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Chemistry

Analytical chemistry

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  • Published Date
Displaying 301 - 325 of 2094

Characterization of triacontyl (C-30) liquid chromatographic columns

March 15, 2020
Author(s)
Lane C. Sander, Catherine A. Rimmer, Walter B. Wilson
Differences in the performance characteristics of seventeen commercial C30 liquid chromatographic columns were studied for the separation of carotenoid isomers. A mixture consisting of nine xanthophyll and hydrocarbon carotenoids were separated under

NIST Reference Materials: Their Purpose and Their Future

March 15, 2020
Author(s)
Steven J. Choquette, David L. Duewer, Katherine E. Sharpless
The National Institute of Standards and Technology (NIST), formerly the National Bureau of Standards, was established by the U.S. Congress in 1901 and charged with establishing a measurement foundation to facilitate U.S. and international commerce. This

Practical Guide for Inelastic Mean Free Paths, Effective Attenuation Lengths, Mean Escape Depths, and Information Depths in X-ray Photoelectron SpectroscopyInformation Depths in X-ray Photoelectron Spectroscopy

February 20, 2020
Author(s)
Cedric J. Powell
Information is provided on four terms that are used for different purposes in X-ray photoelectron spectroscopy (XPS): the inelastic mean free path (IMFP), the effective attenuation length (EAL), the mean escape depth (MED), and the information depth (ID)

New Insights into Female Humpback Whale (Megaptera novaeangliae) Reproductive Endocrinology Revealed by Steroid Hormone Profile Analysis

February 19, 2020
Author(s)
Greta Dalle Luche, Ashley Boggs, John Kucklick, Jasmin Gross, Darryl Hawker, Susan Bengston Nash
The blubber steroid hormone profiles of 52 female humpback whales migrating along the east coast of Australia were investigated for possible seasonal endocrinological changes associated with reproduction. Individuals were randomly sampled in southeast

Optimization of Confined DART-MS

February 14, 2020
Author(s)
Edward R. Sisco, Matthew E. Staymates, Thomas P. Forbes
The use of direct analysis in real time mass spectrometry (DART-MS) is seeing increased use in a number of fields, including forensic science, environmental monitoring, food safety, and healthcare. With the increased use, novel configurations have been

Low-temperature time-resolved phosphorescence excitation emission matrices for the analysis of phenanthro-thiophenes in chromatographic fractions of complex environmental extracts

February 6, 2020
Author(s)
Sadia Arif, Maha Al-Tameemi, Walter Brent Wilson, Stephen Wise, Fernando Barbosa Jr., Andres Campiglia
Polycyclic aromatic sulfur heterocycles (PASHs) are sulfur analogues of polycyclic aromatic hydrocarbons (PAHs) widely found in environmental samples exposed to oil contamination. Despite their potential carcinogenic and mutagenic properties, only few

Applying Planar, Patterned, Multimetallic Samples to Assess the Impact of Analysis Area in Surface-Chemical Analysis: results of a VAMAS Interlaboratory Comparison

February 3, 2020
Author(s)
Christina Passiu, WES Unger, P Rupper, L Gregoratti, M Amanti, P Zeller, C Malitesta, S Rella, SJ Spencer, A Shard, A Kim, Shinichiro N. Muramoto, M Engelhard, B Hagenhoff, B Bock, R Heuberger, P Dietrich, A Thissen, M Kjaervik, D Paul, J Newman, T Weimann, S Butefisch, ND Spencer, A Rossi
The lateral resolution of a surface-analysis instrument is commonly measured as one of the indicators of the quality of obtainable analytical results. Different methods exist to measure this quantity, and traditionally the employed method/reference sample

Quantifying protein aggregation kinetics using electrospray differential mobility analysis

January 5, 2020
Author(s)
Kaleb J. Duelge, Jeremie Parot, Vincent A. Hackley, Michael R. Zachariah
Protein aggregation is a significant concern in bioprocessing and end use applications. Here the thermal aggregation kinetics of bovine serum albumin (BSA) and α-chymotrypsinogen A (α- chymo) were measured over a range of concentrations and temperatures by

Development of an LC-APCI-MS Method for Determining Off-Flavor Compounds and its Application Towards Marine Recirculating Aquaculture System Monitoring and Evaluation of Aeration as a Depuration Approach

January 4, 2020
Author(s)
Mary Bedner, Keiko Saito
The off-flavor compounds geosmin and 2-methylisoborneol (2-MIB) are well-known to impact the quality of farmed freshwater fish species, but little is known about off-flavors in marine aquaculture. To begin addressing this knowledge gap, a method for the

Blubber steroid hormone profiles as indicators of physiological state in free-ranging common bottlenose dolphins (Tursiops truncatus)

December 31, 2019
Author(s)
Thomas M. Galligan, Ashley Boggs, Brian C. Balmer, Teresa Rowles, Cynthia Smith, Forrest Townsend, Randall Wells, Nicholas Kellar, Eric Zolman, Lori Schwacke
Assessing endocrine health in free-ranging marine mammals can be difficult due to limited access to blood samples, which is the most commonly used sample matrix for endocrine assessment in wildlife. Blubber contains steroid hormones and can be collected

The role of ICP-MS in Separation Science

December 17, 2019
Author(s)
Antonio R. Montoro Bustos
Since its introduction in the 1980s, inductively coupled plasma mass spectrometry (ICP-MS) has evolved to become arguably the most versatile and powerful technique for the elemental analysis of metals, metalloids and selected non-metals at (ultra-)trace

Application of INAA methods for KRISS infant forumla CRM analysis: Standardization of INAA at KRISS

November 15, 2019
Author(s)
Hana Cho, Kishore B. Dasari, Radojko Ja?imovi?, Rolf L. Zeisler, Nicholas Sharp, Sun-Ha Kim, Gwang Min Sun, Yong-Hyeon Yim
We have established an instrumental neutron activation analysis (INAA) method, including k0- based INAA, at the Korea Research Institute of Standards and Science (KRISS) for the certification of reference materials. As part of establishing INAA

Metabolomics Test Materials for Quality Control: A Study of a Urine Materials Suite

November 7, 2019
Author(s)
Dan Bearden, David A. Sheen, Yamil Simon, Bruce A. Benner Jr., Werickson Fortunato de Carvalho Rocha, Niksa Blonder, Katrice A. Lippa, Richard Beger, Laura Schnackenberg, Jinchun Sun, Khyati Mehta, Amrita Cheema, Haiwei Gu, Ramesh Marupaka, Nagana Gowda, Daniel Raftery
There is a lack of experimental reference materials and standards for metabolomics measurements, such as urine, plasma, and other human fluid samples. Reasons include difficulties with supply, distribution, and dissemination of information about the

Contactless Resonant Cavity Dielectric Spectroscopic Studies of Recycled Office Papers

November 5, 2019
Author(s)
Mary Kombolias, Jan Obrzut, Michael T. Postek, Dianne L. Poster, Yaw S. Obeng
Current product composition and quality test methods for the paper and pulp industry are rooted in wet-bench chemistry techniques which are highly subjective. These techniques have rather limited utility and cannot be used to distinguish between virgin and
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