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Search Publications by: Aaron Urbas, Ph.D. (Fed)

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Displaying 1 - 25 of 39

Certification of Standard Reference Material(R) 1955a Homocysteine in Frozen Human Serum

June 21, 2024
Author(s)
Carolyn Burdette, Elena Wood, Jerome Mulloor, Michael Nelson, Blaza Toman, Aaron Urbas
Standard Reference Material (SRM) 1955a Homocysteine in Frozen Human Serum is intended for use in validating homocysteine measurement procedures used by in vitro diagnostics manufacturers, reference laboratories, and clinical laboratories in the United

Determination of D9-THC, THCA, D8-THC, and total D9-THC in 53 Smokable Hemp Plant Products by Liquid Chromatography and Photodiode Array Detection

January 8, 2024
Author(s)
Walter Brent Wilson, Aaron Urbas, MARYAM ABDUL-RAHMAN, Arianna Romares, Ewelina Mistek-Morabito
The passage of the 2018 Farm Bill has led to an estimated value of $824M for hemp production in the United States (US) in 2021 with an approximately 76% of it focused on floral hemp that is used to produce hemp-derived finished products such as smokable

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

Expanding NIST’s Calibration of Fluorescent Microspheres for Flow Cytometry to More Fluorescence Channels and Smaller Particles

September 16, 2020
Author(s)
Paul C. DeRose, Linhua Tian, Elzafir B. Elsheikh, Aaron A. Urbas, Yu-Zhong Zhang, Lili Wang
NIST, NIH and other industry stakeholders have been working together to enable fluorescence intensities of flow cytometer calibration beads to be assigned quantitative 'ERF' values with high accuracy and precision. The ultimate goal of this effort is to

An untargeted approach to determine the authenticity of Ginkgo biloba L. plant materials and dried leaf extracts by liquid chromatography-mass spectrometry (LC-HRMS) and chemometrics.

August 5, 2020
Author(s)
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

NIST Spectroscopic Measurement Standards

May 1, 2018
Author(s)
Paul C. DeRose, Kenneth D. Cole, Aaron Urbas, Steven J. Choquette, Evelyn Solis, Erica V. Stein, John E. Schiel, Brian Lang, Hua-Jun He
Ultraviolet (UV) absorbance measurements provide a rapid and reliable method to determine protein concentrations. The National Institute of Standards and Technology (NIST) has developed Standard Reference Material (SRM) 2082as a pathlength standard for UV

Development of NIST Standard Reference Material 2082, a Pathlength Standard for Measurements in the Ultraviolet Spectrum

July 10, 2017
Author(s)
Brian Lang, Aaron A. Urbas, Paul C. DeRose, Hung-Kung Liu, John C. Travis, Steven J. Choquette, Kenneth D. Cole
New spectrophotometers and cuvettes have been designed to allow the measurement of absorbance values from samples using microliter volume sizes. These measurements are done using short pathlengths to decrease the sample volumes required. The major

An azeotropic cross-linked styrene-methacrylate network formed through rapid visible-light photo- polymerization

July 15, 2016
Author(s)
Yin Yang, Aaron A. Urbas, Andres Gonzalez-Bonet, Richard J. Sheridan, Jonathan E. Seppala, Kathryn L. Beers, Jirun Sun
A system containing well-defined functional material, a clinically practical procedure to make the material in situ, and proper analytical tools for chemical structure and kinetic studies is appealing, but currently unavailable. Herein, we introduce an all