Quantitative analysis Raman

The IR spectra of all four crystal modifications were reported by Cady and Smith (1962) and by Holston (1962). The latter did point out some distinguishing features among the polymorphs, but Cady and Smith noted that problems with sample preparation and conversions among forms indicated that the optical properties described by McCrone (1950a) were the basis for the best rapid qualitative and even rough quantitative analysis. Raman spectroscopy, which requires less potentially destructive sample preparation, has been used to distinguish the polymorphs (Goetz and Brill 1979). The low resolution NMR spectra of the four crystal modifications were reported by Landers et al. (1985). The nuclear quadrupole resonance spectrum... 

Examples that use Raman spectroscopy in the quantitative analysis of materials are enonnous. Technology that takes Raman based techniques outside the basic research laboratory has made these spectroscopies also available to industry and engineering. It is not possible here to recite even a small portion of applications. Instead we simply sketch one specific example. 

Failloux, N, Bonnet, I, Baron, MH, and Perrier, E, 2003. Quantitative analysis of vitamin A degradation by Raman spectroscopy. Appl Spectrosc 57, 1117-1122. 

Raman spectra may facilitate qualitative analysis, asking what is it and also quantitative analysis - asking how much ... 

An important tool for the fast characterization of intermediates and products in solution-phase synthesis are vibrational spectroscopic techniques such as Fourier transform infrared (FTIR) or Raman spectroscopy. These concepts have also been successfully applied to solid-phase organic chemistry. A single bead often suffices to acquire vibrational spectra that allow for qualitative and quantitative analysis of reaction products,3 reaction kinetics,4 or for decoding combinatorial libraries.5... 

Quantitative Raman spectroscopy is an established technique used in a variety of industries and on many different sample forms from raw materials to in-process solutions to waste streams, including most of the applications presented here [1]. Most of the applications presented in the next section rely on quantitative analysis. Similar to other spectroscopic techniques, many factors influence the accuracy and precision of quantitative Raman measurements, but high quality spectra from representative samples are most important. 

R. Szostak and S. Mazurek, A quantitative analysis of liquid hydrocarbon mixtures on the basis of FT-Raman spectra registered under unstable conditions, J. Mol. Struct., 704, 235-245 (2004). 

S. C. Park, M. Kim, J. Noh, H. Chung, Y. Woo, J. Lee and M.S. Kemper, Reliable and fast quantitative analysis of active ingredient in pharmaceutical suspension using Raman spechoscopy, Aruil. Chim. Acta, 593,46-53 (2007). P. Matousek, I.P. Clark, E.R.C. Draper, et al.. Subsurface probing in diffusely scattering media using spatially offset Raman spechoscopy, Appl. Spectrosc., 59, 393 00 (2005). 

K. Y Noonan, M. Beshire, J. Darnell and K.A. Frederick, Qualitative and quantitative analysis of illicit drug mixtures on paper currency using Raman microspectroscopy, Appl Spectrosc., 59, 1493-1497 (2005). 

Finally, Raman spectroscopy has a potential of being used for qualitative and quantitative analysis. We have used Raman spectroscopy to verify the presence of components in a two-phase system [29]. 

There are, fortunately, several properties that do correlate well with the bond valence as discussed below. They include the bond length and its thermal expansion as well as a bond force constant that can be used for a semi-quantitative analysis of the Raman and infrared spectra of crystals. 

Raman spectroscopy is a related vibrational spectroscopic method. It has a different mechanism and therefore can provide complementary information to infrared absorption for the peptide protein conformational structure determination and some multicomponent qualitative and/or quantitative analysis (Alix et al. 1985). 

For quantitative analysis, how can one avoid confusing the Raman diffusion and the fluorescence of the compound ... 

Like infrared spectrometry, Raman spectrometry is a method of determining modes of molecular motion, especially the vibrations, and their use in analysis is based on the specificity of these vibrations. The methods are predominantly applicable to die qualitative and quantitative analysis of covalently bonded molecules rather than to ionic structures. Nevertheless, they can give information about the lattice structure of ionic molecules in the crystalline state and about the internal covalent structure of complex ions and the ligand structure of coordination compounds both in the solid state and in solution. 

