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Chemistry

Analytical chemistry

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Displaying 101 - 125 of 2094

Host Defense Peptide Piscidin and Yeast-derived Glycolipid Exhibit Synergistic Antimicrobial Action through Concerted Interactions with Membranes

October 19, 2023
Author(s)
Fei Liu, Alexander Greenwood, Yawei Xiong, Rebecca Miceli, Riqiang Fu, Kyle Anderson, Scott McCallum, Ella Mihailescu, Richard Gross, Myriam Cotten
Developing new antimicrobials as alternatives to conventional antibiotics has become an urgent race to eradicate drug-resistant bacteria and save human lives. Conventionally, antimicrobial molecules are studied independently even though they can be co

CCQM_Retrospectoscope Reference Manual: A detailed reference to the CCQM_Retrospectoscope, a suite of graphical tools for the meta-analysis of measurement results from CCQM studies

September 12, 2023
Author(s)
David L. Duewer, Michael Nelson, Christina Cecelski
The CCQM_Retrospectoscope system combines a nominally complete database of results from Consultative Committee for the Amount of Substance: Metrology in Chemistry and Biology (CCQM) studies with a number of graphical tools for trying to make sense of the

Target and Suspect Screening Integrated with Machine Learning to Discover Per- and Polyfluoroalkyl Substance Source Fingerprints

September 11, 2023
Author(s)
Nayantara Joseph, Trever Schwichtenberg, Dunping Cao, Gerrad Jones, Alix Rodowa, Joe Charbonnet, Christopher Higgins, Damian Helbling, Jennifer Field
This study elucidates per- and polyfluoroalkyl substance (PFAS) fingerprints for specific PFAS source types. Ninety-two samples were collected from aqueous film-forming foam impacted groundwater (AFFF-GW), landfill leachate, biosolids leachate, municipal

Inferring the nominal molecular mass of an analyte from its electron ionization mass spectrum

August 23, 2023
Author(s)
Arun Moorthy, Anthony J. Kearsley, William Mallard, William E. Wallace, Stephen E. Stein
The performance of three algorithms for predicting nominal molecular mass from an analyte's electron ionization mass spectrum is presented. The Peak Interpretation Method (PIM) attempts to quantify the likelihood that a molecular ion peak is contained in

Mid-Infrared, Near-Infrared, and Visible Nanospectroscopy of Hydrogen-Intercalated MoO3

August 21, 2023
Author(s)
Jeffrey Schwartz, Sergiy Krylyuk, Devon Jakob, Albert Davydov, Andrea Centrone
Control over the local chemical composition and spatial heterogeneities in nanomaterials provides a means to impart new functions and to tailor their properties in many applications. For two-dimensional (2D) van der Waals materials, intercalation is one

Rapid chemical screening of microplastics and nanoplastics by thermal desorption and pyrolysis mass spectrometry with unsupervised fuzzy clustering

August 11, 2023
Author(s)
Thomas P. Forbes, John Pettibone, Eric S. Windsor, Joseph M. Conny, Robert A. Fletcher
The transport and chemical identification of microplastics and nanoplastics (MNPs) are critical to the concerns over plastic accumulation in the environment. Chemically and physically transient MNP species present unique challenges for isolation and

Recommendations for Setting a Criterion for Assessing Commutability of Secondary Calibrator Certified Reference Materials

August 11, 2023
Author(s)
W. Greg Miller, Thomas Keller, Jeffrey Budd, Jesper Johansen, Mauro Panteghini, Neil Greenberg, Vincent Delatour, Ferruccio Ceriotti, Robert Rej, Johanna Camara, Liesbet Deprez, Finlay MacKenzie, Alicia Lyle, Eline van der Hagen, Chris Burns, Pernille Fauskanger, Sverre Sandberg
A secondary higher-order calibrator is required to be commutable with clinical samples to be suitable for use in the calibration hierarchy of an end-user clinical laboratory in vitro diagnostic medical device (IVD-MD). Commutability is a property of a

