Lee L. Yu

National Institute of Standards and Technology

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Savelas A. Rabb

National Institute of Standards and Technology

Laura J. Wood

Royal Surrey NHS Foundation Trust

John R. Sieber

National Centre for Nuclear Research

Gregory C. Turk

D.I. Mendeleyev All-Russian Institute for Metrology

Tinh Nguyen

Hue University

Michael R. Winchester

Material Measurement Laboratory

Rolf Zeisler

National Institute of Standards and Technology

Rick L. Paul

National Institute of Standards and Technology

William C. Davis

National Institute of Standards and Technology

Karen E. Murphy

National Institute of Standards and Technology

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National Institute of Standards and Technology

159

National Institute of Standards

Material Measurement Laboratory

United States Department of Commerce

Information Technology Laboratory

NOAA Chemical Sciences Laboratory

National Institute of Metrology

United States Geological Survey

University of Maryland, College Park

Environmental Protection Agency

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Investigating the Process of Surface Degradation and Nanoparticle Release of a Commercial Nanosilica / Polyurethane Coating Under UV Exposure | NIST

Deborah S. Jacobs Yu Cheng Savelas A. Rabb Peter J. Krommenhoek Lee L. Yu

NIST

Degradation

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Citations (0)

A simple and sensitive LC-ICP-MS method for the accurate determination of vitamin B12 in fortified breakfast cereals and multivitamin tablets

Journal of Analytical Atomic Spectrometry (2013)

Chinthalapati Siva Kesava Raju Lee L. Yu John E. Schiel Stephen E. Long

A sensitive liquid chromatographic (LC) method coupled with inductively coupled plasma mass spectrometry (ICP-MS) has been developed for the determination of vitamin B12. The method was based on efficient isocratic separation with a mobile phase consisting of 20 mmol L−1 ethylenediaminetetraacetic acid (EDTA) in 25/75 methanol–water mixture (volume fractions) operating at a flow rate of 0.2 mL min−1. After LC separation, ionic cobalt (Co), cyanocobalamin, methylcobalamin, and hydroxocobalamin were measured as 59Co by ICP-MS. For Co as cyanocobalamin, the analyte of interest of this work, the method has shown good repeatability with relative standard deviation (RSD) of 3% for ten measurements and excellent linearity between 0.1 ng g−1 and 100 ng g−1 (linear regression, r2 > 0.999). The limit of detection (LOD) for cyanocobalamin was found to be less than 1 ng g−1, which permits the method to be employed for the determination of ultra-trace concentrations of vitamin B12 in various types of dietary supplements and fortified food products. Cyanocobalamin in aqueous solution was found to decompose under the ambient light of the laboratory; therefore, dark room conditions are required for the determination of vitamin B12 in the form of cyanocobalamin to minimize the photon-induced decomposition. To determine total Co in a commercial high-purity cyanocobalamin using direct ICP-MS measurement as part of an effort to characterize the chemical for use as a calibrant, it was observed that quantitative measurement of Co was achieved only through a complete acid digestion. The method was applied to the determination of vitamin B12 in Standard Reference Material (SRM) 3233 Fortified Breakfast Cereal. SRM 3280 Multivitamin/Multielement Tablet was used for quality assurance of the cereal sample measurements. The vitamin B12 value of (0.187 ± 0.016) mg kg−1 found in SRM 3233 was comparable to (0.219 ± 0.066) mg kg−1 obtained by Grocery Manufacturers Association's Food Industry Analytical Chemists Committee (FIACC) using microbiological assay. The (4.38 ± 0.05) mg kg−1 of vitamin B12 found in quality assurance samples of SRM 3280 was in good agreement with the certified values of (4.8 ± 1.0) mg kg−1.

Methylcobalamin

Hydroxocobalamin

Fortified Food

Repeatability

10.1039/c3ja30383g

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Citations (28)

Salivary Antigen-5/CAP Family Members Are Cu2+-dependent Antioxidant Enzymes That Scavenge O2⨪ and Inhibit Collagen-induced Platelet Aggregation and Neutrophil Oxidative Burst

Journal of Biological Chemistry (2013)

Teresa C. F. Assumpção Dongying Ma Alexandra Schwarz Karine Reiter Jaime M. Santana

