Temporally and spectrally resolved UV absorption and laser-induced fluorescence measurements during the pyrolysis of toluene behind reflected shock waves

Zabeti, S.; Drakon, A. V.; Faust, S.; Dreier, Thomas; Welz, Oliver; Fikri, Mustapha; Schulz, Christof

doi:10.1007/s00340-014-5986-8

Cited by 13 publications

(2 citation statements)

References 40 publications

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“…In addition, the UV fluorescence intensity excited at 263 nm (UV263) slightly increased when toluene was applied. However, it has been reported that toluene (Zabeti et al 2015) and a-pinene (Lee et al 2013) exhibit fluorescence emission in UV and visible, respectively, so the observed increases may be due to the fluorescence emission from the VOCs themselves and not totally necessarily representative of a reaction with the E. coli particles. The time-dependent change of fluorescence spectra and integrated band intensities where two variables were applied in combination are shown in Figure 4.…”

Section: Changes In Fluorescence Intensity and Profilementioning

confidence: 98%

Changes of fluorescence spectra and viability from aging aerosolized E. coli cells under various laboratory-controlled conditions in an advanced rotating drum

Kinahan

Tezak

Lucero

et al. 2019

Aerosol Science and Technology

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An advanced rotating aerosol chamber was developed to study the changes of fluorescence spectral profile and intensity, the viability and the quantitative polymerase chain reaction (qPCR) signal of Escherichia coli aerosol particles as they are exposed to simulated atmospheric conditions over time. These conditions included relative humidity (RH) below 30% or $75%, ozone $100 ppb, volatile organic compounds (VOCs) a-pinene ($5 ppb) or toluene ($45 ppb), and simulated solar (SS) irradiation. Individual experiments examined the effects of these conditions applied individually and in combination. Experimental results demonstrate that the 263 nm laser excited UV fluorescence band (280-400 nm) showed the greatest rate of decrease, and the visible band (400-580 nm) generally had a smaller change rate which followed the change in the UV band. The 351 nm excited visible band (380-650 nm) had the smallest decay rates, and sometimes increased, when exposed to ozone, high RH, and VOCs. Generally, the viability, qPCR signal intensity, and the fluorescence intensity decayed faster when more variables were applied in combination. Simulated solar irradiation was the most dominant factor in the aging process, followed by the combination of high RH and ozone. Interestingly, the decay of fluorescence and qPCR signal do not appear to correlate directly with loss in viability. Therefore, additional studies are expected to further understand the mechanisms by which atmospheric chemical processes impact viability, qPCR signal intensity, and the fluorescence of biological aerosols.

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Section: Changes In Fluorescence Intensity and Profilementioning

confidence: 98%

Changes of fluorescence spectra and viability from aging aerosolized E. coli cells under various laboratory-controlled conditions in an advanced rotating drum

Kinahan

Tezak

Lucero

et al. 2019

Aerosol Science and Technology

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show abstract

“…In such cases, a method that is capable of simultaneously recording absorption time profiles over a wide spectral region is desirable. Several studies employed broadband absorption techniques, utilizing an incoherent light source and a spectrograph equipped with a frame transfer charge coupled device (CCD) chip, to achieve temporally and spectrally resolved absorption measurements behind shock waves. − However, the method has been limited to single-pass detection and only a few chemical kinetics applications have been reported.…”

Section: Introductionmentioning

confidence: 99%

Time-Resolved Broadband Cavity-Enhanced Absorption Spectroscopy behind Shock Waves

et al. 2016

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A fast and sensitive broadband absorption technique for measurements of high-temperature chemical kinetics and spectroscopy has been developed by applying broadband cavity-enhanced absorption spectroscopy (BBCEAS) in a shock tube. The developed method has effective absorption path lengths of 60-200 cm, or cavity enhancement factors of 12-40, over a wavelength range of 280-420 nm, and is capable of simultaneously recording absorption time profiles over an ∼32 nm spectral bandpass in a single experiment with temporal and spectral resolutions of 5 μs and 2 nm, respectively. The accuracy of the kinetic and spectroscopic measurements was examined by investigating high-temperature reactions and absorption spectra of formaldehyde behind reflected shock waves using 1,3,5-trioxane as a precursor. The rate constants obtained for the thermal decomposition reactions of 1,3,5-trioxane (to three formaldehyde molecules) and formaldehyde (to HCO + H) agreed well with the literature data. High-temperature absorption cross sections of formaldehyde between 280 and 410 nm have been determined at the post-reflected-shock temperatures of 955, 1265, and 1708 K. The results demonstrate the applicability of the BBCEAS technique to time- and wavelength-resolved sensitive absorption measurements at high temperatures.

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Understanding Phenomena by Building Models: Methodological Studies on Physical Chemistry

Carrier

Kohse‐Höinghaus

2017

Progress in Science, Progress in Society

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Temporally and spectrally resolved UV absorption and laser-induced fluorescence measurements during the pyrolysis of toluene behind reflected shock waves

Cited by 13 publications

References 40 publications

Changes of fluorescence spectra and viability from aging aerosolized E. coli cells under various laboratory-controlled conditions in an advanced rotating drum

Changes of fluorescence spectra and viability from aging aerosolized E. coli cells under various laboratory-controlled conditions in an advanced rotating drum

Time-Resolved Broadband Cavity-Enhanced Absorption Spectroscopy behind Shock Waves

Understanding Phenomena by Building Models: Methodological Studies on Physical Chemistry

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