Digital Spectrometers based on field programmable gate arrays will soon change the face of NMR spectroscopy as a routine use analytical instrument. Stan Sykora in his excellent blog (http://www.ebyte.it/stan/blog07.html#07jun14) describes how the transition of NMR spectrometers to digital electronics has drastically reduced the footprint and price of NMR spectrometers and increased the potential complexity of the RF synthesis as well as the NMR post processing on the same chip. In fact single chips can hold multiple spectrometers enabling the building of single spectrometers that can perform experiments on multiple magnet systems.

One of the best journal articles on the topic is by Kazuyuki Takeda “OPENCORE NMR: Open-source core modules for implementing an integrated FPGA-based NMR spectrometer”, Journal of Magnetic Resonance, 192(2), 218-229, 2008. This gentleman also included all the core modules, console software, pulse programs and board designs required to build your own spectrometer (see Opencore Website). The availability of superconducting NMR magnets are still the barrier to entry for cheaper high field NMR systems but in the lower field NMR area these spectrometers will enable a drastic reduction in instrumentation cost and perhaps lead to a larger NMR market. In the near future I feel that NMR systems in the 200/300 MHz range will be quite affordable especially if the consoles are married to older magnets that are currently gathering dust in rear storage areas.

The appearance of Bruker’s Fourier 300 NMR spectrometer bears witness to the market that is there for a company that can deliver a well priced NMR instrument in combination with strong application software. In fact I think that these cheaper spectrometers will facilitate the development of a market where NMR instrumentation will be sold to address individual analytical problems in routine testing laboratories. Perhaps NMR standard methods will become as prevalent as GC and MS methods currently are. Imagine an NMR spectrometer sold to a laboratory not as a general research tool but as a dedicated instrument performing authentification testing on olive oils sold in the EU. This is a new concept for NMR chemists to wrap their heads around….smaller, cheaper NMR instruments driven by applications rather than magnetic field strength.

A two FPGA spectrometer design is illustrated in the two figures.

Presented here are several simple reactions monitored by 60 MHz process NMR performed in a 5 mm NMR tube.

Reaction #1: Acetic Anhydride in Water – Reacts to form Acetic Acid

NMR Monitored Reaction Profile

Reaction #2: Acetic Anhydride + Excess of Methanol + Acid – Yields Acetic Acid and Acetic Methyl Ester

First Reaction was Performed without Shaking the Sample before Observation

NMR Monitored Reaction Profile

Second Reaction was Performed with a vigorous shake of the NMR tube before observation.

NMR Monitored Reaction Profile

For More Information Contact John Edwards

These are non-spinning spectra obtained on a Qualion process NMR spectrometer operating at 58 MHz. The spec on water at this shim level is 1.5/5/20 Hz at 50%/10%/0.5% peak height. The first spectrum is of 91% isopropyl alcohol in water – store bought pharmacy product. The second spectrum shows the comparison of a 300 MHz 1H NMR spectrum of Advil compared to a non-spinning 58 MHz spectrum.

Presented on June 18, 2009
Philadelphia, PA

“Spectroscopy Based Crude Assays for Laboratory, At-Line, and On-Line Applications”

This Presentation can be found at the Crude Oil Quality Group Website (http://www.coqa-inc.org/061809Giammatteo.pdf)