ChemAnalytical
ChemAnalytical
ChemAnalytical
ChemAnalytical
FT-IR Services at ChemAnalytical

FT-IR Spectra Examples:

ft_ir_spectra_example

FT-IR (Fourier Transform Infrared) Spectroscopy is an Analytical Technique for many materials (solids, liquids or gas), pure or mixture of chemical compounds, pharmaceuticals etc. In this method of chemical analysis, one measures the infrared light absorption by the molecular vibrations in a material at different frequencies (expressed in wave number, cm-1) of infrared light. Based upon the frequency of infrared light or radiation absorbed, FT-IR can be categorized as:

  1. Far infrared (4 ~ 400 cm-¹) or Far-IR
  2. Mid infrared (400 ~ 4,000 cm-¹) or Mid-IR and
  3. Near infrared (4,000 ~ 14,000 cm-¹) or Near-IR

The mid-IR is commonly used as an extremely powerful analytical tool to detect the presence of molecular fragments or groups such as carbonyl C=O, amide NH2, etc. in the molecule or material.

List of Some FT-IR Spectra Examples:

List of Some FT-IR Spectra Examples:

FT-IR of Polymer (Polyethylene glycol) FT-IR of Polyethylene terephthalate FT-IR of Polyvinyl alcohol
FT-IR of Silicon(II) oxide FT-IR of Tetraisopropyl Orthosilicate FT-IR of Acrylonitrile
FT-IR of PolyAcrylonitrile FT-IR of Cyanamide FT-IR of Boron Nitride

List of Some FT-IR Less Common Samples:

FT-IR of Hexamethylphosphorous triamide FT-IR of Amino Acid L-Leucine FT-IR of Boron Carbide
FT-IR of Styrene FT-IR of Polystyrene FT-IR of Boron Carbide

Contact us for FT-IR Spectral Analysis and Consulting for a wide variety of materials at reasonable cost……


Infrared spectroscopy detects the vibration characteristics of chemical functional groups in a sample. When an infrared light interacts with the matter, chemical bonds will stretch, contract and bend. As a result, a chemical functional group tends to absorb infrared radiation close to a specific wave number range regardless of the structure of the rest of the molecule.

For example, the C=O stretch of a carbonyl group appears at around 1700 cm-1 in a variety of molecules. Hence, the correlation of this band wave number position with the carbonyl functional group in the chemical structure is used to identify the carbonyl functional group in a sample.

Infrared spectroscopy is extensively applied to various sample states such as liquid, gas, and solid-state matter to identify and to quantify unknown materials. It is a very good technique for identifying compounds and is used extensively to detect functional groups.

The FT-IR is routinely applied for the analysis of:

  • Pure organic or inorganic compound analysis
  • Impurity analysis
  • Analysis of Polymers
  • Analysis of biodiesels and gasoline and their additives
  • Analysis of Cooking Oils
  • Quantitative analysis of a compound in a mixture
  • Analysis of thin films

An Example of Molecular Vibration is shown for the Benzene Molecule:

benzene_mole

The Mid-FT-IR Spectrum of Benzene is shown below:

benzene

The IR spectrum for benzene, C6H6, has only four prominent bands because it is a very symmetric molecule. Every carbon has a single bond attached to a hydrogen atom. Each carbon is bonded to two other carbons and the carbon-carbon bonds are alike for all six carbons. The molecule is planar. The aromatic CH stretch appears at 3100-3000 cm-1 There are aromatic CC stretch bands (for the carbon-carbon bonds in the aromatic ring) at about 1500 cm-1. Two other bands are caused by bending motions involving carbon-hydrogen bonds. The bands for CH bends appear at approximately 1000 cm-1 for the in-plane bends and at about 675 cm-1 for the out-of-plane bend.

Contact us for FT-IR Spectral Analysis and Consulting for a wide variety of materials at reasonable cost……

FT-IR Spectra Examples:

polystyrene
FT-IR Spectrum of Polystyrene
styrene
FT-IR Spectrum of Styrene
polyacrylonitrile
FT-IR Spectrum of Polyacrylonitrile
acrylonitrile
FT-IR Spectrum of Acrylonitrile
terephthalate
FT-IR of Polyethylene Terephthalate
tetraisopropyl_orthosilicate
FT-IR of Silicon Compound Tetraisopropyl Orthosilicate
boron_carbide
FT-IR of Boron Compound Boron Carbide
boron_nitride
FT-IR of Boron Compound Boron Nitride
N-methylformamide
FT-IR of Nitrogen Compound N-methylformamide
cyanamide
FT-IR of Nitrogen Compound Cyanamide
hexamethylphosphorous_triamide
FT-IR of Phosphorous Compound Hexamethylphosphorous triamide
phenylphosphinic_acid
FT-IR of Phosphorous Compound Phenylphosphinic acid
triphenyl_phosphate
FT-IR of Phosphorous Compound Triphenyl phosphate
L_Leucine
FT-IR of Amino Acid L-Leucine
L_Isoleucine
FT-IR of Amino Acid L-Isoleucine_FTIR

Contact us for FT-IR Spectral Analysis and Consulting for a wide variety of materials at reasonable cost……

Characteristic FT-IR Band Positions of Functional Groups:

Functional Group Frequency Range (cm-¹)
OH stretching vibrations
Free OH 3610-3645 (sharp)
Intramolecular H bonds 3450-3600 (sharp)
Intermolecular H Bonds 3200-3550 (broad)
Chelate Compounds 2500-3200 (very broad)
NH Stretching vibrations
Free NH 3300-3500
H bonded NH 3070-3350
CH Stretching vibrations
=-C-H 3280-3340
=C-H 3000-3100
C-CH3 2862-2882, 2652-2972
O-CH3 2815-2832
N-CH3 (aromatic) 2810-2820
N-CH3 (aliphatic) 2780-2805
CH2 2843-2863,2916-2936
CH 2880-2900
SH Stretching Vibrations
Free SH 2550-2600
C=-N Stretching Vibrations
Nonconjugated 2240-2260
Conjugated 2215-2240
C=-C Stretching Vibrations
C=-CH (terminal) 2100-2140
C-C=-C-C 2190-2260
C-C=-C-C=-CH 2040-2200
C=O Stretching Vibrations
Nonconjugated 1700-1900
Conjugated 1590-1750
Amides ~1650
C=C Sretching Vibrations
Nonconjugated 1620-1680
Conjugated 1585-1625
CH Bending Vibrations
CH2 1405-1465
CH3 1355-1395, 1430-1470
C-O-C Vibrations in Esters
Formates ~1175
Acetates ~1240, 1010-1040
Benzoates ~1275
C-OH Stretching Vibrations
Secondary Cyclic Alcohols 990-1060
CH out-of-plane bending vibrations in substituted ethylenic systems
-CH=CH2 905-915, 985-995
-CH=CH-(cis) 650-750
-CH=CH-(trans) 960-970
-C=CH2 885-895

Contact us for FT-IR Spectral Analysis and Consulting for a wide variety of materials at reasonable cost……

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