Near-infrared reflectance analysis NIRA

Near Infrared Reflectance Analysis (NIRA) is in use at over 5000 sites for the analysis of multiple constituents in food and other products. The technology is based upon correlation transform spectroscopy, which combines NIR spectrophotometry and computerized analysis of a "learning set" of samples to obtain calibrations without the need for detailed spectroscopic knowledge of factors being analyzed. The computer can obtain spectral characteristics of the analyte (based upon a correlation with data from an accepted reference analysis) without separation of the sample s constituents. 

For all of the above reasons, studies of relationships between mineral sites and mineral reactivity would be simplified, and the confidence in the findings increased, if statistically testable methods were to be used to identify key variables and to test hypotheses. Near infrared reflectance analysis (NIRA) is such a method. It was developed by Karl Norris in the 1960 s to quantitate the concentration of key constituents in multicomponent mixtures such as wheat (22). 

A. Picarelli, M. Greco, F. Di Giovambattista, A. Ramazzotti, C. Cedrone, E. Coarzziari, and A. Torsoli. Quantitative determination of faecal fat, nitrogen and water by means of a spectrophotometric technique near infrared reflectance analysis (NIRA). Assessment of its accuracy and reproducibility compared with chemical methods. Clin. Chim. Acta 234 147 (1995). 

Due to the absorption bands in NIR being weaker than in UV-Vis absorption, NIR spectrometry is not as useful for quantitative measurements but offers better qualitative analysis because of improved selectivity. NIR techniques can handle both liquid and solid samples. Near infrared reflectance analysis (NIRA) has found wide application in process analysis, especially for highly absorbing compounds such as foodstuffs Coal, grain, pulp and paper products and some pharmaceuticals can also be determined by NIRA ". The reflectance from the sample is reported relative to reflectance from a standard reference surface. 

In contrast to the well-known difficulties of traditionally applied quantitative IR spectroscopy of mixtures in solid (powdered) samples, the near-infrared reflectance analysis (NIRA) technique [32] has gained importance over the last decade and can now be implemented on a variety of commercially available Instruments In a number of applications to Industrial, agricultural and pharmaceutical analyses. Both the NIRA instruments equipped with grating monochromators and those fitted with filter systems feature built—In microprocessors with software suited to the Intrinsic characteristics of this spectroscopic alternative. Filter Instruments generate raw optical data for only a few wave-... 

Source M. Dzwinczyk, Proc. 8th Int. Symposium on Near Infrared Reflectance Analysis (NIRA), Technicon, Tarrytown, New York,... 

Burns, D.A. and H. Mark., Indicator Variables in NIRA How to Use Them, in 7th Int. Symposium on Near Infrared Reflectance Analysis NIRA, Technicon. 1985. Tarrytown, NY. 

NIRS has been used for qualitative identification of textile fibres, polymer microstructure and composition studies, determination of finishes on textile fibres and colour deviations in dye batches. As shown in Table 1.18, near-infrared reflectance analysis (NIRA) is useful for characterising textile raw materials, fibres, yarns, and fabrics and is an excellent means to obtain real-time process/product information in textile manufacturing [312]. The nondestructive quantitative analysis is simple to use and... 

Near-infrared reflectance analysis is a useful technique for characterizing textile raw materials, fiber, yarns, and fabrics. It is a nondestructive quantitative analysis that is simple to use and allows rapid testing of the sample. Its ability to measure multiple components of the sample simultaneously and eliminate extensive sample preparation are major advantages of NIRA in the characterization of textile materials. Many innovative mathematical treatments, for example, discriminant analysis and spectral reconstruction, have been developed by instrument manufactures and software companies. These instruments not only aid in the quantitative analysis of the data but also allow morphological investigations of fibers and yarns and rapid, qualitative identification of specific sample sets. 

E. V. Valdes, L. G Young, I. McMillan, and J. E. Winch, Analysis of Hay, Haylage, and Corn Silage Samples by Near Infrared Reflectance Spectroscopy, in Proc. Inti Symp. on NIRA, Technicon Instrs., Tarrytown, NY, 1984. 

R. J. Bear and J. F. Frank, Analysis of Nonfat Dry Milk Using Near Infrared Reflectance Spectroscopy, Proc. 2nd Annual NIRA Symposium, Technicon, Tarry-town, New York, 1982. 

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