Differentiation of Regioisomeric Aromatic Ketocarboxylic Acids by Positive Mode Atmospheric Pressure Chemical Ionization Collision-Activated Dissociation Tandem Mass Spectrometry in a Linear Quadrupole Ion Trap Mass Spectrometer

Abstract

Positive-mode atmospheric pressure chemical ionization tandem mass spectrometry (APCI-MS n ) was tested for the differentiation of regioisomeric aromatic ketocarboxylic acids. Each analyte forms exclusively an abundant protonated molecule upon ionization via positive-mode APCI in a commercial linear quadrupole ion trap (LQIT) mass spectrometer. Energy-resolved collision-activated dissociation (CAD) experiments carried out on the protonated analytes revealed fragmentation patterns that varied based on the location of the functional groups. Unambiguous differentiation between the regioisomers was achieved in each case by observing different fragmentation patterns, different relative abundances of ion-molecule reaction products, or different relative abundances of fragment ions formed at different collision energies. The mechanisms of some of the reactions were examined by H/D exchange reactions and molecular orbital calculations.

A Fundamental Tandem Mass Spectrometry Study of the Collision‐Activated Dissociation of Small Deprotonated Molecules Related to Lignin

“…[14][15][16][17][18] These experiments most commonly utilize collision-activated dissociation (CAD), which involves kinetic excitation of an isolated ion to induce nonadiabatic collisions with an inert gas. [14][15][16][17][18] These experiments most commonly utilize collision-activated dissociation (CAD), which involves kinetic excitation of an isolated ion to induce nonadiabatic collisions with an inert gas.…”

“…Ta ndem mass spectrometry is ap owerful analytical tool that allows for molecular level characterization of unknown analytes, even if presenti nc omplex mixtures. [14][15][16][17][18] These experiments most commonly utilize collision-activated dissociation (CAD), which involves kinetic excitation of an isolated ion to induce nonadiabatic collisions with an inert gas. These collisions convert part of the kinetic energy of the ion into its internal energy,w hich causes fragmentation [19][20][21] that can provide information about the ion's structure.…”

Fragmentation of Protonated N-(3-Aminophenyl)Benzamide and Its Derivatives in Gas Phase

“…Tremendous efforts have been made with MS techniques for the identification of positional aromatic isomers [1][2][3][4][5][6][7][8]. Unlike radical ions generated with electron impact (EI) ionization [9], most of the modern atmospheric ionization (API) methods produce even-electron gaseous ions.…”

Analysis of Sulfonated Anthraquinone Dyes by Electrospray Ionization Quadrupole Time-of-flight Tandem Mass Spectrometry

“…This approach allows for the determination of the molecular weights and elemental composition of known and unknown analytes. In order to obtain detailed information on the molecular structures of these analytes, tandem mass spectrometry (MS/MS) is required [11][12][13][14][15][16][17]. MS/MS elucidates the structures of ionized compounds by their fragmentation reactions through collision-activated dissociation (CAD) [18][19][20].…”