The function of the antigen-5/CAP family of proteins found in the salivary gland of bloodsucking animals has remained elusive for decades. Antigen-5 members from the hematophagous insects Dipetalogaster maxima (DMAV) and Triatoma infestans (TIAV) were expressed and discovered to attenuate platelet aggregation, ATP secretion, and thromboxane A2 generation by low doses of collagen (<1 μg/ml) but no other agonists. DMAV did not interact with collagen, glycoprotein VI, or integrin α2β1. This inhibitory profile resembles the effects of antioxidants Cu,Zn-superoxide dismutase (Cu,Zn-SOD) in platelet function. Accordingly, DMAV was found to inhibit cytochrome c reduction by O2⨪ generated by the xanthine/xanthine oxidase, implying that it exhibits antioxidant activity. Moreover, our results demonstrate that DMAV blunts the luminescence signal of O2⨪ generated by phorbol 12-myristate 13-acetate-stimulated neutrophils. Mechanistically, inductively coupled plasma mass spectrometry and fluorescence spectroscopy revealed that DMAV, like Cu,Zn-SOD, interacts with Cu2+, which provides redox potential for catalytic removal of O2⨪. Notably, surface plasmon resonance experiments (BIAcore) determined that DMAV binds sulfated glycosaminoglycans (e.g. heparin, KD ∼100 nmol/liter), as reported for extracellular SOD. Finally, fractions of the salivary gland of D. maxima with native DMAV contain Cu2+ and display metal-dependent antioxidant properties. Antigen-5/CAP emerges as novel family of Cu2+-dependent antioxidant enzymes that inhibit neutrophil oxidative burst and negatively modulate platelet aggregation by a unique salivary mechanism. The function of the antigen-5/CAP family of proteins found in the salivary gland of bloodsucking animals has remained elusive for decades. Antigen-5 members from the hematophagous insects Dipetalogaster maxima (DMAV) and Triatoma infestans (TIAV) were expressed and discovered to attenuate platelet aggregation, ATP secretion, and thromboxane A2 generation by low doses of collagen (<1 μg/ml) but no other agonists. DMAV did not interact with collagen, glycoprotein VI, or integrin α2β1. This inhibitory profile resembles the effects of antioxidants Cu,Zn-superoxide dismutase (Cu,Zn-SOD) in platelet function. Accordingly, DMAV was found to inhibit cytochrome c reduction by O2⨪ generated by the xanthine/xanthine oxidase, implying that it exhibits antioxidant activity. Moreover, our results demonstrate that DMAV blunts the luminescence signal of O2⨪ generated by phorbol 12-myristate 13-acetate-stimulated neutrophils. Mechanistically, inductively coupled plasma mass spectrometry and fluorescence spectroscopy revealed that DMAV, like Cu,Zn-SOD, interacts with Cu2+, which provides redox potential for catalytic removal of O2⨪. Notably, surface plasmon resonance experiments (BIAcore) determined that DMAV binds sulfated glycosaminoglycans (e.g. heparin, KD ∼100 nmol/liter), as reported for extracellular SOD. Finally, fractions of the salivary gland of D. maxima with native DMAV contain Cu2+ and display metal-dependent antioxidant properties. Antigen-5/CAP emerges as novel family of Cu2+-dependent antioxidant enzymes that inhibit neutrophil oxidative burst and negatively modulate platelet aggregation by a unique salivary mechanism.

10.1074/jbc.m113.466995

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Citations (67)

Quantification of ligand packing density on gold nanoparticles using ICP-OES

Analytical and Bioanalytical Chemistry (2012)

Sherrie Elzey De‐Hao Tsai Savelas A. Rabb Lee L. Yu Michael R. Winchester

10.1007/s00216-012-5830-0

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Citations (71)

Preliminary evaluation of a microwave-assisted metal-labeling strategy for quantification of peptides via RPLC–ICP-MS and the method of standard additions

Talanta (2011)

Steven J. Christopher Eric L. Kilpatrick Lee L. Yu William C. Davis Blakely M. Adair

Sample Preparation

Standard addition

10.1016/j.talanta.2011.11.064

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Real-time size discrimination and elemental analysis of gold nanoparticles using ES-DMA coupled to ICP-MS

Analytical and Bioanalytical Chemistry (2013)

Sherrie Elzey De-Hao Tsai Lee L. Yu Michael R. Winchester Michael E. Kelley

Differential mobility analyzer

Condensation particle counter

10.1007/s00216-012-6617-z

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Citations (66)

A simple and sensitive HPLC-ICP-MS method for the accurate determination of Vitamin B12 in Fortified Breakfast Cereals and Multivitamin Tablet Reference Materials

Journal of Analytical Atomic Spectrometry (2013)

Siva K. Chinthalapati Lee L. Yu John E. Schiel Stephen E. Long

Multivitamin

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Mass fraction assignment of folic acid in a high purity material

Metrologia (2018)

Steven Westwood R D Josephs Tiphaine Choteau Adeline Daireaux Norbert Stoppacher

The comparison required the assignment of the mass fraction of folic acid present as the main component in the comparison sample. Performance in the comparison is representative of a laboratory's measurement capability for the purity assignment of organic compounds of medium structural complexity [molecular weight range 300–500] and high polarity ( pK OW < −2). Methods used by the eighteen participating NMIs or DIs were based on a mass balance (summation of impurities) or qNMR approach, or the combination of data obtained using both methods. The qNMR results tended to give slightly lower values for the content of folic acid, albeit with larger associated uncertainties, compared with the results obtained by mass balance procedures. Possible reasons for this divergence are discussed in the report, without reaching a definitive conclusion as to their origin. The comparison demonstrates that for a structurally complex polar organic compound containing a high water content and presenting a number of additional analytical challenges, the assignment of the mass fraction content property value of the main component can reasonably be achieved with an associated relative standard uncertainty in the assigned value of 0.5% Main text To reach the main text of this paper, click on Final Report . Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/ . The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Mass fraction

Mutual Recognition

Fraction (chemistry)

Molecular mass

10.1088/0026-1394/55/1a/08013

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Citations (8)

Development and certification of the new SRM 695 trace elements in multi-nutrient fertilizer

Analytical and Bioanalytical Chemistry (2007)

Elizabeth A. Mackey M. P. Cronise C. N. Fales Robert R. Greenberg Stefan D. Leigh

Certified reference materials

Addendum

10.1007/s00216-007-1124-3

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Citations (12)

Certification of Standard Reference Material 916b :

Michael A. Nelson Jeanice B. Thomas Brian E. Lang Jerome Mulloor John R. Sieber

Standard Reference Material (SRM) 916b Bilirubin comprises neat unconjugated bilirubin that is certified as a chemical substance of known purity. It is intended for use in the calibration and standardization of measurement procedures for the determination of bilirubin in clinical samples and for assignment of bilirubin quantity values to in-house control materials. A unit of SRM 916b consists of 100 mg of bilirubin. This publication documents the production, analytical methods, and computations involved in characterizing this product.

Certified reference materials

10.6028/nist.sp.260-212

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Citations (3)