In the past few years, NIR spectroscopy has been applied to a steadily increasing extent in process and quality controls in the food, chemical, and pharmaceutical industry and in agriculture. The method is based on the use of infrared radiation for excitation of molecular bonds in organic compounds. Detection is in the near infrared (760-2500 nm). The NIR spectrum shows higher order harmonics and/or combination vibrations of the first harmonic vibrations. These lead to a large number of combinations of bands showing in the spectrum such that no discrete absorption bands can be differentiated in the case of complex mixtures, such as are present in food items. The harmonic and combination bands are not interpreted directly in the analysis of samples, but rather by means of statistical procedures. |
Mathematical analysis is done by means of algorithms. For quantitative determinations, data sets for known contents of the compound of interest are prepared ahead of the analysis. The quality of the correlation between the calibration and the predicted results is checked.
|Selection of Spectrometer Systems|