Infrared spectroscopic monitoring

Vibrational (e.g. infrared, Raman or preferably near-infrared) spectroscopic monitoring of the reaction mixtnre... 

Kirsch, J.D. Drennen, J.K., Near-infrared spectroscopic monitoring of the film coating process Pharm. Res. 1996, 13, 234—237. 

Y. S. Chang, W. S. Park, M. Lee, K. S. Kim, S. M. Shin, and J. H. Choi, Near-Infrared Spectroscopic Monitoring of Secondary Cerebral Energy Failure after Transient Global Hypoxia-Ischemia in the Newborn Piglet, Neurological Res., 21(2), 216-224 (1999). 

Figure 12-10 Infrared spectroscopic monitoring of coupling and deprotection reactions on polymer-bound substrates and gel permeation chromatograms of the liberated sequences (monomer, dimer, tetramer, octamer, hexadecamer, and 32-mer). In the IR spectra n represents the number of repetitive reaction cycles for example, n=l and n=l correspond to trimethylsilyl-protected and unprotected dimer, respectively.

Introduction to Real Time Infrared Spectroscopic Monitoring... 

A fast-response infrared spectroscopic reactor system has been described which is capable of operating at high temperatures (e.g., 450-500°C). The infrared reactor system was successfully used to monitor the response of the surface concentration of CO to step changes or oscillations in the feedstream composition, under both reactive and nonreactive conditions. 

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). 

Arnold, S.A. Harvey, L.M. McNeil, B. etal., Employing near-infrared spectroscopic methods of analysis for fermentation monitoring and control. Part 1 Method development BioPharm Int. 2002, 15, 26-34, and Arnold, S.A. Harvey, L.M. McNeil, B. etal., Employing near-infrared spectroscopic methods of analysis for fermentation monitoring and control. Part 2 Implementation strategies BioPharm Int. 2003, 16, 47 19, 70. 

Infrared spectroscopy is one of the most powerful tools for functional studies of hemoproteins reactive to external hgands with infared absorptions in the triple bond region (1900-2200 cm ) where the background level due to absorptions of proteins and water molecules is quite low as described above. However, recent improvement in the sensitivity and stability of the FTIR apparatus with an MCT detector has enabled infrared spectroscopic examination of the protein moiety also. In fact, one of the most sensitive methods for monitoring the dissociation of a COOH group is infrared spectroscopy. 

Infrared spectroscopy has been used to monitor the kinetics of the sol-gel reaction by Prassas and Hench (18). In particular, the time-dependent behavior of bands they observed at 1060 and 950 cm, assigned to the asymmetric Si-O-Si stretch and Si-OH vibrations, respectively, provides on interpretive baseline for the infrared spectroscopic studies of the more complex sol-gel reaction that takes place within the polymer matrix as reported in our work. It was reported that, as the reaction proceeds, the 1060 cm peak shifts to lower wave numbers, with new bands appearing in its neighborhood, and that the appearance of cyclic structures in the later stages is evidenced by a band at around 1080 cm. ... 

The infrared absorption results presented above demonstrate that it is possible to spectroscopically monitor shock induced chemical reactions on picosecond time scales at the beginning of the reaction zone. This demonstration opens the door to further probing of such events with the myriad of ultrafast laser based spectroscopic tools now available, promising to provide more insight into the effects of extreme pressure and temperature jumps at the molecular scale. 

This paper summarizes a series of experiments directed to the development of Fourier transform infrared spectroscopic (FT-IR) techniques for monitoring the events that occur when blood contacts the surface of a biomedical device. Special emphasis is placed on the methodology used for quantification and compositional analysis of protein adsorption from complex protein mixtures in aqueous solutions. 

We have been investigating Fourier transform infrared spectroscopic methods for monitoring blood-surface interactions for over six years, during which period the following capabilities of the FT-IR technique for this application have been demonstrated ... 

To understand how polymer degradation may be monitored by using infrared spectroscopic techniques. 

B. M. Zacour, B. Igne, J. K. Drennen III, and C. A. Anderson, Efficient Near-Infrared Spectroscopic Calibration Methods for Pharmaceutical Blend Monitoring, /. Pharm. Innov., 6,10 (2011). 

For monitoring the pressure in anvil cells we use the frequncy shift of internal, chemically inert pressure calibrants. For Raman spectroscopic measurements, the most commonly used method is based on the pressure-induced frequency shift of the fluorescence line of a small piece of ruby that is placed in the sample compartment of the cell, next to the sample [1]. For infrared spectroscopic measurements, we have developed a quartz pressure scale [9], a BaSO pressure scale [10], and an HOD pressure scale [11], In the case of the first two techniques, a small amount of powdered quartz or BaSO powder are placed in the sample hole on the gasket, together with the sample under investigation. The infrared spectra of quartz or BaSO, which are relatively simple, are recorded simultaneously with the spectrum of the sample and the pressure on the sample b then determined from the frequency shift of the infrared bands of quartz or BaSO. The HOD pressure scale was developed specifically for aqueous solutions. In this case, the pressure in solution is determined from the frequency shift of the uncoupled O-H stretching band of residual HOD in DjO solutions, or from the uncoupled O-D stretching band of residual HOD in HjO solutions [11]. 

Infrared spectroscopic experiments directed towards studying the thermotropic phase behavior of membrane lipids involve collecting the spectrum of the same system at various temperatures and monitoring changes in band parameters as a function of temperature. This process can be brought completely under the control of the spectrometer computer, which records a spectrum, increments the temperture, waits for temperature equilibration then records another spectrum (10,11). 

For the visible and near-ultraviolet portions of the spectmm, tunable dye lasers have commonly been used as the light source, although they are being replaced in many appHcation by tunable soHd-state lasers, eg, titanium-doped sapphire. Optical parametric oscillators are also developing as useful spectroscopic sources. In the infrared, tunable laser semiconductor diodes have been employed. The tunable diode lasers which contain lead salts have been employed for remote monitoring of poUutant species. Needs for infrared spectroscopy provide an impetus for continued development of tunable infrared lasers (see Infrared technology and RAMAN spectroscopy). 

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