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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
Infrared (IR) absorption spectroscopy is a powerful tool that can quantify complex biomolecules and their structural conformations. However, conventional approaches to protein analysis in aqueous solutions have been significantly challenged because the
Sean Lehman, Ioannis Karageorgos, Wyatt Vreeland, Jeremy Filteau
Protein aggregation can affect the quality of protein-based therapeutics and is an important aspect of disease progression in multiple illnesses. Attempting to unravel the mechanisms and factors influencing protein aggregation involves systematic studies
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
Rapid, reliable, and sensitive detection of Plasmodium infection is central to malaria control and elimination. Malaria Rapid Diagnostic Tests developed for this purpose depend upon immunoassays that should be improved by advances in bound antibody sensor
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
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
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
John Molloy, Michael Winchester, Therese 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)
Megan Harries, Samuel Wasserman, Jennifer Berry, Kavita Jeerage
PLOT-cryoadsorption concentrates headspace vapors by sweeping them through porous layer open tubular (PLOT) capillaries chilled to 0 °C to promote adsorption onto an alumina layer. Compared to passive headspace concentration employing activated charcoal
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
Hugh V. Hayes, Walter B. Wilson, Lane C. Sander, Stephen A. Wise, Andres D. Campiglia
Complete normal-phase liquid chromatography (NPLC) retention behavior was investigated for 25 molecular mass (MM, g mol-1) 302 PAHs on an aminopropyl (NH2) stationary phase. Retention behaviors were used to develop a NPLC fractionation procedure for
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
David L. Duewer, Jeanice M. Brown Thomas, Katherine E. Sharpless, S A. Margolis
Vitamin C is a necessary micronutrient that is involved in many biological processes. In preserved human plasma and serum, vitamin C is most meaningfully analyzed as total ascorbic acid (TAA). From 1993 through 2015, the National Institute of Standards and
Rolf L. Zeisler, Danyal J. Turkoglu, Nicholas Sharp, Huaiyu Chen-Mayer
Traditional instrumental neutron activation analysis (INAA) subjects a sample to in- or near- reactor irradiation to determine concentrations of trace and major elements in a variety of matrices. Depending on the facility-specific neutron spectrum for INAA
Sergiy Tyukhtenko, Girija Rajarshi, Ioannis Karageorgos, Nikolai Zvonok, Kiran Vemuri, Jeffrey W. Hudgens, Xiaoyu Ma, Mahmoud L. Nasr, Alexandros Makriyannis, Kyle Anderson, Jason J. Guo, Gerhard Wagner
Inhibition of human Monoacylglycerol Lipase (hMGL) offers a novel approach for treating neurological diseases. The design of inhibitors, targeting active-inactive conformational transitions of the enzyme, can be aided by understanding the interplay between
Ashley Russell, Lisa Kilpatrick, Carolyn Burdette, Denise S. Tevis, Zachary A. Fultz, Michael Nelson, Jeff M. Jarrett, Stephen A. Wise, Brittany Kassim, Stephen E. Long
Background Concentrations of critical metabolites, hormones, and nutritional elements change significantly throughout pregnancy. Therefore, increased matrix complexity is a challenge for the measurement of these biomarkers. To provide a quality assurance
Lee L. Yu, Karen E. Murphy, Colleen E. Bryan Sallee, Thomas W. Vetter, Robert C. Hagwood, George C. Caceres, Stephen E. Long, J M. Jarrett, M A. Franklin, J Castro Georgi, D M. Jones, Robert Jones, Z Li, Y L. Sommer, D S. Tevis, K Wallon, C D. Ward, M Maras, S Erdahl, C Gilmer, M Wermers, H Woldeysus, K F. Mehigan, M Morrissette, Christopher D. Palmer, Patrick J. Parsons
Standard Reference Material (SRM) 955d is intended for use in validating analytical methods for measuring toxic elements and mercury species in human blood, and in value assigning locally produced control materials analyzed using the validated methods. A
Bowen Du, Zhenyu Tian, Katherine Peter, Edward P. Kolodziej, Charles S. Wong
Non-point source pollution in urban receiving waters often adversely impacts both humans and ecosystems. Identifying such pollution sources is challenging and limits the effectiveness of management actions intended to reduce risk. Here, we evaluated the
The use of reference materials (RMs) is critical to improve measurements accuracy for validating and testing the accuracy of analytical protocols. To the best of our knowledge, there is no food-based matrix RM currently available for glyphosate. The
Brian J. Nablo, Jungjoon Ahn, Kiran Bhadriraju, Jong M. Lee, Darwin Reyes-Hernandez
Neutral red is a supravital stain that estimates the number of viable cells based on its accumulation and retention within lysosomes. The standard protocol relies on a destructive extraction process in order to spectrophotometrically quantify the amount of
The analysis of complex samples without extensive preparation steps (e.g., filtration or centrifugation) is a persistent challenge for applications ranging from forensic identification to high-throughput security screening. Here, a capillary-based
Katrice A. Lippa, Mary Bedner, Susan Tai, Carolyn Q. Burdette
The National Institute of Standards and Technology (NIST) established a Vitamin D Metabolites Quality Assurance Program (VitDQAP) in collaboration with the National Institutes of Health Office of Dietary Supplements (NIH-ODS) in 2009. The VitDQAP at NIST