Analytical Instrument Documents

NMR Probe for Fluorine NMR. What is needed is a Robust Routine HFX NMR Probe that can do every routine experiment well! Including all HFX experiments, 1H{19F}, 19F{1H}, 13C{1H,19F} & X{1H,19F}.

The JEOL ROYAL HFX NMR probe is the world’s first liquid NMR probe switchable between single tune and dual tune mode on the High Frequency coil without compromising the NMR performance. The ROYAL HFX probe operating in single tune mode has the same sensitivity and pulse width performance as the standard ROYAL NMR probe.

Fluorine is found with an ever-increasing frequency in materials science and both legal and illicit drugs [ref 1-5]. In this application note results are presented to illustrate the simplification afforded by the routine application of triple-resonance NMR to clearly assign voriconazole, a molecule containing proton, carbon, and nitrogen molecules with many atoms exhibiting J-coupling to fluorine. The HFX ROYAL probe is a completely new probe technology utilizing magnetic coupling to afford highly efficient HF-X tuning which can function as a simple switch to highest sensitivity dedicated 1H or 19F or very well balanced dual 1H/19F performance on demand. References 6-8 detail the technological developments for the HFX ROYAL probe.

Datasheet / nail polish (neat) before and after

Datasheet / 1D and 2D cis-3-hexenylcinnamate data

Before Gradient Shimming; After 2 iterations automatic 1H gradient shimming - no deuterated solvent - no manual retouching of shims.

Before Gradient Shimming; After 2 iterations automatic 2H gradient shimming - no manual retouching of shims

Data obtained from two-dimensional NMR experiments is incredibly useful for structure elucidation of complex molecules, especially when their one-dimensional spectra feature overlapping peaks. However, some experiments require significant amounts of time in order to yield data with adequate resolution or signal to noise for unambiguous interpretation. Any means of reducing the total acquisition time is useful. In this Note, we’ll explore a technique known as Non Uniform Sampling (NUS), demonstrate how it can be used to speed up data collection, and highlight how it can be employed in Delta™ on JEOL Spectrometers.

A very powerful and useful general NMR technique is to use selective excitation to focus directly on a resonance frequency or region to allow acquisition of very specific information to efficiently answer a specific question. Many experiments have been developed that are in essence 1-dimensional analogues of 2-dimensional experiments. In particular NOESY-1D1 and TOCSY-1D have gained wide spread use and acceptance in the NMR community. The NOESY-1D and TOCSY-1D experiments can provide specific answers to questions in a fraction of the time needed for a full 2D result even with NUS techniques. In this Applications Note, we will explore the StepNoesy1D2 experiment, which can yield information typically obtained by performing time consuming 3D experiments.

Looking back, NMR spectroscopy has been in use as a research tool and under constant development for almost 80 years. Some principles of magnetic resonance were initially described by Isidor Isaac Rabi of Columbia University in 1938. With further fundamental research being done in the late 1930s and early ’40s, the official birth of the technique is generally accepted to have been in 1946 and is attributed to Edward M. Purcell and Felix Bloch. Both were honored with the Nobel Prize for Physics in 1952 for the discovery of NMR spectroscopy. Dr. Ray Freeman, one of the pioneers of NMR applications technology, has created a resource for further reading on the history of both the science and development of NMR technology.