R. Graham Cooks

article

Reaction acceleration at air‐solution interfaces: Anisotropic rate constants for Katritzky transamination

Yangjie Li, Tsdale F. Mehari, Zhenwei Wei, Yong Liu, more

Journal of Mass Spectrometry > 56 > 4 > n/a - n/a

To disentangle the factors controlling the rates of accelerated reactions in droplets, we used mass spectrometry to study the Katritzky transamination in levitated Leidenfrost droplets of different yet constant volumes over a range of concentrations while holding concentration constant by adding back the evaporated solvent. The set of concentration and droplet volume data indicates that the reaction...

article

Reaction Acceleration at Solid/Solution Interfaces: Katritzky Reaction Catalyzed by Glass Particles

Yangjie Li, Tsdale F. Mehari, Zhenwei Wei, Yong Liu, more

Angewandte Chemie > 133 > 6 > 2965 - 2969

The Katritzky reaction in bulk solution at room temperature is accelerated significantly by the surface of a glass container compared to a plastic container. Remarkably, the reaction rate is increased by more than two orders of magnitude upon the addition of glass particles with the rate increasing linearly with increasing amounts of glass. A similar phenomenon is observed when glass particles are...

article

Reaction Acceleration at Solid/Solution Interfaces: Katritzky Reaction Catalyzed by Glass Particles

Yangjie Li, Tsdale F. Mehari, Zhenwei Wei, Yong Liu, more

Angewandte Chemie International Edition > 60 > 6 > 2929 - 2933

The Katritzky reaction in bulk solution at room temperature is accelerated significantly by the surface of a glass container compared to a plastic container. Remarkably, the reaction rate is increased by more than two orders of magnitude upon the addition of glass particles with the rate increasing linearly with increasing amounts of glass. A similar phenomenon is observed when glass particles are...

article

High‐Throughput Label‐Free Enzymatic Assays Using Desorption Electrospray‐Ionization Mass Spectrometry

Nicolás M. Morato, Dylan T. Holden, R. Graham Cooks

Angewandte Chemie > 132 > 46 > 20639 - 20644

High‐throughput (HT) enzymatic assays, which typically rely on labeled compounds and plate readers, are important for drug discovery. Mass spectrometry (MS) provides an alternative method of performing HT label‐free assays. Here we demonstrate the use of a HT platform based on desorption electrospray ionization (DESI) MS for the label‐free study of enzymatic reactions directly from the bioassay matrix...

article

High‐Throughput Label‐Free Enzymatic Assays Using Desorption Electrospray‐Ionization Mass Spectrometry

Nicolás M. Morato, Dylan T. Holden, R. Graham Cooks

Angewandte Chemie International Edition > 59 > 46 > 20459 - 20464

High‐throughput (HT) enzymatic assays, which typically rely on labeled compounds and plate readers, are important for drug discovery. Mass spectrometry (MS) provides an alternative method of performing HT label‐free assays. Here we demonstrate the use of a HT platform based on desorption electrospray ionization (DESI) MS for the label‐free study of enzymatic reactions directly from the bioassay matrix...

article

High‐Throughput Bioassays using “Dip‐and‐Go” Multiplexed Electrospray Mass Spectrometry

Zhenwei Wei, Zhuoer Xie, Reshma Kuvelkar, Vinit Shah, more

Angewandte Chemie International Edition > 58 > 49 > 17594 - 17598

A multiplexed system based on inductive nanoelectrospray mass spectrometry (nESI‐MS) has been developed for high‐throughput screening (HTS) bioassays. This system combines inductive nESI and field amplification micro‐electrophoresis to achieve a “dip‐and‐go” sample loading and purification strategy that enables nESI‐MS based HTS assays in 96‐well microtiter plates. The combination of inductive nESI...

article

High‐Throughput Bioassays using “Dip‐and‐Go” Multiplexed Electrospray Mass Spectrometry

Zhenwei Wei, Zhuoer Xie, Reshma Kuvelkar, Vinit Shah, more

Angewandte Chemie > 131 > 49 > 17758 - 17762

A multiplexed system based on inductive nanoelectrospray mass spectrometry (nESI‐MS) has been developed for high‐throughput screening (HTS) bioassays. This system combines inductive nESI and field amplification micro‐electrophoresis to achieve a “dip‐and‐go” sample loading and purification strategy that enables nESI‐MS based HTS assays in 96‐well microtiter plates. The combination of inductive nESI...

article

Reaction Acceleration in Electrospray Droplets: Size, Distance, and Surfactant Effects

Brett M. Marsh, Kiran Iyer, R. Graham Cooks

Journal of The American Society for Mass Spectrometry > 2019 > 30 > 10 > 2022-2030

Phenylhydrazone formation from isatin is used to examine the effects on the reaction rate of (i) electrospray emitter distance from the mass spectrometer (MS) inlet, (ii) emitter tip diameter, and (iii) presence of surfactant. Reaction rates are characterized through measurement of conversion ratios. It is found that there is an increase in the conversion ratio as (i) the electrospray source is moved...

