| Journal Articles: 29 results |
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"As Simple as Possible, but Not Simpler"—The Case of Dehydroascorbic Acid Robert C. Kerber
Textbooks routinely assign dehydroascorbic acid a tricarbonyl structure that is highly improbable in aqueous solution and inconsistent with its colorless appearance. Studies of oxidized forms of ascorbic acid are summarized here, and a plea is entered for accurate descriptions of chemical structures in this and other cases, even at the cost of some simplicity.
Kerber, Robert C. J. Chem. Educ. 2008, 85, 1237.
Bioorganic Chemistry |
Free Radicals |
Natural Products |
NMR Spectroscopy |
Vitamins
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Radical Quenching of 1,1-Diphenyl-2-picrylhydrazyl: A Spectrometric Determination of Antioxidant Behavior John M. Berger, Roshniben J. Rana, Hira Javeed, Iqra Javeed, and Sandi L. Schulien
Describes a colorimetric assay using the persistent radical 1,1-diphenyl-2-picrylhydrazyl to measure the activity of common antioxidants. This exercise is particularly appropriate for a course geared for nutrition or food science majors.
Berger, John M.; Rana, Roshniben J.; Javeed, Hira; Javeed, Iqra; Schulien, Sandi L. J. Chem. Educ. 2008, 85, 408.
Food Science |
Free Radicals |
UV-Vis Spectroscopy |
Vitamins
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The Chemistry of Paper Preservation Henry A. Carter
This article examines the applications of chemistry to paper preservation. The acid-catalyzed hydrolysis of cellulose accounts for the deterioration of paper in library books and other written records. To combat this threat to our written heritage, new permanent papers have been developed that are relatively chemically stable and undergo a very slow rate of deterioration.
Carter, Henry A. J. Chem. Educ. 2007, 84, 1937.
Acids / Bases |
Applications of Chemistry |
Aqueous Solution Chemistry |
Free Radicals |
Gas Chromatography |
HPLC |
pH |
Kinetics |
Rate Law
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The Quantitative Determination of Butylated Hydroxytoluene in Chewing Gum Using GC–MS A. E. Witter
An undergraduate experiment for the quantitative determination of the synthetic antioxidant butylated hydroxytoluene (BHT) in chewing gum is described. A simple extraction procedure was used that did not require sample derivatization for analysis.
Witter, A. E. J. Chem. Educ. 2005, 82, 1538.
Food Science |
Free Radicals |
Instrumental Methods |
Mass Spectrometry |
Quantitative Analysis |
Aromatic Compounds |
Chromatography |
Consumer Chemistry |
Gas Chromatography
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The Stereochemistry of Biochemical Molecules: A Subject to Revisit Josep J. Centelles and Santiago Imperial
This article reports on errors in stereochemistry of complex hydrosoluble vitamin B12 molecule. Twenty-five popular biochemistry textbooks were examined for their treatment of the stereoisomery of vitamin B12. Mistakes, discrepancies, and oddities reported in vitamin B12 are just an example of this problem. Biochemistry textbook authors and teachers should pay more attention to the stereoisomery of biochemical molecules to avoid students confusion.
Centelles, Josep J.; Imperial, Santiago. J. Chem. Educ. 2005, 82, 75.
Stereochemistry |
Vitamins
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Studying Current–Potential Curves Using Bipotentiometric Iodometric Back-Titration for the Determination of Ascorbic Acid in Fruits and Vegetables Roxana A. Verdini and Claudia M. Lagier
A method for the determination of the ascorbic acid content in fruits and vegetables was used to introduce the principles of voltammetry. The procedure combines an iodometric back-titration with voltammetric (bipotentiometric) end point detection, which minimizes the risk of ascorbic acid oxidation, allowing for a rapid and efficient quantification of vitamin C in fruits and vegetables. A better understanding of the titration curve is achieved by analyzing the schematic currentpotential curves of the anodic and cathodic half-cell reactions during the titration.
Verdini, Roxana A.; Lagier, Claudia M. J. Chem. Educ. 2004, 81, 1482.
Constitutional Isomers |
Electrochemistry |
Food Science |
Instrumental Methods |
Oxidation / Reduction |
Titration / Volumetric Analysis |
Vitamins |
Consumer Chemistry
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Radioactivity, Radiation, and the Chemistry of Nuclear Waste Nick Zevos
A course that emphasizes an understanding of the nuclear waste generated from the production of plutonium at sites such as Hanford, WA, and Savannah River, GA.
Zevos, Nick. J. Chem. Educ. 2002, 79, 692.
Aqueous Solution Chemistry |
Free Radicals |
Nuclear / Radiochemistry |
Nonmajor Courses
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Motivating Students in Sophomore Organic Chemistry by Examining Nature's Way- Why Are Vitamins E and C Such Good Antioxidants? Bruce D. Beaver
Motivating students in sophomore organic chemistry by integrating material from an area of contemporary research activity into the course. This article contains an overview of the antioxidant function of vitamins E and C.
