Structural Characterization of Chlorophyll-a by High Resolution Tandem Mass Spectrometry

Abstract

A high resolution Fourier transform ion cyclotron resonance (FTICR) mass spectrometer is used for characterizing the fragmentation of chlorophyll-a. Three tandem mass spectrometry (MS/MS) techniques, including electron-induced dissociation (EID), collisionally activated dissociation (CAD), and infrared mutiphoton dissociation (IRMPD) are applied to the singly protonated chlorophyll-a. Some previously unpublished fragments are identified unambiguously by utilizing high resolution and accurate mass value provided by the FTICR mass spectrometer. According to this research, the two long aliphatic side chains are shown to be the most labile parts, and favorable cleavage sites are proposed. Even though similar fragmentation patterns are generated by all three methods, there are much more abundant peaks in EID and IRMPD spectra. The similarities and differences are discussed in detail. Comparatively, cleavage leading to odd electron species and H(•) loss both seem more common in EID experiments. Extensive loss of small side groups (e.g., methyl and ethyl) next to the macrocyclic ring was observed. Coupling the high performance FTICR mass spectrometer with contemporary MS/MS techniques, especially IRMPD and EID, proved to be very promising for the structural characterization of chlorophyll, which is also suitable for the rapid and accurate structural investigation of other singly charged porphyrinic compounds.

d-α-tocopheryl Polyethylene Glycol 1000 Succinate: A View from FTICR MS and Tandem MS

“…The intensity of this peak is likely driven by the thermodynamic stability of a larger conjugated structure as in Scheme 1. A similar situation was reported in the precious work with Chlorophyll a, 11 where a frequent 2H abstraction leading to a larger conjugated structure was observed. In the ECD and EID results, similarly, no fragment ions were detected on the EID spectrum of [M + Na] + , and more fragments are produced from the higher charge-state precursors.…”

Differentiating Fragmentation Pathways of Cholesterol by Two-Dimensional Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

“…2D FT-ICR MS can also be adapted to other fragmentation methods for small molecules, such as electroninduced dissociation (EID) [56,57].…”

Fragmentation patterns of boron‐dipyrromethene (BODIPY) dyes by electrospray ionization high‐resolution tandem mass spectrometry

“…In recent years, ion‐electron dissociation techniques have been increasingly applied to study the structure of small molecules, as activation of radical ions usually leads to extensive cleavages and provides more structural information . However, due to the extremely low fragmentation efficiency compared with CID, ion‐electron dissociation techniques are not commonly applied in routine structural elucidation experiments.…”