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Real‐Time Reaction Monitoring of an Organic Multistep Reaction by Electrospray Ionization‐Ion Mobility Spectrometry
Author(s) -
Zühlke Martin,
Sass Stephan,
Riebe Daniel,
Beitz Toralf,
Löhmannsröben HansGerd
Publication year - 2017
Publication title -
chempluschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.201700296
Subject(s) - electrospray ionization , chemistry , mass spectrometry , ion mobility spectrometry , selected reaction monitoring , electrospray , chromatography , analytical chemistry (journal) , ionization , chemical ionization , ion , detection limit , tandem mass spectrometry , organic chemistry
The capability of electrospray ionization (ESI)‐ion mobility (IM) spectrometry for reaction monitoring is assessed both as a stand‐alone real‐time technique and in combination with HPLC. A three‐step chemical reaction, consisting of a Williamson ether synthesis followed by a hydrogenation and an N ‐alkylation step, is chosen for demonstration. Intermediates and products are determined with a drift time to mass‐per‐charge correlation. Addition of an HPLC column to the setup increases the separation power and allows the determination of further species. Monitoring of the intensities of the various species over the reaction time allows the detection of the end of reaction, determination of the rate‐limiting step, observation of the system response in discontinuous processes, and optimization of the mass ratios of the starting materials. However, charge competition in ESI influences the quantitative detection of substances in the reaction mixture. Therefore, two different methods are investigated, which allow the quantification and investigation of reaction kinetics. The first method is based on the pre‐separation of the compounds on an HPLC column and their subsequent individual detection in the ESI‐IM spectrometer. The second method involves an extended calibration procedure, which considers charge competition effects and facilitates nearly real‐time quantification.