chemistry is possible thanks to a number of developments in biology. This review summarizes the progress in the synthesis of close models of complex metalloproteins, followed by a description of recent advances in using the approach for making novel compounds that are unprecedented in either inorganic chemistry or biology. The focus is mainly on synthetic "tricks" learned from biology, as well as novel structures and insights obtained. The advantages and disadvantages of this biosynthetic approach are discussed.

  15. Coordination chemistry of two heavy metals: I, Ligand preferences in lead(II) complexation, toward the development of therapeutic agents for lead poisoning: II, Plutonium solubility and speciation relevant to the environment

    SciTech Connect

    Neu, Mary Patricia

    1993-11-01

    The coordination chemistry and solution behavior of the toxic ions lead(II) and plutonium(IV, V, VI) have been investigated. The ligand pKas and ligand-lead(II) stability constants of one hydroxamic acid and four thiohydroaxamic acids were determined. Solution thermodynamic results indicate that thiohydroxamic acids are more acidic and slightly better lead chelators than hydroxamates, e.g., N-methylthioaceto-hydroxamic acid, pKa = 5.94, logβ120 = 10.92; acetohydroxamic acid, pKa = 9.34, logβ120 = 9.52. The syntheses of lead complexes of two bulky hydroxamate ligands are presented. The X-ray crystal structures show the lead hydroxamates are di-bridged dimers with irregular five-coordinate geometry about the metal atom and a stereochemically active lone pair of electrons. Molecular orbital calculations of a lead hydroxamate and a highly symmetric pseudo octahedral lead complex were performed. The thermodynamic stability of plutonium(IV) complexes of the siderophore, desferrioxamine B (DFO), and two octadentate derivatives of DFO were investigated using competition spectrophotometric titrations. The stability constant measured for the plutonium(IV) complex of DFO-methylterephthalamide is logβ120 = 41.7. The solubility limited speciation of 242Pu as a function of time in near neutral carbonate solution was measured. Individual solutions of plutonium in a single oxidation state were added to individual solutions at pH = 6.0, T = 30.0, 1.93 mM dissolved carbonate, and sampled over intervals up to 150 days. Plutonium solubility was measured, and speciation was investigated using laser photoacoustic spectroscopy and chemical methods.

  16. Miniaturizing and automation of free acidity measurements for uranium (VI)-HNO3 solutions: Development of a new sequential injection analysis for a sustainable radio-analytical chemistry.

    PubMed

    Néri-Quiroz, José; Canto, Fabrice; Guillerme, Laurent; Couston, Laurent; Magnaldo, Alastair; Dugas, Vincent

    2016-10-01

    A miniaturized and automated approach for the determination of free acidity in solutions containing uranium (VI) is presented. The measurement technique is based on the concept of sequential injection analysis with on-line spectroscopic detection. The proposed methodology relies on the complexation and alkalimetric titration of nitric acid using a pH 5.6 sodium oxalate solution. The titration process is followed by UV/VIS detection at 650nm thanks to addition of Congo red as universal pH indicator. Mixing sequence as well as method validity was investigated by numerical simulation. This new analytical design allows fast (2.3min), reliable and accurate free acidity determination of low volume samples (10µL) containing uranium/[H(+)] moles ratio of 1:3 with relative standard deviation of <7.0% (n=11). The linearity range of the free nitric acid measurement is excellent up to 2.77molL(-1) with a correlation coefficient (R(2)) of 0.995. The method is specific, presence of actinide ions up to 0.54molL(-1) does not interfere on the determination of free nitric acid. In addition to automation, the developed sequential injection analysis method greatly improves the standard off-line oxalate complexation and alkalimetric titration method by reducing thousand fold the required sample volume, forty times the nuclear waste per analysis as well as the analysis time by eight fold. These analytical parameters are important especially in nuclear-related applications to improve laboratory safety, personnel exposure to radioactive samples and to drastically reduce environmental impacts or analytical radioactive waste.

  17. Label-free porous silicon immunosensor for broad detection of opiates in a blind clinical study and results comparison to commercial analytical chemistry techniques.

    PubMed

    Bonanno, Lisa M; Kwong, Tai C; DeLouise, Lisa A

    2010-12-01

    In this work, we evaluate for the first time the performance of a label-free porous silicon (PSi) immunosensor assay in a blind clinical study designed to screen authentic patient urine specimens for a broad range of opiates. The PSi opiate immunosensor achieved 96% concordance with liquid chromatography-mass spectrometry/tandem mass spectrometry (LC-MS/MS) results on samples that underwent standard opiate testing (n = 50). In addition, successful detection of a commonly abused opiate, oxycodone, resulted in 100% qualitative agreement between the PSi opiate sensor and LC-MS/MS. In contrast, a commercial broad opiate immunoassay technique (CEDIA) achieved 65% qualitative concordance with LC-MS/MS. Evaluation of important performance attributes including precision, accuracy, and recovery was completed on blank urine specimens spiked with test analytes. Variability of morphine detection as a model opiate target was <9% both within-run and between-day at and above the cutoff limit of 300 ng mL(-1). This study validates the analytical screening capability of label-free PSi opiate immunosensors in authentic patient samples and is the first semiquantitative demonstration of the technology's successful clinical use. These results motivate future development of label-free PSi technology to reduce complexity and cost of diagnostic testing particularly in a point-of-care setting.

  18. A Label-Free Porous Silicon Immunosensor for Broad Detection of Opiates in a Blind Clinical Study and Result Comparison to Commercial Analytical Chemistry Techniques

    PubMed Central

    Bonanno, Lisa M.; Kwong, Tai C.; DeLouise, Lisa A.

    2010-01-01

    In this work we evaluate for the first time the performance of a label-free porous silicon (PSi) immunosensor assay in a blind clinical study designed to screen authentic patient urine specimens for a broad range of opiates. The PSi opiate immunosensor achieved 96% concordance with liquid chromatography-mass spectrometry/tandem mass spectrometry (LC-MS/MS) results on samples that underwent standard opiate testing (n=50). In addition, successful detection of a commonly abused opiate, oxycodone, resulted in 100% qualitative agreement between the PSi opiate sensor and LC-MS/MS. In contrast, a commercial broad opiate immunoassay technique (CEDIA®) achieved 65% qualitative concordance with LC-MS/MS. Evaluation of important performance attributes including precision, accuracy, and recovery was completed on blank urine specimens spiked with test analytes. Variability of morphine detection as a model opiate target was < 9% both within-run and between-day at and above the cutoff limit of 300 ng ml−1. This study validates the analytical screening capability of label-free PSi opiate immunosensors in authentic patient samples and is the first semi-quantitative demonstration of the technology’s successful clinical use. These results motivate future development of PSi technology to reduce complexity and cost of diagnostic testing particularly in a point-of-care setting. PMID:21062030

  19. Emergency control system based on the analytical hierarchy process and coordinated development degree model for sudden water pollution accidents in the Middle Route of the South-to-North Water Transfer Project in China.

    PubMed

    Long, Yan; Xu, Guobin; Ma, Chao; Chen, Liang

    2016-06-01

    Water transfer projects are important for realizing reasonable allocation of water resources, but once a water pollution accident occurs during such a project, the water environment is exposed to enormous risks. Therefore, it is critical to determine an appropriate emergency control system (ECS) for sudden water pollution accidents that occur in water transfer projects. In this study, the analytical hierarchy process (AHP) integrated with the coordinated development degree model (CDDM) was used to develop the ECS. This ECS was developed into two parts, including the emergency risk assessment and the emergency control. Feasible emergency control targets and control technology were also proposed for different sudden water pollution accidents. A demonstrative project was conducted in the Fangshui to Puyang channel, which is part of the Beijing-Shijiazhuang Emergency Water Supply Project (BSP) in the Middle Route of the South-to-North Water Transfer Project (MR-SNWTP) in China. However, we could not use an actual toxic soluble pollutant to validate our ECS, so we performed the experiment with sucrose to test the ECS based on its concentration variation. The relative error of peak sucrose concentration was less than 20 %.

