Method 0031: Sampling Method for Volatile Organic Compounds
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Sensitive Determination of PAH-DNA Adducts
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Matrix Design for Matrix-Assisted Laser Desorption Ionization: Sensitive Determination of PAH-DNA Adducts M. George, J. M. Y. Wellemans, R. L. Cerny, and M. L. Gross* Midwest Center for Mass Spectrometry, Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska USA K. Li and E. L. Cavalieri Eppley institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 600 South 42nd Street, Omaha, Nebraska USA Two matrices, 4-phenyl-cw-cyanocinnamic acid (ICC) and 4-benzyloxy-cu-cyanocinnamic acid (BCC), were identified for the determination of polycyclic aromatic hydrocarbon @‘AH) adducts of DNA bases by matrix-assisted laser desorption ionization. These matrices were designed based on the concept that the matrix and the analyte should have structural similarities. PCC is a good matrix for the desorption of not only PA&modified DNA bases, but also PAHs themselves and their rnetabolites. Detections can be made at the femtomolar level. (1 Am Sot Mass Spectrum 1994, 5, 1021-1025) he success of matrix-assisted laser desorption quire sensitive detection methods at the low picomole ionization (MALDI) for the sensitive detection of and mid-femtomole level, respectively [6]. T an analyte depends on the nature of the matrix. One method for detection that also gives structural Rational design of a matrix requires understanding of information is fast-atom bombardment (FAB) coupled the mechanism of MALDI. The mechanism is not fully with tandem mass spectrometry [6-81. Unfortunately, understood. Nevertheless, empirical criteria for matrix the combination lacks sensitivity because there is in selection have been suggested 111. -
EOR G IA Ourval of Cievce
GEORGIA JOURNAL OF SCIENCE Peer Reviewed Publication of the Georgia Academy of Science Georgia ISSN: 0147-9369 Vol. 73 No. 1 - 2015 Vol. http://www.GaAcademy.org for the Advancement of Science affiliated with the American Association Academy of Science GEORGIA ACADEMY OF SCIENCE President: Richard W. Schmude, Jr. Dept. of Math & Nat Sci, Gordon College 419 College Dr., Barnesville, GA 30204 O: (770) 358-0728 • [email protected] President Elect: Shane A. Webb Dept of Biology, U of N Georgia Dahlonega, GA 30597 O: (706) 867-2947 • [email protected] Past President: Bob Powell Physics Department, Univ of W GA 1601 Maple St., Carrollton, GA 30118 O: (678) 839-4095 • [email protected] Vice-President: Susan Kirkpatrick Smith Geography & Anthropology, Kennesaw State U (770) 423-6247 • [email protected] Secretary: Joseph Sloop Georgia Gwinnett College 1000 University Center Ln, Lawrenceville, GA 30043 O: (678) 485-5021 • [email protected] Treasurer: James Nienow Biology Department, Valdosta State University Valdosta, GA 31698 • [email protected] O: (229) 333-5759 • Fax: (229) 245-6585 Journal Editor: John V. Aliff GA Perimeter College P.O. Box 506, Auburn, GA 30011 O: (678) 630-8119 • [email protected] COUNCILOR-AT-LARGE 2012-2015: Neal Chesnut, Dept of Physics, U of W GA, Carrollton, GA 30118 2013-2016: Sandra Rucker, Dept of Mathematical Sciences, Clark Atlanta U, Atlanta, GA 30314 2014-2017: Linda Jones, Dept of Biology, Young Harris College, Young Harris, GA 30582 SECTION COUNCILORS I. Biological Sciences Linda Jones, Dept of Biology, Young Harris College, Young Harris 30582 II. Chemistry S. -
Corning Glass and Equipment Selection Guide
Corning Glass and Equipment Selection Guide PYREX® Introduction Corning Life Sciences is pleased to present our Glass and Equipment Product Selection Guide. In this guide, you will find a selection of Corning’s newest and most requested products. For up-to-date information on Corning Life Sciences’ comprehensive range of products and services, go to www.corning.com/lifesciences where you can access: Q New Products Information Q Technical Information including: - Application Notes - Instruction Manuals - Product Bulletins Q Product Catalog Information Q Product Literature Q Complete Distributor Information You can always reach our Customer Support Center at 1.80 0.492.1110. Ordering Information Corning products are available through any authorized Corning support office or distributor. Please see our web site for a complete listing. To place an order, simply contact the distributor of your choice. For each requested product, provide the Corning catalog number, product description, and desired quantity. Glass and Equipment REUSABLE GLASS . 