Engineering Nanopore Approaches toward Protein Sequencing

July 25, 2023
Author(s)
Xiaojun Wei, Tadas Penkauskas, Joseph Reiner, Mark Uline, Qian Wang, Sheng Li, Aleksei Aksimentiev, Joseph Robertson, Chang Liu
Biotechnological innovations have vastly improved the capacity to perform large-scale protein studies, while the methods we have of identifying and quantifying individual proteins are still inadequate to perform protein sequencing at the single-molecule

On the challenge of unambiguous identification of fentanyl analogs: exploring measurement diversity using standard reference mass spectral libraries

July 11, 2023
Author(s)
Arun Moorthy, Edward Erisman, Anthony J. Kearsley, Yuxue Liang, Edward Sisco, William E. Wallace
Fentanyl analogs are a class of designer drugs that are particularly challenging to unambiguously identify due to the mass spectral and retention time similarities of unique compounds. In this paper, we use agglomerative hierarchical clustering to explore

Use of non-targeted and suspect screening analysis to detect sources of human exposure to environmental contaminants

June 28, 2023
Author(s)
Katherine Manz, Anna Feerick, Joseph Braun, Yong-Lai Feng, Amber Hall, Jeremy Koelmel, Carlos A. Manzano, Seth Newton, Kurt Pennell, Benjamin Place, Krystal Godri Pollitt, Carsten Prasse, Joshua Young
Non-targeted analysis (NTA) and suspect screening analysis (SSA) are powerful techniques that rely on high-resolution mass spectrometry (HRMS) and computational tools to detect and identify unknown or suspected compounds in environmental media and human

Direct Visualization of Chemically Resolved Multilayered Domains in Mixed-Linker Metal-Organic Frameworks

June 15, 2023
Author(s)
Andrea Centrone, Belen Lerma-Berlanga, Adam Biacchi, Carmen Fernandez Conde, Georges Pavlidis, Carlos Marti-Gastaldo
The modular synthesis approach for assembling inorganic nodes and organic multidentate linkers into reticular solids enables rational engineering in porous materials known as metal-organic frameworks (MOFs). Incorporation of two or more linker types in MOF

Food Nutrition and Safety Measurements Quality Assurance Program: Exercise 1 Final Report

May 18, 2023
Author(s)
Colleen E. Bryan Sallee, Melissa M. Phillips, Charles Barber, Carolyn Burdette, Laura Wood, Shaun Kotoski
The Food Nutrition and Safety Measurements Quality Assurance Program (FNSQAP) was launched in 2021. FNSQAP was established to assist laboratories in the development and validation of new analytical methods, in improving the quality of their analytical

Determination of 24,25-dihydroxyvitamin D3 in Vitamin D External Quality Assessment Scheme samples using a reference measurement procedure

May 9, 2023
Author(s)
Stephen Wise, Grace Hahm, Carolyn Burdette, Susan Tai, Johanna Camara, Adam Kuszak, Emma Williams
Ninety archived human serum samples from the Vitamin D External Quality Assessment Scheme (DEQAS) were analyzed using a reference measurement procedure (RMP) based on isotope dilution liquid chromatography - tandem mass spectrometry (ID LC-MS/MS) for the

Per- and Polyfluoroalkyl Substances in New Firefighter Turnout Gear Textiles

May 1, 2023
Author(s)
Andrew Maizel, Andre Thompson, Meghanne Tighe, Samuel Escobar Veras, Alix Rodowa, Ryan Falkenstein-Smith, Bruce A. Benner Jr., Kathleen Hoffman, Michelle K. Donnelly, Olivia Hernandez, Nadine Wetzler, Trung Ngu, Jessica Reiner, Benjamin Place, John Kucklick, Kate Rimmer, Rick D. Davis
Turnout gear is increasingly recognized as a potential source of per- and polyfluoroalkyl substance (PFAS) exposure to firefighters. To determine the type, concentration, and prevalence of PFAS potentially present in new firefighter turnout gear, fifty

Size-exclusion chromatography

April 20, 2023
Author(s)
Andre Striegel
Over the past half-century, size-exclusion chromatography (SEC) has become the premier method by which to determine the molar mass (M) averages and the molar mass distribution (MMD) of natural and synthetic macromolecules. When coupled to a multiplicity of
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