Beaver, Bruce D. J. Chem. Educ. 1999, 76, 1108.
Nutrition |
Mechanisms of Reactions |
Free Radicals |
Learning Theories |
Applications of Chemistry
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Homogeneous Immunoassays: Historical Perspective and Future Promise Edwin F. Ullman
The founding and growth of Syva Company is examined in the context of its leadership role in the development of homogeneous immunoassays. The simple mix and read protocols of these methods offer advantages in routine analytical and clinical applications.
Ullman, Edwin F. J. Chem. Educ. 1999, 76, 781.
Biotechnology |
Enzymes |
Atomic Properties / Structure |
Free Radicals |
Photochemistry |
Medicinal Chemistry |
Proteins / Peptides
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Iron as Nutrient and Poison N. M. Senozan and M. P. Christiano
Iron containing compounds of the body and the ingestion and elimination of iron, the function and transport of this metal among different sites and substances of the body, and biochemical defects and nutritional habits that lead to excessive accumulation of iron and some unexpected consequences of this accumulation are described.
Senozan, N. M.; Christiano, M. P. J. Chem. Educ. 1997, 74, 1060.
Bioinorganic Chemistry |
Bioorganic Chemistry |
Food Science |
Metals |
Vitamins |
Toxicology |
Nutrition |
Applications of Chemistry |
Descriptive Chemistry
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Free Radical Reactions in Aqueous Solutions: Examples from Advanced Oxidation Processes for Wastewater from the Chemistry in Airborne Water Droplets N. Colin Baird
A common free radical reaction in aqueous solution is electron transfer, especially to the hydroxyl radical and to ozone. Hydrogen peroxide and free radicals related to it act as weak acids, so both their neutral and deprotonated forms must be considered in reactions. Free radical reactions also play an important role in the chemistry of water droplets suspended in air in clouds and fogs.
Baird, N. Colin. J. Chem. Educ. 1997, 74, 817.
Aqueous Solution Chemistry |
Free Radicals |
Reactive Intermediates |
Atmospheric Chemistry |
Acids / Bases |
Oxidation / Reduction
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Environmental Laboratory Exercise: Analysis of Hydrogen Peroxide by Fluorescence Spectroscopy Judith Weinstein--Lloyd and Jai H. Lee
Procedure in which students analyze precipitation samples for trace concentrations of hydrogen peroxide (a deleterious air pollutant) using fluorescence spectroscopy.
Weinstein-Lloyd, Judith; Lee, Jai H. J. Chem. Educ. 1995, 72, 1053.
Fluorescence Spectroscopy |
Free Radicals |
Photochemistry |
Acids / Bases |
Atmospheric Chemistry
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Introducing Atmospheric Reactions: A Systematic Approach for Students Baird, N. Colin
Outline of the dominant reactions that occur in air, particularly with regard to atmospheric pollutants.
Baird, N. Colin J. Chem. Educ. 1995, 72, 153.
Photochemistry |
Free Radicals |
Atmospheric Chemistry
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Determination of the effect of various modes of cooking on the vitamin C content of a common food, green pepper: An introductory biochemistry experiment Johnson, Eric R.
A great laboratory experiment that examines the effects of baking, boiling, steaming, and microwaving a green pepper on the pepper's nutritional level.
Johnson, Eric R. J. Chem. Educ. 1988, 65, 926.
Nutrition |
Titration / Volumetric Analysis |
Vitamins |
Food Science |
Applications of Chemistry
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Undergraduate experiments with a long-lived radical (Fremy's salt): Synthesis of 1,4-benzoquinones by degradative oxidation of p-hydroxybenzyl alcohols Morey, J.
The long-lived, stable radical described in this article can be prepared and stored for several months and therefore is an excellent basis for a series of experiments that the author designed for his class.
Morey, J. J. Chem. Educ. 1988, 65, 627.
Aqueous Solution Chemistry |
Free Radicals |
Alcohols |
Aromatic Compounds
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Thioxanthone sulfone radical anion: A relatively stable ketyl Castrillon, Jose
Thioxanthone sulfone is induced to produce a deep blue color upon standing that disappears on shaking.
Castrillon, Jose J. Chem. Educ. 1987, 64, 352.
Free Radicals |
Oxidation / Reduction
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Analysis of vitamin C by high-pressure liquid chromatography Goodney, David E.
Using HPLC to determine the concentration of vitamin C in a variety of juices.
Goodney, David E. J. Chem. Educ. 1987, 64, 187.
Vitamins |
HPLC |
Separation Science |
Quantitative Analysis
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Aromatic substitution reactions: when you've said ortho, meta, and para you haven't said it all Traynham, James G.
