Rachel A. Harris

Virginia Innovation Partnership Corporation

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John A. McLean

Vanderbilt University

Jody C. May

Vanderbilt University

James J. O’Brien

University of Missouri–St. Louis

L. C. O’Brien

Southern Illinois University Edwardsville

Gary L. Glish

University of North Carolina at Chapel Hill

Ian D. Tomlinson

University of Oxford

Samantha L. Isenberg

National Center for Environmental Health

David M. Hercules

Emory University

Kimberly Handler

Southern Illinois University Edwardsville

Katrina L. Leaptrot

Virginia Innovation Partnership Corporation

Cooperative Institutions

Vanderbilt University

University of North Carolina at Chapel Hill

Virginia Innovation Partnership Corporation

Brigham Young University

Vanderbilt-Ingram Cancer Center

Breast Cancer Research Foundation

Institute of Chemical Biology and Fundamental Medicine

Nashville Oncology Associates

United States Military Academy

Merck & Co., Inc., Rahway, NJ, USA (United States)

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Resolving powers of >7900 using linked scans: how well does resolving power describe the separation capability of differential ion mobility spectrometry

The Analyst (2015)

Brandon G. Santiago Rachel A. Harris Samantha L. Isenberg Gary L. Glish

Differential ion mobility spectrometry (DIMS) separations are described using similar terminology to liquid chromatography, capillary electrophoresis, and drift tube ion mobility spectrometry. The characterization and comparison of all these separations are typically explained in terms of resolving power, resolution, and/or peak capacity. A major difference between these separations is that DIMS separations are in space whereas the others are separations in time. However, whereas separations in time can, in theory, be extended infinitely, separations in space, such as DIMS separations, are constrained by the physical dimensions of the device. One method to increase resolving power of DIMS separations is to use helium in the DIMS carrier gas. However, ions have a greater mobility in helium which causes more ions to be neutralized due to collisions with the DIMS electrodes or electrode housing, i.e. the space constraints. This neutralization of ions can lead to the loss of an entire peak, or peaks, from a DIMS scan. To take advantage of the benefits of helium use while reducing ion losses, linked scans were developed. During a linked scan the amount of helium present in the DIMS carrier gas is decreased as the compensation field is increased. A comparison of linked scans to compensation field scans with constant helium is presented herein. Resolving powers >7900 are obtained with linked scans. However, this result highlights the limitation of using resolving power as a metric to describe DIMS separations.

Ion-mobility spectrometry

Drift tube

10.1039/c5an00845j

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Citations (9)

Improved Differential Ion Mobility Separations Using Linked Scans of Carrier Gas Composition and Compensation Field

Journal of the American Society for Mass Spectrometry (2015)

Brandon G. Santiago Rachel A. Harris Samantha L. Isenberg Mark E. Ridgeway Alice L. Pilo

Differential ion mobility spectrometry (DIMS) separates ions based on differences in their mobilities in low and high electric fields. When coupled to mass spectrometric analyses, DIMS has the ability to improve signal-to-background by eliminating isobaric and isomeric compounds for analytes in complex mixtures. DIMS separation power, often measured by resolution and peak capacity, can be improved through increasing the fraction of helium in the nitrogen carrier gas. However, because the mobility of ions is higher in helium, a greater number of ions collide with the DIMS electrodes or housing, yielding losses in signal intensity. To take advantage of the benefits of helium addition on DIMS separations and reduce ion losses, linked scans were developed. In a linked scan the helium content of the carrier gas is reduced as the compensation field is increased. Linked scans were compared with conventional compensation field scans with constant helium content for the protein ubiquitin and a tryptic digest of bovine serum albumin (BSA). Linked scans yield better separation of ubiquitin charge states and enhanced peak capacities for the analysis of BSA compared with compensation field scans with constant helium carrier gas percentages. Linked scans also offer improved signal intensity retention in comparison to compensation field scans with constant helium percentages in the carrier gas.

