Aston Labs

A solution containing the reagents is electrosprayed towards the mass spectrometer inlet, trough a heated double coil, which acts as reaction chamber.

Ion/molecule reactions are powerful tools for studying intrinsic reactivities. We are engaged in their study in the ordinary ambient environment, using new mass spectrometry methods.

Studies on solvent-free ions contribute to the understanding of reaction mechanisms. Traditionally conducted in the high vacuum environment of the mass spectrometer, our experiments are done under high pressure conditions in the ambient environment.

In addition to fundamental studies, atmospheric pressure ion/molecule reactions are applied to enhance selectivity and sensitivity of analysis with ionization techniques such as atmospheric pressure chemical ionization (APCI), desorption atmospheric pressure chemical ionization (DAPCI), and desorption electrospray ionization (reactive DESI) .

Objectives

• Ionization and ion/molecule reactions to be performed in the ambient environment.
• Reactivities and mechanisms of substrates and reactions with practical and theoretical significance.
• Finding reagents and reactions that can be applied for reactive DESI.

Past projects

• Hydrogen/chloride exchange reactions of gaseous carbanions carried out by tandem mass spectrometry.
• Reactivity of acetonyl anion with nitroaromatics studied by atmospheric pressure chemical ionization.
• Recognition of cis-diol functional group by reactive DESI using complexation reactions with cyclic boronates.
• Selective detection of nitroaromatic explosives by APCI and DAPCI using reagent ions such as CH₂CN^- and CN^- generated from acetonitrile, and O^-., OH^- and OOH^- produced from the oxygen in air.
• Eberlin transacetalization reactions studied at atmospheric pressure in heterogeneous liquid/gas and liquid/solid phases.
• Thermally induced ionic reactions at atmospheric pressure: the Fischer indole synthesis and Borsche-Drechsel cyclization.

Current projects

• Gas phase methylation of organic bases at atmospheric pressure via ion/molecule reactions using Atmospheric Pressure Thermal Desorption Ionization (APTDI).
• Development of charge labeled reagents to be used in reactive Desorption Electrospray Ionization (DESI) experiments.
• Gas phase substitution of C60 using APTDI.

Personnel

• Dr. R. Graham Cooks (Professor)
• Chunping Wu (Graduate Student)
• Anastasia Kharlamova (Graduate Student)
• Marcela Nefliu (Graduate Student)

Funding

• National Science Foundation
• Crane NSWC/DTRA
• Department of Energy, Office of Basic Energy Services

Publications

• Hao Chen, R. Graham Cooks, Eduardo C. Meurer and Marcos N. Eberlin "Hydrogen/Chlorine Exchange Reactions of Gaseous Carbanions", Journal of the American Society of Mass Spectrometry, 2005, 16, 2045-2051.
• Hao Chen, Dina R. Justes and R. Graham Cooks "Proton Affinities of N- Heterocyclic Carbene Super Bases", Organic Letters, 2005, 7, 3949-3952.
• Yishu Song, Hao Chen and R. Graham Cooks "Reactivity of Acetonyl Anion with Nitroaromatics: An Atmospheric Pressure Chemical Ionization Study", Rapid Communications in Mass Spectrometry, 2005, 19, 3493-3499.
• Cooks, R. G.; Chen, Hao; Eberlin, M. N.; Zheng, X.; Tao, W. A. "Polar Acetalization and Transacetalization in the Gas Phase: The Eberlin Reaction", Chemical Reviews, 2006, 106, 188-211.
• Hao Chen, Zheng Ouyang, R. Graham Cooks "Thermal Production and Reactions of Organic Ions at Atmospheric Pressure", Angewandte Chemie International Edition, 2006, 45, 3656-3660.
• Hao Chen, Ismael Cotte-Rodríguez, R. Graham Cooks "cis-Diol functional group recognition by reactive desorption electrospray ionization (DESI)", Chemical Communications, 2006, 6, 597-599.
• Yishu Song and R. Graham Cooks "Atmospheric Pressure Ion/Molecule Reactions for the Selective Detection of Nitroaromatic Explosives using Acetonitrile and Air as Reagents", Rapid Communications in Mass Spectrometry, 2006, 20, 3130-3138.
• Rodinei Augusti, Hao Chen, Livia Schiavinato Eberlin, Marcela Nefliu and R. Graham Cooks "Atmospheric pressure Eberlin transacetalization reactions in the heterogeneous liquid/gas phase", International Journal of Mass Spectrometry, 2006, 253, 281-287.
• Regina Sparrapan, Livia S. Eberlin, Renato Haddad, R. Graham Cooks, Marcos N. Eberlin and Rodinei Augusti "Ambient Eberlin Reactions via Desorption Electrospray Ionization", Journal of Mass Spectrometry, 2006, 41, 1242-1264
• Yishu Song and R. Graham Cooks "Atmospheric pressure ion/molecule reaction of 1,3,5-trinitrobenzene with phenol and accompanying aromatic H/D exchange", Journal of Mass Spectrometry, 2007, submitted.