What is NIRS Spectroscopy, its theoretical foundations and what we offer.
NIRS spectroscopy ( Near Infrared Reflectance Spectroscopy ) is an analytical technique .
- It is a technique currently in expansion thanks to the growing interest in improving the quality of products. It is essential in the study of traceability throughout the production chain.
- Consequently, conventional chemical analysis sometimes needs to be replaced by agile analytical techniques that minimize said cost and time.
- NIRS technology is a non- destructive technique . It allows us to obtain quantitative or qualitative analysis in feed and raw materials of different analytical parameters. We talk about parameters such as: protein, fiber, fat, ash, moisture, starch, etc.
- We can obtain the result of the analysis in approximately one minute without the need to grind the sample.
- All these characteristics make NIR spectroscopy offer many advantages over other analytical techniques in at-line quality control.
NIRS Spectroscopy: Theoretical Foundation of NIRS
- The sample (in solid or liquid state) is irradiated at different wavelengths . In NIRS, these wavelengths are located between the visible and the near infrared (578 and 1842 nm).
- Said radiation is absorbed by the sample, producing the vibration of the carbon-hydrogen (CH), oxygen-hydrogen (OH) and nitrogen-hydrogen (NH) bonds, which are the main constituents of the basic structure of organic substances.
- These vibrations constitute a set of values at different wavelengths that give rise to a characteristic spectrum of each sample that can be considered its fingerprint.
- The spectrum is stored and registered in a processor for later mathematical treatment.
- To develop a NIRS calibration, it is necessary to relate, through algorithms, the information provided by the spectrum with the information provided by the analysis of said samples by the wet method, using conventional methods.
- This relationship is possible thanks to the application of statistical models such as simple regression , main components and least squares . Because the interaction of energy with matter obeys the Lambert-Beer law, where the absorbance at any wavelength is proportional to the number or concentration of absorbing molecules in the path traveled by the radiation.
Convet, from its NIR calibration department, offers:
- Analysis of feed and raw materials in situ and immediately.
- Installation , verification of calibrations . If you have an NIR instrument for quality control in your facility, we can install the appropriate equations and check the accuracy of the readings.
- Calibration Development. On occasions, the sector introduces new raw materials in response to economic fluctuations in the sector. Convet can develop new equations that adapt to the needs of each company. The development of a calibration depends on the parameters to be calibrated (protein, fiber…). Once defined, between 60 – 70 samples analyzed by the wet method are needed. With the development of these analytical values and a correct mathematical analysis, we will obtain the equations of each of the requested parameters that is installed in the instrument for routine analysis.
- Calibration maintenance. The calibrations require maintenance. The periodicity of the maintenance will be at least annually, although if, at any time, a certain dispersion is observed in the analytical ranges (high SEP, high GH values, etc…) it will be necessary to proceed to an adjustment of the calibration .Convet, to ensure the correct maintenance of the calibrations, offers a complete treatment service for the generated spectra. It also offers outlier spectra treatment and calibration adjustments by sending verification patterns (every 4 months) and remotely.