2 DISPOSABLE GLASS . 102 PYREX® VISTA™ GLASSWARE . 108 EQUIPMENT . 113 Reusable Glass, page 2 1 REUSABLE GLASS Reusable Glass ADAPTERS 7800 PYREX ® Brand, Drying Tube Adapter, Joint Inverted form with the inner joint at one end only, with a single bulb. The chamber is approxi - mately 110 mm long including the bulb, 30 mm O.D. and will take a No. 2 rubber stopper. Joint Approx. Bulb Approx. Cat. No. Size O.D. (mm) Length (mm) Qty/Pk Qty/Cs 7800-24 24/40 30 183 1 12 7805 PYREX Brand, Drying Tube Adapter With one bulb and medium-sized joints. Cat. No. Approx. Length (mm) Joint Size Qty/Cs 7805-24 125 24/40 1 *This tube is also a replacement part for organic chemistry kit Cat. -
Brandtech Bottletop Burette Catalog 2019
Titrette® Burrettes The BRAND® Titrette® bottletop burette makes routine titrations faster, easier, and more accurate. The Titrette® minimizes the risk of spills from poured transfers to glass or plastic burettes, eliminates meniscus reading errors and offers accuracy that satisfies the tolerances for Class A glass burettes. The instrument is well suited for general chemistry, water treatment applications, food/beverage analysis, industrial titrations, and environmental work in the lab or field. CLEAR/select button Multifunction button clears display, transfers data via optional PC interface Digital display PC interface (optional) User selectable resolution of two or three decimal places Eliminates transcription errors User replaceable batteries Power button Pause button Power on/off with user adjustable auto-off function Stops incrementing of display, useful for re-priming of instrument Hand wheels Non-slip handwheels provide Inspection window variable titration speed from Allows visual confirmation of the absence steady stream to dropwise of bubbles, amber windows included for light sensitive reagents Drying tube (optional) Titration and recirculating valve Accessory port for drying tube (rear) affords Eliminates reagent waste and protection of moisture-sensitive titrants splashing during priming Freely rotating valve block Titrating tube GL 45 mm thread allows bottle label to always face user Horizontally and vertically adjustable Threaded safety cap Telescoping filling tube Coarse thread allows fingertip on/off (inside bottle) Adjusts easily to a broad range of bottle sizes with no measuring or cutting required The world’s only bottletop burette with Class A precision BrandTech® Scientific, Inc. 888-522-2726 www.brandtech.com 53 Titrette® Bottletop Burette Burrettes Lightweight and compact User serviceable Light protection All components move within The Titrette® can be quickly and easily Amber colored light shield inspection the housing, reducing headroom disassembled for cleaning, to replace windows are included to protect light requirements. -
Durridge RAD H2O User Manual
RAD H2O Radon in Water Accessory for the RAD7 User Manual INTRODUCTION Te RAD H2O is an accessory to the RAD7 that enables you to measure radon in water over a concentration range of from less than 10 pCi/L to greater than 400,000 pCi/L. By diluting your sample, or by waiting for sample decay, you can extend the method's upper range to any concentration. Te equipment is portable and battery operated, and the measurement is fast. You can have an accurate reading of radon in water within an hour of taking the sample. Te RAD H2O gives results afer a 30 minutes analysis with a sensitivity that matches or exceeds that of liquid scintillation methods. Te method is simple and straightforward. Tere are no harmful chemicals to use. Once the procedure becomes familiar and well understood it will produce accurate results with minimal effort. It is assumed that the user has a good, working knowledge of the RAD7. If both the RAD7 and the RAD H2O are new to the user, then time should be spent learning how to make good measurements of radon in air with the RAD7 before embarking on radon in water measurements. Instructions for RAD7 operation with the RAD H2O are given in this manual but, for more detail about the instrument and its use, the reader is referred to the RAD7 manual. Grateful acknowledgment is made of the signifcant contribution to this manual by Stephen Shefsky, who wrote most of the original NITON RAD H2O manual, much of which is incorporated in this version. -