  20. Statistical comparison of the results from six analytical chemistry laboratories of the mercury content of muscle tissue of two species of sharks.

    PubMed

    Walker, T I

    1977-01-01

    Statistical tests were carried out on the results of chemical analysis for total mercury concentrations of replicate samples of muscle tissue of school shark Galeorhinus australis (Macleay) and gummy shark Mustelus antarcticus Guenther from six independent analytical laboratories. These tests showed that one laboratory produced results 9% below the overall average of all results, another 1% below average while the other four were all 5% above average. Moreover, one laboratory had significantly lower scatter of results than the others, and the percentage scatter (standard error expressed as a percentage of the mean) in two of the laboratories tended to diminish as the magnitude of the results increased. Correction for what were concluded to be wild points indicated that the scatter for all laboratories was below 14%.

  1. Beginning Chemistry Can Be Relevant

    ERIC Educational Resources Information Center

    Corwin, James F.

    1971-01-01

    Reviews ways of applying laboratory work in general and analytical chemistry to supermarket products. Describes ways water and air pollution analysis can illustrate acid-base reactions, redox reactions, precipitimetry, and colorimetry. (PR)

  2. USSR Report, Chemistry, No. 105

    DTIC Science & Technology

    2007-11-02

    This USSR Report contains articles on Chemistry. Some of the topics covered are Alkaloids, Catalysis, Analytical Chemistry, Chemical Industry, Coal Gasification , Combustion, Electrochemistry, Fertilizers, Free Radials, Nitrogen Compounds, Organometallic Compounds, Organophosphorus Compounds, Pesticides, Petroleum Processing Technology, Polymers and Polymerization and Rubber and Elastomers.,

  3. The Role of Dafachronic Acid Signaling in Development and Longevity in Caenorhabditis elegans: Digging Deeper Using Cutting-Edge Analytical Chemistry

    PubMed Central

    Aguilaniu, Hugo; Fabrizio, Paola; Witting, Michael

    2016-01-01

    Steroid hormones regulate physiological processes in species ranging from plants to humans. A wide range of steroid hormones exist, and their contributions to processes, such as growth, reproduction, development, and aging, is almost always complex. Understanding the biosynthetic pathways that generate steroid hormones and the signaling pathways that mediate their effects is thus of fundamental importance. In this work, we review recent advances in (i) the biological role of steroid hormones in the roundworm Caenorhabditis elegans and (ii) the development of novel methods to facilitate the detection and identification of these molecules. Our current understanding of steroid signaling in this simple organism serves to illustrate the challenges we face moving forward. First, it seems clear that we have not yet identified all of the enzymes responsible for steroid biosynthesis and/or degradation. Second, perturbation of steroid signaling affects a wide range of phenotypes, and subtly different steroid molecules can have distinct effects. Finally, steroid hormone levels are critically important, and minute variations in quantity can profoundly impact a phenotype. Thus, it is imperative that we develop innovative analytical tools and combine them with cutting-edge approaches including comprehensive and highly selective liquid chromatography coupled to mass spectrometry based on new methods such as supercritical fluid chromatography coupled to mass spectrometry (SFC-MS) if we are to obtain a better understanding of the biological functions of steroid signaling. PMID:26903948

  4. The Role of Dafachronic Acid Signaling in Development and Longevity in Caenorhabditis elegans: Digging Deeper Using Cutting-Edge Analytical Chemistry.

    PubMed

    Aguilaniu, Hugo; Fabrizio, Paola; Witting, Michael

    2016-01-01

    Steroid hormones regulate physiological processes in species ranging from plants to humans. A wide range of steroid hormones exist, and their contributions to processes, such as growth, reproduction, development, and aging, is almost always complex. Understanding the biosynthetic pathways that generate steroid hormones and the signaling pathways that mediate their effects is thus of fundamental importance. In this work, we review recent advances in (i) the biological role of steroid hormones in the roundworm Caenorhabditis elegans and (ii) the development of novel methods to facilitate the detection and identification of these molecules. Our current understanding of steroid signaling in this simple organism serves to illustrate the challenges we face moving forward. First, it seems clear that we have not yet identified all of the enzymes responsible for steroid biosynthesis and/or degradation. Second, perturbation of steroid signaling affects a wide range of phenotypes, and subtly different steroid molecules can have distinct effects. Finally, steroid hormone levels are critically important, and minute variations in quantity can profoundly impact a phenotype. Thus, it is imperative that we develop innovative analytical tools and combine them with cutting-edge approaches including comprehensive and highly selective liquid chromatography coupled to mass spectrometry based on new methods such as supercritical fluid chromatography coupled to mass spectrometry (SFC-MS) if we are to obtain a better understanding of the biological functions of steroid signaling.

  5. Soap bubbles in analytical chemistry. Conductometric determination of sub-parts per million levels of sulfur dioxide with a soap bubble.

    PubMed

    Kanyanee, Tinakorn; Borst, Walter L; Jakmunee, Jaroon; Grudpan, Kate; Li, Jianzhong; Dasgupta, Purnendu K

    2006-04-15

    Soap bubbles provide a fascinating tool that is little used analytically. With a very low liquid volume to surface area ratio, a soap bubble can potentially provide a very useful interface for preconcentration where mass transfer to an interfacial surface is important. Here we use an automated system to create bubbles of uniform size and film thickness. We utilize purified Triton-X 100, a nonionic surfactant, to make soap bubbles. We use such bubbles as a gas-sampling interface. Incorporating hydrogen peroxide into the bubble provides a system where electrical conductance increases as the bubble is exposed to low concentrations of sulfur dioxide gas. We theoretically derive the conductance of a hollow conducting spherical thin film with spherical cap electrodes. We measure the film thickness by incorporating a dye in the bubble making solution and laser transmission photometry and find that it agrees well with the geometrically computed thickness. With the conductance of the bubble-making soap solution being measured by conventional methods, we show that the measured values of the bubble conductance with known bubble and electrode dimensions closely correspond to the theoretically computed value. Finally, we demonstrate that sub-ppm levels of SO(2) can readily be detected by the conductivity change of a hydrogen peroxide-doped soap bubble, measured in situ, when the gas flows around the bubble.

  6. Coordination chemistry in fused-salt solutions

    NASA Technical Reports Server (NTRS)

    Gruen, D. M.

    1969-01-01

    Spectrophotometric work on structural determinations with fused-salt solutions is reviewed. Constraints placed on the method, as well as interpretation of the spectra, are discussed with parallels drawn to aqueous spectrophotometric curves of the same materials.

