Magnetic Field Reversal in the KU NMR lab!

What happened?

As some of you may know, there is a phenomena known as "Geomagnetic Reversal" in which a planet's magnetic field can reverse polarity, flipping the magnetic north and south poles.  Geologist tell us that on Earth these reversal are statistically random and that there have been 183 over the last 83 million years (on average once every ~450,000 years).

(See https://en.wikipedia.org/wiki/Geomagnetic_reversal for more information)

Image of the earth showing normal and reversed polarity of magnetic field
from Wiers, Steffen. (2020). The Arctic Ocean Palaeomagnetic Record - A Stratigraphic Approach.

What most people do not know is that superconducting magnets, including the ones we use for NMR, can also reverse.  This process is also statistically random.  Speaking with NMR lab staff at other universities, it seems like this phenomena occurs very, very, very rarely!  Hence, it is very alarming to report that this event has occurred at the University of Kansas on our 500 MHz NMR in ISB room B143 (aka "Siena", see - https://nmrlab.ku.edu/gray-little-hall-integrated-science-building).

The magnet remains stable and the magnitude of the field is holding at 11.7T.  Shimming remains excellent.  For the users, there is one negative effect.  The peaks all point in the negative direction.  Below is an example of a spectrum of the molecule 3-heptanone recorded last December (before the reversal) and recently (after the reversal).

Stack plot of 1D 1H NMR spectra of 3-heptanone prior to and after the magnetic reversal.

As you can see, the spectra are nearly identical, except the peaks now point down.

What can be done? 

Unfortunately, there is nothing that can be done at this stage, except hope the magnet flips back.  Spectra acquired on this instrument can still be published, however, you will have to add a disclaimer to your Materials and Methods section.  I recommend the boilerplate text below:

Due to a recent reversal in polarity of the magnet field of the superconducting magnet on the 500 MHz NMR spectrometer used in this research, all peaks point in the negative direction in spectra recorded on this instrument.  Integral values are also reported as negative numbers.

Regarding analysis, I understand it can be challenging to learn to look at spectra with peaks pointing in the negative direction.  I recommend turning your monitor 180 degrees or flipping you laptop upside down when you examine spectra (see picture below)

Justin Looking at His Laptop flipped upside down.

I know that this incident is frustrating, but I remain confident that we can still do excellent science using this instrument.  As always, the KU NMR lab staff remain ready to assist with any issues you may have with the instruments.

 

Justin Douglas

Director, KU NMR core lab

4/1/2022