Transportable Mass Spectrometry and NMR instruments for in-situ chemical reaction monitoring and real time analysis

Abstract

An on-line reaction monitoring system consisting of transportable NMR and MS instruments
has been designed and validated for a number of chemical reactions, each reaction posing a
different set of analytical challenges. The designed configuration consists of two instruments,
a nominal mass single quadrupole electrospray mass spectrometer (QDa, Waters Corp.) and a
43 MHz permanent magnet NMR spectrometer (SpinSolve, Magritek) fitted with flow cell.
These two instruments were coupled together with a Mass Rate Attenuator providing the
dilution required to bridge the gap between the concentration used in the NMR and that
required for the mass spectrometer.
The utility of the system has been demonstrated for a number of chemical reactions, and the
capabilities of the system with regard to solvent systems and temperatures of the reaction
determined. The benefits of combining two orthogonal analytical techniques for reaction
monitoring is clearly demonstrated, with the low field NMR and nominal mass MS instruments
each shown to be able to compensate for the limitations of the other. Here, the NMR is
shown to detect the presence of, and degree of, ion suppression in the mass spectrometer
was demonstrated and validated against standard isotopic labelling based techniques, while
methods to overcome the presence of solvent signals in the NMR were trialled.
19F reaction monitoring on the Spinsolve was demonstrated for the first time, with the
sensitivity of the instrument for fluorine monitoring established and the results of the
monitoring validated against those achieved by mass spectrometry, producing kinetic data
which agreed within the margin of error.
A transportable ASAP MS device was trialled for the analysis of toxicological samples and was
shown to be capable of identifying compounds in seized drug samples, including mixed
samples, and of operating outside of a laboratory environment using ambient air.