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Chemistry

Analytical chemistry

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  • Published Date
Displaying 451 - 475 of 2094

Nanostructured lipid-based films for substrate-mediated applications in biotechnology

January 10, 2018
Author(s)
Minjee Kang, Mohit Tuteja, Andrea Centrone, Daniel Topgaard, Cecilia Leal
Amphiphilic in nature, lipids spontaneously self-assemble into a range of nanostructures in the presence of water. Among lipid self-assembled structures, liposomes and supported lipid bilayers have long held scientific interest for their main applications

The Influence of the Aromaticity in the Gas Chromatography Retention: The Case of Polycyclic Aromatic Sulfur Heterocycles

December 15, 2017
Author(s)
Jorge O. Ona-Ruales, Yosadara Ruiz-Morales, Fernando Alvarez-Ramirez, Walter Brent Wilson, Stephen A. Wise
The aromaticity has been used as a criterion to explain the GC retention of cata-condensed polycyclic aromatic sulfur heterocycles (PASHs) C12H8S, C16H10S, C20H12S; and peri-condensed PASHs C18H10S, in a GC column with 50% phenyl / 50% methyl silphenylene

Normal-phase liquid chromatography retention behavior of polycyclic aromatic sulfur heterocycles (PASHs) and alkyl-substituted PASH isomers on an aminopropyl stationary phase

December 14, 2017
Author(s)
Walter Wilson, Hugh Hayes, Lane Sander, Andres Campiglia, Stephen Wise
Retention indices for 67 polycyclic aromatic sulfur heterocycles (PASHs) and 80 alkyl- substituted PASHs were determined using normal-phase liquid chromatography (NPLC) on a aminopropyl (NH2) stationary phase. The retention behavior of PASH on the NH2

Development of a kelp powder (Thallus laminariae) Standard Reference Material

December 9, 2017
Author(s)
Lee L. Yu, Joseph Browning, Carolyn Q. Burdette, George C. Caceres, Kaitlyn Chieh, William C. Davis, MIchael Ellisor, Brittany Kassim, Stephen E. Long, Karen E. Murphy, Rabia Oflaz, Rick L. Paul, Katherine E. Sharpless, Laura J. Wood, James H. Yen, Rolf L. Zeisler
A Standard Reference Material (SRM) of seaweed, SRM 3232 Kelp Powder (Thallus laminariae) has been developed to support food and dietary supplement measurements in compliance with the Food Safety Modernization Act (FSMA) and the Dietary Supplement Health

Assessment of PGAA capability for low-level measurements of H in Ti alloy

December 1, 2017
Author(s)
Danyal J. Turkoglu, Huaiyu H. Chen-Mayer, Rick L. Paul, Rolf L. Zeisler
The accuracy of low-level hydrogen measurements with prompt gamma-ray activation analysis (PGAA) depends on identifying and accounting for all background H signal, including interfering signals. At the cold-neutron (CN)PGAA facility at the NIST Center for

Selenium protein identification and profiling by mass spectrometry: A tool to assess progression of cardiomyopathy in a whale model

December 1, 2017
Author(s)
Colleen E. Bryan Sallee, Steven J. Christopher, William C. Davis, Lisa E. Kilpatrick, Gregory D. Bossart, Wayne E. McFee, Terrance X. O'Brien
Non-ischemic cardiomyopathy is a leading cause of congestive heart failure and sudden cardiac death in humans and in some cases the etiology of cardiomyopathy can include the downstream effects of an essential element deficiency. Of all mammal species

Symmetry-breaking inelastic wave-mixing atomic magnetometry

December 1, 2017
Author(s)
Feng Zhou, Edward W. Hagley, Lu Deng, Chengjie Zhu
The nonlinear magneto-optical rotation (NMOR) effect has prolific applications ranging from precision mapping of Earth's magnetic field to biomagnetic sensing. Studies on collisional spin relaxation effects have led to ultrahigh magnetic field

Analysis of PFAAs in American alligators Part 2: Potential dietary exposure of South Carolina hunters from recreationally harvested alligator meat