  7. Novel Coordination Chemistry of Aluminum Borohydride

    DTIC Science & Technology

    2014-08-01

    rocket propulsion . Due to its highly pyrophoric nature ABH poses extreme handling hazards. This reactivity can be significantly tamed through the...toxicity can limit transportation options Hydrazine – A state of the art rocket fuel Distribution A: Public Release, Distribution unlimited As of...today, most of our in-space propulsion systems are powered by the MMH and NTO bi-propellant system, known to be hypergolic and severely toxic.  In the

  8. Spotlight on medicinal chemistry education.

    PubMed

    Pitman, Simone; Xu, Yao-Zhong; Taylor, Peter; Turner, Nicholas; Coaker, Hannah; Crews, Kasumi

    2014-05-01

    The field of medicinal chemistry is constantly evolving and it is important for medicinal chemists to develop the skills and knowledge required to succeed and contribute to the advancement of the field. Future Medicinal Chemistry spoke with Simone Pitman (SP), Yao-Zhong Xu (YX), Peter Taylor (PT) and Nick Turner (NT) from The Open University (OU), which offers an MSc in Medicinal Chemistry. In the interview, they discuss the MSc course content, online teaching, the future of medicinal chemistry education and The OU's work towards promoting widening participation. SP is a Qualifications Manager in the Science Faculty at The OU. She joined The OU in 1993 and since 1998 has been involved in the Postgraduate Medicinal Chemistry provision at The OU. YX is a Senior Lecturer in Bioorganic Chemistry at The OU. He has been with The OU from 2001, teaching undergraduate courses of all years and chairing the master's course on medicinal chemistry. PT is a Professor of Organic Chemistry at The OU and has been involved with the production and presentation of The OU courses in Science and across the university for over 30 years, including medicinal chemistry modules at postgraduate level. NT is a Lecturer in Analytical Science at The OU since 2009 and has been involved in the production of analytical sciences courses, as well as contributing to the presentation of a number of science courses including medicinal chemistry.

  9. Forensic Chemistry--A Symposium Collection.

    ERIC Educational Resources Information Center

    Journal of Chemical Education, 1985

    1985-01-01

    Presents a collection of articles to provide chemistry teachers with resource materials to add forensic chemistry units to their chemistry courses. Topics range from development of forensic science laboratory courses and mock-crime scenes to forensic serology and analytical techniques. (JN)

  10. Supplemental Instruction in Physical Chemistry I

    ERIC Educational Resources Information Center

    Toby, Ellen; Scott, Timothy P.; Migl, David; Kolodzeji, Elizabeth

    2016-01-01

    Physical chemistry I at Texas A&M University is an upper division course requiring mathematical and analytical skills. As such, this course poses a major problem for many Chemistry, Engineering, Biochemistry and Genetics majors. Comparisons between participants and non-participants in Supplemental Instruction for physical chemistry were made…

  11. ENVIRONMENTAL CHEMISTRY CAREERS IN GOVERNMENT AGENCIES

    EPA Science Inventory

    Careers in chemistry and chemistry related fields can be very rewarding and enriching. Being an environmental chemist for a government agency requires a broad background in the field of chemistry. A knowledge of the operation of several analytical and preparatory instruments is...

  12. Poisson Coordinates.

    PubMed

    Li, Xian-Ying; Hu, Shi-Min

    2013-02-01

    Harmonic functions are the critical points of a Dirichlet energy functional, the linear projections of conformal maps. They play an important role in computer graphics, particularly for gradient-domain image processing and shape-preserving geometric computation. We propose Poisson coordinates, a novel transfinite interpolation scheme based on the Poisson integral formula, as a rapid way to estimate a harmonic function on a certain domain with desired boundary values. Poisson coordinates are an extension of the Mean Value coordinates (MVCs) which inherit their linear precision, smoothness, and kernel positivity. We give explicit formulas for Poisson coordinates in both continuous and 2D discrete forms. Superior to MVCs, Poisson coordinates are proved to be pseudoharmonic (i.e., they reproduce harmonic functions on n-dimensional balls). Our experimental results show that Poisson coordinates have lower Dirichlet energies than MVCs on a number of typical 2D domains (particularly convex domains). As well as presenting a formula, our approach provides useful insights for further studies on coordinates-based interpolation and fast estimation of harmonic functions.

  13. Chemistry-nuclear chemistry division. Progress report, October 1979-September 1980

    SciTech Connect

    Ryan, R.R.

    1981-05-01

    This report presents the research and development programs pursued by the Chemistry-Nuclear Chemistry Division of the Los Alamos National Laboratory. Topics covered include advanced analytical methods, atmospheric chemistry and transport, biochemistry, biomedical research, element migration and fixation, inorganic chemistry, isotope separation and analysis, atomic and molecular collisions, molecular spectroscopy, muonic x rays, nuclear cosmochemistry, nuclear structure and reactions, radiochemical separations, theoretical chemistry, and unclassified weapons research.

  14. Microfluidics in inorganic chemistry.

    PubMed

    Abou-Hassan, Ali; Sandre, Olivier; Cabuil, Valérie

    2010-08-23

    The application of microfluidics in chemistry has gained significant importance in the recent years. Miniaturized chemistry platforms provide controlled fluid transport, rapid chemical reactions, and cost-saving advantages over conventional reactors. The advantages of microfluidics have been clearly established in the field of analytical and bioanalytical sciences and in the field of organic synthesis. It is less true in the field of inorganic chemistry and materials science; however in inorganic chemistry it has mostly been used for the separation and selective extraction of metal ions. Microfluidics has been used in materials science mainly for the improvement of nanoparticle synthesis, namely metal, metal oxide, and semiconductor nanoparticles. Microfluidic devices can also be used for the formulation of more advanced and sophisticated inorganic materials or hybrids.

  15. Automation and quality in analytical laboratories

    SciTech Connect

    Valcarcel, M.; Rios, A.

    1994-05-01

    After a brief introduction to the generic aspects of automation in analytical laboratories, the different approaches to quality in analytical chemistry are presented and discussed to establish the following different facets emerging from the combination of quality and automation: automated analytical control of quality of products and systems; quality control of automated chemical analysis; and improvement of capital (accuracy and representativeness), basic (sensitivity, precision, and selectivity), and complementary (rapidity, cost, and personnel factors) analytical features. Several examples are presented to demonstrate the importance of this marriage of convenience in present and future analytical chemistry. 7 refs., 4 figs.

  16. Bringing inorganic chemistry to life with inspiration from R. J. P. Williams.

    PubMed

    Hill, H Allen O; Sadler, Peter J

    2016-03-01

    Our appreciation of the scholarly ideas and thinking of Bob Williams is illustrated here by a few of the areas in which he inspired us. His journey to bring inorganic chemistry to life began with an early interest in analytical chemistry, rationalising the relative stabilities of metal coordination complexes (The Irving-Williams Series), and elucidating the organometallic redox chemistry of vitamin B12. He (and Vallee) recognised that metal ions are in energised (entatic) states in proteins and enzymes, which themselves are dynamic structures of rods and springs. He played a key role in helping Rosenberg to pave the road toward the clinic for the anticancer drug cisplatin. He believed that evolution is not just dependent on DNA, but also on the metallome. Organisms and the environment are one system: does DNA code directly for all the essential elements of life?

  17. Biophysical chemistry.

    PubMed

    Häussinger, Daniel; Pfohl, Thomas

    2010-01-01

    Biophysical chemistry at the Department of Chemistry, University of Basel, covers the NMR analysis of protein-protein interaction using paramagnetic tags and sophisticated microscopy techniques investigating the dynamics of biological matter.

  18. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1983

    1983-01-01

    Presents background information, laboratory procedures, classroom materials/activities, and chemistry experiments. Topics include sublimation, electronegativity, electrolysis, experimental aspects of strontianite, halide test, evaluation of present and future computer programs in chemistry, formula building, care of glass/saturated calomel…

  19. Chemistry Notes

    ERIC Educational Resources Information Center

    School Science Review, 1976

    1976-01-01

    Described are eight chemistry experiments and demonstrations applicable to introductory chemistry courses. Activities include: measure of lattice enthalpy, Le Chatelier's principle, decarboxylation of soap, use of pocket calculators in pH measurement, and making nylon. (SL)

  20. Chemistry Dashboard

    EPA Pesticide Factsheets

    The Chemistry Dashboard is part of a suite of dashboards developed by EPA to help evaluate the safety of chemicals. The Chemistry Dashboard provides access to a variety of information on over 700,000 chemicals currently in use.

