FTIR Analysis – Infrared Spectroscopy

JASCO FTIR 6100 System with Specac Golden Gate MKII Diamond Window ATR at AME Labs

FTIR Analysis or Infrared Spectroscopy Capabilities

  • ATR – FTIR analysis or FTIR in transmission identify chemical bond functional groups by their characteristic absorption of infrared radiation in vibrational modes 
  • May be used in transmission mode for low absorbance samples
  • In attenuated total reflectance (ATR) mode, the detection depth is generally 1-2μm deep, but can be much less or a bit more dependent upon the material. Black, highly absorbing, or highly scattering materials tend to have smaller sampling depths and sometimes provide too weak a signal as a result.
  • Especially capable of identifying the chemical bonds of organic and polymeric materials
  • Detects and identifies organic contaminants or additives, though this capability is much enhanced by additional GC-MS analysis
  • Determines bonds undergoing degradation reactions or changing with processing
  • Identifies water, carbonate, phosphate, sulfate, nitrate, nitrite, and ammonium ions, silica, silicones, talc, alumina, titanium dioxide, zinc oxide, bentonite, and other inorganic chemicals
  • Detection limits vary greatly, but are sometimes <1013 bonds/cm3 or sometimes sub monolayer
  • Useful in characterizing solids, liquids, or gases using small amounts of material

System Capabilities

  • In transmission mode, area of analysis is about 1mm x 1mm. Liquid layer thickness may be from sub-micrometer to a few millimeters. Sample material may be dispersed on KBr pellets.  The sample lateral dimensions may be at least 12in x 12in.
  • Using the Specac Golden Gate MKII Diamond single-reflection ATR with KRS-5 lenses, the area analyzed is about 0.6 mm x 0.6mm. The thickness may be from sub-micrometer to a few millimeters. The width of a sample must be less than 108 mm or about 4¼ inches. The window is a rugged type IIIa diamond. Pressure is applied on the sample at a uniform setting of 80lbs. by a sapphire anvil.  This will deform many samples and may make the analysis destructive.
  • Using the Pike Technologies Veemax II variable angle specular reflectance accessory, the sample may be many centimeters thick. The surface should be flat and relatively smooth. Sample widths must be less than 196mm or about 7¾ inches. This accessory is especially useful for thin coatings on metal surfaces, polymer films on semiconductor wafer surfaces, or thin films on glass slides where a high sensitivity to a thin layer is required.  Variable angle specular reflectance allows the depth of analysis to be varied and can be useful for looking deeper into a surface than ATR FTIR does.  This technique can be useful for measuring organic film thicknesses as well.
  • The spectral range is 7800 cm–1 to 400 cm–1 (1.28 µm to 25 µm)
  • Resolution up to ½ cm-1, though most spectra of solids or liquids are taken with 4 cm-1 resolution
  • Signal-to-noise ratio greater than 42000:1
  • Temperature controlled DLATGS detector
  • 62° Michelson interferometer with retro-reflecting corner cube mirrors
  • KRS-5 interferometer and DTGS detector windows
  • KRS-5 lenses are thallium bromoiodide lenses and have a nearly flat response in the entire IR range from 400 to 4500 cm-1 range, compared to ZnSe which is only flat above 650 cm-1 and Ge which is only flat above 900 cm-1
The KRS-5 thallium bromoiodide lenses offer a flatter transmission to a lower energy in the infra-red spectrum than do ZnSe and Ge lenses

FTIR Analysis Spectra Databases

While chemical bond type identifications can be very useful for identifying strange and unusual material compositions or to understand materials degradation or processing problems, it is very useful to have large databases of FTIR spectra when one wants to match a particular substance to various specific manufactured products or product types or even to a simple material. Even when a particular material does not precisely match a manufactured material in a database, it is often helpful to know what products are similar to it. We presently have the following materials databases to assist us in these identifications:

Fiveash Data Management FTIR Databases (79,000 Plus Total Spectra)

