A5026248299- Mass Spectrometry Techniques and Applications
- Analytical Chemistry and Chromatography
- Advanced Chemical Sensor Technologies
- Cultural Heritage Materials Analysis
- Analytical chemistry methods development
- Conservation Techniques and Studies
- Microfluidic and Capillary Electrophoresis Applications
- Building materials and conservation
- Ion-surface interactions and analysis
- Atmospheric chemistry and aerosols
- Identification and Quantification in Food
- Isotope Analysis in Ecology
- Spectroscopy and Chemometric Analyses
- Electrowetting and Microfluidic Technologies
- Pesticide Residue Analysis and Safety
- Plant Pathogens and Fungal Diseases
- Corrosion Behavior and Inhibition
- Dye analysis and toxicity
- Proteins in Food Systems
- Wood and Agarwood Research
- Microfluidic and Bio-sensing Technologies
- Food Allergy and Anaphylaxis Research
- Electrohydrodynamics and Fluid Dynamics
- Ancient Near East History
- Biosensors and Analytical Detection
Museum Conservation Institute
2018-2025
Smithsonian Institution
2018-2025
Nova Research Company (United States)
2014-2016
Center for Food Safety and Applied Nutrition
2012-2013
United States Food and Drug Administration
2012-2013
University of North Carolina at Chapel Hill
2009-2011
University of Arizona
2005
University of Georgia
2005
Nearly finished sequences for model organisms provide a foundation from which to explore genomic diversity among other taxonomic groups. We genome-wide microsynteny patterns between the rice sequence and two sorghum physical maps that integrate genetic markers, bacterial artificial chromosome (BAC) fingerprints, BAC hybridization data. The largely tile component containing 41% of BACs but 80% single-copy genes shows conserved with partially nonsyntenic 46% only 13% genes. remaining are...
Post-plasma ambient desorption/ionization (ADI) sources are fundamentally dependent on surrounding water vapor to produce protonated analyte ions. There two reports of humidity effects ADI spectra. However, it is unclear whether will affect all and analytes, by what mechanism affects Flowing atmospheric pressure afterglow (FAPA) ionization direct analysis in real time (DART) mass spectra various surface-deposited gas-phase analytes were acquired at temperature across a range observed values....
Unstable explosive hexamethylene triperoxide diamine (HMTD) is dangerous in quantity and benefits from the minimal sampling handling associated with atmospheric pressure chemical ionization for mass spectral analysis. Seasonal variation observed HMTD spectra suggested a humidity dependence. Therefore, direct analysis real time (DART) were acquired at range of values. An enclosure was designed to fit around ion source spectrometer inlet pressure. The supplied controlled amounts humidified air...
Intact bovine 15N-αS1-casein was used as an internal standard in a selected reaction monitoring (SRM) assay for milk protein baked food samples containing fats, sugar, and gums. Effects on SRM results of sample matrix composition two biscuit recipes nonfat dry (NFDM) were studied, including from allergen ELISA proficiency trial. Following extraction defatted with carbohydrate-degrading enzymes acid precipitation casein, the exhibited LOQ <3 ppm NFDM 60–80% recovery. levels measured by...
Textiles provide a valuable source of information regarding past cultures and their artistic practices. Understanding ancient textiles requires identifying the raw materials used, since origin dyes fibers may be from plants or animals, with specific species used varying based on geography, trade routes cultural significance. A selection nine Chancay textile fragments attributed to 800-1200 CE were studied liquid chromatography mass spectrometry (LC-MS) direct analysis in real time (DART-MS)...
Eosin is a synthetic organic colorant prone to fading under the influence of light. On basis growing interest in understanding discoloration mechanism eosin-based lakes, this study compares ability two ultrafast and ultrasensitive mass spectrometry techniques detect eosin derivatives complex matrices, such as oil media without use conventional separation columns or additional sample preparation protocols. Direct analysis real time (DART-MS) direct infusion electrospray ionization (DI-ESI-MS)...
Zinc (carboxylate) soaps, formed by reactions between zinc oxide (ZnO) and fatty acids in a drying oil, are known to cause deterioration the paint layers of modern contemporary oil paintings. This study investigates carboxylates that developed an painting test panel designed mimic aging degradation encountered actual works art. Following accelerated natural aging, protrusions were noted on surface panel. A large protrusion with erupted gel features was extracted from panel, mounted top view,...
