Chemistry
Organic Analysis
Organic analysis involves the identification and quantification of organic compounds present in a sample. This process often utilizes techniques such as chromatography, spectroscopy, and mass spectrometry to separate and analyze the components of a complex mixture. The goal of organic analysis is to determine the chemical composition and structure of organic substances.
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12 Key excerpts on "Organic Analysis"
eBook - PDFMicroscale Organic Laboratory
With Multistep and Multiscale Syntheses
- Dana W. Mayo, Ronald M. Pike, David C. Forbes(Authors)
- 2013(Publication Date)
- Wiley(Publisher)
573 ORGANIC QUALITATIVE ANALYSIS One of the exciting challenges that a chemist faces on a regular basis is identifying organic compounds. This challenge is an excellent way for a stu- dent to be initiated into the arena of chemical research. Millions of organic compounds are recorded in the chemical literature. At first glance it may seem a bewildering task to attempt to identify one certain compound from this vast array, but most of these substances can be grouped, generally by functional groups, into a comparatively small number of classes. In addition, chemists have an enormous database of chemical and spectroscopic information, which has been correlated and organized over the years, at their disposal. Determi- nation of the physical properties of a molecule, the functional groups present, and the reactions the molecule undergoes has allowed the chemist to estab- lish a systematic, logical identification scheme. Forensic chemistry, the detection of species causing environmental pollu- tion, the development of new pharmaceuticals, progress in industrial research, and development of polymers all depend to a large extent on the ability of the chemist to isolate, purify, and identify specific chemicals. The objective of or- ganic qualitative analysis is to place a given compound, through screening tests, into one of a number of specific classes, which in turn greatly simplifies the identification of the compound. This screening is usually done by using a series of preliminary observations and chemical tests, in conjunction with the instrumental data that developments in spectroscopy have made available to the analyst. The advent of infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) have had a profound effect on the approach taken to identify a specific organic compound. Ultraviolet (UV) spec- tra may also be utilized to advantage with certain classes of materials.
eBook - PDFMicroscale Organic Laboratory
With Multistep and Multiscale Syntheses
- Dana W. Mayo, Ronald M. Pike, David C. Forbes(Authors)
- 2023(Publication Date)
- Wiley(Publisher)
649 C 9 H 12 apter 9 QUALITATIVE IDENTIFICATION OF ORGANIC COMPOUNDS ORGANIC QUALITATIVE ANALYSIS One of the exciting challenges that a chemist faces on a regular basis is identifying organic compounds. This challenge is an excellent way for a student to be initiated into the arena of chemical research. Millions of organic compounds are recorded in the chemical literature. At first glance it may seem a bewildering task to attempt to identify one certain compound from this vast array, but most of these substances can be grouped, generally by functional groups, into a comparatively small number of classes. In addition, chemists have an enormous database of chemical and spectroscopic informa- tion, which has been correlated and organized over the years, at their disposal. Determination of the physical properties of a molecule, the functional groups present, and the reactions the molecule undergoes has allowed the chemist to establish a systematic, logical identification scheme. Forensic chemistry, the detection of species causing environmental pollu- tion, the development of new pharmaceuticals, progress in industrial research, and development of polymers all depend to a large extent on the ability of the chemist to isolate, purify, and identify specific chemicals. The objective of organic qualitative analysis is to place a given compound, through screening tests, into one of a number of specific classes, which in turn greatly simplifies the identification of the compound. This screening is usually done by using a series of preliminary observations and chemical tests, in conjunction with the instrumental data that developments in spectroscopy have made available to the analyst. The advent of infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) have had a profound effect on the approach taken to identify a specific organic compound. Ultraviolet (UV) spectra may also be utilized to advantage with certain classes of materials.
