Commonly referred to as FTIR, Fourier Transform Infrared Spectroscopy is the most recent addition to the Air Compliance Testing technological toolbox. FTIR can be used to identify chemicals from paints, polymers, coatings, spills, drugs, and contaminants (qualitative analysis). FTIR is likely the most powerful tool for identifying types of chemical bonds (functional groups). The wavelength of light absorbed is characteristic of the chemical bond as can be seen in this annotated spectrum. Because the strength of the absorption is proportional to the concentration, FTIR can also be used for some quantitative analyses.
FTIR Applications include:
- Identifying gas stream organic compounds and many inorganic compounds
- Chemical process monitoring and optimization
- On-line process monitoring
- Measuring moisture in corrosive gases
- Reaction end point determinations
- Measuring catalyst efficiency
- Control equipment optimization
- Real time speciated VOC emission analysis
- Indoor air monitoring of VOC's and semi-volatiles at very low levels
- Blending processes optimization
- Ambient air and employee exposure monitoring
By now you’re probably wondering how FTIR works: Because chemical bonds absorb infrared energy at specific frequencies (or wavelengths), the basic structure of compounds can be determined by the spectral locations of their IR absorptions. The plot of a compound's IR transmission vs. frequency is its "fingerprint" that can be compared to reference spectra to identify the material. FTIR spectrometers offer speed and sensitivity impossible to achieve with older wavelength-dispersive instruments. This capability allows rapid analysis of micro-samples down to the nanogram level is some cases, making the FTIR unmatched as a problem-solving tool in organic analysis.
Fourier transform infrared spectroscopy is preferred over dispersive or filter methods of infrared spectral analysis for several reasons:
- It is non-destructive
- There are few sample constraints; solids, liquids and gases can be accommodated.
- It provides a precise measurement method which requires no external calibration
- Because all of the frequencies are measured simultaneously, most measurements by FT-IR are made in a matter of seconds rather than several minutes.
- It has greater optical throughput
- Mechanical Simplicity: The moving mirror in the interferometer is the only continuously moving part in the instrument. Thus, there is very little possibility of mechanical breakdown.
- Sensitivity is dramatically improved with FTIR. The detectors employed are much more sensitive, the optical throughput is much higher, which results in much lower noise levels, and the fast scans enable the coaddition of several scans in order to reduce the random measurement noise to any desired level.
- These instruments are self-calibrating and never need to be calibrated by the user.
Contact Air Compliance Testing at 1-800-EPA-AIR1 to see how we can apply this incredible diagnostic tool to your process improvement or problem.
More info at http://www.aircomp.com