Ion-mobility spectrometry

Buffer gas

10.1007/s13361-015-1208-9

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Citations (12)

Intracavity laser absorption spectroscopy of platinum fluoride, PtF

Journal of Molecular Spectroscopy (2010)

Kimberly Handler Rachel A. Harris L. C. O’Brien James J. O’Brien

Molecular electronic transition

Atomic electron transition

10.1016/j.jms.2010.10.006

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Citations (12)

Research and development on characterization of electromagnetic materials. Final report, 17 Apr 1972--30 Jun 1974

D. Earley Priscilla Franklin Rachel A. Harris Stanley M. Stevens

This report is in two sections. The first section covers research on thermodynamic property measurements and calculations of (Hg,Cd,Te) system, CdTe, ZnSe, samarium, cobalt and titanium-iron alloy systems. A bibliography on high temperature mass spectrometry from Chemical Abstracts from 1970-1973 includes 343 references. The second section includes chemical physical studies on dye laser materials. Dye laser materials were characterized as to: (1) absorption spectrum, (2) fluorescence emission spectrum, (3) radiative decay lifetime of fluorescence, (4) intersystem crossing rate and triplet-triplet absorption spectrum, and (5) various laser emission parameters. (Author) (GRA)

Intersystem crossing

Characterization

Absorption cross section

Source

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Citations (0)

Excess enthalpies at 323.15, 348.15, and 373.15 K, and (liquid+liquid) equilibria for (cyclohexane+acetonitrile) at 0.4 and 15 MPa

The Journal of Chemical Thermodynamics (1988)

J. Bevan Ott J.E. Purdy Brian J. Neely Rachel A. Harris

Liquid liquid

Liquid phase

Binodal

10.1016/0021-9614(88)90114-0

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Citations (14)

Nanoscale Electrostatic Membrane Actuation for Nanofluidic Pumping

2022 Intermountain Engineering, Technology and Computing (IETC) (2020)

Grant Stagg Rachel A. Harris Hollis Belnap Aaron R. Hawkins

We describe a device intended for pumping fluids through nanoscale channels. The nanofluidic pump is created from flexible silica membranes grown through chemical vapor deposition and actuated through electrostatic force. A packaging technique using dry film to create fluid interfaces is demonstrated.

Nanofluidics

Electrostatics

10.1109/ietc47856.2020.9249148

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Citations (2)

High Confidence Shotgun Lipidomics Using Structurally Selective Ion Mobility-Mass Spectrometry

Methods in molecular biology (2021)

Bailey S. Rose Katrina L. Leaptrot Rachel A. Harris Stacy D. Sherrod Jody C. May

Ion-mobility spectrometry

Shotgun

Drift tube

10.1007/978-1-0716-1410-5_2

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Citations (10)

Flavored e-cigarette liquids reduce proliferation and viability in the CALU3 airway epithelial cell line

AJP Lung Cellular and Molecular Physiology (2017)

Temperance R. Rowell Steven L. Reeber Shernita L. Lee Rachel A. Harris Rachel C. Nethery

E-cigarettes are generally thought of as a safer smoking alternative to traditional cigarettes. However, little is known about the effects of e-cigarette liquids (e-liquids) on the lung. Since over 7,000 unique flavors have been identified for purchase in the United States, our goal was to conduct a screen that would test whether different flavored e-liquids exhibited different toxicant profiles. We tested the effects of 13 different flavored e-liquids [with nicotine and propylene glycol/vegetable glycerin (PG/VG) serving as controls] on a lung epithelial cell line (CALU3). Using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay as an indicator of cell proliferation/viability, we demonstrated a dose-dependent decrease of MTT metabolism by all flavors tested. However, a group of four flavors consistently showed significantly greater toxicity compared with the PG/VG control, indicating the potential for some flavors to elicit more harmful effects than others. We also tested the aerosolized "vapor" from select e-liquids on cells and found similar dose-dependent trends, suggesting that direct e-liquid exposures are a justifiable first-pass screening approach for determining relative e-liquid toxicity. We then identified individual chemical constituents for all 13 flavors using gas chromatography-mass spectrometry. These data revealed that beyond nicotine and PG/VG, the 13 flavored e-liquids have diverse chemical constituents. Since all of the flavors exhibited some degree of toxicity and a diverse array of chemical constituents with little inhalation toxicity available, we conclude that flavored e-liquids should be extensively tested on a case-by-case basis to determine the potential for toxicity in the lung and elsewhere.

