Spectroscopic near-infrared

In the near-infrared, Al Ga As and In Ga As P lasers, and in the far-infrared lead compound semiconductor lasers are tunable by varying temperature and operating current. Many exceUent spectroscopic studies have been performed using them. However, they do have relatively limited tuning ranges for any one device. 

Fischbacher C, Jagemann K-U, Danzer K, Muller UA, Papenkordt L, Schuler J (1997) Enhancing calibration models for non-invasive near-infrared spectroscopical blood glucose determination. Fresenius J Anal Chem 359 78... 

Arun KT, Ramaiah D (2005) Near-infrared fluorescent probes synthesis and spectroscopic investigations of a few amphiphilic squaraine dyes. J Phys Chem A 109 5571-5578... 

Near-infrared spectroscopy is quickly becoming a preferred technique for the quantitative identification of an active component within a formulated tablet. In addition, the same spectroscopic measurement can be used to determine water content since the combination band of water displays a fairly large absorption band in the near-IR. In one such study [41] the concentration of ceftazidime pentahydrate and water content in physical mixtures has been determined. Due to the ease of sample preparation, near-IR spectra were collected on 20 samples, and subsequent calibration curves were constructed for active ingredient and water content. An interesting aspect of this study was the determination that the calibration samples must be representative of the production process. When calibration curves were constructed from laboratory samples only, significant prediction errors were noted. When, however, calibration curves were constructed from laboratory and production samples, realistic prediction values were determined ( 5%). 

However, any vibrating system not only has a natural vibration frequency but will also vibrate at twice that frequency, which is known as the first overtone. The first overtone of the vibrations of molecules like water, proteins and fats correspond to a frequency in the near-infrared. Because these frequencies are overtones all of the spectroscopic problems that preclude making quantitative measurements in the mid-infrared are not present in the near-infrared. 

Miniaturized chemical analysis systems have been developed for most macroscopic counterparts (Dittrich et al. 2006). The availability of optical fibers, light sources, and detectors in the visible UV and near-infrared (NIR) wavelengths makes it possible to integrate spectroscopic measurements in microreactors (Lobbecke et al. 2005). Fourier transform infrared spectroscopy (FTIR) is an efficient, broadly applicable... 

Kamat, M. S., Lodder, R. A., De Luca, P. R Near-infrared spectroscopic determination of residual moisture in lyophilized sucrose through intact glass vials. Pharmaceutical Research 6, p. 961-965, 1989. Copyright 1989 Plenum Publishing Corp, New York, N. Y USA... 

I. Miyai, H. Tanabe, I. Sase, H. Eda, I. Oda, I. Konishi, Y. Tsunazawa, T. Suzuki, T. Yanagida, and K. Kubota. Cortical mapping of gait in humans A near-infrared spectroscopic topography study. Neuroimage, 14 1186-1192, 2001. 

E. Watanabe, A. Maki, F. Kawaguchi, K. Takashiro, Y. Yamashita, H. Koizumi, and Y. Mayanagi. Non-invasive assessment of language dominance with near-infrared spectroscopic mapping. Neuroscience Letters, 256 49-52, 1998. 

E. Watanabe, Y. Yamashita, A. Maki, Y. Ito, and H. Koizumi. Noninvasive functional mapping with multi-channel near infrared spectroscopic topography in humans. Neuroscience Letters, 205 41-44, 1996. 

Transitions between different electronic states result in absorption of energy in the ultraviolet, visible and, for many transition metal complexes, the near infrared region of the electromagnetic spectrum. Spectroscopic methods that probe these electronic transitions can, in favourable conditions, provide detailed information on the electronic and magnetic properties of both the metal ion and its ligands. 

The absorption spectroscopy has been widely used for monitoring the rate of chemical reactions. During the reaction, if there is either appearance of colour in a colourless solution or disappearance of colour in a coloured solution or a species which absorbed at a specific wavelength is formed, the spectroscopic technique can be used. Instruments like colorimeters and spectrophotometers are available to cover the visible, near infrared and ultra violet region of the spectrum (200-1000 nm). The absorption spectroscopy is governed by well-known Beer-Lambert s Law according to which ... 

M. A. Czarnecki, Near infrared spectroscopic study of hydrogen bonding in chiral and racemic octan 2 ol. J. Phys. Chem. A 107, 1941 1944 (2003). 

G. Patonay, G. A. Casay, M. Lipowska, and L. Strekowski, Spectroscopic studies of a near-infrared absorbing pH sensitive aminodienone-carbocyanine dye system, Talanta 40, 935-942 (1993). 

P. J. Treado, I. W. Levin, and E. N. Lewis, Near-infrared acousto-optic filtered spectroscopic microscopy A solid-state approach to chemical, Imaging. Appl. Sped. 46, 553-559 (1991). 

M. K. Phelan, C. H. Barlow, J. J. Kelly, T. M. Jinguji, and J. B. Callis, Measurement of caustic and caustic brine solutions by spectroscopic detection of the hydroxide ion in the near-infrared region, 700-1150 nm, Anal. Chem. 61, 1419-1424(1989). 

LS.2.1. Prigogine, Contribution a I etude spectroscopique dans I infra-rouge proche de la liaison d hydrogene et la structure des solutions, (Contribution to the spectroscopic studies in the near infrared of the hydrogen bond and the structure of solutions), Memoires Acad. Roy. Belg., Cl. Sciences, tome XX. 

U. Hoffman and N. Zanier-Szydlowski, Portability of near-infrared spectroscopic calibrations for petrochemical parameters, J. Near Infrared Spectrosc., 7, 33 5 (1999). 

T. Fearn and A.M.C. Davies, A comparison of Fourier and wavelet transforms in the processing of near-infrared spectroscopic data part 1. Data compression, J. Near Infrared Spectrosc., 11, 3-15 (2003). 

E. Bouveresse, D.L. Massart and P. Dardenne, Calibration transfer across near-infrared spectroscopic instruments using Shenk s algorithm effects of different standardisation samples. Anal. Chim. Acta, 297, 405 16 (1994). B.G. Osborne and T. Feam, Collaborative evaluation of universal cahbrations for the measurement of protein and moisture in flour by near-infrared reflectance, /. Food TechnoL, 18, 453 60 (1983). 

D.J. Wargo and J.K. Drennen, Near-infrared spectroscopic characterization of pharmaceutical powder blends, J. Pharm. Biomed. Anal., 14, 1415-1423 (1996). 

M.J. Barajas, A.R. Cassiana, W. Vargas, C. Conde, J. Ropero, J. Figueroa and R.J. Romanach, Near-infrared spectroscopic method for real-time monitoring of pharmaceutical powders during voiding, Appl Spectrosc., 61(5), 490-496 (2007). 

N. Broad, P. Graham, P. Hailey, et al., Guidelines for the development and validation of near-infrared spectroscopic methods in the pharmaceutical industry. In Handbook of Vibrational Spectroscopy, vol. 5, J.M. Chalmers and PR. Griffiths (eds), John Wiley Sons Ltd, Chichester, 3590-3610, 2002. 

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