Near-infrared Fourier transform

Finally, in the field of full-spectrum NIRS methods, Fourier transform near-infrared (FTIR) analyzers are included (Figure 5.5). FTIR techniques are predominant in mid-infrared spectroscopy because there are clear and absolute advantages for the FTIR analyzer in the mid-infrared compared with any other available technology. This arises because of the low power output of mid-infrared sources and the low specific detectivity... 

Near-infrared Spectroscopy for Process Analytical Technology 127 5.3.4 Fourier transform near-infrared analyzers... 

FTNIR (Fourier transform near-infrared spectrophotometry), 663 FuUerene adducts, regioselective... 

Huck, C. et al., Quantitative Fourier transform near infrared reflectance spectroscopy (NIRS) compared to high performance liquid chromatography (HPLC) of a flavone in Primulae veris Flos extracts, Pharm. Pharmacol Lett., 9, 26, 1999. 

Ulmschneider, M., and Pdnigault, E. (2000b), Direct identification of key-intermediates in containers using Fourier-Transform near-infrared spectroscopy through the protective polyethylene primary packaging, Analusis, 28,136-140. 

Although the Fourier compression method can be effective for reducing data into frequency components, it cannot effectively handle situations where the dominant frequency components vary as a function of position in the spectrum. For example, in Fourier transform near-infrared (FTNIR) spectroscopy, where wavenumber (cm-1) is used as the x-axis, the bandwidths of the combination bands at the lower wavenumbers can be much smaller than the bandwidths of the overtone bands at the higher wavenumbers.31,32 In any such case where relevant spectral information can exist at different frequencies for different positions, it can be advantageous to use a compression technique that compresses based on frequency but still preserves some position information. The Wavelet transform is one such technique.33... 

Pudelko-Koerner, C., Fischer, A., Lentzen, H., Glombitza, K.W. and Madaus, A.G. (1996) Quantitative Fourier transform-near infrared reflectance spectroscopy of sennosides in Senna pods Pharm. Pharmacol. Lett. 6, 34-36. 

A mid-infrared absorption instrument generally consists of a Fourier transform design with the same basic components as noted above for the Fourier transform near-infrared spectrometers (broadband light source, Michelson interferometer, and detector optimized for the mid-infrared spectral region.)... 

Small GW, Arnold MA, Marquardt LA. Strategies for coupling digital filtering with partial least-squares regression application to the determination of glucose in plasma by Fourier-transform near-infrared spectroscopy. Analytical Chemistry 1993, 65, 3279-3289. 

Dreassi, E. Ceramelli, G. Corti, P. Massacesi, M. Perruc-cio, P.L. Quantitative fourier transform near-infrared spectroscopy in the quality control of solid formulations. Analyst 1995, 120, 2361-2365. 

Recently Benali et al. (2004) reported the development of a new laboratory-made system that allows the combination of rheometric (Alessi et al, 2005) and spectroscopic (Fourier-transform-near infrared (FT-NIR) spectroscopy) measurements for reactive polyurethane materials along the lines of these principles. 

There are also more recent developments of other dual physio-chemical experimental methods. For example Durand et al (2006) presented a laboratory-made system that allows the coupling of dielectric analysis and Fourier-transform near-infrared spectroscopy (FT-NIR) to follow the cure of polyepoxy reactive systems. Complementary data are provided by the simultaneous dielectric analysis (the vitrification phenomenon) and near-infrared spectroscopic analysis (the extent of the reaction). 

Nimaiyar et al. (2004) also found stearic acid to be the most difficult fatty acid to predict using Fourier-Transform near-infrared spectroscopy over the 833 to 2500 nm range. Stearic acid had the lowest R value and lowest RPD value of all five fatty acids tested. 

Arnold, M. A, Small, G. W. (1990) Determination of physiological levels of glucose in an aqueous matrix with digitally filtered Fourier-transform near-infrared spectra. Ana/. Chem. 62,1457-1464. 

Finally, a quick, non-destructive method, based on Fourier transform near-infrared (FT-NIR) spectroscopy for egg content deteimination of dry pasta was presented by Fodor et al. (2011) with good results. 

Abstract Fourier-transform near infrared (FT-NIR) spectroscopy in combination with a... 

Previous work of one of the authors dealt with mid IR monitoring of IB polymerization using fiber-optic equipment. Fourier transform near infrared spectroscopy can be accomplished without expensive hardware. It therefore seemed to be a desirable goal to combine the advantage of fiber optics with low-cost fibers available for measurements in the NIR range. The NIR spectrum of IB obtained after solvent subtraction (Figure 2) reveals at least three signals, which should be suitable for the determination of monomer conversion. 

Fats and Oils with emphasis on Trans Fatty Acids Using Fourier Transform Near Infrared Spectroscopy (FT-NIR), 40 855—867 (2005). 

Fourier transform near-infrared reflectance spectrometry 1.5 mg/500 mg Wheat flour... 

A. Heinz, M. Savolainen, T. Rades, and C. J. Strachan, Comparative Evaluation of the Degree of Indomethacin Crystallinity by Chemoinfometrical Fourier-Transformed Near-Infrared Spectroscopy and Conventional Powder X-Ray Diffractometry, Eur. J. Pharm. ScL, 32,182 (2007). 

Fourier Transform Near-Infrared Raman Spectroscopy... 

The advantages of Fourier transform near-infrared Raman spectroscopy are ... 

Aghenyega and co-workers [24] have investigated the application of Fourier transform near-infrared Raman spectroscopy in the synthetic polymer field. Their investigations covered the following areas ... 

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