eBook - PDF- L. Pataki, E. Zapp, R. Belcher, D Betteridge, L Meites(Authors)
- 2013(Publication Date)
- Pergamon(Publisher)
Chapter 6 Analysis of organic compounds The analysis of organic samples is concerned most frequently with the identification and determination of organic substances, either alone or in admixture. The first step of an analysis is therefore to search for a known compound which agrees in physical and chemical properties with the sample or one of its components. The physical properties include melting and boiling point, solubilities in various solvents, refractive index, infrared absorption spectrum and Chromatographie behaviour. Physical properties of organic compounds can be found in handbooks, collections and tables. Agreement in these properties between a known compound and the sample makes it very probable that they are identical. Chemical investigations yield information on the nature and proportions of elementary components and certain functional groups, thereby supporting the identification. The main steps in the chemical identification of organic compounds include elementary analysis of the sample, measurement of solubility and dissociation constants, and the determination of functional groups. The results of these chemical investigations must be in agree-ment with the data established on the basis of the physical properties of the sample. Only pure, homogeneous substances can be used for identification. As even trace amounts of impurities may affect the melting point, boiling point etc. of the sample, it must be checked at the outset of analysis whether repeated purification steps (distillation, recrystalli-zation, etc.) change the physical properties of the sample. If not, the sample can be regarded as pure. Preliminary tests must be used to decide whether the sample is a relatively pure organic substance, a slightly contaminated organic substance, or a mixture of various organic compounds. Therefore, when the sample is a solid, it is recrystallized several times and the melting point is measured after each crystallization.
eBook - ePub- Philippa B. Cranwell, Laurence M. Harwood, Christopher J. Moody(Authors)
- 2017(Publication Date)
- Wiley(Publisher)
4 Qualitative analysis of organic compounds4.1 Purity
4.1.1 Why bother to analyse compounds?
All scientists study systems, make observations and draw conclusions from their results. It is this protocol that, if rigorously adhered to in the laboratory, is most likely to turn a chance observation into an important discovery. However, before any meaningful results can be obtained, the scientist must know for certain exactly what is under scrutiny, otherwise any results obtained are simply a worthless jumble of irreproducible facts. Organic chemists are no exception to this general situation and, as the systems under study in the laboratory are usually chemical substances, the worker must establish at the outset the nature of the material under investigation, and whether it is a single substance or a mixture of components.All this may seem obvious, but the regularity with which students commence analysing an unknown before actually determining the purity of their sample makes this reminder very necessary. Nobody would dream of undertaking an analysis of the active constituents contained in the extract of some obscure species of tropical plant without first making a thorough examination of the complexity of the extract. Likewise, the fact that a sample has been taken from a bottle on a shelf is no assurance of purity or even that the substance is what the label says it is! Quite apart from the contrived machinations of academics devising unknown mixtures for analysis in the teaching laboratory, labelling mistakes occur only too frequently; particularly with samples that have been relabelled or repackaged after purchase. Additionally, it must be remembered that many organic compounds degrade on storage and, although the age of the sample might be known, it is impossible to estimate its stability under the specific conditions of storage. Consequently, even commercial samples, apparently pristine in their original wrapping, should always be checked for purity before use. Too frequently this apparently self‐evident precaution is overlooked by even the most experienced research chemists – often to their downfall. The least important consequences of such poor technique are erroneous results, lowered yields or wasted laboratory time; the potential for disaster is only too obvious.
eBook - PDF- F. Feigl, V. Anger(Authors)
- 2012(Publication Date)
- Elsevier Science(Publisher)
In contrast, the detection of ele-ments has only an orienting value in qualitative Organic Analysis, because the important goal is the detection of particular compounds or the identifi-cation of characteristic groups in organic compounds, whose ultimate consti-tuents are usually known. Chemical methods cannot contribute beyond a limited extent to the solution of these two problems, especially the former. The reason resides not only in the enormous number of organic compounds and the variety in their architecture. The decisive factors are that many organic compounds undergo chemical changes under conditions which can-not be realized in analytical work, and furthermore a uniform mode of reaction is encountered incomparably more often than with inorganic ions. Consequently, specificity and selectivity are much rarer in tests for organic compounds than in inorganic identifications and separation processes, such as those successfully used in the systematic qualitative inorganic scheme in the form of group precipitations or group solutions, play little or no part in qualitative Organic Analysis. Many tests for organic materials depend on the participation of certain groups in chemical reactions; but entirely apart from the fact that some important groups are not reactive, it must be kept in mind that the detection of groups gives information only about a certain region of the molecule of an organic compound. Therefore, reliable identifica-tions of individual compounds by purely chemical tests are infrequent. As a rule, appeal must be made also to physical methods based on the deter-mination of physical properties related to the structure and size of the or-ganic molecule. Despite this limitation, chemical tests have a considerable practical importance in qualitative Organic Analysis and its many fields of application. Problems whose solution is facilitated by analytical proce-dures seldom involve totally unknown materials or artificial mixtures.
