Introduction -- The 60 MHz Proton nuclear
magnetic resonance (NMR) spectrometer consists of a Varian EM-360 permanent magnet and a recent upgrade of the electronics and software by Anaszi
Instruments. This instrument provides a way to introduce modern
FT-NMR spectrometry. The Acorn software called "Nuts"
permits advanced NMR data processing. The instrument provides
excellent low-field proton spectra of organic compounds. Relaxation
time measurements and two-dimensional COSY (COrrelated SpectroscopY)
experiments can also be performed. The instrument is located in
building 95 room W187, between two organic teaching laboratories.
There are several layers of software. First Windows95 over a DOS environment, second the Anasazi PNMR software to produce a FID, and third the Acorn program "Nuts" which transforms the FID and
allows the 1-D spectrum to be labeled and integrated. The commands
for each software level vary.
Continuous Wave (CW) versus Pulsed NMR Spectrometers -- There are two "classes" of NMR spectrometers, continuous
wave spectrometers and pulse spectrometers. Using a CW spectrometer,
the sample is placed in the magnetic field and subjected to a
slowly swept frequency. The CW NMR spectrum consists of frequency
peaks at which there is absorption of energy as well as the intensities
of these absorptions. Using a pulsed spectrometer, the sample
is placed in the magnetic field and is pulsed with high power
radio frequency (RF) waves sufficient to simultaneously excite
all nuclei in the sample. After the pulse, the nuclei, over time,
return to the ground state and radiate the absorbed energy. The
pulsed spectrometer collects this energy and produces the Free
Induction Decay (FID) signal which is the sum of all nuclei radiating over time. The FID does
not lend itself to direct interpretation. However, Fourier
transformation (FT) converts the time data of the FID
into frequency data which is interpreted just like the original
Background -- Developed in the 1960's, NMR is an invaluable
tool for organic and analytical chemists. It is used to identify
fairly pure unknown substances. The Anazasi EM360 NMR spectrometer
is a practical machine. Continuous wave NMR spectrometers have
the sample irradiated by a continuous radio frequency (RF) signal
while in a strong magnetic field. The spectrum is generated by
sweeping a small change in magnetic field over the sample.
Anasazi Instruments -- Model EFT converts existing permanent
magnet CW NMR instruments into FT NMR spectrometers. The EFT is
an easy to use WindowsTM based PC system that is available
for the many CW NMR instruments, e. g. the Varian EM300.
The FT NMR configurations available for the EFT upgrade are 1H
and is capable of covering the range 1H -19F
and 31P -29Si. Complete 1H spectra
can be obtained in less than ten minutes.
Model EFT -- It includes an operating console with fixed
frequency or synthesizer based RF system of heterodyne design
with all frequencies phase locked to a 1.0 MHz oscillator, a state
of the art PC computer, CRT, pulse programmer (100 nanosecond
time resolution), quadrature phase detection and a HP DeskjetTM printer. Standard NMR routines are available for 1D survey spectrum
with peak pick and integration, T1 measurements, COSY, Kinetics,
DEPT, and HETCOR. Other NMR routines are available via the programmable pulse programmer. The library of EFT experiments
is designed for users with little or no prior NMR operating experience. This is one tutorial for the Anasazi EFT-60.
Nuclear Magnetic Resonance (NMR) Spectrometer
Anasazi Spectrometer -- The Anasazi EFT-60 Spectrometer
uses the magnet from a Varian EM360 CW spectrometer and all new
electronics and software operating in a Windows environment to
obtain proton NMR spectra. Upon placing the sample in the magnetic
field, Anasazi's PNMR
software controls the data acquisition parameters and obtains
the FID. Acorn's NUTS software converts the FID into the frequency
spectrum. The NUTS software can be used to process data from a
wide variety of NMR spectrometers. A free, tutorial version of
NUTS is available on the web and free software.
The following describe various parts of
To Prepare a Sample for NMR,
Start Up Protocol,
Explanations of PNMR commands,
Windows 95 to run PNMR or Nuts, and
with Accorn's Nuts Software.