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Chromatography 2016
September 21-23, 2016
Volume 7, Issue 5(Suppl) J Chromatogr Sep Tech 2016
ISSN: 2157-7064 JCGST, an open access journal
conferenceseries .com
September 21-23, 2016 Amsterdam, Netherlands
World Congress on Chromatography
Chromatography in the NMR tube
Michael John, Thomas Niklas, Jannis Gottwald and Dietmar Stalke
Institute of Anorganische Chemie, Germany
Recent developments in nuclecar magnetic resonance (NMR) equipment permit the spatially resolved observation of NMR
signals on routine instruments that are part of virtually every chemistry laboratory. Specifically, a series of thin (~ 1 mm)
horizontal slices may be excited and recorded of the sample instead of the ~20 mm bulk volume within the rf coil. Through
referencing with solutions of known concentrations, local concentrations can be determined. We have recently applied slice-
selective NMR spectroscopy to a range of chemical problems: A first example was the monitoring of the anisotropic swelling
of cross-linked polymers in organic solvents and determination of the homogeneity of anisotropy across the polymer. Further
applications were a "single-shot" NMR titration, where the signal of the first component was resolved over a concentration
gradient of the "titrated" component, and a reaction monitoring, where two reagents diffuse towards each other in the
sample tube. Here, we present another application: “chromatography in the NMR tube” (a glass tube with Ø = 5 mm): Two
compounds that may differ in molecular size or polarity diffuse downwards through a polymeric matrix (which may be cross-
linked polystyrene or even silicone grease) at their individual rates and appear in the slices at the bottom with individual
concentrations. Although no complete separation of the compounds is achieved, signal assignment is facilitated, and diffusion
coefficients may be calculated as an alternative to the DOSY method.
Biography
Michael John completed his PhD with Horst Kessler at the Technical University of Munich in 2004, and then spent 2 years with Gottfried Otting at the Australian
National University, Canberra. Since 2007, he is Lecturer and Director of the NMR facility at the University of Göttingen. His list of publications includes more than
60 papers in peer-reviewed journals and 25 conference contributions.
Michael John et al., J Chromatogr Sep Tech 2016, 7:5(Suppl)