Spatially resolved spectroscopy using tapered stripline NMR

- New method to produce arbitrary shape B1 profiles, including linear gradients.
- Full characterization by numerical and spatially resolved nutation mapping.
- Application to spatially resolved spectroscopy without switching gradients.
- Application to fast in-situ reaction monitoring.
- Application to compensate spectral resolution in inhomogeneous magnetic field.

Magnetic field B0 gradients are essential in modern Nuclear Magnetic Resonance spectroscopy and imaging. Although RF/B1 gradients can be used to fulfill a similar role, this is not used in common practice because of practical limitations in the design of B1 gradient coils. Here we present a new method to create B1 gradients using stripline RF coils. The conductor-width of a stripline NMR chip and the strength of its radiofrequency field are correlated, so a stripline chip can be tapered to produce any arbitrary shaped B1 field gradient. Here we show the characterization of this tapered stripline configuration and demonstrate three applications: magnetic resonance imaging on samples with nL-μL volumes, reaction monitoring of fast chemical reactions (10−2-101 s) and the compensation of B0 field gradients to obtain high-resolution spectra in inhomogeneous magnetic fields.

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