Elemental Analysis

6 Key excerpts on "Elemental Analysis"

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  eBook - ePub

  Analytical Methods in Chemical Analysis

  An Introduction

  • Shikha Kaushik, Banty Kumar, Shikha Kaushik, Banty Kumar(Authors)
  • 2023(Publication Date)
  • De Gruyter

    (Publisher)

  One of the main objectives of analytical chemistry is to improve scientifically corroborated methods that offer the qualitative and quantitative assessment of samples with a definite accuracy in a stipulated time. The methods for measuring the content of an element in a sample and methods for achieving an analytical goal can be separated into qualitative analysis (identification methods) and quantitative analysis, respectively. The detection method is generally the initial stage in the investigation of an unknown sample, and it also incorporates the analysis of its qualitative structure in order to classify the substance (e.g., as a mineral, dirt, and alloy).

  The qualitative analytical methods have been used in the analysis for the determination of

  1. The constituents of a substance of the material under analysis, for example, identification of the grade of an alloy.
  2. The presence or absence of certain elements in the material.
  3. The total content of ions, elements, or the simplest combinations which constitute the studied product.
  4. The species of the mixtures such as sulfur, carbon, and phosphorus in the analysis of finished products such as iron and steel.

  However, in various cases, determination of elements in a product is not sufficient for the estimation of its chemical properties. An idea of molecular composition is also necessary. Molecular composition means the form of compounds in which the components are present in the material and the content of these compounds. For example, in order to evaluate the properties of an alloy, it is not sufficient to know the total content of just carbon and sulfur, but it is also necessary to know the form in which they are present in the alloy.

  Basically, analytical chemistry is a quantitative science. For determining the concentration of an analyte species in a solution, monitoring the rate of a reaction, estimating an equilibrium constant, and elucidating the structure of an unknown compound, it is all about measurements/recording data and performing calculations. Before proceeding further into the classification of analytical methods, let us briefly review some standard terms and definitions which are of great use in analytical chemistry.

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  eBook - ePub

  Environmental Chemistry

  Eleventh Edition

  • Stanley E Manahan, Stanley E. Manahan(Authors)
  • 2022(Publication Date)
  • CRC Press

    (Publisher)

  24 Chemical Analysis in Environmental and Toxicological Chemistry

  DOI: 10.1201/9781003096238-24

  24.1 Analytical Chemistry

  Analytical chemistry is that branch of the chemical sciences employed to determine the composition of a sample of material. A qualitative analysis is performed to determine what is in a sample. The amount, concentration, composition, or percentage of a substance present is determined by quantitative analysis. Often, both qualitative and quantitative analyses are performed as part of the same process.

  Analytical chemistry is important in practically all areas of human endeavor and in all spheres of the environment. Industrial raw materials and products processed in the anthrosphere are assayed by chemical analysis, and analytical monitoring is employed to monitor and control industrial processes. Hardness, alkalinity, and trace-level pollutants (see Chapters 2 –7 ) are measured in water by chemical analyses. Nitrogen oxides, sulfur oxides, oxidants, and organic pollutants (see Chapters 9 –12 ) are determined in air by chemical analysis. In the geosphere (see Chapters 13 –15 ), fertilizer constituents in soil and commercially valuable minerals in ores are measured by chemical analysis. In the biosphere, xenobiotic materials and their metabolites (see Chapters 22 and 23 ) are monitored by chemical analysis. Analytical chemistry is very important in the area of occupational health and the practice of industrial hygiene.

  Analytical chemistry is a dynamic discipline. New chemicals and increasingly sophisticated instruments and computational capabilities are constantly coming into use to improve the ways in which chemical analyses are done. Some of these improvements involve the determination of ever smaller quantities of substances; others simplify the procedures for analysis, greatly shortening the time required for analysis; and some enable analysts to tell with much greater specificity the identities of a large number of compounds in a complex sample.

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  eBook - ePub

  Analytical Chemistry for Technicians

  • John Kenkel(Author)
  • 2013(Publication Date)
  • CRC Press

    (Publisher)

  Application Note 1.1 ).

  Analysis procedures can be additionally classified into procedures that involve physical properties, wet chemical analysis procedures, and instrumental chemical analysis procedures. Analysis using physical properties involves no chemical reactions and at times relatively simple devices (although possibly computerized) to facilitate the measurement. Physical properties are especially useful for identification, but may also be useful for quantitative analysis in cases where the value of a property, such as specific gravity or refractive index (Chapter 7 ), varies with the quantity of an analyte in a mixture.

  Wet chemical analysis usually involves chemical reactions and/or classical reaction stoichiometry, but no electronic instrumentation beyond a weighing device. Wet chemical analysis techniques are classical techniques, meaning they have been in use in analytical laboratory for many years, before electronic devices came on the scene. If executed properly, they have a high degree of inherent accuracy and precision, but they take more time to execute.

