Commonly referred to as FTIR, Fourier Transform Infrared Spectroscopy is one of the most powerful tools in 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 quantitative analyses.
FTIR Applications include:
Identifying Organic Compounds and many Inorganic Compounds
Hazardous Air Pollutant (HAP) Speciation
Ambient Air and Employee Exposure Monitoring
Contaminants Analysis
Analyzing Oil and Lubricants
Thin Film Metrology and Composition
Chemical Process Monitoring and Optimization
Measuring Catalyst Efficiency
Real Time VOC Emission Analysis
Control Equipment Optimization
In-situ Chemical Vapor Monitoring
Blending Processes Optimization
Indoor Air Monitoring of VOC's and Semi-Volatiles at very Low Levels
Measuring Moisture in Corrosive Gases
On-Line Process Monitoring
Remote Sensing of Fugitive Emissions
Reaction End Point Determinations
Here's 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 FTIR 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 for many reasons. The detectors employed are much more sensitive, the optical throughput is much higher (referred to as the Jacquinot Advantage) 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 (referred to as signal averaging).
These instruments employ a HeNe laser as an internal wavelength calibration standard (referred to as the Connes Advantage). These instruments are self-calibrating and never need to be calibrated by the user.
Contact us to see how we can apply this incredible diagnostic tool to your process improvement or energy management problem.
