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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
Xinyu Li, Maribel Garc?a-Ib??ez, Brendan Carter, Baoshen Chen, Qian Li, Regina Easley, Wei-Jun Cai
Ocean acidification, a phenomenon of seawater pH decreasing due to increasing atmospheric CO2, has a global effect on seawater chemistry, marine biology, and ecosystems. Ocean acidification is a gradual and global long-term process that demands high
The chemical analysis of homemade explosives (HMEs) and improvised explosive devices (IEDs) remains challenging for fieldable analytical instrumentation and sensors. Complex explosive fuel-oxidizer mixtures, black and smokeless powders, flash powders, and
Interaction polymer chromatography (IPC) is an umbrella term covering a large variety of primarily enthalpically-dominated macromolecular separation methods. These include temperature- gradient interaction chromatography, interactive gradient polymer
Nicholas Ritchie, Dale E. Newbury, John Fournelle, Aurelien Moy, Heather Lowers, Anette von der Handt, Paul Carpenter, Emma Bullock, John Donovan
The electron excited microanalysis community is increasingly running into the limitations of its ability to derive accurate an composition from measured x-ray intensities. Many of these limitations could be mitigated if the standard matrix correction
Partition coefficients describe the relative concentration of a chemical equilibrated between two phases. In the design of air samplers, the sorbent-air partition coefficient is a critical parameter, as is the ability to extrapolate or predict partitioning
NIST Special Publication (SP) 922 is an aid in the identification of the chemical structures of polycyclic aromatic hydrocarbons (PAHs). The Structure Index consists of two parts: (1) a cross index of named PAHs listed in alphabetical order and (2)
Meryl B. Cruz, Benjamin Place, Laura J. Wood, Aaron A. Urbas, Werickson Rocha, Andrzej Wasik
The lack of stringent regulations regarding raw materials for herbal supplements used for medicinal purposes has been a constant challenge in the industry. Ginkgo biloba L. leaf extracts attract consumers because of the supposed positive effect on mental
The 2019 MicroTAS conference (the 23rd International Conference of Miniaturized Systems for Chemistry and Life Sciences) held in Basel, Switzerland, brought great opportunities to viewinspiring microscale compositions. Many of the best images were
The effective attenuation length (EAL) is a useful parameter in quantitative applications of X- ray photoelectron spectroscopy (XPS). This parameter is used in place of the inelastic mean free path (IMFP) in expressions for different XPS applications to