Infrared Spectroscopy - Revision history

Dnanji: Dnanji moved page Fourier-Transform Infrared Spectrometer (FTIR) to Infrared Spectroscopy

2022-11-09T16:55:33Z

Dnanji moved page Fourier-Transform Infrared Spectrometer (FTIR) to Infrared Spectroscopy

← Older revision		Revision as of 12:55, 9 November 2022
(No difference)

Rzhou95 at 02:58, 6 October 2021

2021-10-06T02:58:37Z

← Older revision		Revision as of 22:58, 5 October 2021
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	{\|class="infobox"		{\|class="infobox"
	!style="font-size:135%;text-align:center;" \| Nicolet FTIR		!style="font-size:135%;text-align:center;" \| Nicolet FTIR [https://sites.gatech.edu/mse-mill/sop/ftir/ [SOP<nowiki>]</nowiki>]
	\|-		\|-
	\|[[File:FTIR-052621.png\|center\|300px]]		\|[[File:FTIR-052621.png\|center\|300px]]

Rzhou95 at 23:00, 17 July 2021

2021-07-17T23:00:56Z

← Older revision		Revision as of 19:00, 17 July 2021
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	\|'''Detector''': DTGS (deuterated triglycine sulfate)		\|'''Detector''': DTGS (deuterated triglycine sulfate)
	\|-		\|-
	\|'''Accessories''': ~~iD5~~ ATR (attenuated total reflectance), iD1 Transmission		\|'''Accessories''': iD7 ATR (attenuated total reflectance), iD1 Transmission
	\|}		\|}

Rzhou95 at 23:00, 17 July 2021

2021-07-17T23:00:42Z

← Older revision		Revision as of 19:00, 17 July 2021
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	\|'''IR Activity''': Bonds must have dipoles		\|'''IR Activity''': Bonds must have dipoles
	\|-		\|-
	\|'''Sample''': Solids (bulk, powder, fiber, film), Liquids (solution, paste, gel), Gas (transmission only, needs proper cell)		\|'''Sample Type''': Solids (bulk, powder, fiber, film), Liquids (solution, paste, gel), Gas (transmission only, needs proper cell)
	\|-		\|-
	\|'''Detector''': DTGS (deuterated triglycine sulfate)		\|'''Detector''': DTGS (deuterated triglycine sulfate)

Rzhou95 at 23:00, 17 July 2021

2021-07-17T23:00:27Z

← Older revision		Revision as of 19:00, 17 July 2021
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	\|'''IR Activity''': Bonds must have dipoles		\|'''IR Activity''': Bonds must have dipoles
	\|-		\|-
	\|'''Sample:''' Solids (bulk, powder, fiber, film) & Liquids (solution, paste, gel)		\|'''Sample''': Solids (bulk, powder, fiber, film), Liquids (solution, paste, gel), Gas (transmission only, needs proper cell)
	\|-		\|-
	\|'''Detector:''' DTGS (deuterated triglycine sulfate)		\|'''Detector''': DTGS (deuterated triglycine sulfate)
	\|-		\|-
	\|'''Accessories:''' iD5 ATR (attenuated total reflectance), iD1 Transmission		\|'''Accessories''': iD5 ATR (attenuated total reflectance), iD1 Transmission
	\|}		\|}

Rzhou95 at 22:56, 17 July 2021

2021-07-17T22:56:58Z

← Older revision		Revision as of 18:56, 17 July 2021
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	\|-		\|-
	\|'''IR Activity''': Bonds must have dipoles		\|'''IR Activity''': Bonds must have dipoles
			\|-
			\|'''Sample:''' Solids (bulk, powder, fiber, film) & Liquids (solution, paste, gel)
			\|-
			\|'''Detector:''' DTGS (deuterated triglycine sulfate)
			\|-
			\|'''Accessories:''' iD5 ATR (attenuated total reflectance), iD1 Transmission
	\|}		\|}