The author presents a range of examples for nucleophilic, electrophilic, and free-radical reactions where the ipso is an important, predominant, or even exclusive site of reaction.
Traynham, James G. J. Chem. Educ. 1983, 60, 937.
Nucleophilic Substitution |
Electrophilic Substitution |
Free Radicals |
Diastereomers |
Stereochemistry |
Reactions
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A versatile chemical system for instruction in ESR spectroscopy Darcy, Raphael
A radical precursor is sued to generate a number of interconvertible, long-lived free radicals whose spectra are observed at room temperature and show variations in detail that illustrate spectroscopic principles.
Darcy, Raphael J. Chem. Educ. 1980, 57, 907.
Spectroscopy |
EPR / ESR Spectroscopy |
Reactive Intermediates |
Magnetic Properties |
Free Radicals
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Excretion of ingested ascorbic acid: An easy, interesting undergraduate experiment Sirota, G. R.; MacInnis, W. K.; Rasmussen, P. W.
The student ingests ascorbic acid and then measures the amount excreted in his urine using a microfluorometric procedure.
Sirota, G. R.; MacInnis, W. K.; Rasmussen, P. W. J. Chem. Educ. 1979, 56, 421.
Carboxylic Acids |
Vitamins |
Quantitative Analysis
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Vitamin C content of commercial orange juices. An analytical project Haddad, Paul
Studying the magnitude and stability of the ascorbic acid content of commercial orange juices; students were interested in ascertaining if orange juice represents a suitable source of Vitamin C after one or two weeks in the refrigerator.
Haddad, Paul J. Chem. Educ. 1977, 54, 192.
Vitamins |
Quantitative Analysis |
Consumer Chemistry |
Applications of Chemistry |
Toxicology
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Analysis of commercial vitamin C tablets by iodometric and coulometric titrimetry Marsh, Daniel G.; Jacobs, Deborah L.; Veening, Hans
The ascorbic acid content of vitamin C tablets is determined iodometrically using a back titration with standard thiosulfate; ascorbic acid is then titrated coullometrically by direct oxidation to dehydroascorbic acid using electrolytically generated bromine.
Marsh, Daniel G.; Jacobs, Deborah L.; Veening, Hans J. Chem. Educ. 1973, 50, 626.
Vitamins |
Titration / Volumetric Analysis |
Oxidation / Reduction |
Electrochemistry
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Organic ion radical chemistry Maler, Larry L.
This paper will briefly introduce ion radicals as a relatively new class of reactive intermediates.
Maler, Larry L. J. Chem. Educ. 1971, 48, 168.
Free Radicals |
Reactions
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The reactive intermediates of organic chemistry Stewart, Ross
The purpose of this paper is to outline a logical presentation of the more important reactive intermediates the student is likely to encounter in organic chemistry.
Stewart, Ross J. Chem. Educ. 1961, 38, 308.
Reactive Intermediates |
Free Radicals |
Mechanisms of Reactions
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Balancing organic redox equations Burrell, Harold P. C.
This paper presents a method for balancing organic redox equations based on the study of structural formulas and an artificial device - the use of hypothetical free radicals.
Burrell, Harold P. C. J. Chem. Educ. 1959, 36, 77.
Stoichiometry |
Oxidation / Reduction |
Free Radicals
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The laboratory preparation of a simple vitamin: p-aminobenzoic acid Kremer, Chester B.
Describes the laboratory preparation of a simple vitamin, p-aminobenzoic acid, with beneficial physiological activity.
Kremer, Chester B. J. Chem. Educ. 1956, 33, 71.
Vitamins |
Synthesis
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Aromatic substitution by free radicals Nelson, Peter F.
This article summarizes recent investigations upon orientation and reaction rates with respect to homolytic substitution.
Nelson, Peter F. J. Chem. Educ. 1955, 32, 606.
Free Radicals |
Aromatic Compounds |
Reactions |
Rate Law |
Molecular Properties / Structure
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The vitamin C content of wild rose hips Markham, Sister Clare.; Markham, Sister M. Justin
Describes the extraction and determination of the vitamin C content of wild rose hips.
Markham, Sister Clare.; Markham, Sister M. Justin J. Chem. Educ. 1953, 30, 580.
Vitamins |
Natural Products |
Separation Science |
Quantitative Analysis
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The mechanisms of the reactions of aliphatic hydrocarbons Schmerling, Louis
Examines the formation of carbonium ions and free radicals, the polymerization of olefins, hydrogen-halogen exchange, the condensation of haloalkanes with alkenes, the alkylation of paraffins, the condensation of paraffins with chloroolefins, the cracking of paraffins and olefins, and the isomerization of paraffins.
Schmerling, Louis J. Chem. Educ. 1951, 28, 562.
Mechanisms of Reactions |
Alkanes / Cycloalkanes |
Free Radicals |
Polymerization
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