  1. Chemistry Notes

    ERIC Educational Resources Information Center

    School Science Review, 1972

    1972-01-01

    Thirteen ideas are presented that may be of use to chemistry teachers. Topics covered include vitamin C, industrial chemistry, electrical conductivity, electrolysis, alkali metals, vibration modes infra-red, dynamic equilibrium, and some new demonstrations in gaseous combinations. (PS)

  2. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1982

    1982-01-01

    Presents background information, laboratory procedures, classroom materials/activities, and experiments for chemistry. Topics include superheavy elements, polarizing power and chemistry of alkali metals, particulate carbon from combustion, tips for the chemistry laboratory, interesting/colorful experiments, behavior of bismuth (III) iodine, and…

  3. Analytical chemistry: Virulence caught green-handed

    NASA Astrophysics Data System (ADS)

    Sanchez, Laura M.; Dorrestein, Pieter C.

    2013-03-01

    Many of us eat mushrooms, but few of us have probably ever thought about -- let alone witnessed -- the epic battle of kingdoms that can occur between this delicacy and its bacterial pathogens. Now, imaging mass spectrometry has enabled the identification of a bacterium's potent antifungal weapon of choice.

  4. Quality assurance for environmental analytical chemistry: 1980

    SciTech Connect

    Gladney, E.S.; Goode, W.E.; Perrin, D.R.; Burns, C.E.

    1981-09-01

    The continuing quality assurance effort by the Environmental Surveillance Group is presented. Included are all standard materials now in use, their consensus or certified concentrations, quality control charts, and all quality assurance measurements made by H-8 during 1980.

  5. COORDINATED AV.

    ERIC Educational Resources Information Center

    CLEAVES, PAUL C.; AND OTHERS

    THE INSTRUCTIONAL MATERIALS CENTER IS LOCATED IN THE LOCAL HIGH SCHOOL AND SUPPLIES ALL SCHOOLS IN THE AREA. AUDIOVISUAL EQUIPMENT ORDERS, AFTER SELECTIONS ARE MADE BY THE CLASSROOM TEACHER, ARE PROCESSED BY THE CENTER, CONFIRMED AND DELIVERED BY TRUCK THREE TIMES EACH WEEK. EACH SCHOOL HAS A BUILDING COORDINATOR WHO CHECKS THE ORDERS INTO THE…

  6. Coordination responsive tellurium-containing multilayer film for controlled delivery.

    PubMed

    Cao, Wei; Wang, Lu; Xu, Huaping

    2015-03-28

    A coordination-responsive tellurium containing film was fabricated for controlled release. The coordination chemistry between telluride molecules and cisplatin was utilized for the loading of cisplatin, while competitive ligands were used for triggered release. This work could enrich the coordination responsive system and further tune the release kinetics of cisplatin.

  7. A coordination theory for intelligent machines

    NASA Technical Reports Server (NTRS)

    Wang, Fei-Yue; Saridis, George N.

    1990-01-01

    A formal model for the coordination level of intelligent machines is established. The framework of the coordination level investigated consists of one dispatcher and a number of coordinators. The model called coordination structure has been used to describe analytically the information structure and information flow for the coordination activities in the coordination level. Specifically, the coordination structure offers a formalism to (1) describe the task translation of the dispatcher and coordinators; (2) represent the individual process within the dispatcher and coordinators; (3) specify the cooperation and connection among the dispatcher and coordinators; (4) perform the process analysis and evaluation; and (5) provide a control and communication mechanism for the real-time monitor or simulation of the coordination process. A simple procedure for the task scheduling in the coordination structure is presented. The task translation is achieved by a stochastic learning algorithm. The learning process is measured with entropy and its convergence is guaranteed. Finally, a case study of the coordination structure with three coordinators and one dispatcher for a simple intelligent manipulator system illustrates the proposed model and the simulation of the task processes performed on the model verifies the soundness of the theory.

  8. Analytic materials

    NASA Astrophysics Data System (ADS)

    Milton, Graeme W.

    2016-11-01

    The theory of inhomogeneous analytic materials is developed. These are materials where the coefficients entering the equations involve analytic functions. Three types of analytic materials are identified. The first two types involve an integer p. If p takes its maximum value, then we have a complete analytic material. Otherwise, it is incomplete analytic material of rank p. For two-dimensional materials, further progress can be made in the identification of analytic materials by using the well-known fact that a 90° rotation applied to a divergence-free field in a simply connected domain yields a curl-free field, and this can then be expressed as the gradient of a potential. Other exact results for the fields in inhomogeneous media are reviewed. Also reviewed is the subject of metamaterials, as these materials provide a way of realizing desirable coefficients in the equations.

  9. Analytic materials.

    PubMed

    Milton, Graeme W

    2016-11-01

    The theory of inhomogeneous analytic materials is developed. These are materials where the coefficients entering the equations involve analytic functions. Three types of analytic materials are identified. The first two types involve an integer p. If p takes its maximum value, then we have a complete analytic material. Otherwise, it is incomplete analytic material of rank p. For two-dimensional materials, further progress can be made in the identification of analytic materials by using the well-known fact that a 90(°) rotation applied to a divergence-free field in a simply connected domain yields a curl-free field, and this can then be expressed as the gradient of a potential. Other exact results for the fields in inhomogeneous media are reviewed. Also reviewed is the subject of metamaterials, as these materials provide a way of realizing desirable coefficients in the equations.

  10. Chemistry Notes

    ERIC Educational Resources Information Center

    School Science Review, 1972

    1972-01-01

    Twelve new chemistry expermiments are described. Broad areas covered include atomic structure, solubility, gaseous diffusion, endothermic reactions, alcohols, equilibrium, atomic volumes, and some improvised apparatus. (PS)

  11. Satellite Coordination

    NASA Astrophysics Data System (ADS)

    Cohen, R. J.

    2004-06-01

    The Radio Regulations set out complex procedures to ensure that when new systems start to use the frequency bands allocated to them there is minimal disruption to existing systems using the same bands. The process of satellite coordination is described, and the issues for radio astronomy are discussed. In order to be protected by the ITU-R machinery radio telescopes need to be officially registered. The issue of paper satellites highlights the need for early registration to gain priority over incoming systems. Modern developments including the use of complex Monte-Carlo simulations to predict interference levels, and the issue of adjacent band interference, are discussed.

  12. Cationized Carbohydrate Gas-Phase Fragmentation Chemistry.

    PubMed

    Bythell, Benjamin J; Abutokaikah, Maha T; Wagoner, Ashley R; Guan, Shanshan; Rabus, Jordan M

    2016-11-28

    We investigate the fragmentation chemistry of cationized carbohydrates using a combination of tandem mass spectrometry, regioselective labeling, and computational methods. Our model system is D-lactose. Barriers to the fundamental glyosidic bond cleavage reactions, neutral loss pathways, and structurally informative cross-ring cleavages are investigated. The most energetically favorable conformations of cationized D-lactose were found to be similar. In agreement with the literature, larger group I cations result in structures with increased cation coordination number which require greater collision energy to dissociate. In contrast with earlier proposals, the B n -Y m fragmentation pathways of both protonated and sodium-cationized analytes proceed via protonation of the glycosidic oxygen with concerted glycosidic bond cleavage. Additionally, for the sodiated congeners our calculations support sodiated 1,6-anhydrogalactose B n ion structures, unlike the preceding literature. This affects the subsequent propensity of formation and prediction of B n /Y m branching ratio. The nature of the anomeric center (α/β) affects the relative energies of these processes, but not the overall ranking. Low-energy cross-ring cleavages are observed for the metal-cationized analytes with a retro-aldol mechanism producing the (0,2) A 2 ion from the sodiated forms. Theory and experiment support the importance of consecutive fragmentation processes, particularly for the protonated congeners at higher collision energies. Graphical Abstract ᅟ.