NIR, Raman would be expected to offer advantages such as ease of use for quantitative analysis. The reason for less widespread use of process Raman spectroscopy is due in part to more expensive equipment, relative to NIR. A broader implementation of process Raman spectroscopy in the pharmaceutical industry has previously also been hampered by inherent weaknesses in sampling in remote measurements on solids. This is discussed further in Section 10.3. 

Additional source of information for UHMWPE acetabular cups arises from the quantitative analysis of polarized Raman spectra. Figure 17.6 shows photographs and the outcome of such analysis for two acetabular cups, which were retrieved after substantially different in vivo lifetimes. The retrieved acetabular cups were both belonging to male patients and sterilized by y-rays, but produced by different processes. One acetabular component (manufactured in 2002 by Biomet Inc.) was prepared by isostatic compression molding and sterilized before implantation by a dose of 33 kGy of y-rays. It was retrieved due to infection after 2 years 5 months. This cup will be referred to as the short-term retrieval. The other retrieval (manufactured in 1995 by Zimmer Inc.) was prepared by Ram-extruded molding and sterilized in air by a dose of 25-37 kGy of y-rays. For this latter cup, the follow-up pe-... 

For a quantitative analysis or classification of biological or medical problems by means of Raman spectroscopy the application of multivariate spectral analysis methods is required. These multivariate methods allow one to extract diagnostic, chemical, and morphological relevant information out of the complex Raman spectrum and must be applied due to the high amount of similar spectral features. 

Pelletier, M.J. Quantitative Analysis Using Raman Spectroscopy Appl. Spectrosc. 2003,57,20A-42A. 

Rohleder D, Kiefer W, Petrich W. Quantitative analysis of serum and serum ultrafiltrate by means of Raman spectroscopy. Analyst 2004, 129, 906-911. 

A limiting factor in noninvasive optical technology is variations in the optical properties of samples under investigation that result in spectral distortions44 8 and sampling volume (effective optical path length) variability 49-54 These variations will impact a noninvasive optical technique not only in interpretation of spectral features, but also in the construction and application of a multivariate calibration model if such variations are not accounted for. As a result, correction methods need to be developed and applied before further quantitative analysis. For Raman spectroscopy, relatively few correction methods appear in the literature, and most of them are not readily applicable to biological tissue.55-59... 

The same general principle that applies for intrinsic fluorescence should hold true for Raman spectroscopy as well. Unlike in fluorescence spectroscopy, spectral distortion owing to prominent absorbers is less of an issue in the NIR wavelength range. However, for quantitative analysis the turbidity-induced sampling volume variations become very significant and usually dominate over spectral distortions. 

Because Raman scattering involves vibrational and rotational modes within a sample, its explanation must necessarily involve a quantum mechanical treatment [21]. This is certainly true when the incident light corresponds to an intrinsic region of absorption in the sample, but it is also required for a quantitative analysis of the simpler Stokes and anti-Stokes Raman scattering, which is the subject of the discussion in this chapter. A detailed quantum mechanical understanding of Raman scattering, however, is not necessary for the applications that are of interest in this book, and for that reason, only a brief account is offered here. 

Another quantitative spectroscopic technique for the analysis of additives in lubricants and hydrocarbons is Raman spectroscopy (Coates, 1975). Theoretically, Raman spectroscopy should be as good as infrared for quantitative analysis. The... 

Vibrational Spectroscopy [Infrared (mid-IR, NIR), Raman]. In contrast to X-ray powder diffraction, which probes the orderly arrangement of molecules in the crystal lattice, vibration spectroscopy probes differences in the influence of the solid state on the molecular spectroscopy. As a result, there is often a severe overlap of the majority of the spectra for different forms of the pharmaceutical. Sometimes complete resolution of the vibrational modes of a particular functional group suffices to differentiate the solid-state form and allows direct quantification. In other instances, particularly with near-infrared (NIR) spectroscopy, the overlap of spectral features results in the need to rely on more sophisticated approaches for quantification. Of the spectroscopic methods which have been shown to be useful for quantitative analysis, vibrational (mid-IR absorption, Raman scattering, and NIR) spectroscopy is perhaps the most amenable to routine, on-line, off-line, and quality-control quantitation. 

Langkilde FW, Sjoblom J, Tekenbers-Hjelte L, Mrak J. 1997. Quantitative FT-Raman analysis of two crystal forms of a pharmaceutical compound. J. Pharm. Biomed. Anal. 13 687-696. 

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