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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: 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.

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: 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.

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