  13. Cationized Carbohydrate Gas-Phase Fragmentation Chemistry

    NASA Astrophysics Data System (ADS)

    Bythell, Benjamin J.; Abutokaikah, Maha T.; Wagoner, Ashley R.; Guan, Shanshan; Rabus, Jordan M.

    2016-11-01

    We investigate the fragmentation chemistry of cationized carbohydrates using a combination of tandem mass spectrometry, regioselective labeling, and computational methods. Our model system is D-lactose. Barriers to the fundamental glyosidic bond cleavage reactions, neutral loss pathways, and structurally informative cross-ring cleavages are investigated. The most energetically favorable conformations of cationized D-lactose were found to be similar. In agreement with the literature, larger group I cations result in structures with increased cation coordination number which require greater collision energy to dissociate. In contrast with earlier proposals, the B n -Y m fragmentation pathways of both protonated and sodium-cationized analytes proceed via protonation of the glycosidic oxygen with concerted glycosidic bond cleavage. Additionally, for the sodiated congeners our calculations support sodiated 1,6-anhydrogalactose B n ion structures, unlike the preceding literature. This affects the subsequent propensity of formation and prediction of B n /Y m branching ratio. The nature of the anomeric center (α/β) affects the relative energies of these processes, but not the overall ranking. Low-energy cross-ring cleavages are observed for the metal-cationized analytes with a retro-aldol mechanism producing the 0,2 A 2 ion from the sodiated forms. Theory and experiment support the importance of consecutive fragmentation processes, particularly for the protonated congeners at higher collision energies.

  14. Biosensors in clinical chemistry.

    PubMed

    D'Orazio, Paul

    2003-08-01

    Biosensors are analytical devices composed of a recognition element of biological origin and a physico-chemical transducer. The biological element is capable of sensing the presence, activity or concentration of a chemical analyte in solution. The sensing takes place either as a binding event or a biocatalytical event. These interactions produce a measurable change in a solution property, which the transducer converts into a quantifiable electrical signal. Present-day applications of biosensors to clinical chemistry are reviewed, including basic and applied research, commercial applications and fabrication techniques. Recognition elements include enzymes as biocatalytic recognition elements and immunoagents and DNA segments as affinity ligand recognition elements, coupled to electrochemical and optical modes of transduction. The future will include biosensors based on synthetic recognition elements to allow broad applicability to different classes of analytes and modes of transduction extending lower limits of sensitivity. Microfabrication will permit biosensors to be constructed as arrays and incorporated into lab-on-a-chip devices.

  15. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1981

    1981-01-01

    Outlines laboratory procedures, demonstrations, teaching suggestions, and content information related to chemistry. Topics include polarizing power; calorimetry and momentum; microcomputers in school chemistry; a constant-volume dispenser for liquids, floating magnets, and crystal lattices; preparation of chromium; and solvent polarity and…

  16. 40 CFR 136.6 - Method modifications and analytical requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... person or laboratory using a test procedure (analytical method) in this Part. (2) Chemistry of the method... (analytical method) provided that the chemistry of the method or the determinative technique is not changed... prevent efficient recovery of organic pollutants and prevent the method from meeting QC requirements,...

  17. Multifunctional nanoparticles: analytical prospects.

    PubMed

    de Dios, Alejandro Simón; Díaz-García, Marta Elena

    2010-05-07

    Multifunctional nanoparticles are among the most exciting nanomaterials with promising applications in analytical chemistry. These applications include (bio)sensing, (bio)assays, catalysis and separations. Although most of these applications are based on the magnetic, optical and electrochemical properties of multifunctional nanoparticles, other aspects such as the synergistic effect of the functional groups and the amplification effect associated with the nanoscale dimension have also been observed. Considering not only the nature of the raw material but also the shape, there is a huge variety of nanoparticles. In this review only magnetic, quantum dots, gold nanoparticles, carbon and inorganic nanotubes as well as silica, titania and gadolinium oxide nanoparticles are addressed. This review presents a narrative summary on the use of multifunctional nanoparticles for analytical applications, along with a discussion on some critical challenges existing in the field and possible solutions that have been or are being developed to overcome these challenges.

  18. Environmental Chemistry in the Undergraduate Laboratory.

    ERIC Educational Resources Information Center

    Wenzel, Thomas J.; Austin, Rachel N.

    2001-01-01

    Discusses the importance of environmental chemistry and the use of laboratory exercises in analytical and general chemistry courses. Notes the importance of lab work in heightening student interest in coursework including problem-based learning in undergraduate curricula, ready adaptability of environmental coursework to existing curricula, and…

  19. Circumstellar chemistry

    NASA Technical Reports Server (NTRS)

    Glassgold, Alfred E.; Huggins, Patrick J.

    1987-01-01

    The study of the outer envelopes of cool evolved stars has become an active area of research. The physical properties of CS envelopes are presented. Observations of many wavelengths bands are relevant. A summary of observations and a discussion of theoretical considerations concerning the chemistry are summarized. Recent theoretical considerations show that the thermal equilibrium model is of limited use for understanding the chemistry of the outer CS envelopes. The theoretical modeling of the chemistry of CS envelopes provides a quantitive test of chemical concepts which have a broader interest than the envelopes themselves.

  20. Analytical testing

    NASA Technical Reports Server (NTRS)

    Flannelly, W. G.; Fabunmi, J. A.; Nagy, E. J.

    1981-01-01

    Analytical methods for combining flight acceleration and strain data with shake test mobility data to predict the effects of structural changes on flight vibrations and strains are presented. This integration of structural dynamic analysis with flight performance is referred to as analytical testing. The objective of this methodology is to analytically estimate the results of flight testing contemplated structural changes with minimum flying and change trials. The category of changes to the aircraft includes mass, stiffness, absorbers, isolators, and active suppressors. Examples of applying the analytical testing methodology using flight test and shake test data measured on an AH-1G helicopter are included. The techniques and procedures for vibration testing and modal analysis are also described.

  1. Catalytic Chemistry.

    ERIC Educational Resources Information Center

    Borer, Londa; And Others

    1996-01-01

    Describes an approach for making chemistry relevant to everyday life. Involves the study of kinetics using the decomposition of hydrogen peroxide by vegetable juices. Allows students to design and carry out experiments and then draw conclusions from their results. (JRH)

  2. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1980

    1980-01-01

    Describes equipment, activities, and experiments useful in chemistry instruction, including among others, a rapid method to determine available chlorine in bleach, simple flame testing apparatus, and a simple apparatus demonstrating the technique of flash photolysis. (SK)

  3. Chemistry Notes

    ERIC Educational Resources Information Center

    School Science Review, 1973

    1973-01-01

    Several ideas are proposed for chemistry teachers to try in their classrooms. Subjects included are polymerization of acrylate, polymerization of styrene, conductivity, pollution, preparation of chlorine, redox equations, chemiluminescence, and molecular sieves. (PS)

  4. Nuclear Chemistry.

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1979

    1979-01-01

    Provides a brief review of the latest developments in nuclear chemistry. Nuclear research today is directed toward increased activity in radiopharmaceuticals and formation of new isotopes by high-energy, heavy-ion collisions. (Author/BB)

  5. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1981

    1981-01-01

    Describes 13 activities, experiments and demonstrations, including the preparation of iron (III) chloride, simple alpha-helix model, investigating camping gas, redox reactions of some organic compounds, a liquid crystal thermometer, and the oxidation number concept in organic chemistry. (JN)

  6. Precolumbian Chemistry.

    ERIC Educational Resources Information Center

    Robinson, Janet Bond

    1995-01-01

    Describes the content and development of a curriculum that provides an approach to descriptive chemistry and the history of technology through consideration of the pottery, metallurgy, pigments, dyes, agriculture, and medicine of pre-Columbian people. (DDR)

  7. Stratospheric chemistry

    SciTech Connect

    Brune, W.H. )

    1991-01-01

    Advances in stratospheric chemistry made by investigators in the United States from 1987 to 1990 are reviewed. Subject areas under consideration include photochemistry of the polar stratosphere, photochemistry of the global stratosphere, and assessments of inadvertent modification of the stratosphere by anthropogenic activity. Particular attention is given to early observations and theories, gas phase chemistry, Antarctic observations, Arctic observations, odd-oxygen, odd-hydrogen, odd-nitrogen, halogens, aerosols, modeling of stratospheric ozone, and reactive nitrogen effects.