Toxicant

Viability assay

10.1152/ajplung.00392.2016

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Citations (101)

Investigating Performance of the SLIM-Based High Resolution Ion Mobility Platform for Separation of Isomeric Phosphatidylcholine Species

Journal of the American Society for Mass Spectrometry (2023)

Komal Kedia Rachel A. Harris Kim Ekroos Kelly Wormwood Moser Daniel DeBord

Lipids are structurally diverse molecules that play a pivotal role in a plethora of biological processes. However, deciphering the biological roles of the specific lipids is challenging due to the existence of numerous isomers. This high chemical complexity of the lipidome is one of the major challenges in lipidomics research, as the traditional liquid chromatography-mass spectrometry (LC-MS) based approaches are often not powerful enough to resolve these isomeric and isobaric nuances within complex samples. Thus, lipids are uniquely suited to the benefits provided by multidimensional liquid chromatography-ion mobility-mass spectrometry (LC-IM-MS) analysis. However, many forms of lipid isomerism, including double-bond positional isomers and regioisomers, are structurally similar such that their collision cross section (CCS) differences are unresolvable via conventional IM approaches. Here we evaluate the performance of a high resolution ion mobility (HRIM) system based on structures for lossless ion manipulation (SLIM) technology interfaced to a high resolution quadrupole time-of-flight (QTOF) analyzer to address the noted lipidomic isomerism challenge. SLIM implements the traveling wave ion mobility technique along an ∼13 m ion path, providing longer path lengths to enable improved separation of isomeric features. We demonstrate the power of HRIM-MS to dissect isomeric PC standards differing only in double bond (DB) and stereospecific number (SN) positions. The partial separation of protonated DB isomers is significantly enhanced when they are analyzed as metal adducts. For sodium adducts, we achieve close to baseline separation of three different PC 18:1/18:1 isomers with different cis-double bond locations. Similarly, PC 18:1/18:1 (cis-9) can be resolved from the corresponding PC 18:1/18:1 (trans-9) form. The separation capacity is further enhanced when using silver ion doping, enabling the baseline separation of regioisomers that cannot be resolved when measured as sodium adducts. The sensitivity and reproducibility of the approach were assessed, and the performance for more complex mixtures was benchmarked by identifying PC isomers in total brain and liver lipid extracts.

Ion-mobility spectrometry

Lipidome

Structural isomer

10.1021/jasms.3c00157

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Citations (14)

Mass spectrometry and ion mobility study of poly(ethylene glycol)‐based polyurethane oligomers

Rapid Communications in Mass Spectrometry (2019)

Rachel A. Harris Jaqueline A. Picache Ian D. Tomlinson Emanuel Zlibut Berkley M. Ellis

Commercial-grade polymer synthesis is performed via melt polymerization, which leads to polydispersion. The work reported herein provides a synthetic strategy to produce mono-dispersive polyurethane oligomers and an analytical strategy to distinguish these oligomers, providing chemists with the tools necessary to synthesize and identify specific polymer structures that exhibit a desired property.Three isomeric poly(ethylene glycol)-polyurethane (PEG-PUR) oligomers were synthesized and analyzed via flow-injection ion mobility mass spectrometry (IM-MS). Each polymer oligomer was injected and run independently via flow injection at 100 μL•min-1 and analyzed in positive ion mode on a drift tube quadrupole time-of-flight (QTOF) instrument. Mobility measurements were determined using a single-field approach. For tandem mass spectrometry (MS/MS) experiments, the sodium-adducted singly charged precursor ion was isolated in the quadrupole and subjected to a range of collision energies.In MS experiments, both +1 and +2 sodium-adducted species were observed for each oligomer at m/z 837.4 and 430.2, respectively. When isolated and fragmented via MS/MS, the +1 precursor yielded distinct product ions for each of the three isomeric oligomers. Fragmentation generally occurred at urethane linkages via 1,3- and 1,5-H shift mechanisms. IM was also used to distinguish the three isomers, with greater IM separation observed for the +2 versus the +1 species.Mono-disperse PEG-PUR oligomers were synthesized and analyzed. Although the polymeric oligomers analyzed in this study are quite small and structurally simple, this work serves as a model system for the synthesis and structural characterization of larger, more complex block copolymers.

Oligomer

Fragmentation

10.1002/rcm.8662

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Citations (6)