  • Polymers and Polymer Additives (580 spectra, 500-4000 cm-1 range, 4 cm-1 resolution)
  • Surfactants (430 spectra, 500-4000 cm-1 range, 4 cm-1 resolution)
  • Organic Compounds Important to Industrial Processes (950 spectra, 400-4000 cm-1 range, 4 cm-1)
  • Minerals and Inorganic Compounds (310 spectra, 450-4000 cm-1 range, 4 cm-1 resolution)
  • Drugs and the Canadian Forensic Laboratory Spectra (3,750 spectra, 500-4000 cm-1 range, 4 cm-1 resolution)
  • Vapor Phase Spectra of Organic Compounds (5,220 spectra, 500-3800 cm-1 range, 8 cm-1)
  • Comprehensive Organic Compounds (10,320 spectra,500-4000 cm-1 range, 8 cm-1)
  • Organics ATR FTIR (1515 spectra, 400-4000 cm-1 range, 2 cm-1 resolution, monolithic diamond crystal)
  • Organics ATR FTIR (422 spectra, 600-4000 cm-1 range, 2 cm-1 resolution, germanium crystal)
  • Polymer, Plasticizer, and Monomer ATR FTIR Spectra (1138 spectra, 400-4000 cm-1 range, 2 cm-1 resolution, monolithic diamond crystal except for 54 spectra Ge crystal)
  • Plastics Kit of 50,000+ ATR Spectra, including Resins Two Components, Resins Three Components, Resins & Fillers, Resins & Plasticizers, and Resins & Polymer Additives
  • Essential Oil and Food Oil ATR FTIR Spectra (460 spectra, 400-4000 cm-1 resolution, monolithic diamond crystal)
  • Inorganic Compound ATR FTIR Spectra (586 spectra, 400-4000 cm-1 range, 2 cm-1 resolution, monolithic diamond crystal)
  • Inorganic Compound ATR FTIR Spectra (498 spectra, 550-4000 cm-1 range, 2 cm-1 resolution, germanium crystal)
  • Dye, Stain, and Pigment ATR FTIR Spectra (150 spectra, 400-4000 cm-1 range, 2 cm-1, monolithic diamond crystal)
  • Dye, Stain, and Pigment ATR FTIR Spectra (150 spectra, 550-4000 cm-1 range, 2 cm-1, germanium crystal)
  • Pharmaceuticals and Illicit Drug ATR FTIR Spectra (439 spectra, 500-4000 cm-1 range, 2 cm-1 resolution, monolithic diamond crystal)
  • Adhesive and Sealant ATR FTIR Spectra (458 spectra, 400-4000 cm-1, 2 cm-1 resolution, monolithic diamond crystal)
  • Cosmetic and Personal Care Product ATR FTIR Spectra (570 spectra, 650-4000 cm-1 range, 2 cm-1 resolution, diamond Zn/Se or Ge crystal)
  • Forensic Vapor Phase FTIR (670 spectra, 500-4000 cm-1 range, 8 cm-1 resolution)
  • High Resolution Vapor Phase FTIR (430 spectra, 400-4000 cm-1 range, 2 cm-1 resolution)

JASCO compound database of 900 compounds with emphasis on polymers

Know It All JASCO Edition compound database with 10,000 compounds with a per use fee to obtain matching spectra

AME, Inc. Compiled Compound and Materials Database

Sample Absorption Spectrum: Adhesive of Double Sided 3M Tape
Sample FTIR Absorption Spectrum: Low Density Polyethylene (LDPE) Trash Bag
Sample FTIR Absorption Spectrum: Low Density Polyethylene (LDPE) Trash Bag

Further Applications of FTIR to Materials Analysis:

Distinguishing the Polytypes 4H and 6H of SiC Single Crystals, Known as Moissanite

FTIR Analysis Services

FTIR Analysis of Products Formed from Overheating a Silicone Material

Identifying Vile Liquid as Marinated Urine

ASTM 1252: General Techniques for Obtaining Infrared Spectra for Qualitative Analysis

Contacts: Vaidheeshwar Ramasubramanian, Ph.D., email: vaidheeshwar.r@andersonmaterials.com