  8. Undergraduate Professional Education in Chemistry: Guidelines and Evaluation Procedures.

    ERIC Educational Resources Information Center

    American Chemical Society, Washington, DC.

    Provided are guidelines for evaluating undergraduate professional education in chemistry. The guidelines summarize an approved program as including: 400 hours of classroom work; 500 hours of laboratory work; a core curriculum covering principles of analytical, inorganic, organic, and physical chemistry; 1 year of advanced work in chemistry or…

  9. Chemistry-Nuclear Chemistry Division. Progress report, October 1980-September 1981

    SciTech Connect

    Ryan, R.R.

    1982-05-01

    This report describes major progress in the research and development programs pursued by the Chemistry-Nuclear Chemistry Division of the Los Alamos National Laboratory during FY 1981. Topics covered include advanced analytical methods, atmospheric chemistry and transport, biochemistry, biomedical research, medical radioisotopes research, element migration and fixation, nuclear waste isolation research, inorganic and structural chemistry, isotope separation, analysis and applications, the newly established Nuclear Magnetic Resonance Center, atomic and molecular collisions, molecular spectroscopy, nuclear cosmochemistry, nuclear structure and reactions, pion charge exchange, radiochemical separations, theoretical chemistry, and unclassified weapons research.

  10. Perspectives on Computational Organic Chemistry

    PubMed Central

    Streitwieser, Andrew

    2009-01-01

    The author reviews how his early love for theoretical organic chemistry led to experimental research and the extended search for quantitative correlations between experiment and quantum calculations. The experimental work led to ion pair acidities of alkali-organic compounds and most recently to equilibria and reactions of lithium and cesium enolates in THF. This chemistry is now being modeled by ab initio calculations. An important consideration is the treatment of solvation in which coordination of the alkali cation with the ether solvent plays a major role. PMID:19518150

  11. Phoenix's Wet Chemistry Lab

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This is an illustration of the analytical procedure of NASA's Phoenix Mars Lander's Wet Chemistry Lab (WCL) on board the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument. By dissolving small amounts of soil in water, WCL can determine the pH, the abundance of minerals such as magnesium and sodium cations or chloride, bromide and sulfate anions, as well as the conductivity and redox potential.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  12. The Fe(III) and Ga(III) coordination chemistry of 3-(1-hydroxymethylidene) and 3-(1-hydroxydecylidene)-5-(2-hydroxyethyl)pyrrolidine-2,4-dione: novel tetramic acid degradation products of homoserine lactone bacterial quorum sensing molecules.

    PubMed

    Romano, Ariel A; Hahn, Tobias; Davis, Nicole; Lowery, Colin A; Struss, Anjali K; Janda, Kim D; Böttger, Lars H; Matzanke, Berthold F; Carrano, Carl J

    2012-02-01

    Bacteria use small diffusible molecules to exchange information in a process called quorum sensing (QS). An important class of quorum sensing molecules used by Gram-negative bacteria is the family of N-acylhomoserine lactones (HSL). It was recently discovered that a degradation product of the QS molecule 3-oxo-C(12)-homoserine lactone, the tetramic acid 3-(1-hydroxydecylidene)-5-(2-hydroxyethyl)pyrrolidine-2,4-dione, is a potent antibacterial agent, thus implying roles for QS outside of simply communication. Because these tetramic acids also appear to bind iron with appreciable affinity it was suggested that metal binding might contribute to their biological activity. Here, using a variety of spectroscopic tools, we describe the coordination chemistry of both the methylidene and decylidene tetramic acid derivatives with Fe(III) and Ga(III) and discuss the potential biological significance of such metal binding.

  13. The Fe(III) and Ga(III) coordination chemistry of 3-(1-hydroxymethylidene) and 3-(1-hydroxydecylidene)-5-(2-hydroxyethyl)pyrrolidine-2,4-dione: Novel tetramic acid degradation products of homoserine lactone bacterial quorum sensing molecules

    PubMed Central

    Romano, Ariel A.; Hahn, Tobias; Davis, Nicole; Lowery, Colin A.; Struss, Anjali K.; Janda, Kim D.; Böttger, Lars H.; Matzanke, Berthold F.; Carrano, Carl J.

    2011-01-01

    Bacteria use small diffusible molecules to exchange information in a process called quorum sensing (QS). An important class of quorum sensing molecules used by Gram-negative bacteria is the family of N-acylhomoserine lactones (HSL). It was recently discovered that a degradation product of the QS molecule 3-oxo-C12-homoserine lactone, the tetramic acid 3-(1-hydroxydecylidene)-5-(2-hydroxyethyl)pyrrolidine-2,4-dione, is a potent antibacterial agent, thus implying roles for QS outside of simply communication. Because these tetramic acids also appear to bind iron with appreciable affinity it was suggested that metal binding might contribute to their biological activity. Here, using a variety of spectroscopic tools, we describe the coordination chemistry of both the methylidene and decylidene tetramic acid derivatives with Fe(III) and Ga(III) and discuss the potential biological significance of such metal binding. PMID:22178671

  14. Analytical Microscopy

    SciTech Connect

    Not Available

    2006-06-01

    In the Analytical Microscopy group, within the National Center for Photovoltaic's Measurements and Characterization Division, we combine two complementary areas of analytical microscopy--electron microscopy and proximal-probe techniques--and use a variety of state-of-the-art imaging and analytical tools. We also design and build custom instrumentation and develop novel techniques that provide unique capabilities for studying materials and devices. In our work, we collaborate with you to solve materials- and device-related R&D problems. This sheet summarizes the uses and features of four major tools: transmission electron microscopy, scanning electron microscopy, the dual-beam focused-ion-beam workstation, and scanning probe microscopy.

  15. Method and apparatus for detecting an analyte

    DOEpatents

    Allendorf, Mark D [Pleasanton, CA; Hesketh, Peter J [Atlanta, GA

    2011-11-29

    We describe the use of coordination polymers (CP) as coatings on microcantilevers for the detection of chemical analytes. CP exhibit changes in unit cell parameters upon adsorption of analytes, which will induce a stress in a static microcantilever upon which a CP layer is deposited. We also describe fabrication methods for depositing CP layers on surfaces.

  16. Polymer Chemistry

    NASA Technical Reports Server (NTRS)

    Williams, Martha; Roberson, Luke; Caraccio, Anne

    2010-01-01

    This viewgraph presentation describes new technologies in polymer and material chemistry that benefits NASA programs and missions. The topics include: 1) What are Polymers?; 2) History of Polymer Chemistry; 3) Composites/Materials Development at KSC; 4) Why Wiring; 5) Next Generation Wiring Materials; 6) Wire System Materials and Integration; 7) Self-Healing Wire Repair; 8) Smart Wiring Summary; 9) Fire and Polymers; 10) Aerogel Technology; 11) Aerogel Composites; 12) Aerogels for Oil Remediation; 13) KSC's Solution; 14) Chemochromic Hydrogen Sensors; 15) STS-130 and 131 Operations; 16) HyperPigment; 17) Antimicrobial Materials; 18) Conductive Inks Formulations for Multiple Applications; and 19) Testing and Processing Equipment.

