Infrared spectroscopy pattern recognition

Near infrared spectroscopy (NIRS), a technique based on absorption and reflectance of monochromatographic radiation by samples over a wavelength range of 400-2500 run, has been successfully applied for food composition analysis, for food quality assessment, and in pharmaceutical production control. NIRS can be used to differentiate various samples via pattern recognitions. The technique is fast and nondestructive method that does not require sample preparation and is very simple to use compared too many other analytical methods such as HPLC. The drawback of NIRS, however, is that the instrument has to be calibrated using a set of samples typically 20-50 with known analyte concentrations obtained by suitable reference methods such as FIPLC in order to be used for quantitative analyses. Simultaneous quantification of the... 

Roggo, Y., Duponchel, L., and Huvenne, J.-P. (2003), Comparison of supervised pattern recognition methods with McNemar s statistical test Application to qualitative analysis of sugar beet by near-infrared spectroscopy, Anal. Chim. Acta, All, 187-200. 

G. Werner, J. Frith, F. Keller, H. Greger, R. L. Somorjai, B. Dolenko, M. Otto and D. Bocker, Mid Infrared Spectroscopy as a Tool for Disease Pattern Recognition from Human Blood (eds H. H. Mantsch and M. Jackson), p. 35, 1998. 

Applications of pattern recognition methodology to chemical problems were first reported in the 1960 s (20,21) with studies of mass spectra. Since then papers have described work in a variety of areas (22,23) including mass spectrometry, infrared spectroscopy, NMR spectroscopy, electrochemistry, materials science and mixture analysis, and the modeling of chemical experiments. Diagnosis of pathological conditions from sets of measurements made on complex biological mixtures, e.g., serum, have been reported (24). The successes in these areas have led to the belief that these methods should prove useful in the development of structure-activity relations. 

Short reviews about pattern recognition applications in infrared spectroscopy have been given by Isenhour and Jurs C1173, and Kowalski C1483. 

Only a few works have been performed on pattern recognition applications in Raman spectroscopy. This is probably due to the lack of suitable computer-readable spectra. Methods of coding and classification would be the same as used for infrared spectra. 

As with all scientific writing there are various levels that can be presented. For example, infrared spectroscopy could be used on simply the pattern recognition level or at the more sophisticated level of quantum mechanics. So it is with physical adsorption. One can use the data from physical adsorption measurements as a simple control device, i.e. Does this powder have the right adsorption isotherm to meet production requirements , or on a different level What is the meaning of the isotherm in terms of surface and pore structure and chemical attractions For most applications, the level of sophistication is somewhat intermediate. 

High performance spectroscopic methods, like FT-IR and NIR spectrometry and Raman spectroscopy are widely applied to identify non-destructively the specific fingerprint of an extract or check the stability of pure molecules or mixtures by the recognition of different functional groups. Generally, the infrared techniques are more frequently applied in food colorant analysis, as recently reviewed. Mass spectrometry is used as well, either coupled to HPLC for the detection of separated molecules or for the identification of a fingerprint based on fragmentation patterns. ... 

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