eBook - PDFHistory of Analytical Chemistry
International Series of Monographs in Analytical Chemistry
- Ferenc Szabadváry, R. Belcher, L. Gordon(Authors)
- 2016(Publication Date)
- Pergamon(Publisher)
When one considers the difficulties inherent in qualitative Organic Analysis this becomes quite understandable. In inOrganic Analysis a qualitative knowledge of the elemental composition is very often sufficient to identify the compound, whereas for an organic compound even a quantitative elemental analysis can give little information as to its structure. Whereas in inorganic chemistry there are about 100 elements which could be tested for (in practice less than half of these are of importance) which together with several radicals form some 35,000 compounds, in organic chemistry con-sisting of carbon, hydrogen, oxygen and occasionally nitrogen there are already more than one million recorded compounds. The reactions used in inorganic qualitative analysis number between fifty to a hundred, while naturally the reactions used in qualitative Organic Analysis number far more. These few facts illustrate the difficulty involved in the development of a systematic scheme of organic qualitative analysis, a process which is still being perfected even today. At the beginning of this century Mulliken [109] began to work on this problem. He attempted to classify compounds on the basis of the physical properties and chemical reactions of their characteristic groups (1904) [110]. This has since been proved to be the only valid basis for a systematic scheme of qualitative Organic Analysis. Other classification systems are also based on this principle. The work of Staudinger [111] is especially notable in this field for he contributed to the development of functional group reactions. His work, which was first published in 1923 [112], placed this subject on a very firm basis and proved very useful in many other branches of analytical chemistry. Stig Veibel [113] and his co-workers, have approached the problem from a different aspect, using quantitative methods for qualitative analysis by preparing the derivatives of the original substance and then determining their equivalent weight.
eBook - ePubEnvironmental Geochemistry
Site Characterization, Data Analysis and Case Histories
- Benedetto DeVivo, Harvey Belkin, Annamaria Lima(Authors)
- 2017(Publication Date)
- Elsevier(Publisher)
Chapter 6Gas Chromatographic Methods of Chemical Analysis of Organics and Their Quality Control
Chris Swyngedouw⁎ ; Robert Lessard†⁎ Exova, Calgary, AB, Canada† Exova, Edmonton, AB, CanadaAbstract
Chromatographic analytical methods for the analysis of organic chemicals are widely available. The majority of these methods have common elements, such as dissolving the analyte in organic solvent, removing the interfering coextractives by column chromatography and then injecting the purified extract onto a gas chromatograph coupled to a detector. This review attempts to summarize the best practices, provides guidelines and some procedures to extract, isolate, concentrate, separate, identify, and quantify organic compounds by chromatography. It also includes some information on the collection, preparation, and storage of samples, as well as specific quality control and reporting criteria. Performance-based processes are described so that individual laboratories can adapt the methods best suited to their situations.Keywords
Sample preparation; Headspace; Extraction; Sample clean-up; Instrumental analysis; Laboratory QA/QC1 Introduction
Analytical organic chemistry is broad ranging in its scope, with analytes ranging from highly volatile single carbon molecules such as chloroform, to larger molecules like the six-ringed dibenzo(a,i)pyrene. The analytes can be aliphatic (e.g., hydrocarbons), aromatic (polycyclic aromatic hydrocarbons, PAHs), or mixed (nonylphenol). They can be halogen substituted (polychlorinated biphenyls (PCBs) and pesticides) or have functional groups like a carboxylic acid (e.g., phthalates, haloacetic acids), hydroxyl (e.g., pentachlorophenol) and amine (e.g., aniline, toluidine) moieties.All sampling and laboratory activities are aimed at one target: the production of quality data that is reliable and has a minimum of errors. Further, reliable data must be produced consistently. To achieve this, an appropriate program of quality control (QC) is needed. QC includes “the operational techniques and activities that are used to satisfy the quality requirements or data quality objectives (DQOs)” (CCME, 2016