  17. Chemistry Experiments

    NASA Technical Reports Server (NTRS)

    Brasseur, Guy; Remsberg, Ellis; Purcell, Patrick; Bhatt, Praful; Sage, Karen H.; Brown, Donald E.; Scott, Courtney J.; Ko, Malcolm K. W.; Tie, Xue-Xi; Huang, Theresa

    1999-01-01

    The purpose of the chemistry component of the model comparison is to assess to what extent differences in the formulation of chemical processes explain the variance between model results. Observed concentrations of chemical compounds are used to estimate to what degree the various models represent realistic situations. For readability, the materials for the chemistry experiment are reported in three separate sections. This section discussed the data used to evaluate the models in their simulation of the source gases and the Nitrogen compounds (NO(y)) and Chlorine compounds (Cl(y)) species.

  18. 40 CFR 158.355 - Enforcement analytical method.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Enforcement analytical method. 158.355... DATA REQUIREMENTS FOR PESTICIDES Product Chemistry § 158.355 Enforcement analytical method. An analytical method suitable for enforcement purposes must be provided for each active ingredient in...

  19. Coordinates of features on the Galilean satellites

    NASA Technical Reports Server (NTRS)

    Davies, M. E.; Katayama, F. Y.

    1980-01-01

    The coordinate systems of each of the Galilean satellites are defined and coordinates of features seen in the Voyager pictures of these satellites are presented. The control nets of the satellites were computed by means of single block analytical triangulations. The normal equations were solved by the conjugate iterative method which is convenient and which converges rapidly as the initial estimates of the parameters are very good.

  20. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1980

    1980-01-01

    Presents 12 chemistry notes for British secondary school teachers. Some of these notes are: (1) a simple device for testing pH-meters; (2) portable fume cupboard safety screen; and (3) Mass spectroscopy-analysis of a mass peak. (HM)

  1. Chemistry Notes

    ERIC Educational Resources Information Center

    School Science Review, 1976

    1976-01-01

    Describes several chemistry projects, including solubility, formula for magnesium oxide, dissociation of dinitrogen tetroxide, use of 1-chloro-2, 4-dinitrobenzene, migration of ions, heats of neutralizations, use of pocket calculators, sonic cleaning, oxidation states of manganese, and cell potentials. Includes an extract from Chemical Age on…

  2. Chemistry Notes

    ERIC Educational Resources Information Center

    School Science Review, 1972

    1972-01-01

    Short articles on the alkylation of aniline, the preparation and properties of perbromate, using scrap copper in chemistry instruction, a safe method of burning hydrogen, and the use of an ion-charge model as an alternative to the mole concept in secondary school instruction. (AL)

  3. Confectionary Chemistry.

    ERIC Educational Resources Information Center

    Levine, Elise Hilf

    1996-01-01

    Presents activities and demonstrations that enable teachers to use various types of confections as tactile experiences to spark chemistry students' interest and generate enthusiasm for learning. Presents uses of candy in teaching about atomic structure, spontaneous nuclear decay, chemical formulas, fractoluminescence, the effect of a molecular…

  4. Chemistry Notes

    ERIC Educational Resources Information Center

    School Science Review, 1972

    1972-01-01

    Short articles on the kinetics of the hydrogen peroxide-iodide ion reaction, simulation of fluidization catalysis, the use of Newman projection diagrams to represent steric relationships in organic chemistry, the use of synthetic substrates for proteolytic enzyme reactions, and two simple clock reactions"--hydrolysis of halogenoalkanes and…

  5. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1983

    1983-01-01

    Presents chemistry experiments, laboratory procedures, demonstrations, teaching suggestions, and classroom materials/activities. These include: game for teaching ionic formulas; method for balancing equations; description of useful redox series; computer programs (with listings) for water electrolysis simulation and for determining chemical…

  6. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1983

    1983-01-01

    Presents chemistry experiments, laboratory procedures, demonstrations, and classroom materials/activities. These include: experiments on colloids, processing of uranium ore, action of heat on carbonates; color test for phenols and aromatic amines; solvent properties of non-electrolytes; stereoscopic applications/methods; a valency balance;…

  7. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1982

    1982-01-01

    Presents procedures, experiments, demonstrations, teaching suggestions, and information on a variety of chemistry topics including, for example, inert gases, light-induced reactions, calculators, identification of substituted acetophenones, the elements, analysis of copper minerals, extraction of metallic strontium, equilibrium, halogens, and…

  8. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1978

    1978-01-01

    Describes some laboratory apparatus, chemistry experiments and demonstrations, such as a Kofler block melting point apparatus, chromatographic investigation of the phosphoric acid, x-ray diffraction, the fountain experiment, endothermic sherbet, the measurement of viscosity, ionization energies and electronic configurations. (GA)

  9. Microscale Chemistry and Green Chemistry: Complementary Pedagogies

    NASA Astrophysics Data System (ADS)

    Singh, Mono M.; Szafran, Zvi; Pike, R. M.

    1999-12-01

    This paper describes the complementary nature of microscale chemistry and green chemistry. Green chemistry emphasizes the concepts of atom economy, source reduction, pathway modification, solvent substitution, and pollution prevention as means of improving the environmental impact of industrial chemistry. Microscale chemistry serves as a tool for incorporating green chemistry ideas across the curriculum in educational institutions. Examples are drawn from microscale laboratory experiments to illustrate the pedagogic connection between the two areas.

  10. Understanding MAOS through computational chemistry.

    PubMed

    Prieto, P; de la Hoz, A; Díaz-Ortiz, A; Rodríguez, A M

    2017-01-23

    The importance of microwave irradiation in organic synthesis today is unquestionable, but in many cases the nature of these improvements remains unknown. Exploiting the benefits that microwave irradiation has in chemistry is still hindered by a lack of understanding of the physical principles of the interaction of microwave irradiation with the components of a reaction. Moreover, dielectric properties vary with temperature and along the reaction coordinate and this makes the situation more complex. Experimental determinations employed to date in Microwave-Assisted Organic Chemistry (MAOS) are characterized by the importance of thermal heating. In this way the separation of thermal heating from any other effect of electromagnetic radiation is completely impossible. This review provides an overview of the use of Computational Chemistry in MAOS to provide a theoretical understanding of the factors that can be used to explain the improvements in MAOS and how computational calculations can be used as a predictive tool.

  11. Synthesis, and characterization of low- and high-spin manganese(II) complexes of polyfunctional adipoyldihydrazone: Effect of coordination of N-donor ligands on stereo-redox chemistry

    NASA Astrophysics Data System (ADS)

    Basumatary, Debajani; Lal, Ram Ashray; Kumar, Arvind

    2015-07-01

    Manganese(II) complexes [MnII(npahH2)] (1), [MnII(npahH2)(A)2] and [MnII(npahH2)(NN)] (where A = pyridine, (2); 2-picoline, (3); 3-picoline, (4); 4-picoline, (5) and NN = 2,2‧ bipyridine, (6); 1,10-phenanthroline, (7)) have been synthesized from bis(2-hydroxy-1-naphthaldehyde)adipoyldihydrazone (npahH4) in methanol. The composition of metal complexes has been established by elemental analyses. Complexes (1) and (3) have been characterized by mass spectral data also. Structural assessments of the complexes have been based on data obtained from molar conductance, magnetic moment, electronic, electron paramagnetic resonance and infrared spectral studies. Conductivity measurements in DMSO suggest that they are non-electrolyte. Electronic spectral studies suggest a six-coordinate octahedral geometry around the manganese center in complexes (2) to (7) and square-planar geometry in complex (1). IR spectral studies reveal that the dihydrazone coordinates to the metal in keto form with an anti-cis configuration. Magnetic moment, and EPR studies suggest manganese in +2 oxidation state in all complexes with high-spin distorted octahedral stereochemistry in complexes (2-7) while low-spin square-planar stereochemistry is involved with significant metal-metal interactions in the solid state in complex (1). Cyclic voltammetric studies reveal that the metal center cycles among the MnII → MnI → Mn0 in complexes (2) to (7) and among MnII → MnI oxidation states in complex (1).

