Low-E probe for 19F–1H NMR of dilute biological solids

Resonator with reduced sample heating and increased homogeneity for solid-state NMR

“…Because of the aforementioned short electrical length of the cylinder, additional tuning capacitors across the gap would be necessary to tune the eigenresonance of the loop-gap cylinder to the proton frequency (see, e.g., [18,19]). A similar system of two overcoupled resonators where a tuned microcoil circuit was placed inside an outer solenoid was successfully applied by Sakellariou et al [29] with the goal of increasing sample filling factors (hence sensitivity) for small-volume (nanoliter) samples and achieving high rf magnetic field amplitudes.…”

“…Some alternative ''single-coil'' [12][13][14]17] or ''cross-coil'' [15,16,18,19] geometries have been proposed that exhibit reduced rf electric fields inside the sample volume. Here single-coil geometry means that the coil exhibits, as for a straightforward solenoidal coil, just two coil ports and that it is compatible with the probe rf circuitry used for solenoidal coils.…”

Experimental and numerical examination of eddy (Foucault) currents in rotating micro-coils: Generation of heat and its impact on sample temperature

“…Under the initial MACS set-up significantly greater heating of the sample, than due to friction, was observed [26]. Much attention -notably pertaining to NMR of biological molecules in high ionic-strength solutionshas recently been given to the issue of radio-frequency induced sample heating [31][32][33]. Although, the heating observed for MACS arises through a very different mechanism, the magnitude of the heating is at least as large, and thus will present a similar barrier to implementation for such samples.…”

Solid-state NMR sequential assignments of the N-terminal domain of HpDnaB helicase

“…Solid-state NMR spectra were acquired at 18.8 and 20.0 T static magnetic field strengths using 3.2 mm Bruker Biospin ''E-free'' probes (Gor'kov et al 2007). The MAS spinning frequency was set to 17.5 and 17.0 kHz for the two fields, respectively.…”