The Bottomless Bottle Explosion Properties of Hydrogen SCIENTIFIC
The Bottomless Bottle Explosion Properties of Hydrogen SCIENTIFIC Introduction Generate hydrogen gas using aluminum metal and sodium hydroxide and ignite. Something interesting will happen! When an empty, bottomless soda bottle is filled with hydrogen and the gas ignited, the hydrogen will burn with the flame decreasing in size. After awhile, the reaction will whistle. Suddenly, the hydrogen will explode with water vapor condensing on the inside surface of the bottle. Concepts • Hydrogen gas • Combustion • Stoichiometric ratio Materials Calcium chloride, anhydrous or Drierite® Ring stand and clamp Sodium hydroxide solution, NaOH, 5.5 M, 50 mL Rubber tubing, 3–4 ft, 3⁄16″ ID × 1⁄16″ wall Aluminum foil Stoppers, one-hole, to fit flask, bottle, and drying tube Bottle, water or soda, tall Tubing, 5–6 mm, 1½″ long piece Butane safety lighter Tubing, Pyrex® glass, 2″ long piece Cotton puff Volumetric flask, 500-mL Drying tube Safety Precautions This is not a demonstration for the inexperienced teacher. The production of the hydrogen is dangerous. Hydrogen is a very flammable and potentially explosive gas but can be safely handled with proper safety procedures. Never generate hydrogen in a closed system; always make sure there are no plugs or blockages in the system. Remove all sources of sparks, flames, and heat from the area where hydrogen gas is produced or used. Sodium hydroxide is very corrosive to all body tissues, especially eyes. Wear chemical splash goggles, chemical- resistant gloves, and a chemical-resistant apron. The reaction between sodium hydroxide and aluminum starts slowly and then proceeds rapidly with the production of excessive heat. -
Grignard Synthesis of Triphenylmethanol Reactions That Form Carbon-Carbon Bonds Are Among the Most Useful to the Synthetic Organic Chemist
1 Experiment 12: Grignard Synthesis of Triphenylmethanol Reactions that form carbon-carbon bonds are among the most useful to the synthetic organic chemist. In 1912, Victor Grignard received the Nobel prize in chemistry for his discovery of a new series of reactions that result in the formation of a carbon-carbon bond. A Grignard synthesis first involves the preparation of an organomagnesium reagent via the reaction of an alkyl bromide with magnesium metal: δ– δ+ R Br + Mg R MgBr The resulting “Grignard reagent” acts as both a good nucleophile and a strong base. Its nucleophilic character allows it to react with the electrophilic carbon in a carbonyl group, thus forming the carbon-carbon bond. Its basic property means that it will react with acidic compounds, such as carboxylic acids, phenols, thiols and even alcohols and water; therefore, reaction conditions must be free from acids and strictly anhydrous. Grignard reagents will also react with oxygen to form hydroperoxides, thus they are highly unstable when exposed to the atmosphere and are generally not isolated from solution. For a variety of reasons, anhydrous diethyl ether is the solvent of choice for carrying out a Grignard synthesis. Vapors from the highly volatile solvent help to prevent oxygen from reaching the reaction solution. In addition, evidence suggests that the ether molecules actually coordinate with and help stabilize the Grignard reagent: Et Et O R Mg Br O Et Et The magnesium metal used in the synthesis contains a layer of oxide on the surface that prevents it from reacting with the alkyl bromide. The pieces of metal must be gently scratched while in the ether solution to expose fresh surface area so that the reaction can commence. -
Isoprene Photochemistry Over the Amazon Rainforest
