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Displaying 176 - 200 of 2028

Development of an LC-MS/MS Reference Method for the Standardization of Analytical Methods to Measure Lipoprotein(a) in Plasma

April 1, 2021
Author(s)
Santica Marcovina, Noemie Clouet-Foraison, Marlys Koschinsky, Mark Lowenthal, Michael Boffa, Andrew Hoofnagle, Tomas Vaisar
Background: Use of Lipoprotein(a) levels for identification of individuals at high risk for cardiovascular disease is hampered by the high size polymorphism of apolipoprotein(a) which strongly impacts immunochemical methods resulting in discordant values

Determination of Total Arsenic and Hydrophilic Arsenic species in Seafood

March 1, 2021
Author(s)
Caleb Luvonga, Catherine A. Rimmer, Lee L. Yu, Sang Bok Lee
Marine organisms are vital sources of staple and functional food but are also the major dietary route of human exposure to total arsenic. We report the total arsenic content and the mass fractions of hydrophilic arsenic species from five different marine

A Comparison of Measurement Methods for Alcohol-Based Hand Sanitizers

February 26, 2021
Author(s)
Mary Bedner, Jacolin Murray, Aaron A. Urbas, William A. MacCrehan, Walter Brent Wilson
The production and demand for hand sanitizers have increased dramatically during the coronavirus disease 2019 (COVID-19) health emergency. To be deemed effective and safe, hand sanitizers should contain at least 60 % alcohol (typically ethanol) as well as

A new highly enriched 233U reference material for improved simultaneous determination of uranium amount and isotope amount ratios in trace level samples

January 26, 2021
Author(s)
Richard Essex, Ross W. Williams, Kayron T. Rogers, Cole R. Hexel, Tashi Parsons-Davis, Kerri C. Treinen
A highly-enriched 233U reference material (>0.99987 n(233U)/n(U)) has been prepared and characterized for use as an isotope dilution mass spectrometry spike. An ion exchange separation was performed on 1 gram of high purity 233U to further reduce trace

Quantitative Analysis of Zirconium Alloys Using Borate Fusion and Wavelength Dispersive X-Ray Fluorescence Spectrometry

January 26, 2021
Author(s)
John R. Sieber, Anthony F. Marlow, Rick L. Paul, Charles A. Barber, Laura J. Wood, Lee L. Yu, Alaina Rieke, Amy Kutnerian, Jessica McCandless, Candace Wallace
The National Institute of Standards and Technology (NIST) uses borate fusion, wavelength dispersive X-ray fluorescence (WDXRF) spectrometry and synthetic calibration standards for high performance, quantitative analyses of a wide range of materials

Entropic-based separation of diastereomers. Size-exclusion chromatography with on-line viscometry and refractometry detection for analysis of blends of mannose and galactose methyl-alpha-pyranosides at "ideal" size-exclusion conditions

January 11, 2021
Author(s)
Andre M. Striegel, Steven Trainoff
TThe separation of carbohydrate diastereomers by an ideal size-exclusion mechanism, i.e., in the absence of enthalpic contributions to the separation, can be considered one of the grand challenges in chromatography: Can a difference in the location of a

Biomonitoring of emerging DINCH metabolites in pregnant women in Charleston, SC: 2011-2014

January 1, 2021
Author(s)
Abby G. Wenzel, Jessica L. Reiner, Satomi Kohno, Bethany J. Wolf, John W. Brock, Lori Cruze, Roger B. Newman
Due to the mounting evidence that phthalates produce adverse endocrine effects in humans and wildlife, the use of other chemicals as replacements has increased. One of the most commonly encountered phthalate replacement is di(isononyl)cyclohexane-1,2

Identifying risk factors for levels of perfluoroalkyl substances in the placenta in a high-risk pregnancy cohort in North Carolina

December 31, 2020
Author(s)
Jacqueline T. Bangma, Lauren A. Eaves, Kirsi Oldenburg, Jessica L. Reiner, Tracy Manuck, Rebecca C. Fry
Prenatal exposure to perfluoroalkyl substances (PFAS), a ubiquitous class of chemicals, is associated with adverse outcomes such as preeclampsia, low infant birth weight and later-life adiposity. The objectives of this study were to examine PFAS levels in

Relationship between the Pacific Decadal Oscillation (PDO) and persistent organic pollutants in sympatric Alaskan seabird (Uria aalge and U. lomvia) eggs between 1999 and 2010

December 31, 2020
Author(s)
Vrinda Kalia, Stacy Schuur, Keith A. Hobson, Howard H. Chang, Lance A. Waller, Steven Hare, Matthew O. Gribble
Although climate change occurs alongside other anthropogenic ecosystem impacts, little is known about how sea-surface temperature variability influences the ecotoxicology of persistent organic pollutants (POPs). We analyzed POP contaminant levels, and

CCQM-K143 Comparison of Copper Calibration Solutions Prepared by NMIs/DIs

December 24, 2020
Author(s)
John L. Molloy, Michael R. Winchester, Therese A. Butler, Olaf Rienitz, Volker Goerlitz, Anita Roethke, Volker Goerlitz, Rodrigo Caciano de Sena, Lu Yang, Kenny Nadeau, Patricia R. Arancibia, Wu Bing, Zhou Tao, James Snell, Jochen Vogl, Maren Koenig, R. K. Kotnala, S. Swarupa Tripathy, Christine Elishian, Rosi Ketrin, Toshihiro Suzuki, Tom Oduor Okumu, Yong-Hyeon Yim, Judith Velina Lara Manzano, Mirella Buzoianu, Alena Sobina, Veniamin Zyskin, Egor Sobina, Pavel Migal, Mare Linsky, Suleyman Z. Can, Betul Ari, Heidi Goenaga Infante
CCQM-K143 is a key comparison that assesses participants' ability to prepare single element calibration solutions. Preparing calibration solutions properly is the cornerstone of establishing a traceability link to the International System of Units (SI)

Comparison of primary laser spectroscopy and mass spectrometry methods for measuring mass concentration of gaseous elemental mercury

December 10, 2020
Author(s)
Abneesh Srivastava, Stephen E. Long, James E. Norris, Colleen E. Bryan Sallee, Jennifer Carney, Joseph Hodges
We present a direct comparison between two independent methods for the measurement of gaseous elemental mercury (GEM) mass concentration: isotope dilution cold-vapor inductively coupled plasma mass spectrometry (ID-CV-ICP-MS) and laser absorption

Study of the Reactions of OH with HCl, HBr, and HI between 298 K and 460 K.

November 25, 2020
Author(s)
Vladimir L. Orkin, Victor Khamaganov, Igor Larin
The reactions between OH radicals and hydrogen halides (HCl, HBr, HI) have been studied between 298 K to 460 K by using a discharge flow – electron paramagnetic resonance technique. The rate constants at room temperature were found to be kHCl(298 K) = (7.9
Displaying 176 - 200 of 2028