  Instrumental analysis can also involve chemical reactions, but always involves modern sophisticated electronic instrumentation. Instrumental analysis techniques are “high-technology” techniques, often utilizing the ultimate in complex hardware and software. Although sometimes not as precise as a carefully executed wet chemical method, instrumental analysis methods are fast and can offer a much greater scope and practicality to the analysis. In addition, instrumental methods are generally used to determine the minor constituents, or constituents that are present in low levels, rather than the major constituents of a sample. We discuss wet chemical methods in Chapters 3 and 5 of this text. Chapter 6 is concerned with instrumental methods in general, and Chapters 7 –15

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  Chemical Methods in Gas Chromatography

  • V.G. Berezkin(Author)
  • 2000(Publication Date)
  • Elsevier Science

    (Publisher)

  Second, it permits the quanti- tative analysis of unseparated zones of compounds that exhibit qualitative and even quantitative differences with respect to elemental composition. In the 1960s, when selective elemental detectors were virtually unknown, Elemental Analysis could be performed only by using chemical methods. Today these methods do not seem as essential as they used to be. However, there are some very important reasons that prompt further work in this field: the chemical methods and equipment are simple; they allow the use of the simplest detectors, such as TCDs and plasma ion detectors; they allow the calculation of individual calibration coefficients; they are accurate; and they make it possible to determine the ratio between elements in the course of a single experiment. In some instances other detectors may be preferred over TCDs. Windsor and Denton [ 1741 , e.g., applied inductively coupled plasma atomic emission spectrometry to the Elemental Analysis of GC effluents. The elemental composition of a compound can be determined on the basis of its high-resolution mass spectrum [124-1261. McLafferty [ 1271 developed ways of using medium- and low-resolution mass spectrometry for the determination of elemental composition, All elements fall into groups (A), (A + 1) and (A + 2), and the grouping of elements is dependent of their isotopic composition, which may differ by one or two mass units. For example, chlorine, whose isotope masses are 35 and 37, belongs to group (A + 2). Group (A) includes hydrogen fluorine and phosphorus; group (A + 1) includes carbon and nitrogen; group (A + 2) includes chlorine, bromine, sulphur, silicon and oxygen. A special computer program was worked out to facilitate calculations [128].

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  Environmental Radioanalysis

  • (Author)
  • 2011(Publication Date)
  • Elsevier Science

    (Publisher)

  222 CHAPTER 9. THE Elemental Analysis OF DRY BIOLOGICAL MATERIAL - The interaction between living organisms and their environment is reflected in their elemental composition, especially in the trace element contents. Thus the determination of the clement,i1 concentra- tions is important for the environmentalist as well as for the phy- siologist. Most of the samples taken from plant or animal are dried to some extent prior to the analysis. This. and the fact that the aliquots taken for analysis are usually small, makes activation analysis and nroton induced X-ray emission convenient tools. - The applications of activation analysis on dry biological material are directed to multielement characterization and to the determina- tion of a few important trace elements. To this end it is necessary to have a rapid snd simple system of group separation as a prepira- tion for Ge(Li) counting. This should then be completed by some sim- ple chemical techniques, performed on separate aliquots and aimed at a few elements which are missing from the gene-a1 system. A suitable combination is presented in this text. - The achievements of radioanalysis in the s i x main groups of biolog- ical material are summarized. The accuracy of the results depends on the sampling procedure primarily. 223 9.1. Introduction - The collective term biological material is often used in (radio-) analytical literature. It comprises all samples, both fluid and dry, which can be obtained from the plant or animal kingdoms. In a more dues of such samples. the following classes may strict sense, it refers to the dried res From the viewpoint of Elemental Analysis be distinguished: I ) Dried plant material. 2) Whole blood and serum. 3) Dried animal tissues. 4 ) Bone and teeth. 5) Tartar, bile, kidney and bladder stones. 6) Hairs and nails. - The demand for information on the distribution of minor constituents through living organisms has increased continuously during recent years L1-61.

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  Forensic Analytical Techniques

  • Barbara H. Stuart(Author)
  • 2012(Publication Date)
  • Wiley

    (Publisher)

  Chapter 5 Elemental Analysis Learning Objectives • To understand atomic spectrometry techniques and how to obtain data from the techniques for forensic samples. • To apply atomic spectrometry to the study of glass, gunshot residues and toxicological samples. • To understand inductively coupled plasma–mass spectrometry (ICP–MS) and how to obtain data from the technique for forensic samples. • To apply ICP–MS to the study of glass, gunshot residue and paint. • To understand X-ray fluorescence spectroscopy and how to obtain data from the technique for forensic samples. • To apply X-ray fluorescence spectroscopy to the study of glass, gunshot residue and paint. • To understand particle induced X-ray emission spectroscopy and how to obtain data from the technique for forensic samples. • To apply particle induced X-ray emission spectroscopy to the study of glass. 5.1 Introduction The identification and quantification of elements in many types of evidence pro-vide a valuable source of information in forensic chemistry. Elemental Analysis can enable a sample to be linked to a crime scene or a perpetrator. Atomic spectroscopy techniques provide a sensitive means of Elemental Analysis. In atomic spectroscopy, a substance is decomposed with a flame, furnace or plasma Forensic Analytical Techniques , First Edition. Barbara Stuart. © 2013 John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. 114 Forensic Analytical Techniques and the concentrations of the species produced can be measured. The forms of atomic spectroscopy most commonly employed in forensic science are atomic spectrometry (including atomic absorption spectrometry and atomic emission spectrometry), inductively coupled plasma–mass spectrometry and X-ray fluo-rescence spectroscopy. An ion beam method, particle-induced X-ray emission spectroscopy, also enables elemental information to be obtained.

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