Isoprene photochemistry over the Amazon rainforest Yingjun Liua, Joel Britob, Matthew R. Dorrisc, Jean C. Rivera-Riosc,d, Roger Secoe, Kelvin H. Batesf, Paulo Artaxob, Sergio Duvoisin Jr.g, Frank N. Keutscha,c,d, Saewung Kime, Allen H. Goldsteinh, Alex B. Guenthere,i, Antonio O. Manzij, Rodrigo A. F. Souzak, Stephen R. Springstonl, Thomas B. Watsonl, Karena A. McKinneya,1, and Scot T. Martina,m,1 aJohn A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138; bDepartment of Applied Physics, University of São Paulo, São Paulo 05508, Brazil; cDepartment of Chemistry, University of Wisconsin-Madison, Madison, WI 53706; dDepartment of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138; eDepartment of Earth System Science, University of California, Irvine, CA 92697; fDivision of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125; gDepartment of Chemistry, Universidade do Estado do Amazonas, Manaus, AM 69050, Brazil; hDepartment of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720; iPacific Northwest National Laboratory, Richland, WA 99354; jInstituto Nacional de Pesquisas da Amazonia, Manaus, AM 69067, Brazil; kDepartment of Meteorology, Universidade do Estado do Amazonas, Manaus, AM 69050, Brazil; lDepartment of Environmental and Climate Sciences, Brookhaven National Laboratory, Upton, NY 11973; and mDepartment of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138 Edited by Mark H. Thiemens, University of California, San Diego, La Jolla, CA, and approved April 13, 2016 (received for review December 23, 2015) Isoprene photooxidation is a major driver of atmospheric chemistry forests like Amazonia where there are few anthropogenic NO over forested regions. -
Overcoming Challenges in Liquid Dispensing by Using the Right Accessories for Bottletop Dispensers Hanaë A
WHITE PAPER No. 38 Overcoming Challenges in Liquid Dispensing by Using the Right Accessories for Bottletop Dispensers Hanaë A. Henke, Eppendorf AG, Hamburg, Germany Executive Summary In this white paper we give some detailed examples of the beneficial use of the correct accessory with bottletop dispensers and show the possibilities beyond simple single stroke dispensing. Bottletop dispensers are used for multiple applications in the laboratory. Special materi- als must be used for parts getting in direct liquid contact to ensure high chemical resistance against aggressive solutions such as acids, bases and solvents. Additionally special adapters made from ETFE increase the chemical stability. Accessories such as a drying tube protect fuming acids from dilution or alkaline solutions from the forma- tion of carbonates and can be easily attached to bottletop dispensers. The usage of a sterile filter on the bottletop dispenser ensures sterility of the medium in the bottle. Figure 1: A bottletop dispenser with attached flexible discharge tube facilitates filling of small vessels or reagent tubes in a rack. Introduction In almost every laboratory worldwide challenging liquids bottletop dispenser can speed up the workflow and reduce such as acids, bases and solvents are used for various risk of contamination. At the same time usage of less plastic applications. Additionally some liquids need to be sterilized consumables, such as tips, by direct dispensing out of the in advance and kept sterile during dispensing. In routine bottle comes with the benefit of protecting the environment tasks where always the same volume of liquid is required, and saving money. bottletop dispensers can be used to facilitate and accelerate With four exemplary applications with a high demand for work. -
Single-Molecule Fluorescence Detection
Proc. Nadl. Acad. Sci. USA Vol. 86, pp. 4087-4091, June 1989 Biophysics Single-molecule fluorescence detection: Autocorrelation criterion and experimental realization with phycoerythrin (laser-induced fluorescence/femtomolar sensitivity/fluorescence assays/phycoerythrin oligomers) KONAN PECK*, LUBERT STRYERt, ALEXANDER N. GLAZERt, AND RICHARD A. MATHIES* *Department of Chemistry, University of California, Berkeley, CA 94720; tDepartment of Cell Biology, Stanford University School of Medicine, Stanford, CA 94305; and tDepartment of Microbiology and Immunology, University of California, Berkeley, CA 94720 Contributed by Lubert Stryer, February 10, 1989 ABSTRACT A theory for single-molecule fluorescence ofindividual molecules. In this paper, we present a theory for detection is developed and then used to analyze data from single-molecule fluorescence detection and apply it in de- subpicomolar solutions of B-phycoerythrin (PE). The distri- tecting phycoerythrin at concentrations as low as 1 fM. bution of detected counts is the convolution of a Poissonian continuous background