article

Screening of the Suzuki Cross-Coupling Reaction Using Desorption Electrospray Ionization in High-Throughput and in Leidenfrost Droplet Experiments

Patrick W. Fedick, Kiran Iyer, Zhenwei Wei, Larisa Avramova, more

Journal of The American Society for Mass Spectrometry > 2019 > 30 > 10 > 2144-2151

Suzuki cross-coupling is a widely performed reaction, typically using metal catalysts under heated conditions. Acceleration of the Suzuki cross-coupling reaction has been previously explored in microdroplets using desorption electrospray ionization mass spectrometry (DESI-MS). Building upon previous work, presented here is the use of a high-throughput DESI-MS screening system to identify optimal reaction...

article

Selective Gas-Phase Mass Tagging via Ion/Molecule Reactions Combined with Single Analyzer Neutral Loss Scans to Probe Pharmaceutical Mixtures

Dalton T. Snyder, Lucas J. Szalwinski, Alice L. Pilo, Nina K. Jarrah, more

Journal of The American Society for Mass Spectrometry > 2019 > 30 > 6 > 1092-1101

We have demonstrated the use of a simple single ion trap mass spectrometer to identify classes of compounds as well as individual components in complex mixtures. First, a neutral reagent was used to mass tag oxygen-containing analytes using a gas-phase ion/molecule reaction. Then, a neutral loss scan was used to indicate the carboxylic acids. The lack of unit mass selectivity in the neutral loss scan...

article

Rapid determination of isocitrate dehydrogenase mutation status of human gliomas by extraction nanoelectrospray using a miniature mass spectrometer

Fan Pu, Clint M. Alfaro, Valentina Pirro, Zhuoer Xie, more

Analytical and Bioanalytical Chemistry > 2019 > 411 > 8 > 1503-1508

Isocitrate dehydrogenase (IDH) I and II mutations in gliomas cause an abnormal accumulation of 2-hydroxyglutarate (2-HG) in these tumor cells. These mutations have potential prognostic value in that knowledge of the mutation status can lead to improved surgical resection. Information on mutation status obtained by immunohistochemistry or genomic analysis is not available during surgery. We report...

article

Nebulization Prior to Isolation, Ionization, and Dissociation of the Neutral Serine Octamer Allows Its Characterization

Hong Zhang, Zhenwei Wei, Jie Jiang, R. Graham Cooks

Angewandte Chemie International Edition > 57 > 52 > 17141 - 17145

Nebulization of enantiomerically mixed serine solutions, followed by ion deflection and gentle on‐line protonation, is used to isolate and characterize the strongly preferred homochiral neutral serine octamer (Ser₈). The separation of the nebulization and ionization steps and the use of the enantiomeric l‐serine ion (l‐d₃Ser)₈H⁺ as a soft protonating agent ensured that neutral (d‐Ser)₈ was characterized...

article

Nebulization Prior to Isolation, Ionization, and Dissociation of the Neutral Serine Octamer Allows Its Characterization

Hong Zhang, Zhenwei Wei, Jie Jiang, R. Graham Cooks

Angewandte Chemie > 130 > 52 > 17387 - 17391

Nebulization of enantiomerically mixed serine solutions, followed by ion deflection and gentle on‐line protonation, is used to isolate and characterize the strongly preferred homochiral neutral serine octamer (Ser₈). The separation of the nebulization and ionization steps and the use of the enantiomeric l‐serine ion (l‐d₃Ser)₈H⁺ as a soft protonating agent ensured that neutral (d‐Ser)₈ was characterized...

article

Comprehensive lipid profiling of early stage oocytes and embryos by MRM profiling

Camila Bruna Lima, Christina Ramires Ferreira, Marcella Pecora Milazzotto, Tiago Jose P. Sobreira, more

Journal of Mass Spectrometry > 53 > 12 > 1247 - 1252

article

Analysis of Residual Explosives by Swab Touch Spray Ionization Mass Spectrometry

Ryan M. Bain, Patrick W. Fedick, Jonathan M. Dilger, R. Graham Cooks

Propellants, Explosives, Pyrotechnics > 43 > 11 > 1139 - 1144

Swab touch spray ionization mass spectrometry, an ambient ionization technique, has been applied to the analysis of six explosives from various surfaces including glass, metal, Teflon, plastic, human hands and three types of gloves (nitrile, vinyl and latex). A swab, attached to a metallic handle, was used to sample explosive residues and acted as the ion source. The explosives, 1,3,5‐trinitro‐1,3,5‐triazinane...

article

Accelerated reactions in field desorption mass spectrometry

Xingshuo Chen, R. Graham Cooks

Journal of Mass Spectrometry > 53 > 10 > 942 - 946

Field desorption mass spectrometry under ambient conditions is used to study solution‐phase organic reactions in micro‐volumes. Reagent solution is transferred onto the microdendrites of the field emitter, and reaction products are examined online by mass spectrometry. Three reactions, hydrazone formation by phenyl hydrazine and indoline‐2,3‐dione, the Katritzky reaction between a pyrylium salt and...

