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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

ESI mass spectrum in the negative ion-mode of the NCC 1, and proposed chemical structure of the [M–H]−-ion of 1. The signal at m/z 643 corresponds to deprotonated molecular ion [M–H]−; signals at m/z 611, 520 and 488 correspond to in-source fragments (NCC 1 was dissolved in 4 mM methanolic NH4OAc). Dashed lines signify formal fragmentation modes.
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fig0010: ESI mass spectrum in the negative ion-mode of the NCC 1, and proposed chemical structure of the [M–H]−-ion of 1. The signal at m/z 643 corresponds to deprotonated molecular ion [M–H]−; signals at m/z 611, 520 and 488 correspond to in-source fragments (NCC 1 was dissolved in 4 mM methanolic NH4OAc). Dashed lines signify formal fragmentation modes.

Mentions: A free propionic acid group is a common feature of most naturally occurring Chl-catabolites and thus predestines NCCs to be also detectable in the negative ion mode (Fig. 2). The base peak of the spectrum was the deprotonated molecular ion [M–H]− at m/z 643. As already shown for the positive ion-mode, the formation of dimers ([2M–H]− at m/z 1287 and ([2M–2H + Na]− at m/z 1309) as well as in-source fragmentation of the [M–H]− were observed in the negative ion-mode too. The three in-source fragment ions (m/z 613, m/z 522, m/z 490 in the positive mode and m/z 611, m/z 520, m/z 488 in the negative mode) are due to loss of MeOH (−32), of ring D (−123), or of both (−155). This type of heterolytic fragmentation pattern is generally observed when Chl-degradation products are analyzed by ‘soft’ ionization MS methods, and thus is considered to be highly diagnostic (see also Sections 3.1 and 3.3). In the negative ion-mode the formation of dianions was not observed for NCC 1.


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)

ESI mass spectrum in the negative ion-mode of the NCC 1, and proposed chemical structure of the [M–H]−-ion of 1. The signal at m/z 643 corresponds to deprotonated molecular ion [M–H]−; signals at m/z 611, 520 and 488 correspond to in-source fragments (NCC 1 was dissolved in 4 mM methanolic NH4OAc). Dashed lines signify formal fragmentation modes.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

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

fig0010: ESI mass spectrum in the negative ion-mode of the NCC 1, and proposed chemical structure of the [M–H]−-ion of 1. The signal at m/z 643 corresponds to deprotonated molecular ion [M–H]−; signals at m/z 611, 520 and 488 correspond to in-source fragments (NCC 1 was dissolved in 4 mM methanolic NH4OAc). Dashed lines signify formal fragmentation modes.
Mentions: A free propionic acid group is a common feature of most naturally occurring Chl-catabolites and thus predestines NCCs to be also detectable in the negative ion mode (Fig. 2). The base peak of the spectrum was the deprotonated molecular ion [M–H]− at m/z 643. As already shown for the positive ion-mode, the formation of dimers ([2M–H]− at m/z 1287 and ([2M–2H + Na]− at m/z 1309) as well as in-source fragmentation of the [M–H]− were observed in the negative ion-mode too. The three in-source fragment ions (m/z 613, m/z 522, m/z 490 in the positive mode and m/z 611, m/z 520, m/z 488 in the negative mode) are due to loss of MeOH (−32), of ring D (−123), or of both (−155). This type of heterolytic fragmentation pattern is generally observed when Chl-degradation products are analyzed by ‘soft’ ionization MS methods, and thus is considered to be highly diagnostic (see also Sections 3.1 and 3.3). In the negative ion-mode the formation of dianions was not observed for NCC 1.

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