TY  - JOUR
A1  - Prüfert, Chris
A1  - Urban, Raphael David
A1  - Fischer, Tillmann Georg
A1  - Villatoro, José Andrés
A1  - Riebe, Daniel
A1  - Beitz, Toralf
A1  - Belder, Detlev
A1  - Zeitler, Kirsten
A1  - Löhmannsröben, Hans-Gerd
T1  - In situ monitoring of photocatalyzed isomerization reactions on a microchip flow reactor by IR-MALDI ion mobility spectrometry
JF  - Analytical and bioanalytical chemistry : a merger of Fresenius' journal of analytical chemistry, Analusis and Quimica analitica
N2  - The visible-light photocatalyticE/Zisomerization of olefins can be mediated by a wide spectrum of triplet sensitizers (photocatalysts). However, the search for the most efficient photocatalysts through screenings in photo batch reactors is material and time consuming. Capillary and microchip flow reactors can accelerate this screening process. Combined with a fast analytical technique for isomer differentiation, these reactors can enable high-throughput analyses. Ion mobility (IM) spectrometry is a cost-effective technique that allows simple isomer separation and detection on the millisecond timescale. This work introduces a hyphenation method consisting of a microchip reactor and an infrared matrix-assisted laser desorption ionization (IR-MALDI) ion mobility spectrometer that has the potential for high-throughput analysis. The photocatalyzedE/Zisomerization of ethyl-3-(pyridine-3-yl)but-2-enoate (E-1) as a model substrate was chosen to demonstrate the capability of this device. Classic organic triplet sensitizers as well as Ru-, Ir-, and Cu-based complexes were tested as catalysts. The ionization efficiency of theZ-isomer is much higher at atmospheric pressure which is due to a higher proton affinity. In order to suppress proton transfer reactions by limiting the number of collisions, an IM spectrometer working at reduced pressure (max. 100 mbar) was employed. This design reduced charge transfer reactions and allowed the quantitative determination of the reaction yield in real time. Among 14 catalysts tested, four catalysts could be determined as efficient sensitizers for theE/Zisomerization of ethyl cinnamate derivativeE-1. Conversion rates of up to 80% were achieved in irradiation time sequences of 10 up to 180 s. With respect to current studies found in the literature, this reduces the acquisition times from several hours to only a few minutes per scan.
KW  - microchip
KW  - reaction monitoring
KW  - IR-MALDI
KW  - ion mobility spectrometry
KW  - photochemistry
KW  - photocatalysis
KW  - Olefin isomerization
Y1  - 2020
U6  - https://doi.org/10.1007/s00216-020-02923-y
SN  - 1618-2642
SN  - 1618-2650
VL  - 412
IS  - 28
SP  - 7899
EP  - 7911
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - INPR
A1  - Baret, Jean-Christophe
A1  - Belder, Detlev
A1  - Bier, Frank Fabian
A1  - Cao, Jialan
A1  - Gruschke, Oliver
A1  - Hardt, Steffen
A1  - Kirschbaum, Michael
A1  - Koehler, J. Michael
A1  - Schumacher, Soeren
A1  - Urban, G. A.
A1  - Viefhues, Martina
T1  - Contributors to the 10th Anniversary Germany issue
T2  - LAB on a chip : miniaturisation for chemistry and biology
Y1  - 2012
U6  - https://doi.org/10.1039/c1lc90139g
SN  - 1473-0197
VL  - 12
IS  - 3
SP  - 419
EP  - 421
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  -