The idea of thoroughly analyzing a material without modifying it in any way may seem like something out of science fiction. This is actually now possible with near-infrared spectroscopy (NIRS) systems. It’s possible to do this with the use of an NIR analyzer and similar instruments.
Like other spectroscopic methods, NIRS is based on theories of the interaction between radiated energy and matter. These theories hold that various substances have their unique reactions to different kinds of radiated energy. The radiated energy used in NIRS is in the form of electromagnetic waves within the 800 to 2500 nanometer wavelength in the electromagnetic spectrum. This places it a little above visible light, but also below ordinary infrared, which has longer wavelengths.
NIR is mainly used in the medical field to detect hemoglobin concentration changes in the human body. The amount of blood in an area is determined based on optical absorption coefficients calculated with the use of NIR instruments. NIR is, likewise, useful in fields such as astronomy, agriculture, and pharmacy, where it’s necessary to analyze bulk material without much sample preparation.
NIR Instruments and How They Work
For an NIR analysis to work, three elements must be present: the NIR source, the detector, and a dispersive element. NIR sources include quartz halogen or incandescent light bulbs and light-emitting diodes (LEDs). Likewise, different detectors work for different ranges; for instance, InGaAs and PbS detectors work for NIR energy above 1000 nm, though they may be less sensitive. The most common dispersive element used for NIRS is a diffraction grating.
The beam from the NIR source is bounced off the sample. The dispersive element then separates the reflected beam into different wavelengths to enable analysis. The detectors record the NIR, and evaluate it accordingly.
NIRS has certain advantages over other spectroscopy methods. For one, NIR isn’t likely to be affected by background noise, as it enjoys a low signal-to-noise ratio, thereby making the readings more accurate. For another, not only is NIR relatively non-invasive, it’s also fast, so the quality of the samples in question is generally preserved. For more information on the advantages of NIRS, read ezinearticles.com/?Advantages-of-Near-Infrared-Spectroscopy&id=5929719.
What You Need to Know About the Workings of an NIR Analyzer