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FTIR

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aishuanju
aishuanju

This document discusses Fourier transform infrared spectroscopy (FTIR). It begins by defining a spectrometer and describing how FTIR obtains infrared spectra using an interferometer and Fourier transform. It then explains the basic components and working of an FTIR, including advantages like higher sensitivity, accuracy and resolution compared to dispersion spectrometers. Specific advantages like Fellgett's multiplex advantage and improved signal-to-noise are covered. Finally, common applications of FTIR are listed.

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Presented by: AISWARYA.A.T, I M.Pharm., Dept. of Pharmacy Practice, Grace college of pharmacy. FTIR
A spectrometer is an optical instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, 5 microns to 20 microns. FTIR (Fourier Transform Infra Red) spectrometer obtains an infrared spectra by first collecting an interferogram of a sample signal using an interferometer, then performs a Fourier Transform on the interferogram to obtain the spectrum. FTIR
An interferometer is an instrument that uses the technique of superimposing (interfering) two or more waves, to detect differences between them. The FTIR spectrometer uses
To separate IR light, a grating is used. Grating Light source Detector Sample Slit To select the specified IR light, A slit is used. Dispersion Spectrometer In order to measure an IR spectrum, the dispersion Spectrometer takes several minutes. Also the detector receives only a few % of the energy of original light source. Fixed CCM B.S. Moving CCM IR Light source Sample Detector An interferogram is first made by the interferometer using IR light. The interferogram is calculated and transformed into a spectrum using a Fourier Transform (FT). FTIR In order to measure an IR spectrum, FTIR takes only a few seconds. Moreover, the detector receives up to 50% of the energy of original light source (larger than D.S) Comparison B/W Dispersion Spectrometer & FTIR
COMPONENTS OF FTIR IR Radiation source Beam Splitter Fixed mirror Moving mirror Collimating mirrors Sample holder Helium Neon laser Detector
FTIR - WORKING Interferometer He-Ne gas laser Fixed mirror Movable mirror Sample chamber Light source (ceramic) Detector Beam splitter
Better sensitivity and brightness High wavenumber accuracy  Enhanced frequency Resolution  Wavenumber range flexibility  less time consuming  Datas can be stored & reanalysed FTIR – ADVANTAGES & DISADVANTAGES More expensive Require precision for mirror movement Detection of compound is influenced by watervapour, pathlength & chemical interference
Fellgett's (multiplex) Advantage FT-IR collects all resolution elements with a complete scan of the interferometer. Successive scans of the FT-IR instrument are coded and averaged to enhance the signal-to- noise of the spectrum. Theoretically, an infinitely long scan would average out all the noise in the baseline. The dispersive instrument collects data one wavelength at a time and collects only a single spectrum. There is no good method for increasing the signal-to-noise of the dispersive spectrum.
Jacquinot Advantage FT-IR uses a combination of circular apertures and interferometer travel to define resolution. To improve signal-to-noise, one simply collects more scans. More energy is available for the normal infrared scan and various accessories can be used to solve various sample handling problems. The dispersive instrument uses a rectangular slit to control resolution and cannot increase the signal-to-noise for high resolution scans. Accessory use is limited for a dispersive instrument.
Connes Advantage An FT-IR uses a He-Ne laser as an internal wavelength standard. The infrared wavelengths are calculated using the laser wavelength, itself a very precise and repeatable 'standard'. Wavelength assignment for the FT-IR spectrum is very repeatable and reproducible and data can be compared to digital libraries for identification purposes.
Opaque or cloudy samples High resolution experiments (as high as 0.001 cm-1 resolution) Trace analysis of raw materials or finished products Depth profiling and microscopic mapping of samples Kinetics reactions on the microsecond time-scale Analysis of chromatographic and thermogravimetric sample fractions APPLICATIONS
FTIR

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FTIR

  • 1. Presented by: AISWARYA.A.T, I M.Pharm., Dept. of Pharmacy Practice, Grace college of pharmacy. FTIR
  • 2. A spectrometer is an optical instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, 5 microns to 20 microns. FTIR (Fourier Transform Infra Red) spectrometer obtains an infrared spectra by first collecting an interferogram of a sample signal using an interferometer, then performs a Fourier Transform on the interferogram to obtain the spectrum. FTIR
  • 3. An interferometer is an instrument that uses the technique of superimposing (interfering) two or more waves, to detect differences between them. The FTIR spectrometer uses
  • 4. To separate IR light, a grating is used. Grating Light source Detector Sample Slit To select the specified IR light, A slit is used. Dispersion Spectrometer In order to measure an IR spectrum, the dispersion Spectrometer takes several minutes. Also the detector receives only a few % of the energy of original light source. Fixed CCM B.S. Moving CCM IR Light source Sample Detector An interferogram is first made by the interferometer using IR light. The interferogram is calculated and transformed into a spectrum using a Fourier Transform (FT). FTIR In order to measure an IR spectrum, FTIR takes only a few seconds. Moreover, the detector receives up to 50% of the energy of original light source (larger than D.S) Comparison B/W Dispersion Spectrometer & FTIR
  • 5. COMPONENTS OF FTIR IR Radiation source Beam Splitter Fixed mirror Moving mirror Collimating mirrors Sample holder Helium Neon laser Detector
  • 6. FTIR - WORKING Interferometer He-Ne gas laser Fixed mirror Movable mirror Sample chamber Light source (ceramic) Detector Beam splitter
  • 7. Better sensitivity and brightness High wavenumber accuracy  Enhanced frequency Resolution  Wavenumber range flexibility  less time consuming  Datas can be stored & reanalysed FTIR – ADVANTAGES & DISADVANTAGES More expensive Require precision for mirror movement Detection of compound is influenced by watervapour, pathlength & chemical interference
  • 8. Fellgett's (multiplex) Advantage FT-IR collects all resolution elements with a complete scan of the interferometer. Successive scans of the FT-IR instrument are coded and averaged to enhance the signal-to- noise of the spectrum. Theoretically, an infinitely long scan would average out all the noise in the baseline. The dispersive instrument collects data one wavelength at a time and collects only a single spectrum. There is no good method for increasing the signal-to-noise of the dispersive spectrum.
  • 9. Jacquinot Advantage FT-IR uses a combination of circular apertures and interferometer travel to define resolution. To improve signal-to-noise, one simply collects more scans. More energy is available for the normal infrared scan and various accessories can be used to solve various sample handling problems. The dispersive instrument uses a rectangular slit to control resolution and cannot increase the signal-to-noise for high resolution scans. Accessory use is limited for a dispersive instrument.
  • 10. Connes Advantage An FT-IR uses a He-Ne laser as an internal wavelength standard. The infrared wavelengths are calculated using the laser wavelength, itself a very precise and repeatable 'standard'. Wavelength assignment for the FT-IR spectrum is very repeatable and reproducible and data can be compared to digital libraries for identification purposes.
  • 11. Opaque or cloudy samples High resolution experiments (as high as 0.001 cm-1 resolution) Trace analysis of raw materials or finished products Depth profiling and microscopic mapping of samples Kinetics reactions on the microsecond time-scale Analysis of chromatographic and thermogravimetric sample fractions APPLICATIONS