Amarin32: /* Applications */

2021-07-02T13:35:17Z

Applications

← Older revision		Revision as of 09:35, 2 July 2021
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	== Applications ==		== Applications ==
	[[File:FtirbasicsreferencechartPRINT.jpg\|thumb\|left\|500px\|A reference chart with some of the most common peaks seen in FTIR]]Infrared spectroscopy has been a workhorse technique for materials analysis in the laboratory for over seventy years. An infrared spectrum represents a fingerprint of a sample with absorption peaks which correspond to the frequencies of vibrations between the bonds of the atoms making up the material. Because each different material is a unique combination of atoms, no two compounds produce the exact same infrared spectrum. Therefore, infrared spectroscopy can result in a positive identification (qualitative analysis) of every different kind of material. In addition, the size of the peaks in the spectrum is a direct indication of the amount of material present. With modern software algorithms, infrared is an excellent tool for quantitative analysis.		[[File:FtirbasicsreferencechartPRINT.jpg\|thumb\|left\|500px\|A reference chart with some of the most common peaks seen in FTIR <ref Name"FTIR chart"> Bradley, M., says, B. B., & says, R. katole. (2021, June 11). Free FTIR Basic Organic Functional Group Reference Chart. Advancing Materials. https://www.thermofisher.com/blog/materials/a-gift-for-you-an-ftir-basic-organic-functional-group-reference-chart/. </ref>]]Infrared spectroscopy has been a workhorse technique for materials analysis in the laboratory for over seventy years. An infrared spectrum represents a fingerprint of a sample with absorption peaks which correspond to the frequencies of vibrations between the bonds of the atoms making up the material. Because each different material is a unique combination of atoms, no two compounds produce the exact same infrared spectrum. Therefore, infrared spectroscopy can result in a positive identification (qualitative analysis) of every different kind of material. In addition, the size of the peaks in the spectrum is a direct indication of the amount of material present. With modern software algorithms, infrared is an excellent tool for quantitative analysis.

	== Dispersive vs Fourier Transform IR ==		== Dispersive vs Fourier Transform IR ==

Amarin32: /* Principle */

2021-07-02T13:26:14Z

Principle

← Older revision		Revision as of 09:26, 2 July 2021
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	== Principle ==		== Principle ==
	The normal instrumental process is as follows:		The normal instrumental process is as follows:<ref Name="FTIR"> Thermo Scientific. (n.d.). Introduction to FTIR. http://tools.thermofisher.com/content/sfs/brochures/BR50555_E_0513M_H_1.pdf. </ref>

	# The Source: Infrared energy is emitted from a glowing black-body source. This beam passes through an aperture which controls the amount of energy presented to the sample (and, ultimately, to the detector).		# The Source: Infrared energy is emitted from a glowing black-body source. This beam passes through an aperture which controls the amount of energy presented to the sample (and, ultimately, to the detector).