- Benedetto DeVivo, Harvey Belkin, Harvey Belkin, Annamaria Lima(Authors)
- 2008(Publication Date)
- Elsevier Science(Publisher)
CHAPTER SIX GAS CHROMATOGRAPHIC METHODS OF CHEMICAL ANALYSIS OF ORGANICS AND THEIR QUALITY CONTROLChristopher Swyngedouw* ,* Consulting Scientist, Bodycote Testing Group, Calgary, CanadaDavid Hope† ,† CEO, Pacific Rim Laboratories, Surrey, CanadaRobert Lessard‡ ,‡ QA Manager, Bodycote Testing Group, Edmonton, CanadaAbstractAnalytical organic chemistry employing common gas chromatographic techniques involves dissolving the analyte in organic solvent, removing the interfering coextractives by solid phase extraction and then injecting the purified extract onto a gas chromatograh coupled to a detector. Analytical methods for the analysis of organic chemicals are widely available. This chapter provides procedures to extract, isolate, concentrate, separate, identify, and quantify organic compounds. It also includes some information on the collection, preparation, and storage of samples, as well as specific quality control and reporting criteria. This chapter attempts to summarize the best practices. A performance-based process is described, whereby individual laboratories can adapt methods best suited to their situations.Contents1. Introduction2. Sample Preparation—Aqueous Samples2.1. Purge and Trap2.2. Headspace2.3. Liquid/liquid extraction2.4. Solid phase extraction3. Sample Preparation—Soil Samples3.1. Soxhlet extraction3.2. Shaker table3.3. Ultrasonic probe3.4. Accelerated solvent extraction4. Cleanup Techniques4.1. Adsorption “cleanup” columns4.2. Size-exclusion columns4.3. Lipid destruction4.4. Sulfur removal4.5. Evaporation steps5. Instrumental Analysis5.1. Flame ionization detector5.2. Electron capture detector5.3. Nitrogen/phosphorus detector5.4. Photo ionization detector5.5. Mass spectrometry5.6. High-resolution mass spectrometry6. Data Analysis
eBook - PDF- James W. Robinson, Eileen Skelly Frame, George M. Frame II(Authors)
- 2014(Publication Date)
- CRC Press(Publisher)
1 CHAPTER 1 Concepts of Instrumental Analytical Chemistry 1.1 INTRODUCTION: WHAT IS ANALYTICAL CHEMISTRY? Perhaps.the.most.functional.definition.of.analytical.chemistry.is.that.it.is.“the.qualitative.and. quantitative.characterization.of.matter .” .The.word.“characterization”.is.used.in.a.very.broad.sense . . It.may.mean.the.identification.of.the.chemical.compounds.or.elements.present.in.a.sample.to.answer. questions.such.as.“Is.there.any.vitamin.E.in.this.shampoo.as.indicated.on.the.label?”.or.“Is.this. white.tablet.an.aspirin.tablet?”.or.“Is.this.piece.of.metal.iron.or.nickel?”.This.type.of.characteriza-tion,.to.tell.us. what .is.present,.is.called.qualitative.analysis . . Qualitative analysis .is.the.identifica-tion.of.one.or.more.chemical.species.present.in.a.material . .Characterization.may.also.mean.the. determination.of.how.much.of.a.particular.compound.or.element.is.present.in.a.sample,.to.answer. questions.such.as.“How.much.acetylsalicylic.acid.is.in.this.aspirin.tablet?”.or.“How.much.nickel.is. in.this.steel?”.This.determination.of. how much .of.a.species.is.present.in.a.sample.is.called.quantita-tive.analysis . . Quantitative analysis .is.the.determination.of.the.exact.amount.of.a.chemical.species. present.in.a.sample . .The.chemical.species.may.be.an.element,.compound,.or.ion . .The.compound. may.be.organic.or.inorganic . .Characterization.can.refer.to.the.entire.sample.( bulk analysis ),.such.as. the.elemental.composition.of.a.piece.of.steel,.or.to.the.surface.of.a.sample.( surface analysis ),.such. as.the.identification.of.the.composition.and.thickness.of.the.oxide.layer.that.forms.on.the.surface.of. most.metals.exposed.to.air.and.water . .The.characterization.of.a.material.may.go.beyond.chemical. analysis.to.include.structural.determination.of.materials,.the.measurement.of.physical.properties.of. a.material,.and.the.measurement.of.physical.chemistry.parameters.like.reaction.kinetics .
