Ryan M. Bain
Purdue University
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Ryan M. Bain.
Angewandte Chemie | 2016
Xin Yan; Ryan M. Bain; R. Graham Cooks
The striking finding that reaction acceleration occurs in confined-volume solutions sets up an apparent conundrum: Microdroplets formed by spray ionization can be used to monitor the course of bulk-phase reactions and also to accelerate reactions between the reagents in such a reaction. This Minireview introduces droplet and thin-film acceleration phenomena and summarizes recent methods applied to study accelerated reactions in confined-volume, high-surface-area solutions. Conditions that dictate either simple monitoring or acceleration are reconciled in the occurrence of discontinuous and complete desolvation as the endpoint of droplet evolution. The contrasting features of microdroplet and bulk-solution reactions are described together with possible mechanisms that drive reaction acceleration in microdroplets. Current applications of droplet microreactors are noted as is reaction acceleration in confined volumes and possible future scale-up.
Journal of the American Society for Mass Spectrometry | 2015
Christopher J. Pulliam; Ryan M. Bain; Joshua S. Wiley; Zheng Ouyang; R. Graham Cooks
AbstractIdentification of active components in a variety of chemical products used directly by consumers is described at both trace and bulk levels using mass spectrometry. The combination of external ambient ionization with a portable mass spectrometer capable of tandem mass spectrometry provides high chemical specificity and sensitivity as well as allowing on-site monitoring. These experiments were done using a custom-built portable ion trap mass spectrometer in combination with the ambient ionization methods of paper spray, leaf spray, and low temperature plasma ionization. Bactericides, garden chemicals, air fresheners, and other products were examined. Herbicide applied to suburban lawns was detected in situ on single leaves 5 d after application. Graphical Abstractᅟ
Angewandte Chemie | 2016
Ryan M. Bain; Christopher J. Pulliam; Fabien Thery; R. Graham Cooks
Leidenfrost levitated droplets can be used to accelerate chemical reactions in processes that appear similar to reaction acceleration in charged microdroplets produced by electrospray ionization. Reaction acceleration in Leidenfrost droplets is demonstrated for a base-catalyzed Claisen-Schmidt condensation, hydrazone formation from precharged and neutral ketones, and for the Katritzky pyrylium into pyridinium conversion under various reaction conditions. Comparisons with bulk reactions gave intermediate acceleration factors (2-50). By keeping the volume of the Leidenfrost droplets constant, it was shown that interfacial effects contribute to acceleration; this was confirmed by decreased reaction rates in the presence of a surfactant. The ability to multiplex Leidenfrost microreactors, to extract product into an immiscible solvent during reaction, and to use Leidenfrost droplets as reaction vessels to synthesize milligram quantities of product is also demonstrated.
Journal of the American Society for Mass Spectrometry | 2017
Ryan M. Bain; Stephen T. Ayrton; R. Graham Cooks
AbstractPrevious reports have shown that reactions occurring in the microdroplets formed during electrospray ionization can, under the right conditions, exhibit significantly greater rates than the corresponding bulk solution-phase reactions. The observed acceleration under electrospray ionization could result from a solution-phase, a gas-phase, or an interfacial reaction. This study shows that a gas-phase ion/molecule (or ion/ion) reaction is not responsible for the observed rate enhancement in the particular case of the Fischer indole synthesis. The results show that the accelerated reaction proceeds in the microdroplets, and evidence is provided that an interfacial process is involved. Graphical Abstract
Analytical Chemistry | 2017
Christopher J. Pulliam; Ryan M. Bain; Heather L. Osswald; Dalton T. Snyder; Patrick W. Fedick; Stephen T. Ayrton; Tawnya G. Flick; R. Graham Cooks
Advances in chemical sampling using miniature mass spectrometer technology are used to monitor slow reactions at a frequency of ca. 180 h-1 (on the Mini 12) with no sample carryover and with inline derivatization in the case of poorly ionizing compounds. Moreover, we demonstrate high reproducibility with a relative error of less than 10% for major components. Monitoring is enabled using a continuous-flow nanoelectrospray (CF-nESI) probe contained in a custom-built 3D-printed rotary holder. The holder position is automatically set using a stepper motor controlled by a microcontroller. Reaction progress of up to six reactions, including hydrazone formation and Katritzky transamination, can be monitored simultaneously without carryover for several hours.
Journal of the American Society for Mass Spectrometry | 2018
Stephen T. Ayrton; X. Chen; Ryan M. Bain; Christopher J. Pulliam; M. Achmatowicz; Tawnya G. Flick; D. Ren; R. G. Cooks
AbstractProof of concept evidence is presented for a new method for the determination of isoaspartate, an important post-translational modification. Chemical derivatization is performed using common reagents for the modification of carboxylic acids and shown to yield suitable diagnostic information with regard to isomerization at the aspartate residue. The diagnostic gas phase chemistry is probed by collision-induced dissociation mass spectrometry, on the timescale of the MS experiment and semi-quantitative calibration of the percentage of isoaspartate in a peptide sample is demonstrated. Graphical Abstractᅟ
Journal of Organic Chemistry | 2018
Shyam Sathyamoorthi; Yin-Hung Lai; Ryan M. Bain; Richard N. Zare
The mechanism of the Ritter-type C-H amination reaction of menthol with acetonitrile using CuBr2, Selectfluor, and Zn(OTf)2, first disclosed by Baran and coworkers in 2012, was studied using a combination of online electrospray ionization mass spectrometry, continuous UV/vis spectrometric monitoring, and density functional theory calculations. In addition to corroborating Barans original mechanistic proposal, these studies uncovered a second pathway to product formation, which likely only occurs in microdroplets. DFT calculations show that neither pathway has a barrier that is greater than 6.8 kcal/mol, suggesting that both mechanisms are potentially operative under ambient conditions.
Chemical Science | 2015
Ryan M. Bain; Christopher J. Pulliam; R. Graham Cooks
Journal of Chemical Education | 2016
Ryan M. Bain; Christopher J. Pulliam; Shannon A. Raab; R. Graham Cooks
Journal of Chemical Education | 2014
Ryan M. Bain; Christopher J. Pulliam; Xin Yan; Kassandra F. Moore; Thomas Müller; R. Graham Cooks