Limits...
Structure elucidation of chlorophyll catabolites (phyllobilins) by ESI-mass spectrometry-Pseudo-molecular ions and fragmentation analysis of a nonfluorescent chlorophyll catabolite (NCC).

Müller T, Vergeiner S, Kräutler B - Int J Mass Spectrom (2014)

Bottom Line: A recent application of this methodology concerned the investigation of the annually occurring degradation of green plant pigments.Since the first structural elucidation of a breakdown product in the early 1990s, a number of similarly structured, tetrapyrrolic catabolites have been discovered with the help of chromatographic, spectroscopic and spectrometric methods.Still, a thorough investigation of the common fragmentation behavior of these ubiquitous, naturally occurring chlorophyll breakdown products is lacking.

View Article: PubMed Central - PubMed

Affiliation: Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria.

ABSTRACT

The hyphenation of high performance chromatography with modern mass spectrometric techniques providing high-resolution data as well as structural information from MS/MS experiments has become a versatile tool for rapid natural product identification and characterization. A recent application of this methodology concerned the investigation of the annually occurring degradation of green plant pigments. Since the first structural elucidation of a breakdown product in the early 1990s, a number of similarly structured, tetrapyrrolic catabolites have been discovered with the help of chromatographic, spectroscopic and spectrometric methods. A prerequisite for a satisfactory, manually operated or database supported analysis of mass spectrometric fragmentation patterns is a deeper knowledge of the underlying gas phase chemistry. Still, a thorough investigation of the common fragmentation behavior of these ubiquitous, naturally occurring chlorophyll breakdown products is lacking. This study closes the gap and gives a comprehensive overview of collision-induced fragmentation reactions of a tetrapyrrolic nonfluorescent chlorophyll catabolite, which is intended to serve as a model compound for the substance class of phyllobilins.

No MeSH data available.


Related in: MedlinePlus

MS/MS experiments (CID) of the isolated deprotonated pseudo-molecular ion [M–H]− (m/z 643) of 1.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4375672&req=5

fig0020: MS/MS experiments (CID) of the isolated deprotonated pseudo-molecular ion [M–H]− (m/z 643) of 1.

Mentions: The fragmentation behavior of the isolated pseudo-molecular ions in the gas phase was studied in the positive (Fig. 3) as well as negative ion-mode (Fig. 4). Collision-induced dissociation (CID) MS/MS experiments were carried out on a Thermo-Finnigan LCQ quadrupole ion trap, applying normalized collision energy of 25% to the isolated ions. Dimeric ions showed complete dissociation of the dimer at normalized collision energies higher than 15%. For the determination of the elemental composition of parent as well as fragment ions high-resolution MS/MS was performed on a Bruker FT-ICR instrument. The [M + H]+, [M + Na]+ and [M + K]+ ions were selected as precursors and fragmented in the linear hexapole ion trap floated with argon. The collision energy was kept at the same level (20 V) for all three types of pseudo-molecular ions. Although it is possible that Na+ and K+ are also fragment ions, high resolution spectra were usually recorded in the mass range from m/z 200 to m/z 1500. As can be seen in Fig. 3, the number of fragment ions was decreasing depending on the charging cation (H+ > Na+ > K+), hence most structural information is provided by the MS/MS analysis of the [M + H]+ ion (see Fig. 3A–C). As a rule, a mass spectrum of a tetrapyrrolic NCC indicates four important types of fragmentation reactions, which will be discussed in detail: (i) the loss of methanol in case of a methoxycarbonyl functionality at the 82-position, (ii) the loss of water and carbon monoxide, (iii) cleavages at the so-called meso-positions C5, C10 and C15, and (iv) decarboxylation reactions. All losses of neutral fragments could unambiguously be identified with the help of the high-resolution data of the remaining cation (see Supporting information, Fig. S3).


Structure elucidation of chlorophyll catabolites (phyllobilins) by ESI-mass spectrometry-Pseudo-molecular ions and fragmentation analysis of a nonfluorescent chlorophyll catabolite (NCC).

Müller T, Vergeiner S, Kräutler B - Int J Mass Spectrom (2014)

MS/MS experiments (CID) of the isolated deprotonated pseudo-molecular ion [M–H]− (m/z 643) of 1.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4375672&req=5

fig0020: MS/MS experiments (CID) of the isolated deprotonated pseudo-molecular ion [M–H]− (m/z 643) of 1.
Mentions: The fragmentation behavior of the isolated pseudo-molecular ions in the gas phase was studied in the positive (Fig. 3) as well as negative ion-mode (Fig. 4). Collision-induced dissociation (CID) MS/MS experiments were carried out on a Thermo-Finnigan LCQ quadrupole ion trap, applying normalized collision energy of 25% to the isolated ions. Dimeric ions showed complete dissociation of the dimer at normalized collision energies higher than 15%. For the determination of the elemental composition of parent as well as fragment ions high-resolution MS/MS was performed on a Bruker FT-ICR instrument. The [M + H]+, [M + Na]+ and [M + K]+ ions were selected as precursors and fragmented in the linear hexapole ion trap floated with argon. The collision energy was kept at the same level (20 V) for all three types of pseudo-molecular ions. Although it is possible that Na+ and K+ are also fragment ions, high resolution spectra were usually recorded in the mass range from m/z 200 to m/z 1500. As can be seen in Fig. 3, the number of fragment ions was decreasing depending on the charging cation (H+ > Na+ > K+), hence most structural information is provided by the MS/MS analysis of the [M + H]+ ion (see Fig. 3A–C). As a rule, a mass spectrum of a tetrapyrrolic NCC indicates four important types of fragmentation reactions, which will be discussed in detail: (i) the loss of methanol in case of a methoxycarbonyl functionality at the 82-position, (ii) the loss of water and carbon monoxide, (iii) cleavages at the so-called meso-positions C5, C10 and C15, and (iv) decarboxylation reactions. All losses of neutral fragments could unambiguously be identified with the help of the high-resolution data of the remaining cation (see Supporting information, Fig. S3).

Bottom Line: A recent application of this methodology concerned the investigation of the annually occurring degradation of green plant pigments.Since the first structural elucidation of a breakdown product in the early 1990s, a number of similarly structured, tetrapyrrolic catabolites have been discovered with the help of chromatographic, spectroscopic and spectrometric methods.Still, a thorough investigation of the common fragmentation behavior of these ubiquitous, naturally occurring chlorophyll breakdown products is lacking.

View Article: PubMed Central - PubMed

Affiliation: Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria.

ABSTRACT

The hyphenation of high performance chromatography with modern mass spectrometric techniques providing high-resolution data as well as structural information from MS/MS experiments has become a versatile tool for rapid natural product identification and characterization. A recent application of this methodology concerned the investigation of the annually occurring degradation of green plant pigments. Since the first structural elucidation of a breakdown product in the early 1990s, a number of similarly structured, tetrapyrrolic catabolites have been discovered with the help of chromatographic, spectroscopic and spectrometric methods. A prerequisite for a satisfactory, manually operated or database supported analysis of mass spectrometric fragmentation patterns is a deeper knowledge of the underlying gas phase chemistry. Still, a thorough investigation of the common fragmentation behavior of these ubiquitous, naturally occurring chlorophyll breakdown products is lacking. This study closes the gap and gives a comprehensive overview of collision-induced fragmentation reactions of a tetrapyrrolic nonfluorescent chlorophyll catabolite, which is intended to serve as a model compound for the substance class of phyllobilins.

No MeSH data available.


Related in: MedlinePlus