eBook - PDF- Douglas Skoog, Donald West, F. Holler, Stanley Crouch, Douglas Skoog(Authors)
- 2021(Publication Date)
- Cengage Learning EMEA(Publisher)
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 4 CHAPTER 1 The Nature of Analytical Chemistry with respect to the many other scientific fields listed in the diagram. Chemistry is often called the central science; its top-center position and the central position of an- alytical chemistry in the figure emphasize this importance. The interdisciplinary na- ture of chemical analysis makes it a vital tool in medical, industrial, government, and academic laboratories throughout the world. 1B Quantitative Analytical Methods We compute the results of a typical quantitative analysis from two measurements. One is the mass or the volume of sample being analyzed. The second measurement is of some quantity that is proportional to the amount of analyte in the sample such as mass, volume, intensity of light, or electrical charge. This second measurement usually completes the analysis, and we usually classify analytical methods according to the nature of this final measurement. Gravimetric methods determine the mass of the analyte or some compound chemically related to it. A volumetric method measures the volume of a solution containing sufficient reagent to react completely with the analyte. Electroanalytical methods measure electrical properties such as potential, current, resistance, and quantity of electrical charge. Spectroscopic methods explore the interaction between electromagnetic radiation and analyte atoms or molecules or the emission of radiation by analytes. Finally, in a group of miscellaneous methods, we measure such quantities as mass-to-charge ratio of ions by mass spectrometry, rate of radioactive decay, heat of reaction, rate of reaction, sample thermal conductivity, optical activity, and refractive index.
eBook - PDFSoil and Environmental Analysis
Modern Instrumental Techniques
- Keith A. Smith, Malcolm S. Cresser, Keith A. Smith, Malcolm S. Cresser(Authors)
- 2003(Publication Date)
- CRC Press(Publisher)
12 Analysis of Organic Pollutants in Environmental Samples Julian J. C. Dawson, Helena Maciel, and Graeme I. Paton The University of Aberdeen, Aberdeen, Scotland Kirk T. Semple Lancaster University, Lancaster, England I. INTRODUCTION The identification and quantification of organic pollutants in environmental matrices have improved significantly over the past two decades. Fundamen-tally, the determination of organic contaminants requires selective solvent extraction of the determinant(s) from the matrix followed by quantifiable analysis using specialized instrumentation. Often the researcher needs to identify a target compound and/or its metabolites, thus focusing the choice of technique to suit the particular matrix and determinant(s). Significant advances in instrument automation and reliability, precision of flow control, detector development, and competitive instrument pricing have greatly increased the number and range of laboratories capable of fulfilling reliable and routine organic pollutant analysis. This chapter describes the main steps required in analysis of key organic pollutants in environmental samples, concentrating on soil analysis to provide illustrative examples, as soil is one of the more challenging matrices. Citations are made to references that provide specific information about instrumentation and the underpinning principles and scientific rationale. Several widely used methods are described and discussed in detail to exemplify the considerations needed for techniques. 515 516 Dawson et al. A. Why Quantify and Identify Organic Contaminants? The presence of organic pollutants in the environment is ubiquitous. From the high arctic to the tropics (Jones and de Voogt, 1999), recalcitrant and volatile pollutants are detectable in all environmental spheres. Soils and sediments are major sinks for organic pollutants and can retain the highest concentrations of released pollutants (Northcott and Jones, 2000).
eBook - PDF- Roger Minear(Author)
- 1984(Publication Date)
- Academic Press(Publisher)
306 J. Ronald Hass and Daniel L. Norwood IX. SELECTED APPLICATIONS Now that the basic principles of organic mass spectrometry have been discussed and procedures have been put forward for their utilization in qualitative and quantitative analysis, it is useful to consider applications of these methods to specific problems in the field of water analysis. Over the past decade or more, the number of studies reported in the scientific literature in this particular field has increased rapidly. The authors feel that it would not be profitable for the reader if large numbers of these were simply listed, because excellent reviews, such as the Analytical Chemis-try Fundamental Reviews [e.g., 95], are readily available and regularly updated. Rather, some representative examples of qualitative and quanti-tative studies are listed and several specific papers that the authors feel are most appropriate are discussed in some detail. The reader should recognize that the choices are somewhat arbitrary and reflects the au-thors' interests. It is hoped that this discussion gives novice mass spec-trometrists as well as more experienced workers from other fields some idea how mass spectrometry can be applied to water quality problems. Qualitative trace Organic Analysis of aqueous samples is an area of study that has received much attention in the literature. Many papers have been published concerning identification of micropollutants in raw and finished drinking waters [e.g., 96], industrial and municipal wastewa-ters [e.g., 97], large bodies of surface water [e.g., 98], and groundwater [e.g., 99]. One study that incorporates the general procedure for qualita-tive analysis discussed in Section VII is reported by Millington et al. [100]. Concern about the presence of toxic and carcinogenic micropollutants in public drinking waters has prompted interest in treatment methods capable of removing these substances.
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