with bursts arising from the passage of individual fluorophores through the focused laser beam. The THEORY autocorrelation function reveals single-molecule events and Consider a solution of fluorophores flowing through a fo- provides a criterion for optimizing experimental parameters. cused laser beam. The emission from the illuminated volume The transit time of fluorescent molecules through the 120-fl consists of bursts of fluorescence from molecules passing imaged volume was 800 ps. The optimal laser power (32 mW through the beam superimposed on a continuous background at 514.5 nm) gave an incident intensity of 1.8 x 1023 due to Rayleigh and Raman scattering from the solvent (Fig. photons-cm 2.S-, corresponding to a mean time of 1.1 ns lA). -
CH 2020 Diels-Alder Reaction: Preparation of a Butadiene Adduct from 3-Sulfolene (Adapted from Organic Chemistry: a Short Course, H
CH 2020 Diels-Alder Reaction: Preparation of a Butadiene Adduct from 3-Sulfolene (adapted from Organic Chemistry: A Short Course, H. Hart, L. E. Craine, D. J. Hart, and T.K. Vinod 13th ed. Houghton-Mifflin, Boston, 2012.) Reference: Bruice, P.Y.,Seventh Edition, Chapter 8. Materials From the Chemicals Hood: From the Stockroom (Blue Bin): 3-Sulfolene ½” “pea-sized” stirbar Reflux condenser Maleic anhydride Stirbar retriever Xylenes Toluene Petroleum ether (60 – 90 °C) 25 mL round-bottom flask Calcium chloride drying Cork ring tube with adapter (2) Wire clips Small metal clamp Introduction The Diels-Alder reaction is a one-step reaction of a conjugated diene and a dienophile, which is reversible. The general reaction and mechanism is depicted in Figure 1. The reaction is the 1,4- addition of an electrophile and a nucleophile to a conjugated diene. However, unlike other 1,4- addition reactions you may have seen, the Diels-Alder reaction is a concerted reaction: the addition of the electrophile and the nucleophile occurs in a single step. This works well because both of the organic substrates are symmetrical. Figure 1. The Diels-Alder reaction to form cis-4-cyclohexene-1,2-dicarboxylic anhydride We will be using 3-sulfolene in our Diels-Alder reaction. 3-Sulfolene thermally decomposes to give the 1,3-butadiene reactant as shown in Figure 2: Figure 2. Thermal decomposition of 3-sulfolene to 1,3-butadiene Procedure Into a 25 mL round-bottom flask, combine 2.0 g 3-sulfolene, 1.2 g powdered maleic anhydride, and a ½” stirbar. Using a pipet, add 1.0 mL xylenes. -
I Fluorescent Detection of Chiral Amino Acids
i Fluorescent Detection of Chiral Amino Acids: A Micelle Approach Gengyu Du Yilong, Sichuan, China B.S. in Chemistry University of Science and Technology of China, Hefei, China, 2015 A Dissertation presented to the Graduate Faculty of the University of Virginia in Candidacy for the Degree of Doctor of Philosophy Department of Chemistry University of Virginia April 2020 ii Abstract Fluorescent Detection of Chiral Amino Acids: A Micelle Approach 1,1’-Bi-2-naphthol (BINOL)-based fluorescent probes have been developed as powerful tools for the molecular recognition of many chiral molecules. High sensitivity and enantioselectivity for chiral amino acids have been achieved in organic media, but the recognition in water media has been limited by their poor solubility in aqueous solution. By using a diblock copolymer PEG-PLLA, 3,3’-diformyl-BINOL was encapsulated into micelles to form a micelle probe. It allowed the detection of chiral lysine (Lys) both chemoselectively and enantioselectively in carbonate buffer solution. A limit of detection (LOD) of 848 nM and 2nd order fit of ee detection was obtained for D-Lys. The chemoselectivity was attributed to the selective reaction of Lys’s terminal amino groups with the probe. Series of monoformyl-BINOL with varying substituents were synthesized and engineered into micelle probes. These probes achieved specific detection of chiral tryptophan (Trp) both enantioselectively and chemoselectively in carbonate buffer solution, with LOD of 2.6 µM and 1st order fit of ee detection. A non-C2 symmetric molecule, 3,3’-diformyl-tetrahydro-BINOL, was fabricated into a micelle probe. It achieved specific detection of chiral His both enantioselectively and chemoselectively in carbonate buffer solution, with LOD of 107 nM and 2nd order fit of ee detection.