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What is NIRS?

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What is NIRS?

Near-Infrared Spectroscopy (NIRS) is an analytical technique that uses the near-infrared region of the electromagnetic spectrum (from 800 to 2500 nm).  Eurofins Agro uses this approach to provide information on the nutritional composition of roughage and raw materials.

In NIRS analysis, a sample is irradiated with near-infrared light.  Advanced equipment then measures how much of each wavelength of light is reflected by the sample.  This reflection, is known as a spectrum.

The spectrum contains information on the sample's composition.  This is because the bonds between different molecules (e.g. hydrogen, carbon, oxygen, nitrogen and sulphur) absorb the near-infrared light in different ways. 

Translating the NIRS Spectrum

The absorption/reflection process itself is too complex to be used to directly derive information about a sample's composition.  Instead, the NIR spectrum acts like a fingerprint.  In the same way that it is possible to identify a person when their fingerprint is held against a database containing the names of individuals, and their fingerprints.  It is also possible to identify the nutritional composition of a sample when it is compared to a database containing NIR spectra and associated reference (wet chemistry) results. 

Eurofins Agro has extensive databases containing both thousands of NIR spectra, and data generated using classical reference methods.  By means of a mathematical model, based on local calibration, we are able to derive a wide range of parameters.  This method is constantly being validated, and our database is always growing. 

Advantages of NIRS

NIRS analysis is an indirect method calibrated on primary classical analytical methods (wet chemistry).  These are known as reference methods.  Whilst these reference methods are the "gold standard", NIRS has a number of advantages for those wishing to understand the nutritional composition of a sample.  These include:

  • Speed: In Eurofins Agro labs, a NIRS analysis takes around 20 seconds to perform.  This is much quicker than the corresponding wet chemistry method.
  • Accuracy: Due to the high degree of automation, extensive database, and finely tuned calibration, results are highly precise.
  • Non-Destructive: The sample material is not destroyed during analysis, and remains in tact for use in other investigations.
  • Lower Cost: NIRS analysis is usually more cost-effective than analysis via wet chemistry.