article

Detection of Neutral CO Lost During Ionic Dissociation Using Atmospheric Pressure Thermal Dissociation Mass Spectrometry (APTD-MS)

Pengyi Zhao, Travis White, R. Graham Cooks, Qinghao Chen, more

Journal of The American Society for Mass Spectrometry > 2018 > 29 > 12 > 2317-2326

Elucidation of ion dissociation patterns is particularly important to structural analysis by mass spectrometry (MS). However, typically, only the charged fragments from an ion dissociation event are detected in tandem MS experiments; neutrals are not identified. In recent years, we have developed an atmospheric pressure thermal dissociation (APTD) technique that can be applied to dissociate ions at...

article

Direct ion generation from swabs

Alan K. Jarmusch, Valentina Pirro, David L. Logsdon, R. Graham Cooks

Talanta > 2018 > 184 > C > 356-363

Medical swabs are used for biofluid and tissue sampling in clinical applications. The use of medical swabs as electrospray ionization probes for direct mass spectrometric analysis is a novel and potentially widely applicable development. Here we discuss ion generation, characterize ionization behavior via microscopic videography and describe some illustrative examples of applications.

article

Accelerated Forced Degradation of Pharmaceuticals in Levitated Microdroplet Reactors

Yangjie Li, Yong Liu, Hong Gao, Roy Helmy, more

Chemistry – A European Journal > 24 > 29 > 7349 - 7353

Forced degradation is a method of studying the stability of pharmaceuticals in order to design stable formulations and predict drug product shelf life. Traditional methods of reaction and analysis usually take multiple days, and include LC‐UV and LC‐MS product analysis. In this study, the reaction/analysis sequence was accelerated to be completed within minutes using Leidenfrost droplets as reactors...

article

Implementation of Precursor and Neutral Loss Scans on a Miniature Ion Trap Mass Spectrometer and Performance Comparison to a Benchtop Linear Ion Trap

Dalton T. Snyder, Lucas J. Szalwinski, Ryan Hilger, R. Graham Cooks

Journal of The American Society for Mass Spectrometry > 2018 > 29 > 7 > 1355-1364

Implementation of orthogonal double resonance precursor and neutral loss scans on the Mini 12 miniature rectilinear ion trap mass spectrometer is described, and performance is compared to that of a commercial Thermo linear trap quadropole (LTQ) linear ion trap. The ac frequency scan version of the technique at constant rf voltage is used here because it is operationally much simpler to implement....

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Search results for: R. Graham Cooks

Reaction acceleration at air‐solution interfaces: Anisotropic rate constants for Katritzky transamination

Reaction Acceleration at Solid/Solution Interfaces: Katritzky Reaction Catalyzed by Glass Particles

Reaction Acceleration at Solid/Solution Interfaces: Katritzky Reaction Catalyzed by Glass Particles

High‐Throughput Label‐Free Enzymatic Assays Using Desorption Electrospray‐Ionization Mass Spectrometry

High‐Throughput Label‐Free Enzymatic Assays Using Desorption Electrospray‐Ionization Mass Spectrometry

High‐Throughput Bioassays using “Dip‐and‐Go” Multiplexed Electrospray Mass Spectrometry

High‐Throughput Bioassays using “Dip‐and‐Go” Multiplexed Electrospray Mass Spectrometry

Reaction Acceleration in Electrospray Droplets: Size, Distance, and Surfactant Effects

Screening of the Suzuki Cross-Coupling Reaction Using Desorption Electrospray Ionization in High-Throughput and in Leidenfrost Droplet Experiments

Selective Gas-Phase Mass Tagging via Ion/Molecule Reactions Combined with Single Analyzer Neutral Loss Scans to Probe Pharmaceutical Mixtures

Rapid determination of isocitrate dehydrogenase mutation status of human gliomas by extraction nanoelectrospray using a miniature mass spectrometer

Nebulization Prior to Isolation, Ionization, and Dissociation of the Neutral Serine Octamer Allows Its Characterization

Nebulization Prior to Isolation, Ionization, and Dissociation of the Neutral Serine Octamer Allows Its Characterization

Comprehensive lipid profiling of early stage oocytes and embryos by MRM profiling

Analysis of Residual Explosives by Swab Touch Spray Ionization Mass Spectrometry

Accelerated reactions in field desorption mass spectrometry

Detection of Neutral CO Lost During Ionic Dissociation Using Atmospheric Pressure Thermal Dissociation Mass Spectrometry (APTD-MS)

Direct ion generation from swabs

Accelerated Forced Degradation of Pharmaceuticals in Levitated Microdroplet Reactors

Implementation of Precursor and Neutral Loss Scans on a Miniature Ion Trap Mass Spectrometer and Performance Comparison to a Benchtop Linear Ion Trap

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