Abstract Two mass spectrometry (MS) methods, solid-phase microextraction gas chromatography (SPME–GC–MS) and direct analysis in real time (DART-MS), have been explored to investigate widespread efflorescence observed on exhibited objects at the Smithsonian’s National Museum of American Indian New York (NMAI-NY). Both methods show great potential, terms speed level information, for identifying organic component as 2,2,6,6-tetramethyl-4-piperidinol (TMP-ol) emitted by structural adhesive...
A focused laser is used to make infrared multiphoton photodissociation (IRMPD) more efficient in a quadrupole ion trap mass spectrometer. Efficient (up 100%) dissociation at the standard operating pressure of 1 x 10(-3) Torr can be achieved without any supplemental activation and with shorter irradiation times. The axial amplitudes trapped clouds are measured using tomography. Laser flux on cloud increased six times by focusing so that beam waist approximates size. Unmodified peptide ions...
An enclosed interface that joins a direct analysis in real time (DART) probe, solid-phase microextraction (SPME) fiber, and the inlet of high-resolution mass spectrometer is described. Unlike other systems to couple SPME sampling ambient spectrometry, able perform discrete analyses on different areas single fiber device for up three technical replicate measurements one event. Inlet flow speed desorption temperature are optimized, reproducibility demonstrated between same derivatized with...
Direct analysis in real time mass spectrometry (DART-MS) analyzes intact object surfaces by exposing them to a stream of heated gas.
Complementary mass spectrometry analyses were performed to study a broken ceremonial hat of the Tlingit in collection Smithsonian Institution National Museum Natural History. The base and an associated cylinder are carved from wood show multiple signs age breakage, as well remnants animal materials used for construction, decoration, repair. Samples tissues embedded attached prepared liquid chromatography-tandem (LC-MS/MS), which identified proteins five clades native object's area origin....
As a reagent gas for positive- and negative-mode chemical ionization mass spectrometry (CI-MS), isobutane (i-C4H10) produces superior analyte signal abundance to methane. Isobutane has never been widely adopted CI-MS because it fouls the ion source more rapidly positive CI spectra that are strongly dependent on pressure compared with was diluted various concentrations in argon use as an unmodified commercial chromatograph-mass spectrometer. Analyte were directly using methane, isobutane,...
The implementation of high-resolution mass spectrometry systems offers new possibilities for the analysis complex art samples such as historical oil paintings. However, these multicomponent generate large and data sets that require advanced visualization tools to aid interpretation, especially when no chromatographic separation is performed. In context this research, it was crucial propose a tool identify products generated during synthesis, drying, aging pigments. This study reports first...
Infrared multiphoton photodissociation (IRMPD) in a quadrupole ion trap is not selective for parent ion. Product ions are decreased abundance by continuous sequential dissociation and may be lost below the low mass cut-off. The IRMPD process made resonantly exciting trapped into an axially offset laser path. form collisionally relax out of path to accumulate center trap. technique, termed broadband (SB) IRMPD, limits preserve first generation product abundance. abundances larger maximized...
This paper discusses colorants found in Tumulus MM, the tomb of King Midas or his father, at Gordion, capital Phrygian kingdom. Chromophores, colorants, and auxiliaries are preserved largely independent textiles they once colored. The MM now fragmentary due to degradation processes that occurred inside chamber. For DHA 26 (Vienna, Austria, 2007), we discussed a group golden-yellow fragments from appeared be tabby cloth but were skeletal lattices goethite, αFeOOH (yellow ochre), as identified...
Selected examples of Native American woven woodsplint basketry created between 1870 and 1983 are studied to recover traditional knowledge about their manufacture by identifying dyes or colorants. An ambient mass spectrometry system is designed sample from intact objects with minimal invasiveness, neither cutting solids the whole, exposing liquid, nor leaving a mark on surface. Baskets up 60 cm wide in one dimension placed height-adjusted mounts. A timed jet inert nitrogen finely positioned...
New analytical functionality is demonstrated with an enclosed interface that joins a solid phase microextraction (SPME) device, direct analysis in real time (DART) probe, and high-resolution mass spectrometer. With single 20 mm long SPME Arrow, the able to perform five discrete DART analyses on different areas of same fiber 1 min practical operation time. Three-fiber replicates for 15 runs total produce 15% or better center variance (CV) values both volatile headspace sampling immersion...
Thermal gas jet probes, including post-plasma desorption/ionization sources, have not been studied using computational fluid dynamics (CFD) models, as other ambient mass spectrometry sampling techniques. Two systems were constructed: a heated nitrogen probe to establish practical bounds for sampling/transmission experiment and CFD model study trajectories of particles desorbed from surface through optimization streamlines temperatures. The physical configuration tested revealed large losses,...