FT-NMR uses Fourier transforms to convert time domain signals from nuclear magnetic resonance into frequency domain spectra. The sample is placed in a strong magnet and exposed to pulses of radio frequency radiation, producing a free induction decay signal that is recorded over time. This time domain signal is then digitized and analyzed using a Fourier transform program on a computer to produce the frequency domain NMR spectrum. FT-NMR provides higher sensitivity than continuous wave NMR, allowing analysis of smaller sample sizes.

1. PRESENTED BY,
Anjali.c
I year m.pharm
Dept. Of pharmacy practice
Grace college of pharmacy

2.  It is the mathematical operation in which the
complex waveform can be broken-down into
simple mathematical operations.
 It is the mathematical operation required to
convert a time domain spectrum to frequency
domain spectrum (or vice versa).

3.  FTNMR or pulse NMR, the sample is irradiated
periodically with brief, highly intense pulses of
radio- frequency radiation, following which the
free induction decay signal - a characteristic radio-
frequency emission signal stimulated by the
irradiation – is recorded as a function of time.
 The frequency- domain spectrum can be obtained
by a Fourier transform employing a digital
computer

6.  The central component of the instrument is a highly
stable magnet in which the sample is placed.
 The sample is surrounded by the transmitter/receiver
coil.
 A crystal controlled frequency synthesizer having an
output frequency of Vc - produces radio-frequency
radiation.
 This signal passes into a pulse switch and power
amplifier, which creates an - intense and reproducible
pulse of RF current in the transmitter coil.
 Resulting signal is picked up by the same coil which
now serves a as - receiver.

7.  The signal is then amplified and transmitted to a
phase sensitive detector.
 The detector circuitry produced the difference
between the nuclear signals Vn and the crystal
oscillator output Vc which leads to the low
frequency time-domain signal .
 This signal is digitalized and collected in the
memory of the computer for analysis by a Fourier
transform program and other data analysis
software.
 The output from this program is plotted giving a
frequency domain spectrum.

8.  FT-NMR is more sensitive and can measure weaker
signals.
 The pulsed FT-NMR is much faster (seconds instead of
min) as compared to continuous wave NMR.
 FT-NMR can be obtained with less than 0.5 mg of
compound. This is important in the biological chemistry,
where only μg quantities of the material may be
available.
 The FT method also gives improved spectra for sparingly
soluble compounds.
 Pulsed FT-NMR is therefore especially suitable for the
examination of nuclei that are magnetic or very dilute
samples.