November 29, 2017
Author(s)
Jessica Tipton, Louis J. Guillette, Susan Lovelace, Benjamin B. Parrott, Thomas R. Rainwater, Jessica L. Reiner
Exposure to perfluorinated alkyl acids (PFAAs) has been linked to many harmful health effects including reproductive disorders, developmental delays, and altered liver and kidney function. Most human exposure to environmental contaminants, including PFAAs

Tissue Distribution of Perfluoroalkyl Acids (PFAAs) and Health Status in Wild Mozambique Tilapia (Oreochromis mossambicus) from Loskop Dam, Mpumalanga, South Africa

November 29, 2017
Author(s)
Jacqueline T. Bangma, Jessica L. Reiner, Hannes Botha, Theresa M. Cantu, Marco Gouws, Matthew P. Guillette, Jeremy P. Koelmel, Wilmien Luus-Powell, Olivia Rynders, Joseph Sara, Willem J. Smit, John Bowden
This study collected male Mozambique tilapia (Oreochromis mossambicus) from Loskop Dam, Mpumalanga, South Africa in 2014 and 2016 to investigate the levels of 15 perfluoroalkyl acids (PFAAs) across six tilapia tissues. Nine of the 15 PFAAs were detected

Combining fragment ion and neutral loss matching during mass spectral library searching: A new general-purpose algorithm applicable to illicit drug identification

November 20, 2017
Author(s)
Arun S. Moorthy, William E. Wallace, Anthony J. Kearsley, Dmitrii V. Tchekhovskoi, Stephen E. Stein
A mass spectral library search algorithm that identifies compounds that differ from library compounds by a single ‘inert’ structural component is described. This algorithm, the Hybrid Similarity Search, generates a similarity score based on matching both

LipidQC: Method Validation Tool for Visual Comparison to SRM 1950 Using NIST Interlaboratory Comparison Exercise Lipid Consensus Mean Estimate Values

November 17, 2017
Author(s)
Candice Z. Ulmer, Jared Ragland, Jeremy P. Koelmel, N. Alan Heckert, Christina Jones, Timothy J. Garrett, Richard A. Yost, John Bowden
As advances in analytical separation techniques, mass spectrometry instrumentation, and data processing platforms continue to spur growth in the lipidomics field, more structurally unique lipid species are detected and annotated. The lipidomics community

Collision-Induced Dissociation of Deprotonated Peptides. Relative Abundance of Side-Chain Neutral Losses, Residue-Specific Product Ions, and Comparison with Protonated Peptides

November 14, 2017
Author(s)
Yuxue Liang, Pedatsur Neta, Xiaoyu (Sara) Yang, Stephen E. Stein
High-accuracy MS/MS spectra of deprotonated ions of 390 dipeptides and 137 peptides with 3 to 6 residues are studied. Many amino acid residues undergo neutral losses from their side chains. The most abundant is the loss of acetaldehyde from threonine. The

Gas Chromatographic Retention Behavior of Polycyclic Aromatic Hydrocarbons (PAHs) and Alkyl- Substituted PAHs on Two Stationary Phases of Different Selectivity

November 8, 2017
Author(s)
Federica Nalin, Lane C. Sander, Walter B. Wilson, Stephen A. Wise
Retention indices (RIs) for 45 polycyclic aromatic hydrocarbons (PAHs) and 63 methyl- substituted PAHs were determined by gas chromatography – mass spectrometry (GC-MS) using two different stationary phases: a 50% (mole fraction) phenyl-substituted

Sucrose density gradient centrifugation for efficient separation of engineered nanoparticles from a model organism, Caenorhabditis elegans

October 11, 2017
Author(s)
Monique E. Johnson, Antonio R. Montoro Bustos, Elijah J. Petersen, Shannon K. Hanna, Karen E. Murphy, Lee L. Yu, Bryant C. Nelson, Michael R. Winchester
This protocol describes a strategy for separating Caenorhabditis elegans (C. elegans) from engineered nanomaterials, a critical step for accurate quantification in uptake studies. Conventional rinsing procedures, typically comprised of water or buffer
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