Fig. 1: Time-resolved kinetic 2D NMR spectrotemporal correlations arising by combining flow-based spatiotemporal encoding and gradient-driven spectroscopic imaging decoding.
A Experimental setup for encoding off-equilibrium kinetics using rapid-mixing and continuous plug-like flow, incorporating a syringe-driven apparatus integrated with a gradient-equipped NMR flow probehead and high-field NMR magnet. B Idealized plot of the time-dependent concentrations evolving from a reaction mixture characterized by a zero-order rate law, in which the depletion and formation of the reactant and product are linear functions in time. As this reaction mixture flows through the NMR coil, the plug-like flow encodes each position along the +z direction with a unique, steady-state proportion of reactant and product, as schematically indicated by the size of the red and blue circles, respectively. C Each position in space is therefore encoded with a unique NMR spectrum that corresponds to a distinct and definite moment along the reaction process. D The echo-planar spectroscopic imaging (EPSI) pulse sequence is used to retrieve and decode the spatially-encoded kinetic information, by resolving NMR spectra as a function of position using an oscillating bipolar gradient-echo train. E, F Post-processing of the 1D EPSI time-domain dataset followed by Fourier transformation with respect to the imaging- and time-domain variables kz and t2, respectively, reveal the spatiotemporally-encoded kinetic NMR spectra.
