In situ Raman microspectroscopic identification and localization of carotenoids: Approach to monitoring of UV-B irradiation stress on antarctic fungus

Arcangeli, Caterina; Cannistraro, Salvatore

doi:10.1002/(sici)1097-0282(2000)57:3<179::aid-bip6>3.0.co;2-4

Cited by 34 publications

(16 citation statements)

References 27 publications

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“…From these large organic molecules, alkenes are formed. [8][9][10][11][12][13][14][15][16] These intermediates do not only split-off the desired olefinic compounds, but can also react further, forming polyaromatic molecules and, eventually, graphitic coke. [17,18] It has been shown that even methylated naphtalenes, which contain two aromatic rings, give low alkene formation rates compared to methylated benzenes, and are therefore minor contributors to product formation.…”

Section: Introductionmentioning

confidence: 99%

“…With the further addition of methanol, more water, as well as catalytic scaffolds, mainly composed of polymethyl‐substituted benzene molecules, are formed. From these large organic molecules, alkenes are formed 8–16. These intermediates do not only split‐off the desired olefinic compounds, but can also react further, forming polyaromatic molecules and, eventually, graphitic coke 17.…”

Section: Introductionmentioning

confidence: 99%

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Space‐ and Time‐Resolved In‐situ Spectroscopy on the Coke Formation in Molecular Sieves: Methanol‐to‐Olefin Conversion over H‐ZSM‐5 and H‐SAPO‐34

Stavitski

Kox

et al. 2008

Chemistry A European J

314

312

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Formation of coke in large H-ZSM-5 and H-SAPO-34 crystals during the methanol-to-olefin (MTO) reaction has been studied in a space- and time-resolved manner. This has been made possible by applying a high-temperature in-situ cell in combination with micro-spectroscopic techniques. The buildup of optically active carbonaceous species allows detection with UV/Vis microscopy, while a confocal fluorescence microscope in an upright configuration visualises the formation of coke molecules and their precursors inside the catalyst grains. In H-ZSM-5, coke is initially formed at the triangular crystal edges, in which straight channel openings reach directly the external crystal surface. At reaction temperatures ranging from 530 to 745 K, two absorption bands at around 415 and 550 nm were detected due to coke or its precursors. Confocal fluorescence microscopy reveals fluorescent carbonaceous species that initially form in the near-surface area and gradually diffuse inwards the crystal in which internal intergrowth boundaries hinder a facile penetration for the more bulky aromatic compounds. In the case of H-SAPO-34 crystals, an absorption band at around 400 nm arises during the reaction. This band grows in intensity with time and then decreases if the reaction is carried out between 530 and 575 K, whereas at higher temperatures its intensity remains steady with time on stream. Formation of the fluorescent species during the course of the reaction is limited to the near-surface region of the H-SAPO-34 crystals, thereby creating diffusion limitations for the coke front moving towards the middle of the crystal during the MTO reaction. The two applied micro-spectroscopic techniques introduced allow us to distinguish between graphite-like coke deposited on the external crystal surface and aromatic species formed inside the zeolite channels. The use of the methods can be extended to a wide variety of catalytic reactions and materials in which carbonaceous deposits are formed.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Space‐ and Time‐Resolved In‐situ Spectroscopy on the Coke Formation in Molecular Sieves: Methanol‐to‐Olefin Conversion over H‐ZSM‐5 and H‐SAPO‐34

Stavitski

Kox

et al. 2008

Chemistry A European J

314

312

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“…mucilaginosa is due to the different environments in which the spectra are recorded. 5 It is possible to obtain spectra from the microorganisms with fiber tips due to the considerably reduced laser power.…”

Section: Resultsmentioning

confidence: 99%

Raman spectroscopy investigation of biological materials by use of etched and silver coated glass fiber tips

Gessner¹,

Rösch²,

Kiefer³

et al. 2002

Biopolymers

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The results for surface enhanced Raman scattering (SERS) studies on biological samples are reported. Etched and silver coated glass fiber tips were used as a SERS substrate. This method enabled the recording of spectra of biological samples, such as plant tissue or microbiological cells, with a high spatial resolution. Because of the low laser power used with the fiber tips, it was even possible to investigate tissues that are very sensitive toward laser power as it is used in a common micro-Raman setup.

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“…Protection is achieved either by storing higher quantities of UV protective pigments or growing beneath soil surface particles, where shading reduces radiation flux. Pigmentation is universally recognized as an adaptive response to high solar radiation and many sun-screening pigments have been reported for fungi and lichens, as carotenoids and mycosporines (Young and Patterson, 1982;Arcangeli et al, 1997;Büdel et al, 1997;Arcangeli and Cannistraro, 2000;Torres et al, 2004). An adequate protection is often achieved by a combination of different pigments; they dissipate excessive energy from increased UV-B radiation and avoid the generation of toxic single oxygen (Wynn-Williams and Edwards, 2001).…”

Section: Adaptations Of Antarctic Nonlichenized Fungimentioning

confidence: 99%

Fungal Associations at the Cold Edge of Life

Onofri

Zucconi

Selbmann

et al. 2007

Cellular Origin, Life in Extreme Habitats and Astrobiology

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In situ Raman microspectroscopic identification and localization of carotenoids: Approach to monitoring of UV-B irradiation stress on antarctic fungus

Cited by 34 publications

References 27 publications

Space‐ and Time‐Resolved In‐situ Spectroscopy on the Coke Formation in Molecular Sieves: Methanol‐to‐Olefin Conversion over H‐ZSM‐5 and H‐SAPO‐34

Space‐ and Time‐Resolved In‐situ Spectroscopy on the Coke Formation in Molecular Sieves: Methanol‐to‐Olefin Conversion over H‐ZSM‐5 and H‐SAPO‐34

Raman spectroscopy investigation of biological materials by use of etched and silver coated glass fiber tips

Fungal Associations at the Cold Edge of Life

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