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Chemistry

Analytical chemistry

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  • Published Date
Displaying 326 - 350 of 2094

Sensitive Method for the Confident Identification of Genetically Variant Peptides in Human Hair

October 31, 2019
Author(s)
Zheng Zhang, Meghan Burke, William E. Wallace, Yuxue Liang, Sergey L. Sheetlin, Yuri Mirokhin, Dmitrii Tchekhovskoi, Stephen Stein
Recent reports have demonstrated that genetically variant peptides (GVPs) derived from human hair shaft proteins can be used to differentiate individuals of different biogeographic origin (Parker, G.J.; et al. PLos One. 2016, e0160653). We report a direct

An updated protocol based on CLSI document C37 for preparation of off-the-clot serum from individual units for use alone or to prepare commutable pooled serum reference materials

October 30, 2019
Author(s)
Johanna Camara, Uliana Danilenko, Hubert W. Vesper, Gary L. Myers, Patric A. Clapshaw, W. Greg Miller
Manufacturers of in-vitro diagnostic medical devices, clinical laboratories, research laboratories and calibration laboratories require commutable reference materials that can be used in the calibration hierarchies of medical laboratory measurement

Enhancing the Accuracy of Measurement of Small Molecule Organic Biomarkers

October 30, 2019
Author(s)
Tang Lin Teo, Katrice Lippa, Lindsey Mackay, Sharon Yong, Qinde Liu, Johanna Camara, Vincent Delatour, Tong Kooi Lee, Beatrice Lalere, Gavin O'Connor, Andr? Henrion, Megumi Kato, Jane L. Fernandes, Masahiko Numata, Ha-Jeong Kwon, Ji-Seon Jeong, Bei Xu, Jintana Nammoommoy, Dewei Song, Wagner Wollinger
Over two decades, the Organic Analysis Working Group (OAWG) of the Consultative Committee for Amount of Substance (CCQM) has organised a number of comparisons for clinically relevant small molecule organic biomarkers. These comparisons are hinged upon the

Live quantification of cell viability via neutral red uptake using lens-free imaging

October 27, 2019
Author(s)
Brian J. Nablo, Jungjoon Ahn, Kiran Bhadriraju, Jong M. Lee, Darwin Reyes-Hernandez
We present the quantification of cell viability during neutral red (NR) uptake with a compact lens-free system utilizing two light sources. Conventionally, the NR uptake assay determines cell viability based on the accumulation of NR within lysosomes and

Absolute quantification of RNA or DNA using acid hydrolysis and mass spectrometry

October 22, 2019
Author(s)
Mark S. Lowenthal, Eva Quittman, Karen W. Phinney
Accurate, traceable quantification of ribonucleotide or deoxyribonucleotide oligomers is achievable using acid hydrolysis and isotope dilution mass spectrometry (ID-MS). In this work, formic acid hydrolysis is demonstrated to generate stoichiometric

Calibration

October 2, 2019
Author(s)
Lane C. Sander
In the context of chemical metrology, calibration is the process of relating a known quantity of an analyte to the corresponding measured instrumental response through a mathematical relationship. Calibration permits the assignment of analyte levels in

Discriminative potential of ion mobility spectrometry for the detection of fentanyl and fentanyl analogues relative to confounding environmental interferents

September 27, 2019
Author(s)
Thomas Forbes, Jeffrey Lawrence, Jennifer R. Verkouteren, R. Michael Verkouteren
The opioid crisis and emergence of fentanyl, fentanyl analogues, and other synthetic opioids has highlighted the need for sensitive and robust detection for interdiction at screening points, notably vehicles at border crossings and packages at postal

A photonic pH sensor based on photothermal spectroscopy

September 12, 2019
Author(s)
Zeeshan Ahmed, Nathan J. Castro, Matthew R. Hartings
Although the determination of pH is a standard laboratory measurement, new techniques capable of measuring pH are being developed to facilitate modern technological advances. Bio-industrial processing, tissue engineering, and intracellular environments

Practical Guidelines to 13C-based NMR Metabolomics

August 29, 2019
Author(s)
Arthur S. Edison, Adrien Le Guennec, Frank Delaglio, Eriks Kupce
We present an overview of 13C-based NMR metabolomics. At first glance, the low sensitivity of 13C relative to 1H NMR might seem like too great an obstacle to use this approach. However, there are several advantages to 13C NMR, whether samples can be

Mass Spectrometry Fingerprints of Small-Molecule Metabolites in Biofluids. Building a Spectral Library of Recurrent Spectra for Urine Analysis.

August 19, 2019
Author(s)
Yamil Simon, Ramesh Marupaka, Xinjian Yan, Yuxue Liang, Kelly H. Telu, Yuri A. Mirokhin, Stephen E. Stein
A large fraction of ions observed in electrospray liquid chromatography-mass spectrometry (LC-MS) experiments of biological samples remain unidentified. One the main reasons for this is that spectral libraries of pure compounds fail to account for the

Mass Spectrometry Fingerprints of Small-Molecule Metabolites in Biofluids: Building a Spectral Library of Recurrent Spectra for Urine Analysis

August 18, 2019
Author(s)
Yamil Simon, Ramesh Marupaka, Xinjian Yan, Yuxue Liang, Kelly H. Telu, Yuri Mirokhin, Stephen E. Stein
A large fraction of ions observed in electrospray liquid chromatography–mass spectrometry (LC–ESI-MS) experiments of biological samples remain unidentified. One of the main reasons for this is that spectral libraries of pure compounds fail to account for

Unusual Regularity in GC Retention of Simple Amino Acid Derivatives

August 8, 2019
Author(s)
Anzor I. Mikaia, Nino G. Todua, Zenkevich G. Igor
Background. Application of simple regularities and the general principles along with direct use of reference retention index data is a useful approach for reliable structure determination of compounds by GC-MS. Objective. Interpretation of anomaly in

Ampoules for Radioactivity Standard Reference Materials

August 6, 2019
Author(s)
Ronald Colle
Standard-sized ampoules for radioactive solution standards have been employed by the National Institute of Standards and Technology (NIST) for nearly the past 70 years. This note briefly summarizes the origins and history of the five different batches of

Liquid chromatography tandem mass spectrometry for the quantitation of steroid hormone profiles in blubber from stranded humpback whales (Megaptera novaeangliae)

July 30, 2019
Author(s)
Greta Dalle Luche, Susan Bengston Nash, John Kucklick, Fletcher M. Mingramm, Ashley Russell
Marine mammal blubber is known to have quantifiable concentrations of steroid hormones and is increasingly chosen as a matrix for the detection of these reproductive and stress biomarkers. Steroid hormones act through complex cascades, often in concert
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