  12. Physical chemistry and the environment

    SciTech Connect

    Dunning, T.H. Jr.; Garrett, B.C.; Kolb, C.E. Jr.; Shaw, R.W.; Choppin, G.R.; Wagner, A.F.

    1994-08-01

    From the ozone hole and the greenhouse effect to plastics recycling and hazardous waste disposal, society faces a number of issues, the solutions to which require an unprecedented understanding of the properties of molecules. We are coming to realize that the environment is a coupled set of chemical systems, its dynamics determining the welfare of the biosphere and of humans in particular. These chemical systems are governed by fundamental molecular interactions, and they present chemists with an unparalleled challenge. The application of current concepts of molecular behavior and of up-to-date experimental and computational techniques can provide us with insights into the environment that are needed to mitigate past damage, to anticipate the impact of current human activity, and to avoid future insults to the environment. Environmental chemistry encompasses a number of separate, yet interlocking, areas of research. In all of these areas progress is limited by an inadequate understanding of the underlying chemical processes involved. Participation of all chemical approaches -- experimental, theoretical and computational -- and of all disciplines of chemistry -- organic, inorganic, physical, analytical and biochemistry -- will be required to provide the necessary fundamental understanding. The Symposium on ``Physical Chemistry and the Environment`` was designed to bring the many exciting and challenging physical chemistry problems involved in environmental chemistry to the attention of a larger segment of the physical chemistry community.

  13. Chemistry Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1981

    1981-01-01

    Outlines a variety of laboratory procedures, discussions, and demonstrations including polarizing power and chemical properties of copper and zinc, preparation of boron coordination complex, demonstration of amino-acid synthesis in the primordial environment, classification and reactions of carbohydrates, and four others. (DS)

  14. Polynitrogen Chemistry

    DTIC Science & Technology

    2013-09-24

    4N3, while As(C6H5)4N3 presents a borderline case.23 Theoretical Calculations High-level theoretical studies of nitrogen, oxygen, selenium and...Dixon, D. A.; Christe, K. O., "Thermochemical Properties of Selenium Fluorides, Oxides, and Oxofluorides," Inorganic Chemistry, p. 2472, vol. 51, (2012...34Thermochemical Properties of Selenium Fluorides, Oxides, and Oxofluorides," Inorg. Chem., p. 2472, vol. 51, (2012). 26. K. S. Thanthiriwatte, M. Vasiliu

  15. Computational chemistry

    NASA Technical Reports Server (NTRS)

    Arnold, J. O.

    1987-01-01

    With the advent of supercomputers, modern computational chemistry algorithms and codes, a powerful tool was created to help fill NASA's continuing need for information on the properties of matter in hostile or unusual environments. Computational resources provided under the National Aerodynamics Simulator (NAS) program were a cornerstone for recent advancements in this field. Properties of gases, materials, and their interactions can be determined from solutions of the governing equations. In the case of gases, for example, radiative transition probabilites per particle, bond-dissociation energies, and rates of simple chemical reactions can be determined computationally as reliably as from experiment. The data are proving to be quite valuable in providing inputs to real-gas flow simulation codes used to compute aerothermodynamic loads on NASA's aeroassist orbital transfer vehicles and a host of problems related to the National Aerospace Plane Program. Although more approximate, similar solutions can be obtained for ensembles of atoms simulating small particles of materials with and without the presence of gases. Computational chemistry has application in studying catalysis, properties of polymers, all of interest to various NASA missions, including those previously mentioned. In addition to discussing these applications of computational chemistry within NASA, the governing equations and the need for supercomputers for their solution is outlined.

  16. X-Ray crystal structures of five-coordinate (salen)MnN3 derivatives and their binding abilities towards epoxides: chemistry relevant to the epoxide-CO2 copolymerization process.

    PubMed

    Darensbourg, Donald J; Frantz, Eric B

    2008-10-07

    The synthesis of several (salen)MnN3 complexes in good yields and purities were achieved by the reaction of manganese(III) acetate and H2salen, followed by metathesis of the remaining acetate ligand with an aqueous solution of NaN3. The X-ray structures of two derivatives, where salen=N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-ethylenediamine and N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexenediamine respectively, were determined. The complexes were shown to be monomeric 5-coordinate derivatives displaying a distorted square pyramidal geometry, and to be d4 high-spin derivatives by solution magnetic moment measurements using the Evans method. Binding studies of the (salen)MnN3 derivatives with added azide ions or cyclohexene oxide showed these complexes to have modest affinities for binding a sixth ligand. These observations are used to rationalize the low activity exhibited by manganese(III) complexes relative to their chromium(III) and cobalt(III) analogs for serving as catalysts for the copolymerization of carbon dioxide and epoxides.

  17. Comparison of two dry chemistry analyzers and a wet chemistry analyzer using canine serum.

    PubMed

    Lanevschi, Anne; Kramer, John W.

    1996-01-01

    Canine serum was used to compare seven chemistry analytes on two tabletop clinical dry chemistry analyzers, Boehringer's Reflotron and Kodak's Ektachem. Results were compared to those obtained on a wet chemistry reference analyzer, Roche Diagnostic's Cobas Mira. Analytes measured were urea nitrogen (BUN), creatinine, glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), cholesterol and bilirubin. Nine to 12 canine sera with values in the low, normal, and high range were evaluated. The correlations were acceptable for all comparisons with correlation coefficients greater than 0.98 for all analytes. Regression analysis resulted in significant differences for both tabletop analyzers when compared to the reference analyzer for cholesterol and bilirubin, and for glucose and AST on the Kodak Ektachem. Differences appeared to result from proportional systematic error occurring at high analyte concentrations.

  18. ENVIRONMENTAL IMMUNOCHEMISTRY RESPONDING TO A SPECTRUM OF ANALYTICAL NEEDS

    EPA Science Inventory

    A review, with 13 references, is given on the field of environmental immunochemistry which brings together several specalties, including analytical chemistry, biochemistry, moluclar biology, and environmental engineering. This multidisciplinary nature is both benefit and a confus...

  19. Linked-View Parallel Coordinate Plot Renderer

    SciTech Connect

    2011-06-28

    This software allows multiple linked views for interactive querying via map-based data selection, bar chart analytic overlays, and high dynamic range (HDR) line renderings. The major component of the visualization package is a parallel coordinate renderer with binning, curved layouts, shader-based rendering, and other techniques to allow interactive visualization of multidimensional data.

  20. (Pesticide chemistry)

    SciTech Connect

    Barnthouse, L.W.

    1990-09-04

    This report summarizes a trip by L. W. Barnthouse of the Environmental Sciences Division (ESD), Oak Ridge National Laboratory (ORNL), to Hamburg, Federal Republic of Germany (FRG), where he participated in the 7th International Congress of Pesticide Chemistry. He chaired a workshop on experimental systems for determining effects of pesticides on nontarget organisms and gave an oral presentation at a symposium on pesticide risk assessment. Before returning to the United States, Dr. Barnthouse visited the Netherlands Institute for Sea Research in Texel, the Netherlands.