Study Set Content:
is directed along both a sample and a reference path and then into the monochromator
The source energy
disperses the light, as water vapor does to make the visible rainbow.
The diffraction grating
Fourier Transform Instruments (FTIR)
•
Use an
interferometer.
It generates a radiation source in which individual wavenumbers can be monitored within a ca 1s pulse of radiation without dispersion being required.
Interferometer
has three major advantages over a typical dispersive infrared spectrometer.
The modern FT-IR spectrometer
These advantages are the reason FT-IR is now the standard tool, having largely displaced dispersive instruments by the
mid-1980’s
does not limit the amount of light reaching the detector using a slit.
FT-IR instrument
Overall, these mean more energy reaches the sample and hence the detector in an FT-IR spectrometer than in a
dispersive spectrometer.
The higher signal leads to an improved signal-to-noise ratio of the FT-IR. ____ls in a sample spectrum will be clearer and more distinguishable.
Higher signal-to-noise
measures the interaction of infrared light with a sample, providing information about the molecular composition
IR spectroscopy
while FTIR spectroscopy rapidly analyzes the entire spectrum () using the
simultaneously Fourier Transform method
Both utilize the
mid-infrared region (4000 to 400 cm-1).
improved speed, sensitivity, and versatility compared to IR spectroscopy, making it widely used in chemistry, materials science, pharmaceuticals, and forensic analysis.
FTIR offers
(also known as NIR spectrometer) is an analytical instrument used to examine pharmaceutical, chemical or medical materials in bulk, with very little sample preparation.
Near infrared spectrometer
Near infrared spectrometers offer spectral wavelength ranges around
12,500 to 4000 cm-1 or more.
NIR spectrometers use high precision diode array detectors and silicon or lead-sulfide CCDs, which are generally
more sensitive.
a non-destructive analytical technique used to identify the molecular composition of a sample by measuring the absorption or reflection of light at different wavelengths (covers approximately 750 – 2,500 nm in wavelength range) in the near-infrared region.
Near Infrared Spectroscopy (NIR)
focuses on mid-infrared wavelengths and detects fundamental vibrations of chemical bonds
IR spectroscopy
covers near-infrared wavelengths, detecting overtones and combinations of vibrations.
NIR spectroscopy
Difference between NIR and FTIR:
The main contrast between NIR and FTIR lies in the____ they utilize for analysis.
spectral range