Amarin32 at 21:14, 1 July 2021

2021-07-01T21:14:56Z

← Older revision		Revision as of 17:14, 1 July 2021
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	Fourier transform infrared (FTIR) spectrometry was developed in order to overcome the limitations encountered with dispersive instruments. The main difficulty was the slow scanning process. A method for measuring all of the infrared frequencies simultaneously, rather than individually, was needed. A solution was developed which employed a very simple optical device called an interferometer. The interferometer produces a unique type of signal which has all of the infrared frequencies “encoded” into it. The signal can be measured very quickly, usually on the order of one second or so. Thus, the time element per sample is reduced to a matter of a few seconds rather than several minutes. Most interferometers employ a beamsplitter which takes the incoming infrared beam and divides it into two optical beams. One beam reflects off of a flat mirror which is fixed in place. The other beam reflects off of a flat mirror which is on a mechanism which allows this mirror to move a very short distance (typically a few millimeters) away from the beam splitter. The two beams reflect off of their respective mirrors and are recombined when they meet back at the beamsplitter. Because the path that one beam travels is a fixed length and the other is constantly changing as its mirror moves, the signal which exits the interferometer is the result of these two beams “interfering” with each other. The resulting signal is called an interferogram which has the unique property that every data point (a function of the moving mirror position) which makes up the signal has information about every infrared frequency which comes from the source. This means that as the interferogram is measured, all frequencies are being measured simultaneously. Thus, the use of the interferometer results in extremely fast measurements. Because the analyst requires a frequency spectrum (a plot of the intensity at each individual frequency) in order to make an identification, the measured interferogram signal can not be interpreted directly. A means of “decoding” the individual frequencies is required. This can be accomplished via a well-known mathematical technique called the Fourier transformation. This transformation is performed by the computer which then presents the user with the desired spectral information for analysis.		Fourier transform infrared (FTIR) spectrometry was developed in order to overcome the limitations encountered with dispersive instruments. The main difficulty was the slow scanning process. A method for measuring all of the infrared frequencies simultaneously, rather than individually, was needed. A solution was developed which employed a very simple optical device called an interferometer. The interferometer produces a unique type of signal which has all of the infrared frequencies “encoded” into it. The signal can be measured very quickly, usually on the order of one second or so. Thus, the time element per sample is reduced to a matter of a few seconds rather than several minutes. Most interferometers employ a beamsplitter which takes the incoming infrared beam and divides it into two optical beams. One beam reflects off of a flat mirror which is fixed in place. The other beam reflects off of a flat mirror which is on a mechanism which allows this mirror to move a very short distance (typically a few millimeters) away from the beam splitter. The two beams reflect off of their respective mirrors and are recombined when they meet back at the beamsplitter. Because the path that one beam travels is a fixed length and the other is constantly changing as its mirror moves, the signal which exits the interferometer is the result of these two beams “interfering” with each other. The resulting signal is called an interferogram which has the unique property that every data point (a function of the moving mirror position) which makes up the signal has information about every infrared frequency which comes from the source. This means that as the interferogram is measured, all frequencies are being measured simultaneously. Thus, the use of the interferometer results in extremely fast measurements. Because the analyst requires a frequency spectrum (a plot of the intensity at each individual frequency) in order to make an identification, the measured interferogram signal can not be interpreted directly. A means of “decoding” the individual frequencies is required. This can be accomplished via a well-known mathematical technique called the Fourier transformation. This transformation is performed by the computer which then presents the user with the desired spectral information for analysis.
	[[File:FT.PNG\|thumb]]		[[File:FT.PNG\|thumb\|500px]]

	=== Advantages of FT vs. Dispersive IR ===		=== Advantages of FT vs. Dispersive IR ===

Amarin32 at 21:14, 1 July 2021

2021-07-01T21:14:32Z

← Older revision		Revision as of 17:14, 1 July 2021
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	# The Interferometer: The beam enters the interferometer where the “spectral encoding” takes place. The resulting interferogram signal then exits the interferometer. The interferometer uses a reference laser for precise wavelength calibration, mirror position control and data acquisition timing.		# The Interferometer: The beam enters the interferometer where the “spectral encoding” takes place. The resulting interferogram signal then exits the interferometer. The interferometer uses a reference laser for precise wavelength calibration, mirror position control and data acquisition timing.
	# The Sample: The beam enters the sample compartment where it is transmitted through or reflected off of the surface of the sample, depending on the type of analysis being accomplished. This is where specific frequencies of energy, which are uniquely characteristic of the sample, are absorbed.		# The Sample: The beam enters the sample compartment where it is transmitted through or reflected off of the surface of the sample, depending on the type of analysis being accomplished. This is where specific frequencies of energy, which are uniquely characteristic of the sample, are absorbed.
	# The Detector: The beam finally passes to the detector for final measurement. The detectors used are specially designed to measure the special interferogram signal.		# The Detector: The beam finally passes to the detector for final measurement. The detectors used are specially designed to measure the special interferogram signal.[[File:FTIRSetup.PNG\|thumb\|left\|500px]]
	# The Computer: The measured signal is digitized and sent to the computer where the Fourier transformation takes place. The final infrared spectrum is then presented to the user for interpretation and any further manipulation.		# The Computer: The measured signal is digitized and sent to the computer where the Fourier transformation takes place. The final infrared spectrum is then presented to the user for interpretation and any further manipulation.

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	== Dispersive vs Fourier Transform IR ==		== Dispersive vs Fourier Transform IR ==
	~~[[File:FTIRSetup.PNG\|thumb\|left\|500px]]~~
	[[File:FTIRLayout.PNG\|thumb\|Simplified layout of a FTIR spectrometer]]		[[File:FTIRLayout.PNG\|thumb\|Simplified layout of a FTIR spectrometer]]

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	* Greater optical throughput		* Greater optical throughput
	* Mechanically simple with only one moving part		* Mechanically simple with only one moving part










	== References ==		== References ==
	<references />		<references />

	[[Category:Equipment\|char]]		[[Category:Equipment\|char]]