Just as it is not advisable to collect high resolution NMR data during (and shortly after) a liquid helium refill, it is similarly not advisable to collect data during a liquid nitrogen fill. The figure below illustrates this point. A 300 MHz NMR spectrometer was set up to collect an NMR spectrum every minute before, during and after a liquid nitrogen refill. The resolution deteriorates as soon as the one-way valves are removed from the nitrogen cryostat. One can see that the resolution during the fill is much worse than before the fill. Even 60 minutes after the fill, the magnet has not fully recovered the resolution attained before the fill. The last spectrum of the series was collected after re-shimming the magnet and is comparable to the spectrum collected before the fill. The resolution profile during a fill may be different for every magnet. For this particular magnet, it is advisable not to collect high resolution data for at least 90 minutes after a nitrogen refill.
[U. of Ottawa NMR Facility Blog] Resolution During a Liquid Helium Refill
Resolution During a Liquid Helium Refill
Students sometimes ask whether or not they can collect NMR data during a liquid helium refill. The answer depends on the type of NMR experiment. For most solids experiments, where high resolution (
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09-14-2011 09:34 PM
[U. of Ottawa NMR Facility Blog] Nitrogen Pressure and Spectral Resolution
Nitrogen Pressure and Spectral Resolution
Super-conducting NMR magnets are cooled with liquid helium. The boil off rate of the liquid helium is minimized by surrounding it with a high vacuum and a liquid nitrogen cryostat. The liquid nitrogen cryostat may either be vented directly to the atmosphere or it may be maintained at a pressure slightly above atmospheric pressure with the use of pressure relief valves. NMR users should be aware that the homogeneity of an NMR magnet is affected drastically by the pressure in the liquid nitrogen cryostat. The left-hand panel of the figure below shows...
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08-25-2011 06:00 AM
[NMR paper] High-resolution NMR studies of encapsulated proteins in liquid ethane.
High-resolution NMR studies of encapsulated proteins in liquid ethane.
High-resolution NMR studies of encapsulated proteins in liquid ethane.
J Am Chem Soc. 2005 Jul 27;127(29):10176-7
Authors: Peterson RW, Lefebvre BG, Wand AJ
Many of the difficulties presented by large, aggregation-prone, and membrane proteins to modern solution NMR spectroscopy can be alleviated by actively seeking to increase the effective rate of molecular reorientation. An emerging approach involves encapsulating the protein of interest within the protective shell of a...
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12-01-2010 06:56 PM
[NMR paper] Nitrogen-15 NMR studies of nitrogen metabolism in Picea glauca buds.
Nitrogen-15 NMR studies of nitrogen metabolism in Picea glauca buds.
Related Articles Nitrogen-15 NMR studies of nitrogen metabolism in Picea glauca buds.
Plant Physiol Biochem. 2004 Dec;42(10):803-9
Authors: Bagh K, Hiraoki T, Thorpe TA, Vogel HJ
In vivo (15)N nuclear magnetic resonance (NMR) as well as (15)N solid-state magic angle spinning (MAS) NMR spectroscopy were used to investigate nitrogen metabolism in cultured white spruce (Picea glauca) buds. Long-term as well as short-term experiments were carried out involving the use of...
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11-24-2010 10:03 PM
[NMR paper] High-resolution heteronuclear NMR of human ubiquitin in an aqueous liquid crystalline
High-resolution heteronuclear NMR of human ubiquitin in an aqueous liquid crystalline medium.
Related Articles High-resolution heteronuclear NMR of human ubiquitin in an aqueous liquid crystalline medium.
J Biomol NMR. 1997 Oct;10(3):289-92
Authors: Bax A, Tjandra N
A mixture of dihexanoyl phosphatidylcholine and dimyristoyl phosphatidylcholine in water forms disc-shaped particles, often referred to as bicelles . These adopt an ordered, liquid crystalline phase, which can be maintained at very low concentrations of the bicelles (down to 3%...
Resolution During a Liquid Nitrogen Refill
The resolution profile during a fill may be different for every magnet. For this particular magnet, it is advisable not to collect high resolution data for at least 90 minutes after a nitrogen refill.
Linear Mode
