title: Fast screening of analytes for chemical reactions by reactive low-temperature plasma ionization mass spectrometry.
abstract: BACKGROUND
  Approaches for analyte screening have been used to aid in the fine-tuning of chemical reactions. Herein, we present a simple and straightforward analyte screening method for chemical reactions via reactive low-temperature plasma ionization mass spectrometry (reactive LTP-MS).
  
  
  METHODS
  Solution-phase reagents deposited on sample substrates were desorbed into the vapor phase by action of the LTP and by thermal desorption. Treated with LTP, both reagents reacted through a vapor phase ion/molecule reaction to generate the product. Finally, protonated reagents and products were identified by LTP-MS.
  
  
  RESULTS
  Reaction products from imine formation reaction, Eschweiler-Clarke methylation and the Eberlin reaction were detected via reactive LTP-MS. Products from the imine formation reaction with reagents substituted with different functional groups (26 out of 28 trials) were successfully screened in a time of 30 s each. Besides, two short-lived reactive intermediates of Eschweiler-Clarke methylation were also detected.
  
  
  CONCLUSIONS
  LTP in this study serves both as an ambient ionization source for analyte identification (including reagents, intermediates and products) and as a means to produce reagent ions to assist gas-phase ion/molecule reactions. The present reactive LTP-MS method enables fast screening for several analytes from several chemical reactions, which possesses good reagent compatibility and the potential to perform high-throughput analyte screening. In addition, with the detection of various reactive intermediates (intermediates I and II of Eschweiler-Clarke methylation), the present method would also contribute to revealing and elucidating reaction mechanisms.
authors.affiliation: Department of Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China (USTC), Hefei, 230026, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China (USTC), Hefei, 230026, P.R. China.
authors.forename: Guangming
authors.identifier: http://orcid.org/0000-0002-8391-4013
authors.initials: G
authors.lastname: Huang